Evaluation of the Influence of Wind-Driven Rain on Moisture in Cellular Concrete Wall Boards

Science.gov (United States)

Alsabry, A.; Nikitsin, V. I.; Kofanov, V. A.; Backiel-Brzozowska, B.

2017-08-01

The non-stationary moisture level of a cellular concrete wall board in a heated utility building located in the northern part of the town of Brest (Belarus), depending on the climatic influence, was assessed in this work. The results were obtained both in a calculation experiment and a physical test. It was observed that the main reason for the high moisture levels in cellular concrete is wind-driven rain intensifying the process of free capillary moisture transfer. A comparative analysis of the results of the physical test and the calculation experiment showed that the THSS software elaborated by the authors was able to predict the actual moisture levels of the shielding structure under study accurately enough when precise data concerning the thermal and physical characteristics of the materials as well as the occurring climatic influences were submitted.

Experimental and numerical studies of hybrid PCM embedded in plastering mortar for enhanced thermal behaviour of buildings

International Nuclear Information System (INIS)

Kheradmand, Mohammad; Azenha, Miguel; Aguiar, José L.B. de; Castro-Gomes, João

2016-01-01

This paper proposes a methodology for improvement of energy efficiency in buildings through the innovative simultaneous incorporation of three distinct phase change materials (here termed as hybrid PCM) in plastering mortars for façade walls. The thermal performance of a hybrid PCM mortar was experimentally evaluated by comparing the behaviour of a prototype test cell (including hybrid PCM plastering mortar) subjected to realistic daily temperature profiles, with the behaviour of a similar prototype test cell, in which no PCM was added. A numerical simulation model was employed (using ANSYS-FLUENT) to validate the capacity of simulating temperature evolution within the prototype containing hybrid PCM, as well as to understand the contribution of hybrid PCM to energy efficiency. Incorporation of hybrid PCM into plastering mortars was found to have the potential to significantly reduce heating/cooling temperature demands for maintaining the interior temperature within comfort levels when compared to normal mortars (without PCM), or even mortars comprising a single type of PCM. - Highlights: • New concept of incorporation of more than 1 type of PCM in plastering mortars (hybrid PCM). • Assessment of thermal performance of hybrid PCM plastering mortar. • Thermo-physical properties of plastering mortars modified with PCMs incorporation. • Experimental and numerical simulations of thermal behaviour on laboratory scale prototype.

Moisture Transfer through Facades Covered with Organic Binder Renders

Directory of Open Access Journals (Sweden)

Carmen DICO

2013-07-01

Full Text Available Year after year we witness the negative effect of water over buildings, caused by direct or indirect actions. This situation is obvious in case of old, historical building, subjected to this aggression for a long period of time, but new buildings are also affected. Moisture in building materials causes not only structural damage, but also reduces the thermal insulation capacity of building components.Materials like plasters or paints have been used historically for a long period of time, fulfilling two basics functions: Decoration and Protection. The most acute demands are made on exterior plasters, as they, besides being an important decorative element for the facade, must perform two different functions simultaneously: protect the substrate against weathering and moisture without sealing, providing it a certain ability to “breathe” (Heilen, 2005. In order to accomplish this aim, the first step is to understand the hygrothermal behavior of coating and substrate and define the fundamental principles of moisture transfer; According to Künzel’s Facade Protection Theory, two material properties play the most important role: Water absorption and Vapor permeability.In the context of recently adoption (2009 of the “harmonized” European standard EN 15824 – „Specifications for external renders and internal plasters based on organic binders”, this paper deals extensively with the interaction of the two mentioned above properties for the coating materials, covered by EN 15824.

Nonlinear Modeling of Autoclaved Aerated Concrete Masonry Wall Strengthened using Ferrocement Sandwich Structure

KAUST Repository

M., Abdel-Mooty; M., El-Kashef; E., Fahmy; M., Abou-Zeid; M., Haroun

2011-01-01

Autoclaved Aerated Concrete (AAC) block are used mainly as non-load-bearing walls that provide heat insulation. This results in considerable saving in cooling energy particularly in hot desert environment with large variation of daily and seasonal

Prediction of moisture migration and pore pressure build-up in concrete at high temperatures

International Nuclear Information System (INIS)

Ichikawa, Y.; England, G.L.

2004-01-01

Prediction of moisture migration and pore pressure build-up in non-uniformly heated concrete is important for safe operation of concrete containment vessels in nuclear power reactors and for assessing the behaviour of fire-exposed concrete structures. (1) Changes in moisture content distribution in a concrete containment vessel during long-term operation should be investigated, since the durability and radiation shielding ability of concrete are strongly influenced by its moisture content. (2) The pressure build-up in a concrete containment vessel in a postulated accident should be evaluated in order to determine whether a venting system is necessary between liner and concrete to relieve the pore pressure. (3) When concrete is subjected to rapid heating during a fire, the concrete can suffer from spalling due to pressure build-up in the concrete pores. This paper presents a mathematical and computational model for predicting changes in temperature, moisture content and pore pressure in concrete at elevated temperatures. A pair of differential equations for one-dimensional heat and moisture transfer in concrete are derived from the conservation of energy and mass, and take into account the temperature-dependent release of gel water and chemically bound water due to dehydration. These equations are numerically solved by the finite difference method. In the numerical analysis, the pressure, density and dynamic viscosity of water in the concrete pores are calculated explicitly from a set of formulated equations. The numerical analysis results are compared with two different sets of experimental data: (a) long-term (531 days) moisture migration test under a steady-state temperature of 200 deg. C, and (b) short-term (114 min) pressure build-up test under transient heating. These experiments were performed to investigate the moisture migration and pressure build-up in the concrete wall of a reactor containment vessel at high temperatures. The former experiment simulated

Evaluation of tritiated water retention capacity of fusion reactor concrete building

International Nuclear Information System (INIS)

Numata, S.; Fujii, Y.; Okamoto, M.

1992-01-01

In this paper the diffusion of tritiated water vapor into concrete walls is studied to evaluate tritiated water retention capacity of a fusion reactor concrete building. Using a model of the tritiated water diffusion determined form experimental results, depth profiles of tritiated water in concrete are calculated in the case of being exposed to air containing tritiated water vapor during the normal operational condition of a fusion reactor. A 0.5-m-thick concrete is sufficient for reactor hall walls from a viewpoint of the tritium containment

Heat and moisture flow in concrete as a function of temperature

Science.gov (United States)

Hundt, J.

1978-01-01

Due to temperature, reactors in operation cause heat and moisture flows in the thick walled prestressed pressure vessels. These flows were studied in three beams of concrete made with crushed limestone aggregate, and in three beams made of crushed gravel/sand aggregate. The flow phenomena were related to the structural development of the concrete by determining the amount of non-evaporatable water, the total porosity, and the pore size distribution. Local temperature and moisture conditions also influenced the technical properties. Compressive strength, changes in length due to shrinkage and contraction, thermal expansion, and thermal conductivity were determined.

Diurnal thermal analysis of microencapsulated PCM-concrete composite walls

International Nuclear Information System (INIS)

Thiele, Alexander M.; Sant, Gaurav; Pilon, Laurent

2015-01-01

Highlights: • Transient heat conduction across microencapsulated PCM-concrete walls was simulated. • Equivalent homogeneous wall with effective thermal properties was rigorously derived. • Adding PCM to the wall increases daily energy savings and delays peak thermal load. • Energy savings is maximum when PCM melting temperature equals indoor temperature. • Energy savings are limited in extreme climates but time delay can be large. - Abstract: This paper examines the benefits of adding microencapsulated phase change material (PCM) to concrete used in building envelopes to reduce energy consumption and costs. First, it establishes that the time-dependent thermal behavior of microencapsulated PCM-concrete composite walls can be accurately predicted by an equivalent homogeneous wall with appropriate effective thermal properties. The results demonstrate that adding microencapsulated PCM to concrete resulted in a reduction and a time-shift in the maximum heat flux through the composite wall subjected to diurnal sinusoidal outdoor temperature and solar radiation heat flux. The effects of the PCM volume fraction, latent heat of fusion, phase change temperature and temperature window, and outdoor temperature were evaluated. Several design rules were established including (i) increasing the PCM volume fraction and/or enthalpy of phase change increased the energy flux reduction and the time delay, (ii) the energy flux reduction was maximized when the PCM phase change temperature was close to the desired indoor temperature, (iii) the optimum phase change temperature to maximize the time delay increased with increasing average outdoor temperature, (iv) in extremely hot or cold climates, the thermal load could be delayed even though the reduction in daily energy flux was small, and (v) the choice of phase change temperature window had little effect on the energy flux reduction and on the time delay. This analysis can serve as a framework to design PCM composite walls

Moisture Durability with Vapor-Permeable Insulating Sheathing

Energy Technology Data Exchange (ETDEWEB)

Lepage, R. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2013-09-01

Exterior sheathing insulation is an effective strategy in increasing the overall R-value of wall assemblies; other benefits include decreasing the effects of thermal bridging and increasing the moisture durability of the built assembly. Vapor-permeable exterior insulation, such as mineral board or expanded polystyrene foam, are one such product that may be used to achieve these benefits. However, uncertainty exists on the effects of inward driven moisture and the interaction of increased sheathing temperatures on the moisture durability of the edifice. To address these concerns, Building Science Corporation (BSC) conducted a series of hygrothermal models for cities representing a range of different climate zones. This report describes the research project, key research questions, and the procedures utilized to analyse the problems.

Moisture Durability with Vapor-Permeable Insulating Sheathing

Energy Technology Data Exchange (ETDEWEB)

Lepage, R. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2013-09-01

Exterior sheathing insulation is an effective strategy in increasing the overall R-value of wall assemblies; other benefits include decreasing the effects of thermal bridging and increasing the moisture durability of the built assembly. Vapor-permeable exterior insulation, such as mineral board or expanded polystyrene foam, are one such product that may be used to achieve these benefits. However,uncertainty exists on the effects of inward driven moisture and the interaction of increased sheathing temperatures on the moisture durability of the edifice. To address these concerns, Building Science Corporation (BSC) conducted a series of hygrothermal models for cities representing a range of different climate zones. This report describes the research project, key research questions, and theprocedures utilized to analyse the problems.

Moisture Performance of Energy-Efficient and Conventional Wood-Frame Wall Assemblies in a Mixed-Humid Climate

Directory of Open Access Journals (Sweden)

Samuel V. Glass

2015-07-01

Full Text Available Long-term moisture performance is a critical consideration for design and construction of building envelopes in energy-efficient buildings, yet field measurements of moisture characteristics for highly insulated wood-frame walls in mixed-humid climates are lacking. Temperature, relative humidity, and moisture content of wood framing and oriented strand board (OSB structural panel sheathing were measured over a period from mid-November 2011 through March 2013 in both north- and south-facing orientations in test structures near Washington, DC, USA. Wall configurations varied in exterior cladding, water-resistive barrier, level of cavity insulation, presence of exterior continuous insulation, and interior vapor retarder. The combination of high interior humidity and high vapor permeance of painted gypsum board led to significant moisture accumulation in OSB sheathing during winter in walls without a vapor retarder. In contrast, wintertime moisture accumulation was not significant with an interior kraft vapor retarder. Extruded polystyrene exterior insulation had a predictable effect on wall cavity temperature but a marginal impact on OSB moisture content in walls with vinyl siding and interior kraft vapor retarder. Hygrothermal simulations approximately captured the timing of seasonal changes in OSB moisture content, differences between north- and south-facing walls, and differences between walls with and without an interior kraft vapor retarder.

Thermal conductivity of newspaper sandwiched aerated lightweight concrete panel

Energy Technology Data Exchange (ETDEWEB)

Ng, Soon-Ching; Low, Kaw-Sai [Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, Setapak, 53300 Kuala Lumpur, Wilayah Persekutuan (Malaysia)

2010-12-15

Investigation on the thermal conductivity of newspaper sandwiched aerated lightweight concrete (ALC) panels is the main purpose of this study. Various densities of ALC panels ranging from 1700, 1400 and 1100 kg/m{sup 3} with three different aerial intensities of newspaper sandwiched were produced. Investigation was limited to the effect of aerial intensity of newspaper sandwiched and the effect of density of ALC on thermal conductivity. It is found that the thermal conductivity of newspaper sandwiched ALC panels reduced remarkably compared to control ALC panels. The reduction was recorded at 18.0%, 21.8% and 20.7% correspond to densities of 1700, 1400 and 1100 kg/m{sup 3} with just a mere 0.05 g/cm{sup 2} aerial intensity of newspaper sandwiched. Newspaper sandwiched has a significant impact on the performance of thermal conductivity of ALC panels based on regression analysis. (author)

Dismantling system of concrete thermal shielding walls

International Nuclear Information System (INIS)

Machida, Nobuhiro; Saiki, Yoshikuni; Ono, Yorimasa; Tokioka, Masatake; Ogino, Nobuyuki.

1985-01-01

Purpose: To enable safety and efficient dismantling of concrete thermal shielding walls in nuclear reactors. Method: Concrete thermal shielding walls are cut and dismantled into dismantled blocks by a plasma cutting tool while sealing the top opening of bioshielding structures. The dismantled blocks are gripped and conveyed. The cutting tool is remote-handled while monitoring on a television receiver. Slugs and dusts produced by cutting are removed to recover. Since the dismantling work is carried out while sealing the working circumstance and by the remote control of the cutting tool, the operators' safety can be secured. Further, since the thermal sealing walls are cut and dismantled into blocks, dismantling work can be done efficiently. (Moriyama, K.)

Performance Evaluation of Modern Building Thermal Envelope Designs in the Semi-Arid Continental Climate of Tehran

Directory of Open Access Journals (Sweden)

Shaghayegh Mohammad

2013-10-01

Full Text Available In this paper we evaluate the thermal performance of a range of modern wall constructions used in the residential buildings of Tehran in order to find the most appropriate alternative to the traditional un-fired clay and brick materials, which are increasingly being replaced in favor of more slender wall constructions employing hollow clay, autoclaved aerated concrete or light expanded clay aggregate blocks. The importance of improving the building envelope through estimating the potential for energy saving due to the application of the most energy-efficient wall type is presented and the wall constructions currently erected in Tehran are introduced along with their dynamic and steady-state thermal properties. The application of a dynamic simulation tool is explained and the output of the thermal simulation model is compared with the dynamic thermal properties of the wall constructions to assess their performance in summer and in winter. Finally, the best and worst wall type in terms of their cyclic thermal performance and their ability to moderate outdoor conditions is identified through comparison of the predicted indoor temperature and a target comfort temperature.

Non-autoclaved aerated concrete with mineral additives

Science.gov (United States)

Il'ina, L. V.; Rakov, M. A.

2016-01-01

We investigated the effect of joint grinding of Portland cement clinker, silica and carbonate components and mineral additives to specific surface of 280 - 300 m2/kg on the properties (strength, average density and thermal conductivity) of non-autoclaved aerated concrete, and the porosity of the hardened cement paste produced from Portland cement clinker with mineral additives. The joint grinding of the Portland cement clinker with silica and carbonate components and mineral additives reduces the energy consumption of non-autoclaved aerated concrete production. The efficiency of mineral additives (diopside, wollastonite) is due to the closeness the composition, the type of chemical bonds, physical and chemical characteristics (specific enthalpy of formation, specific entropy) to anhydrous clinker minerals and their hydration products. Considering the influence of these additions on hydration of clinker minerals and formation of hardened cement paste structure, dispersed wollastonite and diopside should be used as mineral additives. The hardness and, consequently, the elastic modulus of diopside are higher than that of hardened cement paste. As a result, there is a redistribution of stresses in the hardened cement paste interporous partitions and hardening, both the partitions and aerated concrete on the whole. The mineral additives introduction allowed to obtain the non-autoclaved aerated concrete with average density 580 kg/m3, compressive strength of 3.3 MPa and thermal conductivity of 0.131 W/(m.°C).

Radioactivity in houses built of aerated concrete based on alum shale

International Nuclear Information System (INIS)

Swedjemark, G.A.

1980-01-01

The highest activities in commonly used Swedish building materials are found in aerated concrete based on alum shale. The enhanced activity level is due to the high content of radium-226. The average activity concentration of radium-226 varies between different producers of aerated concrete based on alum shale from 700 Bq kg - (20 pCi g - ) to 2 400 Bq kg - (65 pCi g - ). Houses built in the same way with the same amounts of aerated concrete can therefore have very different gamma levels and very different concentrations of radon in the air with the same air exchange rate. Aerated concrete based on alum shale was used as a building material in Sweden from 1930 to 1975. The average concentration of radon daughters found in houses built of aerated concrete based to a major extent on alum shale is about 100 bq/m 3 (2.7 pCi 1 - ). The highest radon concentrations have been found in houses built entirely of aerated concrete based on alum shale. A group of 9 houses with natural draught ventilation systems has been investigated with regard to the concentration of radon, the equilibrium equivalent concentration of radon (EEC) and the gamma dose rate. The air exchange rates varied between the houses from 0.21 to 0.43 h - and the radon concentration from 540 Bq m - (15 pCi 1 - ) to 1 160 Bq m - (31 pCi 1 - ). The values given are averages for each house. (author)

Moisture Conditions in Passive House Wall Constructions

OpenAIRE

Gullbrekken, Lars; Geving, Stig; Time, Berit; Andresen, Inger

2015-01-01

Buildings for the future, i.e zero emission buildings and passive houses, will need well insulated building envelopes, which includes increased insulation thicknesses for roof, wall and floor constructions. Increased insulation thicknesses may cause an increase in moisture levels and thereby increased risk of mold growth. There is need for increased knowledge about moisture levels in wood constructions of well insulated houses, to ensure robust and moisture safe solutions. Monitoring of w...

Comparison of Thermal Stability of Dry High-strength Concrete and Wet High-strength Concrete

Science.gov (United States)

Musorina, Tatiana; Katcay, Aleksandr; Selezneva, Anna; Kamskov, Victor

2018-03-01

High-strength concrete is a modern material, which occupies it`s own niche on the construction material market. It is applicable in a large-scale high-rise construction, particularly an underground construction is a frequently used solution for a space saving. Usually underground structure is related to a wet usage environment. Though not all properties of the high-strength concrete are investigated to the full extent. Under adverse climatic conditions of the Russian Federation one of the most important properties for constructional materials is a thermal capacity. Therefore, the main purpose of the paper is to compare a thermal capacity of the high-strength concrete in humid conditions and a thermal capacity of the high-strength concrete in dry operational condition. During the study dependency between thermal capacity and design wall thickness and ambient humidity has to be proven with two experiments. As a result the theoretical relation between thermal capacity characteristic - thermal inertia and wall thickness and ambient humidity was confirmed by the experimental data. The thermal capacity of a building is in direct ratio to the construction thickness. It follows from the experiments and calculations that wet high-strength concrete has less thermal stability.

Nonlinear Modeling of Autoclaved Aerated Concrete Masonry Wall Strengthened using Ferrocement Sandwich Structure

KAUST Repository

M., Abdel-Mooty

2011-01-01

Autoclaved Aerated Concrete (AAC) block are used mainly as non-load-bearing walls that provide heat insulation. This results in considerable saving in cooling energy particularly in hot desert environment with large variation of daily and seasonal temperatures. However, due to the relatively low strength there use load bearing walls is limited to single storey and low-rise construction. A system to enhance the strength of the AAC masonry wall in resisting both inplane vertical and combined vertical and lateral loads using ferrocement technology is proposed in this research. The proposed system significantly enhances the load carrying capacity and stiffness of the AAC wall without affecting its insulation characteristics. Ferrocement is made of cement mortar reinforced with closely spaced wire mesh. Full scale wall specimens with height of 2100mm and width of 1820mm were tested with different configuration of ferrocement. A finite elementmodel is developed and verified against the experimentalwork. The results of the finite element model correlates well with the experimental results.

Moisture effect on thermal conductivity of some major elements of a typical Libyan house envelope

International Nuclear Information System (INIS)

Suleiman, Bashir M

2006-01-01

The thermal conductivity and the assessment of moisture effect on building materials are essential for the calculation of the thermal loads on houses. Building materials such as simple units e.g. bricks, tiles, cement plasters, mortar and ground soils are investigated in this work. In the eastern coastal province of Libya, old buildings have thick walls (more than 50 cm thick made of mixed clay and stones) and consequently have good capacitive insulation. On the other hand, the relatively new houses have thin walls and need the addition of insulating materials. Unfortunately, these new houses were constructed without having enough technical data on the thermal properties of building materials and thermal loads were not considered. This leads to uncomfortable living conditions during hot and humid summers and cold and wet winters. This article reports the thermal conductivity values of three types of locally produced building materials used in the construction of a typical Libyan house envelope and gives suggestions to improve the thermal performance of such envelopes. The transient plane source technique (TPS) is used to measure the thermal conductivity of these materials at an average room temperature of 25 deg. C. The TPS technique uses a resistive heater pattern (TPS element) that is cut from a thin sheet of metal and covered on both sides with thin layers of an insulating material. The TPS element/sensor is used both as a heat source and as a temperature sensor. This technique has the dual advantage of short measuring time and low temperature rise (around 1 K) across the sample. This will prevent a non-uniform moisture distribution that may arise when the temperature difference across the wet samples is maintained for a long time. In addition, the flat thin shape of the TPS element substantially reduces the contact resistance between the sample and the sensor. More details about the TPS technique are included

PREPARATION OF ULTRA-LOW VOLUME WEIGHT AUTOCLAVED AERATED CONCRETE

Directory of Open Access Journals (Sweden)

Ondrej Koutny

2016-12-01

Full Text Available Autoclaved aerated concrete is a modern construction material that gains its popularity especially due to its thermal insulation performance resulting from low volume weight and porous structure with sufficient mechanical strength. Nowadays, there are attempts to use this material for thermal insulation purposes and to replace current systems, which have many disadvantages, mainly concerning durability. The key for improvement of thermal insulation properties is therefore obtaining a material based on autoclaved aerated concrete with extremely low volume weight (below 200 kg/m ³ ensuring good thermal isolation properties, but with sufficient mechanical properties to allow easy manipulation. This material can be prepared by foaming very fine powder materials such as silica fume or very finely ground sand. This paper deals with the possibilities of preparation and summarizes the basic requirements for successful preparation of such a material.

Thermal performance of air-conditioned office buildings constructed with inclined walls in different climates in China

International Nuclear Information System (INIS)

Chan, A.L.S.; Chow, T.T.

2014-01-01

Highlights: • A generic fully air-conditioned office building with inclined walls was modeled. • Simulations were run under climatic conditions in three modern cities in China. • Reduction in cooling load can outweigh the increase in heating load for Hong Kong. • Inclined angle of 30° is appropriate for inverted pyramidal building in Hong Kong. • Building constructed with inclined walls is not encouraged in Shanghai and Beijing. - Abstract: An inverted pyramidal building is built with inclined walls instead of the traditional vertical façades. In terms of thermal performance, an inverted pyramidal building can provide a self-shading effect against the beam solar radiation, leading to a reduction in solar heat gain as well as building cooling load. On the other hand, the heating requirement of an inverted pyramidal building will be increased in winter. There is a strong dependency of building performance on the climatic condition. In this study, a generic air-conditioned office building with inclined walls set at different inclination angles was modeled using a building energy simulation program. Computer simulations were run to assess the thermal performance of the building constructed with inclined walls under different climatic conditions in three modern cities in China–Hong Kong, Shanghai and Beijing. The results reveal that for the building cases with inclined walls set at different inclination angles in subtropical Hong Kong, the saving in annual cooling load ranges from 0.6% to 10.9% and can outweigh the increase in heating load. Moreover, an inclination angle of 30° was found as a better design option for an inverted pyramidal building with symmetrical layout design under the climatic condition in Hong Kong. For the other two cities: Shanghai and Beijing, the saving in cooling load due to self-shading effect cannot offset the increased heating requirement. Design and construction of an inverted pyramidal building is not encouraged in these two

Moisture transfer in concrete elements under thermal gradients

International Nuclear Information System (INIS)

Lien, H.P.; Wittmann, F.H.

1995-01-01

A realistic simulation of the coupled heat- and mass transfer in concrete elements requires detailed knowledge of the dominant transfer mechanisms. Depending on the the local temperatures and moisture content, a description in terms of diffusion or Darcy flow respectively is appropriate. However, a simultaneous application of these fundamental physical transfer mechanisms necessary when subjecting concrete elements to wide-ranging temperature distributions. With rising temperatures, continuing hydration also influences the moisture distribution in a increasingly important manner in addition to the transport phenomena. The description of the relevant transport process can be handled by thermodynamic concepts and, in general, the resulting time-space evolution of the state variables in described in terms of coupled nonlinear partial differential equations. A numerical model of the coupled heat-and mass transfer as influenced by continuing hydration with a temperature-dependent reaction rate is presented, and the simulation of the hygral transfer is compared with experimentally determined moisture distributions obtained on a prestressed concrete vessel under thermal gradients. (author). 14 refs., 10 figs

Behavior and ultimate strength of an inner concrete structure of a nuclear reactor building subjected to thermal and seismic loads

International Nuclear Information System (INIS)

Omatsuzawa, K.; Suzuki, Y.; Sato, M.; Takeda, T.; Yamaguchi, T.; Yoshioka, K.; Nakayama, T.; Furuya, N.; Kawaguchi, T.; Koike, K.; Naganuma, K.

1987-01-01

Heating tests and heating-plus-seismic-loading tests at high temperature (T max = 175 0 C) were conducted using various concrete structural members such as beams, cylindrical walls, H-section walls, and 1/10-scale models of the inner concrete (I/C) structure in a fast breeder reactor (FBR) building. Concrete subjected to high temperature exceeding 100 0 C has a tendency to have lower Young's modulus and to shrink. As these material constants are temperature-dependent, the thermal stress occurring within the concrete structure is smaller than the values usually obtained by normal crack analysis methods. Although thermal stresses and cracks exert marked influences on the behaviors of the structures during the earlier stages of loading, they hardly affect the ultimate bending and shear strengths. Specifically, as a result of I/C model tests, it was made clear that the ultimate strength of the structure is considerably greater than the design loads under combined thermal and seismic loading conditions. (orig./HP)

Thermal stress-dependent dilation of concrete

International Nuclear Information System (INIS)

Pfeiffer, P.A.; Marchertas, A.H.

1984-01-01

Recent studies in nuclear fast reactor safety consider the possibility of concrete containment being subjected to extremely severe environmental conditions. Certain safety scenarios subject the concrete to very high temperatures hence raising the concern of containment integrity. Some of the main detrimental effects of high temperature on concrete are: reduction of strength, redistribution of moisture and etc. Consequently, analytical prediction of concrete response under the high temperature conditions becomes very complex. A rather simple but important experiment of concrete at high temperatures was conducted by Anderberg and Thelandersson. The test samples were small so that moisture was free to evaporate with no appreciable gradient as the temperature increased. Their results revealed that good correlation with analysis could be obtained if thermal expansion was made a function of both temperature and stress. The method of relating the thermal strain to temperature and stress has been integrated into the TEMP-STRESS code. Thus, high temperature concrete computational capability is now available for thermal-stress calculations

Thermal dynamic simulation of wall for building energy efficiency under varied climate environment

Science.gov (United States)

Wang, Xuejin; Zhang, Yujin; Hong, Jing

2017-08-01

Aiming at different kind of walls in five cities of different zoning for thermal design, using thermal instantaneous response factors method, the author develops software to calculation air conditioning cooling load temperature, thermal response factors, and periodic response factors. On the basis of the data, the author gives the net work analysis about the influence of dynamic thermal of wall on air-conditioning load and thermal environment in building of different zoning for thermal design regional, and put forward the strategy how to design thermal insulation and heat preservation wall base on dynamic thermal characteristic of wall under different zoning for thermal design regional. And then provide the theory basis and the technical references for the further study on the heat preservation with the insulation are in the service of energy saving wall design. All-year thermal dynamic load simulating and energy consumption analysis for new energy-saving building is very important in building environment. This software will provide the referable scientific foundation for all-year new thermal dynamic load simulation, energy consumption analysis, building environment systems control, carrying through farther research on thermal particularity and general particularity evaluation for new energy -saving walls building. Based on which, we will not only expediently design system of building energy, but also analyze building energy consumption and carry through scientific energy management. The study will provide the referable scientific foundation for carrying through farther research on thermal particularity and general particularity evaluation for new energy saving walls building.

The Effect of Temperature on Moisture Transport in Concrete.

Science.gov (United States)

Wang, Yao; Xi, Yunping

2017-08-09

Most concrete structures and buildings are under temperature and moisture variations simultaneously. Thus, the moisture transport in concrete is driven by the moisture gradient as well as the temperature gradient. This paper presents an experimental approach for determining the effect of different temperature gradients on moisture distribution profiles in concrete. The effect of elevated temperatures under isothermal conditions on the moisture transport was also evaluated, and found not to be significant. The non-isothermal tests show that the temperature gradient accelerates the moisture transport in concrete. The part of increased moisture transfer due to the temperature gradient can be quantified by a coupling parameter D HT , which can be determined by the present test data. The test results indicated that D HT is not a constant but increases linearly with the temperature variation. A material model was developed for D HT based on the experimental results obtained in this study.

Hysteresis and Temperature Dependency of Moisture Sorption – New Measurements

DEFF Research Database (Denmark)

Rode, Carsten; Hansen, Kurt Kielsgaard

2011-01-01

measurements of hysteresis and temperature dependency of the moisture sorption characteristics of three different porous building materials: aerated concrete, cement paste and spruce. Scanning curves are measured for all three materials where periods with adsorption and desorption interrupt each other...... intermittently. For one of the materials, aerated concrete, the sorption curves are determined at three different temperatures....

Investigation of thermal effect on exterior wall surface of building material at urban city area

Energy Technology Data Exchange (ETDEWEB)

Md Din, Mohd Fadhil; Dzinun, Hazlini; Ponraj, M.; Chelliapan, Shreeshivadasan; Noor, Zainura Zainun [Institute of Environmental Water Resources and Management (IPASA), Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Remaz, Dilshah [Faculty of Built Environment, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Iwao, Kenzo [Nagoya Institute of Technology, Nagoya (Japan)

2012-07-01

This paper describes the investigation of heat impact on the vertical surfaces of buildings based on their thermal behavior. The study was performed based on four building materials that is commonly used in Malaysia; brick, concrete, granite and white concrete tiles. The thermal performances on the building materials were investigated using a surface temperature sensor, data logging system and infrared thermography. Results showed that the brick had the capability to absorb and store heat greater than other materials during the investigation period. The normalized heat (total heat/solar radiation) of the brick was 0.093 and produces high heat (51% compared to granite), confirming a substantial amount of heat being released into the atmosphere through radiation and convection. The most sensitive material that absorbs and stores heat was in the following order: brick > concrete > granite > white concrete tiles. It was concluded that the type of exterior wall material used in buildings had significant impact to the environment.

Housing: plastered versus un-plastered brooder walls in poultry ...

African Journals Online (AJOL)

An investigation was carried out to study the health impact of inadequate brooder house with poor make-up on chicks. Two brooder houses were constructed with a mixture of sand and cementitious materials consisting of lime and/or gypsum to form concrete blocks. Brooder 1 was plastered with cement (cemented) and ...

Effect of Material Composition and Environmental Condition on Thermal Characteristics of Conductive Asphalt Concrete

Directory of Open Access Journals (Sweden)

Pan Pan

2017-02-01

Full Text Available Conductive asphalt concrete with high thermal conductivity has been proposed to improve the solar energy collection and snow melting efficiencies of asphalt solar collector (ASC. This paper aims to provide some insight into choosing the basic materials for preparation of conductive asphalt concrete, as well as determining the evolution of thermal characteristics affected by environmental factors. The thermal properties of conductive asphalt concrete were studied by the Thermal Constants Analyzer. Experimental results showed that aggregate and conductive filler have a significant effect on the thermal properties of asphalt concrete, while the effect of asphalt binder was not evident due to its low proportion. Utilization of mineral aggregate and conductive filler with higher thermal conductivity is an efficient method to prepare conductive asphalt concrete. Moreover, change in thermal properties of asphalt concrete under different temperature and moisture conditions should be taken into account to determine the actual thermal properties of asphalt concrete. There was no noticeable difference in thermal properties of asphalt concrete before and after aging. Furthermore, freezing–thawing cycles strongly affect the thermal properties of conductive asphalt concrete, due to volume expansion and bonding degradation.

Creep of concrete under various temperature, moisture, and loading conditions

International Nuclear Information System (INIS)

McDonald, J.E.

1976-01-01

An investigation was conducted to obtain information on the time-dependent deformation behavior of concrete in the presence of temperature, moisture, and loading conditions similar to those encountered in a prestressed concrete reactor vessel (PCRV). Variables included concrete strength, aggregate types, curing history, temperature, and types of loading (uniaxial, hydrostatic, biaxial, and triaxial). There were 66 test conditions for creep tests and 12 test conditions for unloaded or control specimens. Experimental results are presented and discussed. Comparisons are made concerning the effect of the various test conditions on the behavior of concrete, and general conclusions are formulated

Effect of paint on vapour resistivity in plaster

Directory of Open Access Journals (Sweden)

de Villanueva, L.

2008-12-01

Full Text Available The vapour resistivity of plaster coatings such as paint and their effectiveness as water repellents were studied in several types of plaster. To this end, painted, unpainted and pigmented specimens were tested. Experimental values were collected on diffusion and vapour permeability, or its inverse, water vapour resistivity.The data obtained were very useful for evaluating moisture exchange between plaster and the surrounding air, both during initial drying and throughout the life of the material. They likewise served as a basis for ensuring the proper evacuation of water vapour in walls, and use of the capacity of the porous network in plaster products to regulate moisture content or serve as a water vapour barrier to avoid condensation.Briefly, the research showed that pigments, water-based paints and silicon-based water repellents scantly raised vapour resistance. Plastic paints, enamels and lacquers, however, respectively induced five-, ten- and twenty-fold increases in vapour resistivity, on average.Se estudia el fenómeno de la resistividad al vapor de los de yeso y el efecto impermeabilizante que producen los recubrimientos de pintura sobre diversos tipos de yeso y escayola. Para ello, se ensayan probetas desnudas y recubiertas con distintos tipos de pintura, así como coloreados en masa. Se obtienen valores experimentales de la difusividad o permeabilidad al vapor o su inverso la resistividad al vapor de agua.Los datos obtenidos son muy útiles para valorar el fenómeno del intercambio de humedad entre el yeso y el ambiente, tanto durante el proceso de su secado inicial, como en el transcurso de su vida. Así como para disponer soluciones adecuadas para la evacuación del vapor de agua a través de los cerramientos, para utilizar la capacidad de regulación de la humedad, que proporciona el entramado poroso de los productos de yeso, o para impedir el paso del vapor de agua y evitar condensaciones.Como resumen de la investigación, se

Experimental study of the leakage rate through cracked reinforced concrete wall elements for defining the functional failure criteria of containment buildings

International Nuclear Information System (INIS)

Choun, Young Sun; Cho, Nam So

2004-01-01

Containment buildings in nuclear power plants should maintain their structural safety as well as their functional integrity during an operation period. To maintain the functional integrity, the wall and dome of the containment buildings have to maintain their air tightness under extreme loading conditions such as earthquakes, missile impact, and severe accidents. For evaluating the functional failure of containments, it is important to predict the leak amount through cracked concrete walls. The leakage through concrete cracks has been studied since 1972. Buss examined the flow rate of air through a pre-existing crack in a slab under air pressure. Rizkalla el al. initiated an experimental study for the leakage of prestressed concrete building segments under uniaxial and biaxial loadings to simulate the loading condition of containment buildings under an internal pressure. Recently, Salmon el al. initiated an experimental program for determining the leak rates in typical reinforced concrete shear walls subjected to beyond design basis earthquakes. This study investigates the cracking behavior of reinforced concrete containment wall elements under a uniaxial tension and addresses the outline of the leakage test for unlined containment wall elements

Effect of temperature and moisture on the fracture energy and the thermal properties of concrete

International Nuclear Information System (INIS)

Kallel, H.; Carre, H.; Laborderie, C.; Masson, B.; Tran, N.C.

2015-01-01

In nuclear power plants, during a severe accident the containment building undergoes an increase of pressure, temperature and relative humidity that can reach respectively 5 bars, 140 C. degrees and the saturation of water vapor. Beyond the regulatory calculations, a suitable knowledge of the thermal and mechanical behaviour of the materials and more specifically of the concrete is required to carry out accurate numerical simulations. An experimental apparatus has been designed to assess the fracture energy (G f ) evolutions for concrete under various experimental conditions in terms of temperature and relative humidity of the concrete. Mechanical tests have been performed under different controlled conditions in terms of temperature (T=30 C. degrees ) and liquid water degree of saturation S w (four target values of 50, 70, 90 and 100%). These values of liquid water degree of saturation have been obtained by conditioning the relative humidity of the sealed environment where specimens have been left for the equalisation process by using potassium salt solutions. DCT (Disk-shape Compact Tension) test has been chosen for determining G f . In comparison with three points bending test, the typology of the test, the equipment and all test devices have been validated. Test results show clearly the decreasing of the fracture energy as saturation degree increases. This evolution has a linear trend for S w ranging from 36 % to 97 %

Moisture performance of building materials: From material characterization to building simulation using the Moisture Buffer Value concept

Energy Technology Data Exchange (ETDEWEB)

Abadie, Marc Olivier [Mechanical Engineering Graduate Program, Pontifical Catholic University of Parana, PUC-PR/CCET, Curitiba, PR 80215-901 (Brazil); LEPTAB, University of La Rochelle, La Rochelle, 17042 Cedex 1 (France); Mendonca, Katia Cordeiro [Mechanical Engineering Graduate Program, Pontifical Catholic University of Parana, PUC-PR/CCET, Curitiba, PR 80215-901 (Brazil)

2009-02-15

Predicting the indoor air relative humidity evolution is of great importance to evaluate people thermal comfort, perceived air quality and energy consumption. In building environments, porous materials of the envelope and furniture act on the indoor air humidity by reducing its variations. Solving the physical processes involved inside the porous materials requires the knowledge of the material hygrothermal properties that needs multiple and, for some of them, time-consuming experimental procedures. Recently, both the NORDTEST Project and Japanese Industrial Standard described a new Moisture Buffer Capacity index that accounts for surrounding air vapor concentration variation. The Moisture Buffer Value (MBV) indicates the amount of water vapor that is transported in or out of a material, during a certain period of time, when the vapor concentration of the surrounding air varies. The MBV evaluation requires only one experimental procedure and its value permits a direct comparison of the building materials moisture performance. However, two limitations can be distinguished: first, no relation between the MBV and the usual material hygrothermal properties has been clearly identified and second, no model has been proposed to actually use the MBV in building simulation. The present study aims to solve these two problems. First, the MBV fundamentals are introduced and discussed; followed by its relation with the usual material properties. Then, a lumped model for building simulation, whose parameters can be determined from the MBV experimental procedure, is described. To finish, examples of the use of this MBV-based lumped model for moisture prediction in buildings are presented. (author)

Multi-criteria thermal evaluation of wall enclosures of high-rise buildings insulated products based on modified fibers

Science.gov (United States)

Pavlov, Alexey; Pavlova, Larisa; Pavlova, Lyudmila

2018-03-01

In article results of research of versions of offered types of heaters on the basis of products from the modified fibers for designing energy efficient building enclosures residential high-rise buildings are presented. Traditional building materials (reinforced concrete, brick, wood) are not able to provide the required value of thermal resistance in areas with a temperate and harsh Russia climate in a single-layered enclosing structure. It can be achieved in a multi-layered enclosing structure, where the decisive role is played by new insulating materials with high thermal properties. In general, modern design solutions for external walls are based on the use of new effective thermal insulation materials with the use of the latest technology. The relevance of the proposed topic is to research thermoinsulation properties of new mineral heaters. Theoretical researches of offered heaters from mineral wool on slime-colloidal binder, bentocolloid and microdispersed binders are carried out. In addition, theoretical studies were carried out with several types of facade systems. Comprehensive studies were conducted on the resistance to heat transfer, resistance to vapor permeation and air permeability. According to the received data, recommendations on the use of insulation types depending on the number of storeys of buildings are proposed.

Experimental study of thermal properties of a new ecological building material based on peanut shells and plaster

Directory of Open Access Journals (Sweden)

M. Lamrani

2017-12-01

Full Text Available The aim of the present work was to investigate the thermal properties of a new building material consisting of a mixture of plaster and peanut shells for use as insulating materials in building. The properties are commonly measured by using the steady state asymmetric hot plate method, the asymmetrical transient hot plate method and the flash method. The experimental study that we have conducted, enabled us to determine the conductivity, the effusivity and the thermal diffusivity of our material. The influence of the size and the mass fraction of the peanut shell shards on thermophysical properties of tested material, was investigated. Our experimental data show a good efficiency and a significant decrease in the thermal conductivity of material with peanut shell shards compared to simple plaster material. The purpose is to obtain ecological composite materials with better thermal performance, which can contribute to improve the thermal comfort in constructions in Morocco. The results show that the density of the new material was not substantially influenced by the size of the peanut shell shards. However, the thermal conductivity and diffusivity decrease from 0.3 Wm−1 K−1 and 3.75 × 10−7 m2 s−1 to 0.14 Wm−1 K−1 and 2.11 × 10−7m2 s−1, respectively, according to the variation of the mass fraction of peanut from 0 to20%.

A predictive model for the chemical vapor deposition of polysilicon in a cold wall, rapid thermal system

Energy Technology Data Exchange (ETDEWEB)

Toprac, A.J.; Trachtenberg, I.; Edgar, T.F. (Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering)

1994-06-01

The chemical vapor deposition of polysilicon from thermally activated silane in a cold wall, single-wafer rapid thermal system was studied by experimentation at a variety of low pressure conditions, including very high temperatures. The effect of diluent gas on polysilicon deposition rates was examined using hydrogen, helium, and krypton. A mass-transfer model for the chemical vapor deposition of polysilicon in a cold wall, rapid thermal system was developed. This model was used to produce an empirical rate expression for silicon deposition from silane by regressing kinetic parameters to fit experimental data. The resulting model provided accurate predictions over widely varying conditions in the experimental data.

Shear reinforced beams in autoclaved aerated concrete

DEFF Research Database (Denmark)

Cornelius, Thomas

2010-01-01

Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different combinat....... Codes for designing prefabricated reinforced components of aircrete structures have adopted these recently developed approaches.......Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different...

Convective Concrete: additive manufacturing to facilitate activation of thermal mass

Directory of Open Access Journals (Sweden)

Dennis de Witte

2017-12-01

Full Text Available Convective Concrete is about a research-driven design process of an innovative thermal mass concept. The goal is to improve building energy efficiency and comfort levels by addressing some of the shortcomings of conventional building slabs with high thermal storage capacity. Such heavyweight constructions tend to have a slow response time and do not make use of the available thermal mass effectively. Convective Concrete explores new ways of using thermal mass in buildings more intelligently. To accomplish this ondemand charging of thermal mass, a network of ducts and fans is embedded in the concrete wall element. This is done by developing customized formwork elements in combination with advanced concrete mixtures. To achieve an efficient airflow rate, the embedded lost formwork and the concrete itself function like a lung.

Thermal stress analysis of reactor containment building considering severe weather condition

International Nuclear Information System (INIS)

Lee, Yun; Kim, Yun-Yong; Hyun, Jung-Hwan; Kim, Do-Gyeum

2014-01-01

Highlights: • We examine that through-wall crack risk in cold weather is high. • It is predicted that cracking in concrete wall will not happen in hot region. • Cracking due to hydration heat can be controlled by appropriate curing condition. • Temperature differences between inner and outer face is relatively small in hot weather. - Abstract: Prediction of concrete cracking due to hydration heat in mass concrete such as reactor containment building (RCB) in nuclear power plant is a crucial issue in construction site. In this study, the numerical analysis for heat transfer and stress development is performed for the containment wall in RCB by considering the severe weather conditions. Finally, concrete cracking risk in hot and cold weather is discussed based on analysis results. In analyses considering severe weather conditions, it is found that the through-wall cracking risk in cold weather is high due to the abrupt temperature difference between inside concrete and the ambient air in cold region. In hot weather, temperature differences between inner and outer face is relatively small, and accordingly the relevant cracking risk is relatively low in contrast with cold weather

Moisture dynamics in building envelopes

Energy Technology Data Exchange (ETDEWEB)

Peuhkuri, R.

2003-07-01

The overall scope of this Thesis 'Moisture dynamics in building envelopes' has been to characterise how the various porous insulation materials investigated performed hygro thermally under conditions similar to those in a typical building envelope. As a result of the changing temperature and moisture conditions in the exterior weather and indoor climate the materials dynamically absorb and release moisture. The complexity of the impact of these conditions on the resulting moisture transport and content of the materials has been studied in this Thesis with controlled laboratory tests. (au)

Scanning electron microscopy of autoclaved aerated concrete with supplementary raw materials

NARCIS (Netherlands)

Straub, C.; Florea, M.V.A.; Brouwers, H.J.H.; Nisperos, Arturo G.; Pöllmann, Herbert

Microscopy is a key analysis technology for the understanding of the achieved properties of building materials. In the case of Autoclaved Aerated Concrete (AAC) it is even more important due to the phase transformation during the hydrothermal hardening. The incorporation of substitution materials in

Thermal insulation of buildings classified as historical monuments with particular emphasis on moisture protection; Hygrisch motivierter Waermeschutz von Altbauten mit denkmalgeschuetzter Fassade

Energy Technology Data Exchange (ETDEWEB)

Haeupl, P.; Martin, R.; Fechner, H.; Neue, J. [Technische Univ. Dresden (Germany). Inst. fuer Bauklimatik

1997-12-31

Buildings classified as historical must not be fitted with external thermal insulation elements. This project investigates a `gentle` type of an internal thermal insulation system with capillary activity permitting diffusion. A 120-year-old building with a historical house-front was thermally insulated at the inside using a 30-millimetre-thick calcium silicate plate with embedded fibres having capillary activity. The paper discusses the heat flow densities between the internal thermal insulation and the original part of the structure. Moisture fields in the wall in the case of mineral wool insulation and internal thermal insulation with capillary activity are compared. Moisture distribution in the area of the juncture between masonry and window and in the area of the beam head is shown by means of diagrams. (MSK) [Deutsch] Weil bei denkmalgeschuetzten Fassanden ein aussen angebrachtes Thermoverbundsystem nicht moeglich ist, wird in diesem Projekt eine sanfte kapillaraktive, diffusionsoffene Innendaemmung untersucht. Als Referenzobjekt wurde ein etwa 120 Jahre altes Gruenderzeithaus mit denkmalgeschuetzter Fassade mit einer 30mm dicken faserdotierten kapillaraktiven Calciumsilikatplatte innenseitig gedaemmt. Im Folgenden werden die Waermestromdichten zwischen Innendaemmung und Altkonstruktion erlaeutert. Die Feuchtefelder in der Wand bei Mineralwolleindaemmung und bei kapillaraktiver Innendaemmung werden verglichen. Die Feuchteverteilung im Bereich des Fenteranschlusses und des Balkenkopfes wird in Diagrammen dargestellt.

Monitoring of Double-Stud Wall Moisture Conditions in the Northeast

Energy Technology Data Exchange (ETDEWEB)

Ueno, K. [Building Science Corporation, Westford, MA (United States)

2015-03-01

Double-stud walls insulated with cellulose or low-density spray foam can have R-values of 40 or higher. However, double-stud walls have a higher risk of interior-sourced condensation moisture damage when compared with high-R approaches using exterior insulating sheathing. Moisture conditions in double-stud walls were monitored in Zone 5A (Massachusetts); three double-stud assemblies were compared.

Monitoring of Double Stud Wall Moisture Conditions in the Northeast

Energy Technology Data Exchange (ETDEWEB)

Ueno, K. [Building Science Corporation, Westford, MA (United States)

2015-03-01

Double-stud walls insulated with cellulose or low-density spray foam can have R-values of 40 or higher. However, double stud walls have a higher risk of interior-sourced condensation moisture damage, when compared with high-R approaches using exterior insulating sheathing.; Moisture conditions in double stud walls were monitored in Zone 5A (Massachusetts); three double stud assemblies were compared.

Improving Thermal Insulation Properties for Prefabricated Wall Components Made Of Lightweight Aggregate Concrete with Open Structure

Science.gov (United States)

Abramski, Marcin

2017-10-01

Porous concrete is commonly used in civil engineering due to its good thermal insulation properties in comparison with normal concrete and high compression strength in comparison with other building materials. Reducing of the concrete density can be obviously obtained by using lightweight aggregate (e.g. pumice). The concrete density can be further minimized by using specially graded coarse aggregate and little-to-no fine aggregates. In this way a large number of air voids arise. The aggregate particles are coated by a cement paste and bonded together with it just in contact points. Such an extremely porous concrete, called ‘lightweight aggregate concrete with open structure’ (LAC), is used in some German plants to produce prefabricated wall components. They are used mainly in hall buildings, e.g. supermarkets. The need of improving thermal insulation properties was an inspiration for the prefabrication plant managers, engineers and a scientific staff of the Technical University of Kaiserslautern / Germany to realise an interesting project. Its aim was to reduce the heat transfer coefficient for the wall components. Three different wall structure types were designed and compared in full-scale laboratory tests with originally produced wall components in terms of load-carrying capacity and stiffness. The load was applied perpendicularly to the wall plane. As the components are not originally used for load-bearing walls, but for curtain walls only, the wind load is the main load for them. The wall components were tested in horizontal position and the load was applied vertically. Totally twelve wall components 8.00 × 2.00 × 0.25m (three for every series) were produced in the prefabrication plant and tested in the University of Kaiserslautern laboratory. The designed and tested components differed from each other in the amount of expanded polystyrene (EPS), which was placed in the plant inside the wall structure. The minimal amount of it was designed in the

The environmental impacts of foamed concrete production and exploitation

Science.gov (United States)

Namsone, E.; Korjakins, A.; Sahmenko, G.; Sinka, M.

2017-10-01

This paper presents a study focusing on the environmental impacts of foamed concrete production and exploitation. CO2 emissions are very important factor for describing durability and sustainability of any building material and its life cycle. The building sector is one of the largest energy-consuming sectors in the world. In this study CO2 emissions are evaluated with regard to three types of energy resources (gas, coal and eco-friendly fuel). The related savings on raw materials are up to 120 t of water per 1000 t of traditionally mixed foamed concrete and up to 350 t of sand per 1000 t of foamed concrete produced with intensive mixing technology. In addition, total reduction of CO2 emissions (up to 60 t per 1000 m3 of material) and total energy saving from introduction of foamed concrete production (depending on the type of fuel) were calculated. In order to analyze the conditions of exploitation, both thermal conductivity and thickness of wall was determined. All obtained and calculated results were compared to those of the commercially produced autoclaved aerated concrete.

The potential role of cattail-reinforced clay plaster in sustainable building

Directory of Open Access Journals (Sweden)

G. Georgiev

2014-06-01

Full Text Available Sustainable development is a key goal in town and country planning, as well as in the building industry. The main aims are to avoid inefficient land use, to improve the energy efficiency of buildings and, thus, to move towards meeting the challenges of climate change. In this article we consider how the use of a traditional low-energy building material, namely clay, might contribute. Recent research has identified a promising connection between the reinforcement of clay for internal wall plastering with fibres from the wetland plant Typha latifolia (cattail and the positive environmental effects of cultivating this species. If large quantities of Typha fibres were to be used in building, the need for cultivation of the plant would increase and create new possibilities for the renaturalisation of polluted or/and degraded peatlands. We explore the topic first on the basis of literature, considering the suitability of Typha for this application and possibilities for its sustainable cultivation, as well as implications for the life cycle analyses of buildings in which it is used. We then report (qualitatively the results of testing different combinations of clay with natural plant (straw and cattail fibres for their suitability as a universal plaster, which demonstrate clearly the superior properties of Typha fibres as a reinforcement material for clay plaster mortars.

Moisture conditions in buildings

DEFF Research Database (Denmark)

Rode, Carsten

2012-01-01

Growth of mould requires the presence of moisture at a certain high level. In a heated indoor environment such moisture levels occur only if there is a reason for the moisture supply. Such moisture can come from the use of the building, because of malfunctioning constructions, or it can be the re......Growth of mould requires the presence of moisture at a certain high level. In a heated indoor environment such moisture levels occur only if there is a reason for the moisture supply. Such moisture can come from the use of the building, because of malfunctioning constructions, or it can...

New building envelope structures. Energy saving and moisture technology; Uudet vaipparakenteet. Energian saeaestoe ja kosteustekniikka

Energy Technology Data Exchange (ETDEWEB)

Kokko, E.; Ojanen, T.; Salonvaara, M. [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology

1997-12-31

insulated wall with a 30 mm air cavity between the drywall and vapor retarder was analyzed. An aluminum foil laminated on paper and attached to the interior surface of the mineral wool insulation bright side facing the air cavity acted as a vapor retarder. The gained benefits were: 30 mm air cavity provides additional thermal resistance and installation space, vapor retarder is maintained undamaged functioning as an effective air barrier and vapor tight layer. Another application investigated was the use of low-emissivity foil installed 50 mm under the floor in the crawl space. The objective was to raise the temperature of the floor surface facing the crawl space and improve moisture conditions and the thermal resistance of the base floor. Both the simulations and the experiments showed that the surface temperature raised several degrees because of the foil which lowered the relative humidity under the floor surface from 90 % to 65 %. Due to the foil the steady-state temperature difference and the heat flux through the floor decreased approximately 40 %. Drying of an invented flat roof insulated with a thick layer of expanded polystyrene (EPS) was investigated in laboratory conditions. The drying of the roof was based on a capillary drainage layer. A continuous, thin layer of capillary conducting cellulose fiber material transferred water from its injection point 6 m away from the gutter all the way all the eaves where the water left the roof first by dripping and later by evaporating at the edge of the capillary layer. Drying of the roof due to capillary flow started approximately one day after the water injection and most of the water had dried out in 21 days. A solar energy collector system having air circulation based on natural convection was studied using simulations and experimental studies. This system, integrated to building structures, proved promising. In the system the collector and accumulator structures were separate from each other but connected through an

Measurement of moisture motion under a temperature gradient in a concrete for SNR-300 using thermal neutrons

International Nuclear Information System (INIS)

Zelinger, A.

1975-01-01

For describing the behavior of the moisture in the concrete of the containment of SNR-300 in a hypothetical accident parameters were determined experimentally. The method is based on transmission of thermal neutrons through a plate of concrete. When a temperature of 170 deg C was applied at one end of the plate migration of moisture and evaporation took place. This could be observed by neutron radiography giving a gross picture of moisture migration. Furthermore the intensity of the transmitted neutron beam was measured with a neutron counter. From these values profiles of the change of moisture concentration could be obtained with a spatial resolution of few millimeters. The method used is entirely different from the conventional moisture meters which use fast neutrons. From the experimental data the mass transfer coefficient of vapour, the diffusion coefficient of vapour in concrete and the porosity of the concrete could be determined

Influence of addition of calcium sulfate dihydrate on drying of autoclaved aerated concrete

Science.gov (United States)

Małaszkiewicz, Dorota; Chojnowski, Jacek

2017-11-01

The quality of the autoclaved aerated concrete (AAC) strongly depends on the chemical composition of the raw materials, as well as on the process of the hydrothermal reaction during autoclaving. Performance parameters depend on material structure: fine micron-scale matrix porosity generated by the packing of thin tobermorite plates and coarse aeration pores arising from the foaming of wet mix. In this study the binder varied in calcium sulfate dihydrate (CaSO4ṡ2H2O) content. Five series of AAC specimens were produced, with gypsum content 0; 0.55; 1.15; 2.3 and 3.5% of dry mass respectively. AAC units were produced in UNIPOL technology. The study presents experimental results of AAC moisture stabilization. The initial moisture content was determined directly after autoclaving. Slower drying process was observed for samples containing over 2% of gypsum. Whereas other performance parameters, compressive and tensile strength, as well as water absorption and capillary rise, were significantly better comparing to the reference AAC samples.

Assessment of seismic design response factors of concrete wall buildings

Science.gov (United States)

Mwafy, Aman

2011-03-01

To verify the seismic design response factors of high-rise buildings, five reference structures, varying in height from 20- to 60-stories, were selected and designed according to modern design codes to represent a wide range of concrete wall structures. Verified fiber-based analytical models for inelastic simulation were developed, considering the geometric nonlinearity and material inelasticity of the structural members. The ground motion uncertainty was accounted for by employing 20 earthquake records representing two seismic scenarios, consistent with the latest understanding of the tectonic setting and seismicity of the selected reference region (UAE). A large number of Inelastic Pushover Analyses (IPAs) and Incremental Dynamic Collapse Analyses (IDCAs) were deployed for the reference structures to estimate the seismic design response factors. It is concluded that the factors adopted by the design code are adequately conservative. The results of this systematic assessment of seismic design response factors apply to a wide variety of contemporary concrete wall buildings with various characteristics.

THE INFLUENCE OF A HALLOYSITE ADDITIVE ON THE PERFORMANCE OF AUTOCLAVED AERATED CONCRETE

Directory of Open Access Journals (Sweden)

Z. Owsiak

2015-03-01

Full Text Available This paper presents the results from the tests of autoclaved aerated concrete with halloysite as a cement additive. Good pozzolanic properties make it a suitable material to be used as a partial replacement of a portion of cement. Basic physical and mechanical properties of the composites with various mineral content are discussed. The compressive strength test results indicate an increase in strength of the AAC containing 2.5 % and 5 % halloysite relative to the reference specimen. Thermal conductivity and density values remained at the same level. Observations of the microstructure in the scanning electron microscope confirmed the results from the XRD tests. Anhydrite was observed in addition to tobermorite. The results from the tests of the autoclaved aerated concretes in which halloysite was incorporated as 7.5 % and 10 % cement replacement showed an increase in compressive strength, density and thermal conductivity values.

Binary Effect of Fly Ash and Palm Oil Fuel Ash on Heat of Hydration Aerated Concrete

Science.gov (United States)

Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa

2014-01-01

The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern. PMID:24696646

Experimental characterization of thermal and hygric properties of hemp concrete with consideration of the material age evolution

Science.gov (United States)

Bennai, F.; Issaadi, N.; Abahri, K.; Belarbi, R.; Tahakourt, A.

2018-04-01

The incorporation of plant crops in construction materials offers very good hygrothermal performance to the building, ensuring substantial environmental and ecological benefits. This paper focuses on studying the evolution of hygrothermal properties of hemp concrete over age (7, 30 and 60 days). The analysis is done with respect to two main hygric and thermal properties, respectively: sorption isotherms, water vapor permeability, thermal conductivity and heat capacity. In fact, most of these parameters are very susceptible to change function of the age of the material. This influence of the aging is mainly due to the evolution of the microstructure with the binder hydration over time and the creation of new hydrates which can reduces the porosity of the material and consequently modify its properties. All the tested hemp concrete samples presented high moisture storage capacity and high-water vapor permeability whatever the age of such hygroscopic material. These hygric parameters increase significantly for high relative humidity requiring more consideration of such variability during the modeling of coupled heat and mass transfer within the material. By the same, the thermal conductivity and heat capacity tests highlighted the impact of the temperature and hygric state of the studied material.

Building materials. Stichwort Baustoff

Energy Technology Data Exchange (ETDEWEB)

Rohwer, W

1981-01-01

To handle building materials properly, one must know about their characteristics. This pocket book will be of help: structured like a glossary, it gives brief descriptions of the most common building materials. It is small and handy enough to be a constant companion to resident engineers, foremen, gangers, building tradesmen, and construction workers and an aid in their training. The following groups of building materials are discussed: Natural stone; units for brick walls, floors, and roofs; mortar and concrete (definitions, binders, aggregates, additives, admixtures, mixing water); special types of plaster and rendering; light-weight building boards and wood wool basis; multilayer light-weight building boards; gypsum plasterboards; chimney construction; sewers; thermal insulation and sound section; structural steels; plastics.

Influence of temperature on strain monitoring of degradation in concrete containment buildings

International Nuclear Information System (INIS)

Ding, Y.; Jaffer, S.; Angell, P.

2015-01-01

Concrete containment buildings (CCBs) are important safety structures in a nuclear power plant (NPP). The CCBs can be made of reinforced and post-tensioned (P-T) concrete. Post-tensioning concrete induces compressive stresses, which have to be overcome for the concrete to crack under tensile loads. However, post-tensioned CCBs may undergo pre-stressing losses as they age, which could affect their performance under accident conditions. CANDU 6 reactor buildings contain grouted post-tensioned tendons as the primary reinforcement. The grouting of the tendons makes direct monitoring of pre-stressing losses via lift-off testing impossible. Therefore, instruments have been installed on an existing reactor building to measure and monitor strains and stresses in the concrete and the deformation of the concrete structure to detect aging degradation and indirectly evaluate the pre-stressing losses. However, the instrumentation readings are affected by temporary volume changes in the concrete caused by the influence of environmental factors, particularly temperature, on concrete. In this work, the focus is on developing an understanding of the effect of temperature on the interpretation of instrumentation data from a reactor building. Vibrating Wire Strain Gauge (VWSG) data has been analysed. The influence of concrete coefficient of thermal expansion and temperature distribution within the reactor building walls, on VWSG data, is discussed based on the analysis of the available instrumentation data and available numerical simulation results. The present study demonstrates that temperature distribution within the containment concrete has a significant impact on the VWSG measurements and the coefficient of thermal expansion of concrete is an important factor in the correction of VWSG data for thermal strain. It is recommended that VWSG data obtained over small temperature variations be considered for interpretation to assess pre-stressing losses. (authors)

INFLUENCE OF NON-PERFORATED SCREEN LOCATION ON HEAT TRANSFER PROCESS IN BUILDING ENCLOSING PARTS

Directory of Open Access Journals (Sweden)

V. D. Sizov

2017-01-01

Full Text Available It is recommended to have a vapor-proof barrier on the internal side of heat insulation system in multi-layer building enclosing parts in order to ensure protection of a heat-insulation layer against humidification because relative humidity of internal air is generally higher than external one and diffusion of water steam is directed from premises outside. While having a barrier with high vapor permeability a part of moisture can be accumulated in the structure and heat insulation core and difference of actual and maximum possible partial pressures leads to condensate formation. In order to improve thermal properties of enclosing parts the necessity arises to create a vapor-proof protection screen. It complies with the design of a panel with a vapor-proof screen in the form of non-perforated aluminium foil. The given screen located at internal panel layer prevents penetration of water vapor from premises into enclosing part and heat insulation layer. In such a case condensation zones and, consequently, their moistening can occur in some layers of enclosing parts according to their thermal and physical characteristics. The paper contains a calculation of thermal and moisture regime of the enclosing parts with vapor-proof layer (non-perforated aluminium foil located in enclosing part core between various layers. An analysis of thermal and moisture regime diagrams for multi-layer external enclosing part demonstrates that the part of non-perforated screen (aluminium foil located between internal concrete layer and perforated heat insulation layer is considered the most rational one. At the same time other screens between separate layers are perforated.

Non-linear thermal optimization and design improvement of a new internal light concrete multi-holed brick walls by FEM

International Nuclear Information System (INIS)

Coz Diaz, J.J. del; Garcia Nieto, P.J.; Suarez Sierra, J.L.; Penuelas Sanchez, I.

2008-01-01

The aim of this work was carried out the optimization and numerical study by the finite element method of internal hollow bricks walls in order to determine the best candidate brick from the thermal point of view. With respect to the energy saving for housing and industrial structures, there is also a great interest in light building materials with good physical and thermal behaviors, which fulfills all thermal requirements of the new CTE Spanish rule. The conduction, convection and radiation phenomena are taking into account in this study for six different types of bricks varying the material conductivity obtained from five experimental tests. Mathematically, the non-linearity is due to the radiation boundary condition inside the inner recesses of the bricks. Optimization of the walls is carried out from the finite element analysis of the new hollow brick geometries by means of the average mass overall thermal efficiency and the equivalent thermal conductivity. Based on the previous thermal analysis and the optimization procedure described in this paper, the best candidate was chosen and then a full 1.22 x 0.23 x 1.05 m wall made of these bricks was simulated for fifteen different compositions. The main variables influencing the thermal conductivity of these walls are illustrated for different concrete and mortar properties and the temperature distribution is shown for some typical configurations. Finally, in order to select the appropriate wall satisfying the CTE requirements, detailed instructions are given and conclusions of this work are exposed

Non-linear thermal optimization and design improvement of a new internal light concrete multi-holed brick walls by FEM

Energy Technology Data Exchange (ETDEWEB)

Coz Diaz, J.J. del [Edificio Departamental Viesques, No. 7-33204 Gijon, Asturias (Spain)], E-mail: juanjo@constru.uniovi.es; Garcia Nieto, P.J. [Departamento de Matematicas, Facultad de Ciencias, C/Calvo Sotelo s/n, 33007 Oviedo, Asturias (Spain); Suarez Sierra, J.L.; Penuelas Sanchez, I. [Edificio Departamental Viesques, No. 7-33204 Gijon, Asturias (Spain)

2008-06-15

The aim of this work was carried out the optimization and numerical study by the finite element method of internal hollow bricks walls in order to determine the best candidate brick from the thermal point of view. With respect to the energy saving for housing and industrial structures, there is also a great interest in light building materials with good physical and thermal behaviors, which fulfills all thermal requirements of the new CTE Spanish rule. The conduction, convection and radiation phenomena are taking into account in this study for six different types of bricks varying the material conductivity obtained from five experimental tests. Mathematically, the non-linearity is due to the radiation boundary condition inside the inner recesses of the bricks. Optimization of the walls is carried out from the finite element analysis of the new hollow brick geometries by means of the average mass overall thermal efficiency and the equivalent thermal conductivity. Based on the previous thermal analysis and the optimization procedure described in this paper, the best candidate was chosen and then a full 1.22 x 0.23 x 1.05 m wall made of these bricks was simulated for fifteen different compositions. The main variables influencing the thermal conductivity of these walls are illustrated for different concrete and mortar properties and the temperature distribution is shown for some typical configurations. Finally, in order to select the appropriate wall satisfying the CTE requirements, detailed instructions are given and conclusions of this work are exposed.

Contribution to the study of fluids transfers within a concrete wall: application to the case of a containment wall subjected to air tightness tests conditions and to accidental situation conditions

International Nuclear Information System (INIS)

Billard, Y.

2003-01-01

The correlation between the leak rate of a containment wall of nuclear power plants reactor buildings measured during periodic airtightness tests and the leak rate during a Loss Of Coolant Accident (LOCA) is a fundamental element in the security analysis of reactor building. The aim of this work is to contribute to the study of the transfers of fluids induced by these two types of loading in the case of a concrete wall integrating inhomogeneities and singularities capable to exist within the containment wall. In a first experimental phase, the development of a test rig allowing to work with concrete specimens having the same height as the thickness of containment wall of future nuclear power plant (1.3 m) permits to develop concrete compositions representative of these high air permeability zones. Their characterization is focused on the types of gaseous flow being able to exist within these high diffuse permeability concretes and on the structuring of their porous network. This step is completed by water vapour sorption measurements and by mercury porosimetry tests in the case of a concrete qualified according a leak flow criterion. In a second experimental phase, this concrete is subjected to air tightness tests conditions and to an accidental situation of LOCA type (141 deg C, effective humid air pressure equal to 4,2 bar) always with a thickness of 1.3 m. The analysis of pressure and temperature fields and the water content distributions is performed by an appropriate instrumentation which also permits the study of kinetics of the mass flux (both gaseous and liquid) crossing to the extrados of the wall. The numerical investigation is carried out with the Thermal-Hydro-Mechanic of non-saturated porous media model, recently implemented in Code Aster (developed by EDF). This model allows to consider all the fluid phases in presence. From a interpretation work of experimental data according to hypotheses of the model, notably towards the particular aspects bound up

Moisture Transfer in Concrete: Numerical Determination of the Capillary Conductivity Coefficient

Directory of Open Access Journals (Sweden)

Simo Elie

2017-03-01

Full Text Available We numerically investigated moisture transfer in buildings made of concrete. We considered three types of concrete: normal concrete, pumice concrete and cellular concrete. We present the results of a 1-D liquid water flow in such materials. We evaluated the moisture distribution in building materials using the Runge-Kutta fourth-and-fifth-order method. The DOPRI5 code was used as an integrator. The model calculated the resulting moisture content and other moisture-dependent physical parameters. The moisture curves were plotted. The dampness data obtained was utilized for the numerical computation of the coefficient of the capillary conductivity of moisture. Different profiles of this coefficient are represented. Calculations were performed for four different values of the outdoor temperature: -5°C, 0°C, 5°C and 10°C. We determined that the curves corresponding to small time intervals of wetting are associated with great amplitudes of the capillary conductivity . The amplitudes of the coefficient of the capillary conductivity decrease as the time interval increases. High outdoor temperatures induce high amplitudes of the coefficient of the capillary conductivity.

Measured moisture in buildings and adverse health effects: a review.

Science.gov (United States)

Mendell, Mark J; Macher, Janet M; Kumagai, Kazukiyo

2018-04-23

It has not yet been possible to quantify dose-related health risks attributable to indoor dampness or mold (D/M), to support the setting of health-related limits for D/M. An overlooked target for assessing D/M is moisture in building materials, the critical factor allowing microbial growth. A search for studies of quantified building moisture and occupant health effects identified three eligible studies. Two studies assessed associations between measured wall moisture content and respiratory health in the UK. Both reported dose-related increases in asthma exacerbation with higher measured moisture, with one study reporting an adjusted odds ratio (OR) of 7.0 for night-time asthma symptoms with higher bedroom moisture. The third study assessed relationships between infrared camera-determined wall moisture and atopic dermatitis in South Korea, reporting an adjusted OR of 14.5 for water-damaged homes and moderate or severe atopic dermatitis. Measuring building moisture has, despite extremely limited available findings, potential promise for detecting unhealthy D/M in homes and merits more research attention. Further research to validate these findings should include measured "water activity," which directly assesses moisture availability for microbial growth. Ultimately, evidence-based, health-related thresholds for building moisture, across specific materials and measurement devices, could better guide assessment and remediation of D/M in buildings. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Hygrothermal behavior for a clay brick wall

Science.gov (United States)

Allam, R.; Issaadi, N.; Belarbi, R.; El-Meligy, M.; Altahrany, A.

2018-06-01

In Egypt, the clay brick is the common building materials which are used. By studying clay brick walls behavior for the heat and moisture transfer, the efficient use of the clay brick can be reached. So, this research studies the hygrothermal transfer in this material by measuring the hygrothermal properties and performing experimental tests for a constructed clay brick wall. We present the model for the hygrothermal transfer in the clay brick which takes the temperature and the vapor pressure as driving potentials. In addition, this research compares the presented model with previous models. By constructing the clay brick wall between two climates chambers with different boundary conditions, we can validate the numerical model and analyze the hygrothermal transfer in the wall. The temperature and relative humidity profiles within the material are measured experimentally and determined numerically. The numerical and experimental results have a good convergence with 3.5% difference. The surface boundary conditions, the ground effect, the infiltration from the closed chambers and the material heterogeneity affects the results. Thermal transfer of the clay brick walls reaches the steady state very rapidly than the moisture transfer. That means the effect of using only the external brick wall in the building in hot climate without increase the thermal resistance for the wall, will add more energy losses in the clay brick walls buildings. Also, the behavior of the wall at the heat and mass transfer calls the three-dimensional analysis for the whole building to reach the real behavior.

Hygrothermal behavior for a clay brick wall

Science.gov (United States)

Allam, R.; Issaadi, N.; Belarbi, R.; El-Meligy, M.; Altahrany, A.

2018-01-01

In Egypt, the clay brick is the common building materials which are used. By studying clay brick walls behavior for the heat and moisture transfer, the efficient use of the clay brick can be reached. So, this research studies the hygrothermal transfer in this material by measuring the hygrothermal properties and performing experimental tests for a constructed clay brick wall. We present the model for the hygrothermal transfer in the clay brick which takes the temperature and the vapor pressure as driving potentials. In addition, this research compares the presented model with previous models. By constructing the clay brick wall between two climates chambers with different boundary conditions, we can validate the numerical model and analyze the hygrothermal transfer in the wall. The temperature and relative humidity profiles within the material are measured experimentally and determined numerically. The numerical and experimental results have a good convergence with 3.5% difference. The surface boundary conditions, the ground effect, the infiltration from the closed chambers and the material heterogeneity affects the results. Thermal transfer of the clay brick walls reaches the steady state very rapidly than the moisture transfer. That means the effect of using only the external brick wall in the building in hot climate without increase the thermal resistance for the wall, will add more energy losses in the clay brick walls buildings. Also, the behavior of the wall at the heat and mass transfer calls the three-dimensional analysis for the whole building to reach the real behavior.

Evaluation of Moisture Buffer Effects by Performing Whole-Building Simulations

DEFF Research Database (Denmark)

Rode, Carsten; Mendes, Nathan; K., Grau

2004-01-01

The humidity of rooms and the moisture conditions of materials in the enclosure of buildings depend much on each other because of the moisture exchange that takes place over the interior surfaces. These moisture influences also depend strongly on the thermal conditions of indoor spaces...... and enclosure elements of buildings. In turn, the moisture and humidity conditions have significant impact on how buildings are operated. In hot, humid climates, it may be desirable to keep the ventilation rates low in order to avoid too high indoor humidity, while in cold climates, ventilation can be used...

Moisture assessment by fast and non-destructive in situ measurements

DEFF Research Database (Denmark)

Hansen, Kurt Kielsgaard; Møller, Eva B.; Hansen, Ernst Jan de Place

2014-01-01

moisture content, which is not revealed by this inspection. The moisture content may become a problem for the buyers. This problem might have been avoided if the moisture content of the Building materials was measured on inspection. This is easily done in wood-based materials but for example in concrete...... to use, easily applicable and suitable for most porous building materials. Furthermore, the measurements must be reliable at the high end of the hygroscopic area and describe absolute moisture content or corresponding relative humidity. The existing methods for moisture measuring cannot meet...... on measurements of the relative humidity of the air in a small hood placed tightly and sealed to the surface of the construction. Results with aerated concrete covered with acrylic paint are presented....

Impact of coupled heat and moisture transfer effects on buildings energy consuption

Directory of Open Access Journals (Sweden)

Ferroukhi Mohammed Yacine

2017-01-01

Full Text Available Coupled heat, air, and moisture transfers through building envelope have an important effect on prediction of building energy requirements. Several works were conducted in order to integrate hygrothermal transfers in dynamic buildings simulations codes. However, the incorporation of multidirectional hygrothermal transfer analysis in the envelope into building simulation tools is rarely considered. In this work, coupled heat, air, and moisture (HAM transfer model in multilayer walls was established. Thereafter, the HAM model is coupled dynamically to a building behavior code (BES.The coupling concerns a co-simulation between COMSOL Multiphysics and TRNSYS software. Afterward, the HAM-BES co-simulation accuracy was verified. Then, HAM-BES co-simulation platform was applied to a case study with various types of climates (temperate, hot and humid, cold and humid. Three simulations cases were carried out. The first simulation case consists of the TRNSYS model without HAM transfer model. The second simulation case, 1-D HAM model for the envelope was integrated in TRNSYS code. For the third one, 1-D HAM model for the wall and 2-D HAM model for thermal bridges were coupled to the thermal building model of TRNSYS. Analysis of the results confirms the significant impact of 2-D envelope hygrothermal transfers on the indoor thermal and moisture behavior of building as well as on the energy building assessment. These conclusions are shown for different studied climates.

Thermophysical properties of hydrophobised lime plasters - The influence of ageing

Science.gov (United States)

Pavlíková, Milena; Zemanová, Lucie; Pavlík, Zbyšek

2017-07-01

The building envelope is a principal responsible for buildings energy loses. Lime plasters as the most popular finishing materials of historical buildings and culture monuments influence the thermal behaviour as well as construction material of masonry. On this account, the effect of ageing on the thermophysical properties of a newly designed lime plasters containing hydrophobic admixture is analysed in the paper. For the comparative purposes, the reference lime plaster is tested. The ageing is accelerated with controlled carbonation process to simulate the final plasters properties. Basic characterization of the tested materials is done using bulk density, matrix density, and porosity measurements. Thermal conductivity and volumetric heat capacity are experimentally assessed using a transient impulse method. The obtained data revealed the significant changes of the both studied thermal parameters in the dependence on plasters composition and age. The assessed material parameters will be stored in a material database, where will find use as an input data for computational modelling of heat transport in this type of porous building materials and evaluation of energy-savings and sustainability issues.

Climate Chamber Experiment-Based Thermal Analysis and Design Improvement of Traditional Huizhou Masonry Walls

Directory of Open Access Journals (Sweden)

Ling Dong

2018-03-01

Full Text Available Supported by thousands of years of history, traditional Huizhou buildings have played a vital role, both functionally and culturally, as residential buildings in China. Masonry walls are one of the key building components of a Huizhou building; however, the traditional Huizhou masonry wall structure, predominantly a hollow brick structure, cannot meet the local building energy code requirements, and thus needs to be improved. Within this context, the present research measures the actual thermal performance of traditional Huizhou masonry walls for historical buildings and new-built buildings, which results in mean thermal transmittances of 1.892 W/m2·K and 2.821 W/m2·K, respectively, while the local building energy code requires a minimum thermal transmittance of 1.500 W/m2·K. In order to improve the thermal performance of traditional Huizhou masonry walls, four design scenarios for wall insulation are proposed and tested in a climate chamber: (1 hollow brick wall with inorganic interior insulation mortar, (2 solid brick wall with inorganic interior insulation mortar, (3 hollow brick wall with foamed concrete, and (4 hollow brick wall with foamed concrete plus inorganic interior insulation mortar. The experiment results indicate that, among the four proposed design scenarios, only scenario 4 can significantly improve the thermal performance of Huizhou masonry walls and meet the building energy code requirements, with a mean thermal transmittance of 1.175 W/m2·K. This research lays the foundation for improving the thermal performance of Huizhou masonry walls with new insulation and construction technology, thereby helping to improve the quality of life of Huizhou residents while respecting the cultural significance of the traditional Huizhou building.

加气混凝土制备工艺影响因素分析%Analysis of Influential Factors on Preparation of Autoclaved Aerated Concrete

Institute of Scientific and Technical Information of China (English)

罗立群; 程琪林

2015-01-01

Aimed at new requirements brought up by domestic building material market, autoclaved aerated concrete has been acclaimed owning to its several particular performance advantages such as lightweight, thermal insulation, acoustic insulation, anti-seismic, etc. After preparation process of auto-claved aerated concrete was briefly summarized, it focused on influence of material characteristics on the properties of the products such as siliceous material, calcareous material, vesicant, water-solid ratio and ad-ditives. Influence mechanism of curing conditions of green body, reaction process of preparation and prod-ucts microstructure on performance of autoclaved aerated concrete were introduced. Eventually, direction of development of autoclaved aerated concrete was prospected in the future.%针对建材市场节能环保产品的需求，加气混凝土制品以其独特的质轻节能、保温隔热、抗震隔音等综合性能优势而备受关注。简述了蒸压加气混凝土的制备过程，重点阐述了制备加气混凝土砌块的硅质材料、钙质材料、发气剂、水料比及添加物等物料特性对制品性能的影响，介绍了坯体养护条件、制备过程反应以及制品微观结构对加气混凝土性能的影响机理，展望了加气混凝土未来的发展方向。

Non-linear thermal optimization and design improvement of a new internal light concrete multi-holed brick walls by FEM

Energy Technology Data Exchange (ETDEWEB)

Del Coz Diaz, J.J.; Suarez Sierra, J.L.; Penuelas Sanchez, I. [Edificio Departamental Viesques, No. 7-33204 Gijon, Asturias (Spain); Garcia Nieto, P.J. [Departamento de Matematicas, Facultad de Ciencias, C/Calvo Sotelo s/n, 33007 Oviedo, Asturias (Spain)

2008-06-15

The aim of this work was carried out the optimization and numerical study by the finite element method of internal hollow bricks walls in order to determine the best candidate brick from the thermal point of view. With respect to the energy saving for housing and industrial structures, there is also a great interest in light building materials with good physical and thermal behaviors, which fulfills all thermal requirements of the new CTE Spanish rule. The conduction, convection and radiation phenomena are taking into account in this study for six different types of bricks varying the material conductivity obtained from five experimental tests. Mathematically, the non-linearity is due to the radiation boundary condition inside the inner recesses of the bricks. Optimization of the walls is carried out from the finite element analysis of the new hollow brick geometries by means of the average mass overall thermal efficiency and the equivalent thermal conductivity. Based on the previous thermal analysis and the optimization procedure described in this paper, the best candidate was chosen and then a full 1.22 x 0.23 x 1.05 m wall made of these bricks was simulated for fifteen different compositions. The main variables influencing the thermal conductivity of these walls are illustrated for different concrete and mortar properties and the temperature distribution is shown for some typical configurations. Finally, in order to select the appropriate wall satisfying the CTE requirements, detailed instructions are given and conclusions of this work are exposed. (author)

Recycling of rubble from building demolition for low-shrinkage concretes.

Science.gov (United States)

Corinaldesi, Valeria; Moriconi, Giacomo

2010-04-01

In this project concrete mixtures were prepared that were characterized by low ductility due to desiccation by using debris from building demolition, which after a suitable treatment was used as aggregate for partial replacement of natural aggregates. The recycled aggregate used came from a recycling plant, in which rubble from building demolition was selected, crushed, cleaned, sieved, and graded. Such aggregates are known to be more porous as indicated by the Saturated Surface Dry (SSD) moisture content. The recycled concrete used as aggregates were added to the concrete mixture in order to study their influence on the fresh and hardened concrete properties. They were added either after water pre-soaking or in dry condition, in order to evaluate the influence of moisture in aggregates on the performance of concrete containing recycled aggregate. In particular, the effect of internal curing, due to the use of such aggregates, was studied. Concrete behavior due to desiccation under dehydration was studied by means of both drying shrinkage test and German angle test, through which shrinkage under the restrained condition of early age concrete can be evaluated. Copyright 2009 Elsevier Ltd. All rights reserved.

Soft impact testing of a wall-floor-wall reinforced concrete structure

Energy Technology Data Exchange (ETDEWEB)

Vepsä, Ari, E-mail: ari.vepsa@vtt.fi; Calonius, Kim; Saarenheimo, Arja; Aatola, Seppo; Halonen, Matti

2017-01-15

Highlights: • A wall-floor-wall reinforced concrete structure was built. • The structure was subjected to three almost identical soft impact tests. • Response was measured with accelerometers, displacement sensors and strain gauges. • Modal tests was also carried out with the same structure in different conditions. • The results are meant to be used for validation of computational methods and models. - Abstract: Assessing the safety of the reactor building of a nuclear power plant against the crash of an airplane calls for valid computational tools such as finite element models and material constitutive models. Validation of such tools and models in turn calls for reliable and relevant experimental data. The problem is that such data is scarcely available. One of the aspects of such a crash is vibrations that are generated by the impact. These vibrations tend to propagate from the impact point to the internal parts of the building. If strong enough, these vibrations may cause malfunction of the safety-critical equipment inside the building. To enable validation of computational models for this type of behaviour, we have conducted a series of three tests with a wall-floor-wall reinforced concrete structure under soft impact loading. The response of the structure was measured with accelerometers, displacement sensors and strain gauges. In addition to impact tests, the structure was subjected to modal tests under different conditions. The tests yielded a wealth of useful data for validation of computational models and better understanding about shock induced vibration physics especially in reinforced concrete structures.

Moisture Management for High R-Value Walls

Energy Technology Data Exchange (ETDEWEB)

Lepage, R.; Schumacher, C.; Lukachko, A.

2013-11-01

The following report explains the moisture-related concerns for High R-value wall assemblies and discusses past Building America research work that informs this study. Hygrothermal simulations were prepared for several common approaches to High R-value wall construction in six cities (Houston, Atlanta, Seattle, St. Louis, Chicago, and International Falls) representing a range of climate zones (2, 3, 4C, 4, 5A, and 7, respectively). The simulations are informed by experience gained from past research in this area and validated by field measurement and forensic experience. The modeling program was developed to assess the moisture durability of the wall assemblies based on three primary sources of moisture: construction moisture, air leakage condensation, and bulk water leakage. The peak annual moisture content of the wood based exterior sheathing was used to comparatively analyze the response to the moisture loads for each of the walls in each given city. Walls which experienced sheathing moisture contents between 20% and 28% were identified as risky, whereas those exceeding 28% were identified as very high risk. All of the wall assemblies perform well under idealized conditions. However, only the walls with exterior insulation, or cavity insulation which provides a hygrothermal function similar to exterior insulation, perform adequately when exposed to moisture loads. Walls with only cavity insulation are particularly susceptible to air leakage condensation. None of the walls performed well when a precipitation based bulk water leak was introduced to the backside of the sheathing, emphasizing the importance of proper flashing details.

The influence of ventilation on moisture conditions in facades with wooden cladding

DEFF Research Database (Denmark)

Hansen, Ernst Jan de Place; Brandt, Erik

2009-01-01

A ventilated cavity behind the cladding of timber frame walls is often considered good building practice that facilitates the removal of moisture from the construction. However, moisture will only be removed from the construction by ventilating it with dry air, whereas ventilating with humid air...... might add moisture to the construction. Full-size wall elements with wooden cladding placed in a test building were exposed to natural climate on the outside and to a humid indoor climate on the inside. Temperature and moisture conditions inside the wall elements and climate parameters were monitored...

THE COMPARATIVE ANALYSIS OF UNHEATED INDUSTRIAL FARM BUILDINGS WALLING FROM THE POSITION OF THEIR HYDRAULIC CONDUCTIVITY

Directory of Open Access Journals (Sweden)

Елена Владимировна Чиркова

2017-05-01

Full Text Available The specificity of dynamics of parametric configuration of microclimate of the agricultural production buildings are considered in the article. The probability of the whole-year exploitation of these category buildings without a heating is validated. The comparison characteristics of moisture permeability properties of reinforced concrete and wood are cited. When designing the necessity of calculation and choice of walling structure subject to the penetration of moisture is showed.

Investigations for determining temperature, pressure and moisture distributions in concrete at high temperatures

International Nuclear Information System (INIS)

Weber, A.; Kamp, C.L.

1987-01-01

The paper gives a report on the test program. The main objective of the tests was the determination of the temperature and moisture fields decisive for the corrosion conditions, which are built up behind the liner in the range of the heated concrete. The determination of transport characteristics of the concrete are another objective. Small concrete specimens are used to determine the following data: Thermal conductivity, heat capacity, diffusion coefficient for liquid water, steam and air, steam sorption therms. The chemical shrinkage of the concrete as a function of moisture and temperature is being evaluated by means of tests and calculations. (orig./HP)

Development of Latent Heat Storage Phase Change Material Containing Plaster

Directory of Open Access Journals (Sweden)

Diana BAJARE

2016-05-01

Full Text Available This paper reviews the development of latent heat storage Phase Change Material (PCM containing plaster as in passive application. Due to the phase change, these materials can store higher amounts of thermal energy than traditional building materials and can be used to add thermal inertia to lightweight constructions. It was shown that the use of PCMs have advantages stabilizing the room temperature variations during summer days, provided sufficient night ventilation is allowed. Another advantage of PCM usage is stabilized indoor temperature on the heating season. The goal of this study is to develop cement and lime based plaster containing microencapsulated PCM. The plaster is expected to be used for passive indoor applications and enhance the thermal properties of building envelope. The plaster was investigated under Scanning Electron Microscope and the mechanical, physical and thermal properties of created plaster samples were determined.

Emission of ammonia from indoor concrete wall and assessment of human exposure.

Science.gov (United States)

Bai, Z; Dong, Y; Wang, Z; Zhu, T

2006-04-01

Addition of urea-based antifreeze admixtures during cement mixing can make it possible to produce concrete cement in construction of buildings in cold weather; this, however, has led to increasing indoor air pollution due to continuous transformation and emission from urea to gaseous ammonia in indoor concrete wall. It is believed that ammonia is harmful to human body and exposure to ammonia can cause some serious symptoms such as headaches, burns, and even permanent damage to the eyes and lungs. In order to understand the emission of ammonia from indoor concrete wall in civil building and assess the health risk of people living in these buildings, the experimental pieces of concrete wall were first prepared by concreting cement and urea-based antifreeze admixtures to simulate the indoor wall in civil building in this work. Then environmental chamber was adopted for studying the effect of temperature, relative humility and air exchange rate on emission of ammonia from experimental pieces of concrete wall. Also the field experiment was made at selected rooms in given civil buildings. Exposure and potential dose of adult and children exposed to indoor/outdoor ammonia in summer and in winter are calculated and evaluated by using Scenario Evaluation Approach. The results indicated that high air exchange rate leads to decreased ammonia concentration, and elevation of temperature causes increasing ammonia concentration and volatilizing rate in chamber. The complete emission of ammonia from the wall containing urea-based antifreeze admixtures needs more than 10 years in general. Ventilating or improving air exchange can play a significant role in reducing ammonia concentration in actual rooms in field experiments. Urea-based antifreeze admixtures in concrete wall can give rise to high exposure and potential dose, especially in summer. Generally, adults have a high potential dose than children, while children have personal average dose rate beyond adults in the same

Characterization of a lime-pozzolan plaster containing phase change material

International Nuclear Information System (INIS)

Pavlíková, Milena; Pavlík, Zbyšek; Trník, Anton; Pokorný, Jaroslav; Černý, Robert

2015-01-01

A PCM (Phase Change Material) modified lime-pozzolan plaster for improvement of thermal energy storage of building envelopes is studied in the paper. The investigated plaster is composed of lime hydrate, pozzolan admixture based on metakaolin and mudstone, silica sand, water and paraffin wax encapsulated in polymer capsule. The reference plaster without PCM application is studied as well. The analyzed materials are characterized by bulk density, matrix density, total open porosity, compressive strength and pore size distribution. The temperature of phase change, heat of fusion and crystallization are studied using DSC (Difference Scanning Calorimetry) analysis performed in air atmosphere. In order to get information on materials hygrothermal performance, determination of thermal and hygric properties is done in laboratory conditions. Experimental data reveal a substantial improvement of heat storage capacity of PCM-modified plaster as compared to the reference material without PCM

Investigation of the Effective Thermal Conductivity in Containment Wall of OPR1000

Energy Technology Data Exchange (ETDEWEB)

Noh, Hyung Gyun [Pohang University, Pohang (Korea, Republic of); Lee, Jong Hwi; Kang, Hie Chan [Kunsan National University, Gunsan (Korea, Republic of)

2016-05-15

Many computational codes used for analyzing pressure of containment was developed such as CAP (Containment Analysis Package). These computational codes consider concrete conductivity instead of thermal conductivity of containment wall which have special geometry as heat sink. For precise analysis, effective thermal conductivity of containment wall has to be measured in individual NPPs. Thermal properties of concrete such as thermal conductivity have been investigated as function of chemical composition and temperature. Generally, containment of OPR1000 is constructed by Prestressed (PS) concrete-a composite material. Containment wall of OPR1000 is made up of steel liner, tendon, rebar and concrete as shown in Figure 1. Role of steel liner protects release of radioactive materials so called leak tightness. The effective thermal conductivity of containment wall in OPR1000 is analyzed by numerical tool (CFD) and compared with thermal conductivity models in composite solids. The effective thermal conductivity of containment wall of OPR1000 is investigated by numerical analysis (CFD). The thermal conductivity of reinforced concrete is 18.6% higher than that of concrete only. Several models were compared with CFD results. Rayleigh-Parallel liner model agrees well with CFD results. Experiment results will be compared with CFD result and models. CFD result was calculated in low steel volume fraction (0.0809) than that of OPR1000 (0.1043). The effective thermal conductivity in OPR1000 has slightly higher than CFD result because of different volume fraction.

Effect of thermal mass on life cycle primary energy balances of a concrete- and a wood-frame building

International Nuclear Information System (INIS)

Dodoo, Ambrose; Gustavsson, Leif; Sathre, Roger

2012-01-01

Highlights: ► The effect of thermal mass on life cycle primary energy balance of concrete and wood building is analyzed. ► A concrete building has slightly lower space heating demand than a wood alternative. ► Still, a wood building has a lower life cycle primary energy use than a concrete alternative. ► The influence of thermal mass on space heating energy use for buildings in Nordic climate is small. -- Abstract: In this study we analyze the effect of thermal mass on space heating energy use and life cycle primary energy balances of a concrete- and a wood-frame building. The analysis includes primary energy use during the production, operation, and end-of-life phases. Based on hour-by-hour dynamic modeling of heat flows in building mass configurations we calculate the energy saving benefits of thermal mass during the operation phase of the buildings. Our results indicate that the energy savings due to thermal mass is small and varies with the climatic location and energy efficiency levels of the buildings. A concrete-frame building has slightly lower space heating demand than a wood-frame alternative, due to the higher thermal mass of concrete-based materials. Still, a wood-frame building has a lower life cycle primary energy balance than a concrete-frame alternative. This is due primarily to the lower production primary energy use and greater bioenergy recovery benefits of the wood-frame buildings. These advantages outweigh the energy saving benefits of thermal mass. We conclude that the influence of thermal mass on space heating energy use for buildings located in Nordic climate is small and that wood-frame buildings with cogeneration based district heating would be an effective means of reducing primary energy use in the built environment.

Novel dynamic thermal characterization of multifunctional concretes with microencapsulated phase change materials

Science.gov (United States)

Pisello, Anna Laura; Fabiani, Claudia; D'Alessandro, Antonella; Cabeza, Luisa F.; Ubertini, Filippo; Cotana, Franco

2017-04-01

Concrete is widely applied in the construction sector for its reliable mechanical performance, its easiness of use and low costs. It also appears promising for enhancing the thermal-energy behavior of buildings thanks to its capability to be doped with multifunctional fillers. In fact, key studies acknowledged the benefits of thermally insulated concretes for applications in ceilings and walls. At the same time, thermal capacity also represents a key property to be optimized, especially for lightweight constructions. In this view, Thermal-Energy Storage (TES) systems have been recently integrated into building envelopes for increasing thermal inertia. More in detail, numerical experimental investigations showed how Phase Change materials (PCMs), as an acknowledged passive TES strategy, can be effectively included in building envelope, with promising results in terms of thermal buffer potentiality. In particular, this work builds upon previous papers aimed at developing the new PCM-filled concretes for structural applications and optimized thermalenergy efficiency, and it is focused on the development of a new experimental method for testing such composite materials in thermal-energy dynamic conditions simulated in laboratory by exposing samples to environmentally controlled microclimate while measuring thermal conductivity and diffusivity by means of transient plane source techniques. The key findings show how the new composites are able to increasingly delay the thermal wave with increasing the PCM concentration and how the thermal conductivity varies during the course of the phase change, in both melting and solidification processes. The new analysis produces useful findings in proposing an effective method for testing composite materials with adaptive thermal performance, much needed by the scientific community willing to study building envelopes dynamics.

Infrared survey of 50 buildings constructed during 100 years: thermal performances and damage conditions

Science.gov (United States)

Ljungberg, Sven-Ake

1995-03-01

Different building constructions and craftsmanship give rise to different thermal performance and damage conditions. The building stock of most industrial countries consists of buildings of various age, and constructions, from old historic buildings with heavy stone or wooden construction, to new buildings with heavy or light concrete construction, or modern steel or wooden construction. In this paper the result from a detailed infrared survey of 50 buildings from six Swedish military camps is presented. The presentation is limited to a comparison of thermal performance and damage conditions of buildings of various ages, functions, and constructions, of a building period of more than 100 years. The result is expected to be relevant even to civilian buildings. Infrared surveys were performed during 1992-1993, with airborne, and mobile short- and longwave infrared systems, out- and indoor thermography. Interpretation and analysis of infrared data was performed with interactive image and analyzing systems. Field inspections were carried out with fiber optics system, and by ocular inspections. Air-exchange rate was measured in order to quantify air leakages through the building envelope, indicated in thermograms. The objects studied were single-family houses, barracks, office-, service-, school- and exercise buildings, military hotels and restaurants, aircraft hangars, and ship factory buildings. The main conclusions from this study are that most buildings from 1880 - 1940 have a solid construction with a high quality of craftsmanship, relatively good thermal performance, due to extremely thick walls, and adding insulation at the attic floor. From about 1940 - 1960 the quality of construction, thermal performance and craftsmanship seem to vary a lot. Buildings constructed during the period of 1960 - 1990 have in general the best thermal performance due to a better insulation capacity, however, also one finds here the greatest variety of problems. The result from this

Studies on use of Copper Slag as Replacement Material for River Sand in Building Constructions

Science.gov (United States)

Madheswaran, C. K.; Ambily, P. S.; Dattatreya, J. K.; Rajamane, N. P.

2014-09-01

This work focuses on the use of copper slag, as a partial replacement of sand for use in cement concrete and building construction. Cement mortar mixtures prepared with fine aggregate made up of different proportions of copper slag and sand were tested for use as masonry mortars and plastering. Three masonry wall panels of dimensions 1 × 1 m were plastered. The studies showed that although copper slag based mortar is suitable for plastering, with the increase in copper slag content, the wastage due to material rebounding from the plastered surfaces increases. It is therefore suggested that the copper slag can be used for plastering of floorings and horizontal up to 50 % by mass of the fine aggregate, and for vertical surfaces, such as, brick/block walls it can be used up to 25 %. In this study on concrete mixtures were prepared with two water cement ratios and different proportions of copper slag ranging from 0 % (for the control mix) to 100 % of fine aggregate. The Concrete mixes were evaluated for workability, density, and compressive strength.

Special protective concretes

International Nuclear Information System (INIS)

Bouniol, P.

2001-01-01

Concrete is the most convenient material when large-scale radiation protection is needed. Thus, special concretes for nuclear purposes are used in various facilities like reactors, reprocessing centers, storage sites, accelerators, hospitals with nuclear medicine equipment, food ionization centers etc.. The recent advances made in civil engineering for the improvement of concrete durability and compactness are for a large part transposable to protection concretes. This article presents the basic knowledge about protection concretes with the associated typological and technological aspects. A large part is devoted to the intrinsic properties of concretes and to their behaviour in irradiation and temperature conditions: 1 - definition and field of application of special protective concretes; 2 - evolution of concepts and technologies (durability of structures, techniques of formulation, new additives, market evolution); 3 - design of protective structures (preliminary study, radiation characteristics, thermal constraints, damping and dimensioning, mechanical criteria); 4 - formulation of special concretes (general principles, granulates, hydraulic binders, pulverulent additives, water/cement ratio, reference composition of some special concretes); 5 - properties of special concretes (damping and thermo-mechanical properties); 6 - induced-irradiation and temperature phenomena (activation, radiolysis, mineralogical transformations, drying, shrinking, creep, corrosion of reinforcement). (J.S.)

Prestressed concrete reactor vessel thermal cylinder model study

International Nuclear Information System (INIS)

Callahan, J.P.; Canonico, D.A.; Richardson, M.; Corum, J.M.; Dodge, W.G.; Robinson, G.C.; Whitman, G.D.

1977-01-01

The thermal cylinder experiment was designed both to provide information for evaluating the capability of analytical methods to predict the time-dependent stress-strain behavior of a 1 / 6 -scale model of the barrel section of a single-cavity prestressed concrete reactor vessel and to demonstrate the structural behavior under design and off-design thermal conditions. The model was a thick-walled cylinder having a height of 1.22 m, a thickness of 0.46 m, and an outer diameter of 2.06 m. It was prestressed both axially and circumferentially and subjected to 4.83 MPa internal pressure together with a thermal crossfall imposed by heating the inner surface to 338.8 K and cooling the outer surface to 297.1 K. The initial 460 days of testing were divided into time periods that simulated prestressing, heatup, reactor operation, and shutdown. At the conclusion of the simulated operating period, the model was repressurized and subjected to localized heating at 505.4 K for 84 days to produce an off-design hot-spot condition. Comparisons of experimental data with calculated values obtained using the SAFE-CRACK finite-element computer program showed that the program was capable of predicting time-dependent behavior in a vessel subjected to normal operating conditions, but that it was unable to accurately predict the behavior during off-design hot-spot heating. Readings made using a neutron and gamma-ray backscattering moisture probe showed little, if any, migration of moisture in the concrete cross section. Destructive examination indicated that the model maintained its basic structural integrity during localized hot-spot heating

Thermal effects, creep and nonlinear responde of concrete reactor vessels

International Nuclear Information System (INIS)

Bazant, Z.P.

1978-01-01

A new mathematical model for prediction of pore pressure and moisture transfer in concrete heated well beyond 100 0 C is outlined. The salient features of the model are:(1) the hypothesis taht the pore space available to capillary water grows with increasing temperature as well as increasing pressure in excess of saturation pressure, and (2) the hypothesis that moisture permeability increases by two orders of magnitude when passing 100 0 C. Permaability below 100 0 C is controlled by migration of adsorbed water through gel-pore sized necks on passages through the material; these necks are lost above 100 0 C and viscosity then governs. The driving force of moisture transfer may be considered as the gradient of pore pressure, which is defined as pressure of vapor rather than liquid water if concrete is not saturated. Thermodynamic properties of water may be used to determine sorption isotherms in saturated concrete. The theory is the necessary first step in rationally predicting thermal stresses and deformations, and assessing the danger of explosive spalling. However, analysis of creep and nonlinear triaxial behavior is also needed for this purpose. A brief review of recent achievements in these subjects is also given. (Author)

Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

International Nuclear Information System (INIS)

Ferretti, D.; Michelini, E.; Rosati, G.

2015-01-01

The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM

Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

Energy Technology Data Exchange (ETDEWEB)

Ferretti, D., E-mail: daniele.ferretti@unipr.it [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, P.co Area delle Scienze 181/A, 43124 Parma (Italy); Michelini, E. [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, P.co Area delle Scienze 181/A, 43124 Parma (Italy); Rosati, G. [Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano (Italy)

2015-01-15

The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM.

UNDERGROUND AIR DUCT TO CONTROL RISING MOISTURE IN HISTORIC BUILDINGS: IMPROVED DESIGN AND ITS DRYING EFFICIENCY

Directory of Open Access Journals (Sweden)

Jiří Pazderka

2017-10-01

Full Text Available The underground air ducts along peripheral walls of a building are a remediation method, which principle is to enable an air flow along the moist building structure’s surface to allow a sufficient evaporation of moisture from the structure. This measure reduces the water transport (rising moisture into the higher parts of the wall where the high water content in masonry is undesirable. Presently, underground air ducts are designed as masonry structures, which durability in contact with ground moisture is limited. The article describes a new design of an underground air duct, which is based on specially shaped concrete blocks (without wet processes, because the blocks are completely precast. The air duct from concrete blocks is situated completely below the ground surface (exterior or below the floor (interior. Thanks to this, the system is invisible and does not disturb the authentic look of rehabilitated historic buildings. The efficiency of the air duct technical solution was verified by the results of tests (based on the measured moisture values conducted on a laboratory model. The experimental study showed that the moisture in the masonry equipped with the presented underground air duct had decreased considerably compared to the reference sample, namely by 43 % on average. The experimental study was numerically validated through numerical simulations performed with the program WUFI 2D.

Measuring of the moisture content in brick walls of historical buildings - the overview of methods

Science.gov (United States)

Hola, A.

2017-10-01

The paper deals with the issue of measuring the moisture content of brick walls in buildings of high historical value. It includes a classification of known methods used to measure the moisture content and their valorisation with regards to the legitimacy of using them in historical buildings. Moreover, the most important considerations for conducting such measurements are also described, which include the choice of an appropriate method for a specific situation, the determination of a correlative or hypothetical dependency for equipment used in tests and also the method of distributing measurement points.

Empirical Validation of Heat Transfer Performance Simulation of Graphite/PCM Concrete Materials for Thermally Activated Building System

Directory of Open Access Journals (Sweden)

Jin-Hee Song

2017-01-01

Full Text Available To increase the heat capacity in lightweight construction materials, a phase change material (PCM can be introduced to building elements. A thermally activated building system (TABS with graphite/PCM concrete hollow core slab is suggested as an energy-efficient technology to shift and reduce the peak thermal load in buildings. An evaluation of heat storage and dissipation characteristics of TABS in graphite/PCM concrete has been conducted using dynamic simulations, but empirical validation is necessary to acceptably predict the thermal behavior of graphite/PCM concrete. This study aimed to validate the thermal behavior of graphite/PCM concrete through a three-dimensional transient heat transfer simulation. The simulation results were compared to experimental results from previous studies of concrete and graphite/PCM concrete. The overall thermal behavior for both materials was found to be similar to experiment results. Limitations in the simulation modeling, which included determination of the indoor heat transfer coefficient, assumption of constant thermal conductivity with temperature, and assumption of specimen homogeneity, led to slight differences between the measured and simulated results.

Degradation of atrazine and isoproturon in surface and sub-surface soil materials undergoing different moisture and aeration conditions.

Science.gov (United States)

Issa, Salah; Wood, Martin

2005-02-01

The influence of different moisture and aeration conditions on the degradation of atrazine and isoproturon was investigated in environmental samples aseptically collected from surface and sub-surface zones of agricultural land. The materials were maintained at two moisture contents corresponding to just above field capacity or 90% of field capacity. Another two groups of samples were adjusted with water to above field capacity, and, at zero time, exposed to drying-rewetting cycles. Atrazine was more persistent (t(1/2) = 22-35 days) than isoproturon (t(1/2) = 5-17 days) in samples maintained at constant moisture conditions. The rate of degradation for both herbicides was higher in samples maintained at a moisture content of 90% of field capacity than in samples with higher moisture contents. The reduction in moisture content in samples undergoing desiccation from above field capacity to much lower than field capacity enhanced the degradation of isoproturon (t(1/2) = 9-12 days) but reduced the rate of atrazine degradation (t(1/2) = 23-35 days). This demonstrates the variability between different micro-organisms in their susceptibility to desiccation. Under anaerobic conditions generated in anaerobic jars, atrazine degraded much more rapidly than isoproturon in materials taken from three soil profiles (0-250 cm depth). It is suggested that some specific micro-organisms are able to survive and degrade herbicide under severe conditions of desiccation. Copyright (c) 2005 Society of Chemical Industry.

Study of air and steam leak rate through damaged concrete wall

International Nuclear Information System (INIS)

Abdeslam Laghcha; Gerard Debicki; Benoit Masson

2005-01-01

Full text of publication follows: The leak rate prediction of air and steam through a cracked concrete wall is an extremely important issue in assessing the safety of nuclear reactor containment building. Furthermore the relation between air leak rate and steam leak rate on the same wall could have some interest for safety prediction. This laboratory study investigates the transfer of fluids through a wall of 1.3 m of thickness, with a focus on two cases: one on a mechanically damaged concrete by compressive stress and another one on a crossing artificial flaw in a construction joint realized in the concrete specimen (cylindrical / section 0.1925 m 2 / length 1.3 m). The both specimens were made of ordinary concrete (compressive strength: 35 MPa). To initiate residual compressive cracks, the specimen (A) was loaded in compression under controlled strains until a level of 90% of the failure strain was reached. To create a crossing artificial flaw in a construction joint, the concrete was set in the mould in two times, the second time, a water saturated sand bed was placed on the surface of the hardened concrete to realize the flaw along a diameter of the specimen (B). The permeability of damaged concrete wall was studied comparatively under two conditions, but without appreciable stresses applied on. The first condition was at ambient temperature, a reference test of permeability, with dry air, gave the characteristics of permeability and the type of flow through the specimen. In this case, the used method consisted to proceed by stages. The imposed pressures on the exposed face were successively 0.1, 0.18, 0.23, 0.28, 0.34 and 0.42 MPa, the other face was at atmospheric pressure. The second condition was an accidental scenario with simultaneous effects of temperature and gas (a mix of air and steam) pressure applied on a face, the other one remaining at atmospheric pressure and temperature. During the test, the lateral face of the cylindrical specimen was thermally

Reinforced concrete wall under hydrogen detonation

International Nuclear Information System (INIS)

Saarenheimo, A.

2000-11-01

The structural integrity of a reinforced concrete wall in the BWR reactor building under hydrogen detonation conditions has been analysed. Of particular interest is whether the containment integrity can be jeopardised by an external hydrogen detonation. The load carrying capacity of a reinforced concrete wall was studied. The detonation pressure loads were estimated with computerised hand calculations assuming a direct initiation of detonation and applying the strong explosion theory. The results can be considered as rough and conservative estimates for the first shock pressure impact induced by a reflecting detonation wave. Structural integrity may be endangered due to slow pressurisation or dynamic impulse loads associated with local detonations. The static pressure following the passage of a shock front may be relatively high, thus this static or slowly decreasing pressure after a detonation may damage the structure severely. The mitigating effects of the opening of a door on pressure history and structural response were also studied. The non-linear behaviour of the wall was studied under detonations corresponding a detonable hydrogen mass of 0.5 kg and 1.428 kg. Non-linear finite element analyses of the reinforced concrete structure were carried out by the ABAQUS/Explicit program. The reinforcement and its non-linear material behaviour and the tensile cracking of concrete were modelled. Reinforcement was defined as layers of uniformly spaced reinforcing bars in shell elements. In these studies the surrounding structures of the non-linearly modelled reinforced concrete wall were modelled using idealised boundary conditions. Especially concrete cracking and yielding of the reinforcement was monitored during the numerical simulation. (au)

Effect of aeration rate, moisture content and composting period on availability of copper and lead during pig manure composting.

Science.gov (United States)

Shen, Yujun; Zhao, Lixin; Meng, Haibo; Hou, Yueqing; Zhou, Haibin; Wang, Fei; Cheng, Hongsheng; Liu, Hongbin

2016-06-01

Pollution by heavy metals, such as copper and lead, has become a limiting factor for the land application of faecal manures, such as pig manure. This study was conducted to investigate the influence of composting process parameters, including aeration rate, moisture content and composting period, on the distribution of heavy metal species during composting, and to select an optimal parameter for copper and lead inactivation. Results showed that the distribution ratios of exchangeable fractions of copper and lead had a bigger decrease under conditions of aeration rate, 0.1 m(3) min(-1) m(-3), an initial moisture content of 65% and composting period of 50 days. Suboptimal composting process conditions could lead to increased availability of heavy metals. Statistical analysis indicated that the aeration rate was the main factor affecting copper and lead inactivation, while the effects of moisture content and composting period were not significant. The rates of reduction of copper-exchangeable fractions and lead-exchangeable fractions were positively correlated with increased pH. The optimal parameters for reducing heavy metal bioavailability during pig manure composting were aeration rate, 0.1 m(3) min(-1) m(-3), initial moisture content, 65%, and composting period, 20 days. © The Author(s) 2016.

Moisture conditions of modern structures made of autoclaved aerated concrete in operation period

OpenAIRE

P.S. Zyryanov; G.I. Grinfeld; Р.A. Morozov; I.A. Sogomonyan

2011-01-01

In St.-Petersburg and area six organizations making cellular concrete of autoclave hardening operate. At all enterprises the cellular concrete is made by the gas way of pore development by molding technology. The molding technology in practice means that the mass humidity of concrete on an exit from autoclaves will be at level of 35-45 % (great values of humidity correspond to smaller density). The similar situation is observed in other regions: more than 80 % of all autoclave cellular concre...

The effects of moisture and temperature variations on the long term durability of polymer concrete

DEFF Research Database (Denmark)

Barbosa, Ricardo; Hansen, Kurt Kielsgaard; Grelk, Bent

2013-01-01

The use of polymer concrete to precast products in construction presents normally many advantages compared to traditional concrete. Higher strength, lower permeability, shorter curing periods, better chemical resistances and a better durability is normally predicated, however this is a research...... and after exposure to different thermal conditions is very important. In this paper, an experimental study concerning the influence of temperature and moisture in cyclic conditions on the durability of polymer concrete based on an unsaturated polyester resin is described and the results are presented...

Moisture Management for High R-Value Walls

Energy Technology Data Exchange (ETDEWEB)

Lepage, R. [Building Science Corporation, Somerville, MA (United States); Schumacher, C. [Building Science Corporation, Somerville, MA (United States); Lukachko, A. [Building Science Corporation, Somerville, MA (United States)

2013-11-01

This report explains the moisture-related concerns for high R-value wall assemblies and discusses past Building America research work that informs this study. In this project, hygrothermal simulations were prepared for several common approaches to High R-value wall construction in six cities (Houston, Atlanta, Seattle, St. Louis, Chicago, and International Falls) representing a range of climate zones. The modeling program assessed the moisture durability of the wall assemblies based on three primary sources of moisture: construction moisture, air leakage condensation, and bulk water leakage; the report presents results of the study.

Innovative Lime Pozzolana Renders for Reconstruction of Historical Buildings

International Nuclear Information System (INIS)

Vejmelkova, E.; Maca, P.; Konvalinka, P.; Cerny, R.

2011-01-01

Bulk density, matrix density, open porosity, compressive strength, bending strength, water sorptivity, moisture diffusivity, water vapor diffusion coefficient, thermal conductivity, specific heat capacity and thermal diffusivity of two innovative renovation renders on limepozzolana basis are analyzed. The obtained results are compared with reference lime plaster and two commercial renovation renders, and conclusions on the applicability of the particular renders in practical reconstruction works are drawn. (author)

Future-proofing the environmental performance of low-income housing: a South African case study

CSIR Research Space (South Africa)

Ampofo-Anti, NL

2012-09-01

Full Text Available on stabilised fill ? Superstructure: Modular, hollow concrete blocks; and precast concrete window frames (applied to four out of seven windows to minimise thermal bridging). ? Finishes: Insulated ceiling board; and thermal plaster to external walls Three... performance of CH: ? Appropriate north-south orientation; ? Appropriate roof overhang combined with north-facing windows; ? Cavity walls (modular, hollow concrete blocks); ? Insulated ceiling; and ? Insulated external walls (thermal plaster). The study...

Delamination of plasters applied to historical masonry walls: analysis by acoustic emission technique and numerical model

Science.gov (United States)

Grazzini, A.; Lacidogna, G.; Valente, S.; Accornero, F.

2018-06-01

Masonry walls of historical buildings are subject to rising damp effects due to capillary or rain infiltrations, which in the time produce decay and delamination of historical plasters. In the restoration of masonry buildings, the plaster detachment frequently occurs because of mechanical incompatibility in repair mortar. An innovative laboratory procedure is described for test mechanical adhesion of new repair mortars. Compression static tests were carried out on composite specimens stone block-repair mortar, which specific geometry can test the de-bonding process of mortar in adherence with a stone masonry structure. The acoustic emission (AE) technique was employed for estimating the amount of energy released from fracture propagation in adherence surface between mortar and stone. A numerical simulation was elaborated based on the cohesive crack model. The evolution of detachment process of mortar in a coupled stone brick-mortar system was analysed by triangulation of AE signals, which can improve the numerical model and predict the type of failure in the adhesion surface of repair plaster. Through the cohesive crack model, it was possible to interpret theoretically the de-bonding phenomena occurring at the interface between stone block and mortar. Therefore, the mechanical behaviour of the interface is characterized.

PRE-CAST WALL PRODUCTS MADE FROM LIGHTWEIGHT CONCRETE FOR ENCLOSING STRUCTURES OF BUILDINGS

Directory of Open Access Journals (Sweden)

M. R. Hadgiev

2014-01-01

Full Text Available The paper is devoted to the actual problem waste dismantling of buildings and structures in the form of brick waste with reception the secondary fine and coarse aggregate and concrete based on them for the manufacture of small-piece wall products. 

Experimental performance evaluation of solid concrete and dry insulation materials for passive buildings in hot and humid climatic conditions

International Nuclear Information System (INIS)

Rehman, Hassam Ur

2017-01-01

Highlights: • Experimental investigation of building insulation materials in UAE from 2012–2014. • Four same calorimeters with different south walls were built in open air laboratory. • Heat flux was reduced by 22–75% in steady state analysis during summer by insulation. • Hence, energy consumption for cooling was reduced by an average 7.6–25.3%. • Heat flow was steady in free floating analysis in winter through insulated walls. - Abstract: It is known that enhancement of building energy efficiency can help in reducing energy consumption. The use of the solar insulating materials are the most efficient and cost effective passive methods for reducing the cooling requirements of the buildings. Apart from theoretical studies, no detailed experimental studies were performed in the UAE on energy savings by using solar insulation materials on buildings. Four (3 m × 3 m × 3 m) solar calorimeters were built in RAK, UAE in order to perform an open air outdoor test for energy savings obtained with solar insulating materials. The design is aimed to determine the heat flux reduction and the energy savings achieved with and without different solar insulating materials, mounted at the south wall of solar calorimeters with similar indoor and ambient conditions. Experimental results are discussed to evaluate the thermal performance during high temperature conditions in summer’s period when cooling demand of the building is at its peak and also in winters when there is no cooling demand. The test is from 2012 to 2014. The controlled-temperature experimental study at a set point of 24 °C showed that if the standard building material, i.e. solid concrete, is retrofitted with polyisocyanurate (PIR) and reflective coatings or completely replaced with energy-efficient dry insulation material walls such as exterior insulation finishing system (EIFS), energy savings up to an average of 7.6–25.3% can be achieved. This is due to the reduction of heat flux by an

Optimization of protection and calibration of the moisture-density gages troxler

International Nuclear Information System (INIS)

RAKOTONDRAVANONA, J.E.

2011-01-01

The purpose of this work is the implementation of the principle of optimization of the protection and calibration of moisture-density gages TROXLER. The main objectives are the application of radiation protection and the feasibility of a calibration laboratory design. The calibration of density and moisture may confirm the calibration of moisture-density gages TROXLER. The calibration of density consists of the assembly of measurements on three calibration blocks (magnesium, aluminium and magnesium/aluminium) built in the TRACKER. The value of density uncertainty is ±32 Kg.m -3 . The calibration of moisture is carried out on two calibration blocks (magnesium and magnesium/polyethylene)The value of moisture uncertainty is ±16 Kg.m -3 . The design of the laboratory returns to the dose limitation. The laboratory is designed mainly wall out of ordinary concrete, a good attenuator of the gamma radiations and neutron. For the design, the value of term source gamma is 25.77±0.20μSv.h -1 and the value of term source neutron is 7.88±0.35μSv.h -1 are used for the thickness of the walls. The importance of the design makes it possible to attenuate to the maximum doses and rates dose until the total absorption of the radiations. [fr

Flexural Behaviour of Precast Aerated Concrete Panel (PACP with Added Fibrous Material: An Overview

Directory of Open Access Journals (Sweden)

Abdul Rahim Noor Hazlin

2017-01-01

Full Text Available The usage of precast aerated concrete panel as an IBS system has become the main alternative to conventional construction system. The usage of this panel system contributes to a sustainable and environmental friendly construction. This paper presents an overview of the precast aerated concrete panel with added fibrous material (PACP. PACP is fabricated from aerated foamed concrete with added Polypropylene fibers (PP. The influence of PP on the mechanical properties of PACP are studied and reviewed from previous research. The structural behaviour of precast concrete panel subjected to flexure load is also reviewed. It is found that PP has significant affects on the concrete mixture’s compressive stregth, tensile strength and flexural strength. It is also found that PP manage to control the crack propagation in the concrete panel.

Influence of PCMs on thermal behavior of building walls: experimental study using the walls of a reduced scale room

Directory of Open Access Journals (Sweden)

Gounni Ayoub

2017-01-01

Full Text Available Using Phase-Change Materials (PCM for lightweight building applications can increase equivalent thermal mass and provide energy savings. In the present experimental work, the heat transfer performance testing of some building walls, with or without PCM, is carried out using a reduced-scale cubic room (the test-cell. The cubic cell is heated by an incandescent bulb placed on its centre, and it is housed in an air-conditioned large-scale room that allows to control the ambient air temperature. The effect of the double PCM layer and of its location relatively to the outside surface of the wall is tested and discussed in terms of overall transmitted heat flux and in terms of reduction of the inside and outside surface temperatures. Findings shows that the additional inertia introduced by the PCM leads to a reduced overall heat flux transmission by the wall and to a lesser daily temperature amplitude on the surface of the wall that enhances the thermal comfort inside the building. In the next step of this work, the case of sandwich walls with air gap, and with wood and PCM layers will be considered.

Influence of PCMs on thermal behavior of building walls: experimental study using the walls of a reduced scale room

Science.gov (United States)

Gounni, Ayoub; Tahar Mabrouk, Mohamed; Kheiri, Abdelhamid; El alami, Mustapha

2017-11-01

Using Phase-Change Materials (PCM) for lightweight building applications can increase equivalent thermal mass and provide energy savings. In the present experimental work, the heat transfer performance testing of some building walls, with or without PCM, is carried out using a reduced-scale cubic room (the test-cell). The cubic cell is heated by an incandescent bulb placed on its centre, and it is housed in an air-conditioned large-scale room that allows to control the ambient air temperature. The effect of the double PCM layer and of its location relatively to the outside surface of the wall is tested and discussed in terms of overall transmitted heat flux and in terms of reduction of the inside and outside surface temperatures. Findings shows that the additional inertia introduced by the PCM leads to a reduced overall heat flux transmission by the wall and to a lesser daily temperature amplitude on the surface of the wall that enhances the thermal comfort inside the building. In the next step of this work, the case of sandwich walls with air gap, and with wood and PCM layers will be considered.

Moisture Research - Optimizing Wall Assemblies

Energy Technology Data Exchange (ETDEWEB)

Arena, L.; Mantha, P.

2013-05-01

The Consortium for Advanced Residential Buildings (CARB) evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls.

Compressive strength, flexural strength and thermal conductivity of autoclaved concrete block made using bottom ash as cement replacement materials

International Nuclear Information System (INIS)

Wongkeo, Watcharapong; Thongsanitgarn, Pailyn; Pimraksa, Kedsarin; Chaipanich, Arnon

2012-01-01

Highlights: ► Autoclaved aerated concrete were produced using coal bottom ash as a cement replacement material. ► Coal bottom ash was found to enhance concrete strengths. ► Thermal conductivity of concrete was not significantly affected. ► X-ray diffraction and thermal analysis show tobermorite formation. -- Abstract: The bottom ash (BA) from Mae Moh power plant, Lampang, Thailand was used as Portland cement replacement to produce lightweight concrete (LWC) by autoclave aerated concrete method. Portland cement type 1, river sand, bottom ash, aluminium powder and calcium hydroxide (Ca(OH) 2 ) were used in this study. BA was used to replace Portland cement at 0%, 10%, 20% and 30% by weight and aluminium powder was added at 0.2% by weight in order to produce the aerated concrete. Compressive strength, flexural and thermal conductivity tests were then carried out after the concrete were autoclaved for 6 h and left in air for 7 days. The results show that the compressive strength, flexural strength and thermal conductivity increased with increased BA content due to tobermorite formation. However, approximately, 20% increase in both compressive (up to 11.61 MPa) and flexural strengths (up to 3.16 MPa) was found for mixes with 30% BA content in comparison to just around 6% increase in the thermal conductivity. Thermogravimetry analysis shows C–S–H formation and X-ray diffraction confirm tobermorite formation in bottom ash lightweight concrete. The use of BA as a cement replacement, therefore, can be seen to have the benefit in enhancing strength of the aerated concrete while achieving comparatively low thermal conductivity when compared to the results of the control Portland cement concrete.

Selection of exterior wall using advantageousness comparison; Ulkoseinaen valinta elinkaariedullisuuden perusteella

Energy Technology Data Exchange (ETDEWEB)

Saari, A.; Vesa, M.

2001-07-01

The objective of the study was to clarify the advantageousness of six chosen exterior wall solutions and at the same time to produce the procedure the measurement of the advantageousness. The examined wall types were: (1) brick wall, (2) brick-wool-concrete wall, (2b) brick-wool-concrete wall (not plastered), (3) brick-wool-wood wall, (4) precast concrete wall, and (5) plaster-wool-concrete wall. The analysis was made to a residential construction project which is built in a frame municipality of the metropolitan area. Here the life cycle costs, environmental burdens, and other factors (the aesthetic character, image, a comfort and easy maintenance) have an affect to the advantageousness of exterior wall. The averages of appreciation of the seven members of the supervising body of this study were used as the weights of the aforementioned value factors in the comparison. The result of the analysis was that the unplastered brick-wool-concrete wall had the equal life cycle costs as the precast concrete wall (an annual cost FIM 70 per apartment floor area). They were superior in relation to other examined wall types. In turn the brick wall had the highest life cycle costs (an annual cost nearly FIM 200 per apartment floor area) from the examined wall solutions on the advantageousness measuring straightforwardly likewise. It was chosen for an examination time period for 50 years. Likewise the brick wall was the distinctly weakest solution eco-economically, irrespective of, how costs and environmental factors are weighted. The brick wall was both the most expensive and unecological from the examined exterior wall types. It had a weak ecological qualities because considerably more building material than to other examined wall types. Also it's thermal insulation capacity was the weakest. But if in the decision-making also the aesthetic character, image, the effect on the comfort, and easy maintenance of the exterior wall indeed are included in addition to the eco

The Application of Buckling Reinforced Bracing and Shear Wall in Retrofitting of Existing Concrete Building

Directory of Open Access Journals (Sweden)

Mahdi Izadi

2015-06-01

Full Text Available Vulnerable buildings and their rehabilitation are important problems for earthquake regions. In recent decades the goal of building rehabilitation and strengthening has gained different rehabilitation systems. However, most of these strengthening techniques disturb the occupants, who must vacate the building during renovation. Several retrofitting techniques such as addition masonry infill wall, application of buckling restrained braces and local modification of components has been studied in order to improve the overall seismic performance of such buildings. In response to many of the practical issues and economic considerations, engineers use often convergent unbuckling steel bracing frames as the lateral load resisting system during an earthquake.This kind of bracings increases the hardness and strength of concrete structures.The aim of the present study is the evaluation and comparison of seismic performance and retrofitting of an existing 7-storeys concrete structure with buckling restrained bracings and shear walls by nonlinear static procedure (NSP and accordance with cod-361. The results show that the buckling restrained bracing, decreased drift to acceptable levels and Structure behaves on the life safety of performance level.

Cast-in-place concrete walls: thermal comfort evaluation of one-storey housing in São Paulo State

Directory of Open Access Journals (Sweden)

H. M. Sacht

Full Text Available This paper presents a proposal of thermal performance evaluation of a one-storey housing typology (TI24A executed by CDHU - Companhia de Desenvolvimento Habitacional e Urbano do Estado de São Paulo, considering the use of cast-in-place monolithic panels of concrete, with different thicknesses panels (8, 10 and 12 cm and density between 1600 and 2400 kg/m³. In this study, the specific purpose was discussing the influence of the characteristic of concrete walls on the housing thermal performance without slab. Was defined of first parameters of study (definition of the one-storey housing typology, survey about housing users behavior and cities choose and executed computational simulation (winter and summer, for four São Paulo State cities (São Paulo, São Carlos, Santos e Presidente Prudente, with the software Arquitrop 3.0 in a one-storey housing. Was observed that in winter and summer the typologies analyzed, the panels thickness variation had more influence about results than different concrete densities. The minimum level of thermal performance (M in winter has been granted for some cities, with exception of Santos. In summer one of São Paulo city’s typology was attended the minimum level of thermal performance in agreement with standard “NBR 15575 Residential buildings up to five storied - Performance, Part 1: General requirements”.

Influence of PCMs in thermal insulation on thermal behaviour of building envelopes

Science.gov (United States)

Dydek, K.; Furmański, P.; Łapka, P.

2016-09-01

A model of heat transfer through a wall consisting of a layer of concrete and PCM enhanced thermal insulation is considered. The model accounts for heat conduction in both layers, thermal radiation and heat absorption/release due to phase change in the insulation as well as time variation in the ambient temperature and insolation. Local thermal equilibrium between encapsulated PCM and light-weight thermal insulation was assumed. Radiation emission, absorption and scattering were also accounted for in the model. Comparison of different cases of heat flow through the building envelope was carried out. These cases included presence or absence of PCM and thermal radiation in the insulation, effect of emissivity of the PCM microcapsules as well as an effect of solar radiation or its lack on the ambient side of the envelope. Two ways of the PCM distribution in thermal insulation were also considered. The results of simulations were presented for conditions corresponding to the mean summer and winter seasons in Warsaw. It was found that thermal radiation plays an important role in heat transfer through thermal insulation layer of the wall while the presence of the PCM in it significantly contributes to damping of temperature fluctuations and a decrease in heat fluxes flowing into or lost by the interior of the building. The similar effect was observed for a decrease in emissivity of the microcapsules containing PCM.

Thermal protection and refurbishment of an old building. Lectures; Waermeschutz und Altbausanierung. Vortraege

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

Within the 22nd Hanseatic Reconstruction Symposium at the Baltic Seaside Heringsdorf/Usedom (Federal Republic of Germany) from 3rd to 5th November 2011, the following lectures were held: (1) Energetic refurbishment possibilities for building within existing properties by means of representative examples (F. Deitschum); (2) Constructional thermal insulation and indoor climate - for the good of the environment? (S. Groer); (3) Innovative insulating materials for the structural refurbishment? (O. Fechner); (4) Energetic half-timbering refurbishment (K. Lissner); (5) Wooden solar facades for existing buildings (U. Schwarz); (6) Timber beam bowls in a historic brickwork (U. Mueller); (7) Timber beam bowls and interior insulation (U. Ruisinger); (8) Innovative solutions for cavity filling insulations (A. Stefenelli); (9) Thermal insulating plaster - also for historical buildings (T. Stahl); (10) Experimental tension analysis of the structural behaviour of historical cross vaults (A.-J. Petereit); (10) Investigation of the increase of the flexural strength of stonework constructions with self-compacting steel fibre reinforced concrete (D. Haessler); (11) Dry and dense - the modified WTA leaflet 4-6, 'Subsequent sealing of components in contact with soil' - Content and innovations (R. Spirgatis); (12) What does the new standard DIN 68800 hold? (H. Willeitner); (13) News from the standard DIN 18195 waterproofing of buildings (H.-P. Sommer); (14) Liability of planning of the offering entrepreneur (H. Immoor); (15) Climate change and preservation of structures (W. Zillig); (16) Typical problems and deficiencies of the energetic refurbishment of old store buildings (H. Boehmer); (17) When do ex post horizontal sealings with injection agents make sense - Fundamentals for evaluation, planning and execution (F.-J. Hoelzen); (18) Drying up behaviour of stonework of different quality and at different variants of insulation (F. Antretter).

Analysis and optimization of the heat-insulating light concrete hollow brick walls design by the finite element method

International Nuclear Information System (INIS)

Coz Diaz, J.J. del; Garcia Nieto, P.J.; Betegon Biempica, C.; Prendes Gero, M.B.

2007-01-01

Department of Public Works, owners and building proprietors are demanding high-capacity heat-insulating exterior masonry components specifically for further energy savings. For housing and industrial structures there is also a great interest in light building materials with good physical material behaviour, with respect to an energy conscious and ecological design, which fulfils all strength and serviceability requirements. The major variables influencing the thermal conductivity of masonry materials are illustrated in this work by taking blocks made from no-fine lightweight concrete and different mortar properties. The finite element method (FEM) is used for finding accurate solutions of the heat transfer equation for five different light concrete hollow brick walls. Mathematically, the non-linearity is due to the radiation boundary condition inside the inner recesses of the bricks. The conduction and convection phenomena are taking into account in this study for three different values of the mortar conductivity and three different values for the bricks. Optimization of the walls is carried out from the finite element analysis of five hollow brick geometries by means of the mass overall thermal efficiency and the equivalent thermal conductivity. Finally, conclusions of this work are exposed

Analysis and optimization of the heat-insulating light concrete hollow brick walls design by the finite element method

Energy Technology Data Exchange (ETDEWEB)

Coz Diaz, J.J. del; Betegon Biempica, C.; Prendes Gero, M.B. [Edificio Departamental Viesques, No 7, 33204 Gijon (Asturias) (Spain); Garcia Nieto, P.J. [Departamento de Matematicas, Facultad de Ciencias, C/Calvo Sotelo s/n, 33007 Oviedo (Asturias) (Spain)

2007-06-15

Department of Public Works, owners and building proprietors are demanding high-capacity heat-insulating exterior masonry components specifically for further energy savings. For housing and industrial structures there is also a great interest in light building materials with good physical material behaviour, with respect to an energy conscious and ecological design, which fulfils all strength and serviceability requirements. The major variables influencing the thermal conductivity of masonry materials are illustrated in this work by taking blocks made from no-fine lightweight concrete and different mortar properties. The finite element method (FEM) is used for finding accurate solutions of the heat transfer equation for five different light concrete hollow brick walls. Mathematically, the non-linearity is due to the radiation boundary condition inside the inner recesses of the bricks. The conduction and convection phenomena are taking into account in this study for three different values of the mortar conductivity and three different values for the bricks. Optimization of the walls is carried out from the finite element analysis of five hollow brick geometries by means of the mass overall thermal efficiency and the equivalent thermal conductivity. Finally, conclusions of this work are exposed. (author)

Optimization of thermal conductivity lightweight brick type AAC (Autoclaved Aerated Concrete) effect of Si & Ca composition by using Artificial Neural Network (ANN)

Science.gov (United States)

Zulkifli; Wiryawan, G. P.

2018-03-01

Lightweight brick is the most important component of building construction, therefore it is necessary to have lightweight thermal, mechanical and aqustic thermal properties that meet the standard, in this paper which is discussed is the domain of light brick thermal conductivity properties. The advantage of lightweight brick has a low density (500-650 kg/m3), more economical, can reduce the load 30-40% compared to conventional brick (clay brick). In this research, Artificial Neural Network (ANN) is used to predict the thermal conductivity of lightweight brick type Autoclaved Aerated Concrete (AAC). Based on the training and evaluation that have been done on 10 model of ANN with number of hidden node 1 to 10, obtained that ANN with 3 hidden node have the best performance. It is known from the mean value of MSE (Mean Square Error) validation for three training times of 0.003269. This ANN was further used to predict the thermal conductivity of four light brick samples. The predicted results for each of the AAC1, AAC2, AAC3 and AAC4 light brick samples were 0.243 W/m.K, respectively; 0.29 W/m.K; 0.32 W/m.K; and 0.32 W/m.K. Furthermore, ANN is used to determine the effect of silicon composition (Si), Calcium (Ca), to light brick thermal conductivity. ANN simulation results show that the thermal conductivity increases with increasing Si composition. Si content is allowed maximum of 26.57%, while the Ca content in the range 20.32% - 30.35%.

Ageing management of CANDUtm concrete containment buildings

International Nuclear Information System (INIS)

Philipose, K.E.; Gregor, F.E.

2009-01-01

The containment system in a Nuclear Power Plant (NPP) provides the final physical barrier against release of radioactive materials to the external environment. Even though there are different physical configurations to meet this fundamental safety function in various reactor types, a common feature is the use of a thick-walled concrete structure as part of the containment system commonly referred to as 'Concrete Containment Building'. In order for the concrete containment buildings to continue to provide the required safety function, it has to maintain its structural integrity. As well, its leak rates under test pressures must be maintained below acceptable limits. As some of the containment buildings of the CANDU nuclear power plants are approaching their fourth decade of successful operation, questions regarding the impact of ageing on their ultimate useful service life emerge. Ageing Management has become the tool for addressing those questions. In this paper, the ageing and ageing management of the CANDU concrete containments are discussed, including the specific programs being implemented to monitor and trend the ageing conditions. Specifically, the usefulness of the embedded strain gauges as a tool for the assessment of the condition of the containment concrete structure is discussed. Some of the operational and test data accumulated over the last 30 years have been evaluated and trended to provide some results and conclusions regarding the satisfactory long-term behaviour of the concrete containment buildings. (authors)

Computational modeling of latent-heat-storage in PCM modified interior plaster

Energy Technology Data Exchange (ETDEWEB)

Fořt, Jan; Maděra, Jiří; Trník, Anton; Pavlíková, Milena; Pavlík, Zbyšek [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic)

2016-06-08

The latent heat storage systems represent a promising way for decrease of buildings energy consumption with respect to the sustainable development principles of building industry. The presented paper is focused on the evaluation of the effect of PCM incorporation on thermal performance of cement-lime plasters. For basic characterization of the developed materials, matrix density, bulk density, and total open porosity are measured. Thermal conductivity is accessed by transient impulse method. DSC analysis is used for the identification of phase change temperature during the heating and cooling process. Using DSC data, the temperature dependent specific heat capacity is calculated. On the basis of the experiments performed, the supposed improvement of the energy efficiency of characteristic building envelope system where the designed plasters are likely to be used is evaluated by a computational analysis. Obtained experimental and computational results show a potential of PCM modified plasters for improvement of thermal stability of buildings and moderation of interior climate.

Mechanical properties of lightweight aerated concrete with different aluminium powder content

Directory of Open Access Journals (Sweden)

Shabbar Rana

2017-01-01

Full Text Available Aerated concrete is produced by introducing gas into a concrete, the amount dependent upon the requirements for strength. One method to achieve this is by using powdered aluminium which reacts with the calcium hydroxide produced upon hydration of the cement. The aim of the current study was to investigate the influence of the powder content on the mechanical properties of aerated concrete namely; compressive and flexural strengths, modulus of elasticity, density and porosity. The results indicated that an increase in aluminium content caused a decrease in the compressive and tensile strengths. It also produced a decrease in the modulus of elasticity. When the aluminium content increased, the density decreased and the porosity increased.

Identification of thermal properties distribution in building wall using infrared thermography

Science.gov (United States)

Brouns, Jordan; Dumoulin, Jean

2016-04-01

In the construction sector, most of the measurements carried out from IR camera devices are exploited in a qualitative way (e.g. observation of thermal bridges). However, unless a quantitative analysis is realized, it is not possible to assess the impact of the observed phenomena. Most of research efforts and proposed solutions to identify quantified thermal properties (e.g. U-values) have to be completed, adapted to the built environment and validated in experimental and real conditions to allow quantified assessment of materials thermal properties thanks to IR camera devices [1]. We still need several steps in terms of scientific and technical developments for such technological progress. The H2020 European Built2Spec research project (http://built2spec-project.eu/) aims at giving highlights on that. Heat transfer through the walls are generally model by 1D heat equation in the wall depth. The built is composed by a multilayer domain representing the construction process. In this context, the thermal parameters of the wall are piecewise constant space functions. We propose a methodology to recover the vector of the wall thermal properties (conductivity and capacity) from boundary measurements obtained from an IR camera. It formulates as an inverse problem where the unknown are sought as minimizers of a cost function evaluating the gap between the measures and the model response. This optimization problem is non linear, and we solve it with the Levenberg-Marquardt algorithm coupled with the conjugate gradient method [2-3]. To shorten the time of the identification process, we use the adjoint method coming from the control theory [4]. This method fasten the gradient computation by solving an associated model, named the adjoint model. We study the ability of the procedure to reconstruct internal wall constitution from different environmental conditions. Furthermore, we propose a controlled experimental test to evaluate the method in laboratory conditions. References

Extent of moisture and mould damage in structures of public buildings

Directory of Open Access Journals (Sweden)

Petri J. Annila

2017-06-01

Full Text Available The study concentrated on the extent of moisture and mould damage in different structures in 25 public buildings in Finland. Users of all the buildings had health symptoms suspected to be the result of moisture and mould damage, which is why moisture performance assessments had been performed. The assessment reports on each building were available as research material. The reports indicated that the examined buildings suffered from multiple moisture and mould problems in several different structures. On average, however, a relatively small proportion of the total number of structures had suffered damage. On the basis of the research material, damage was most extensive in walls in soil contact (16.3% and base floor structures (12.5%. The lowest damage rates were found in partition walls (2.4%, external walls (2.6% and intermediate floors (2.5%. The results of the study underline the importance of thorough moisture performance assessments to ensure that all point-sized moisture and mould damage is detected.

Thermal insulation properties of walls

Directory of Open Access Journals (Sweden)

Zhukov Aleksey Dmitrievich

2014-05-01

Full Text Available Heat-protective qualities of building structures are determined by the qualities of the used materials, adequate design solutions and construction and installation work of high quality. This rule refers both to the structures made of materials similar in their structure and nature and mixed, combined by a construction system. The necessity to ecaluate thermal conductivity is important for a product and for a construction. Methods for evaluating the thermal protection of walls are based on the methods of calculation, on full-scale tests in a laboratory or on objects. At the same time there is a reason to believe that even deep and detailed calculation may cause deviation of the values from real data. Using finite difference method can improve accuracy of the results, but it doesn’t solve all problems. The article discusses new approaches to evaluating thermal insulation properties of walls. The authors propose technique of accurate measurement of thermal insulation properties in single blocks and fragments of walls and structures.

Tubular House - Form Follows Technology, Concrete Shell Structure with Inner Thermal Insulation

Science.gov (United States)

Idem, Robert; Kleczek, Paweł; Pawłowski, Krzysztof; Chudoba, Piotr

2017-10-01

The aim of this paper is the theoretical analysis of the possibilities and limitations of using an unconventional technology and the original architectural form stemming from it - the building with external construction and internal insulation. In Central European climatic conditions, the traditional solution for the walls of heated buildings relies on using external thermal insulation. This stems from building physics: it prevents interstitial condensation of water vapour in the wall. Internal insulation is used exceptionally. This is done e.g. in historical buildings undergoing thermal modernization (due to the impossibility of interfering with facade). In such cases, a thermal insulation layer is used on the internal wall surface, along with an additional layer of vapour barrier. The concept of building concerns the intentional usage of an internal insulation. In this case, the construction is a tight external reinforced concrete shell. The architectural form of such building is strongly interrelated with the technology, which was used to build it. The paper presents the essence of this concept in descriptive and drawing form. The basic elements of such building are described (the external construction, the internal insulation and ventilation). As a case study, authors present a project of a residential building along with the description of the applied materials and installation solutions, and the results obtained from thermal, humidity and energetic calculations. The discussion presents the advantages and disadvantages of the proposed concept. The basic advantage of this solution is potentially low building cost. This stems from minimizing the ground works, the simplicity of the joints and the outer finish, as well as from the possibility of prefabrication of the elements. The continuity of the thermal insulation allows to reduce the amount of thermal bridges. The applied technology and form are applicable most of all for small buildings, due to limited

Monomaterial ecological buildings, with Mopatel® and Ecopierra® concrete

Directory of Open Access Journals (Sweden)

Livia Miron

2013-09-01

Full Text Available This paper presents a case study performed on a pilot building from Gainesti, Suceava county. The constructive system used is unique in that it employs a monomaterial, namely ecological concrete of type MOPATEL® or ECOPIERRA®. These types of concrete, created by eng. Petrache Teleman, possess international patents and have received awards in Brussels, but they are not yet used in Romania. These materials can be used integrally to make all the constructive elements of a building – load-bearing elements (floors, beams, pillars, walls as well as the secondary elements of a partly finished building, such as screeds or non-load-bearing masonry. The constructive system also uses ecological mortars which integrally ensure the interior and exterior finishing. The final result is a building practically made from a single type of material, in which the effect of thermal bridges is reduced to a maximum. The MOPATEL and ECOPIERRA types of concrete have a mechanical resistance similar to regular concrete, but they also have superior thermal insulation qualities (between 0.09 and 0.28 W/mK, they are permeable to the transfer of water vapours from the interior to the exterior of the building, and, in certain compositions, they can also be considered waterproof.

Multi-dimensional SAR tomography for monitoring the deformation of newly built concrete buildings

Science.gov (United States)

Ma, Peifeng; Lin, Hui; Lan, Hengxing; Chen, Fulong

2015-08-01

Deformation often occurs in buildings at early ages, and the constant inspection of deformation is of significant importance to discover possible cracking and avoid wall failure. This paper exploits the multi-dimensional SAR tomography technique to monitor the deformation performances of two newly built buildings (B1 and B2) with a special focus on the effects of concrete creep and shrinkage. To separate the nonlinear thermal expansion from total deformations, the extended 4-D SAR technique is exploited. The thermal map estimated from 44 TerraSAR-X images demonstrates that the derived thermal amplitude is highly related to the building height due to the upward accumulative effect of thermal expansion. The linear deformation velocity map reveals that B1 is subject to settlement during the construction period, in addition, the creep and shrinkage of B1 lead to wall shortening that is a height-dependent movement in the downward direction, and the asymmetrical creep of B2 triggers wall deflection that is a height-dependent movement in the deflection direction. It is also validated that the extended 4-D SAR can rectify the bias of estimated wall shortening and wall deflection by 4-D SAR.

Infill Walls Contribution on the Progressive Collapse Resistance of a Typical Mid-rise RC Framed Building

Science.gov (United States)

Besoiu, Teodora; Popa, Anca

2017-10-01

This study investigates the effect of the autoclaved aerated concrete infill walls on the progressive collapse resistance of a typical RC framed structure. The 13-storey building located in Brăila (a zone with high seismic risk in Romania) was designed according to the former Romanian seismic code P13-70 (1970). Two models of the structure are generated in the Extreme Loading® for Structures computer software: a model with infill walls and a model without infill walls. Following GSA (2003) Guidelines, a nonlinear dynamic procedure is used to determine the progressive collapse risk of the building when a first-storey corner column is suddenly removed. It was found that, the structure is not expected to fail under the standard GSA loading: DL+0.25LL. Moreover, if the infill walls are introduced in the model, the maximum vertical displacement of the node above the removed column is reduced by about 48%.

An integrated study for mapping the moisture distribution in an ancient damaged wall painting.

Science.gov (United States)

Capitani, Donatella; Proietti, Noemi; Gobbino, Marco; Soroldoni, Luigi; Casellato, Umberto; Valentini, Massimo; Rosina, Elisabetta

2009-12-01

An integrated study of microclimate monitoring, IR thermography (IRT), gravimetric tests and portable unilateral nuclear magnetic resonance (NMR) was applied in the framework of planning emergency intervention on a very deteriorated wall painting in San Rocco church, Cornaredo (Milan, Italy). The IRT investigation supported by gravimetric tests showed that the worst damage, due to water infiltration, was localized on the wall painting of the northern wall. Unilateral NMR, a new non-destructive technique which measures the hydrogen signal of the moisture and that was applied directly to the wall, allowed a detailed map of the distribution of the moisture in the plaster underlying the wall panting to be obtained. With a proper calibration of the integral of the recorded signal with suitable specimens, each area of the map corresponded to an accurate amount of moisture. IRT, gravimetric tests and unilateral NMR applied to investigate the northern wall painting showed the presence of two wet areas separated by a dry area. The moisture found in the lower area was ascribed to the occurrence of rising damp at the bottom of the wall due to the slope of the garden soil towards the northern exterior. The moisture found in the upper area was ascribed to condensation phenomena associated with the presence of a considerable amount of soluble, hygroscopic salts. In the framework of this integrated study, IRT investigation and gravimetric methods validated portable unilateral NMR as a new analytical tool for measuring in situ and without any sampling of the distribution and amount of moisture in wall paintings.

First wall thermal hydraulic models for fusion blankets

International Nuclear Information System (INIS)

Fillo, J.A.

1980-01-01

Subject to normal and off-normal reactor conditions, thermal hydraulic models of first walls, e.g., a thermal mass barrier, a tubular shield, and a radiating liner are reviewed. Under normal operation the plasma behaves as expected in a predicted way for transient and steady-state conditions. The most severe thermal loading on the first wall occurs when the plasma becomes unstable and dumps its energy on the wall in a very short period of time (milliseconds). Depending on the plasma dump time and area over which the energy is deposited may result in melting of the first wall surface, and if the temperature is high enough, vaporization

Wood moisture monitoring during log house thermal insulation mounting

Directory of Open Access Journals (Sweden)

Pavla Kotásková

2011-01-01

Full Text Available The current designs of thermal insulation for buildings concentrate on the achievement of the required heat transmission coefficient. However, another factor that cannot be neglected is the assessment of the possible water vapour condensation inside the construction. The aim of the study was to find out whether the designed modification of the cladding structure of an existing log house will or will not lead to a risk of possible water vapour condensation in the walls after an additional thermal insulation mounting. The condensation could result in the increase in moisture of the walls and consequently the constructional timber, which would lead to the reduction of the timber construction strength, wood degradation by biotic factors – wood-destroying insects, mildew or wood-destroying fungi. The main task was to compare the theoretically established values of moisture of the constructional timber with the values measured inside the construction using a specific example of a thermal insulated log house. Three versions of thermal insulation were explored to find the solution of a log house reconstruction which would be the optimum for living purposes. Two versions deal with the cladding structure with the insulation from the interior, the third version deals with an external insulation.In a calculation model the results can be affected to a great degree by input values (boundary conditions. This especially concerns the factor of vapour barrier diffusion resistance, which is entered in accordance with the producer’s specifications; however, its real value can be lower as it depends on the perfectness and correctness of the technological procedure. That is why the study also includes thermal technical calculations of all designed insulation versions in the most unfavourable situation, which includes the degradation of the vapour barrier down to 10% efficiency, i.e. the reduction of the diffusion resistance factor to 10% of the original value

Experimental on moisture migration and pore pressure formation of concrete members subjected to high temperature

International Nuclear Information System (INIS)

Nagao, Kakuhiro; Nakane, Sunao

1993-01-01

The experimental studies concerning temperature, moisture migration, and pore pressure of mass concrete mock-up specimens heated up to high temperature at 110degC to 600degC, were performed, so as to correctly estimate the moisture migration behaviour of concrete members subjected to high temperature, which is considered significantly influenced on physical properties of concrete. As a results, it is confirmed that the moisture migration behavior of concrete members can be explained by temperature and pore pressure, and indicate the characteristics both sealed condition (dissipation of moisture is prevented) and unsealed condition (dissipation of moisture occur). (author)

Comparison of Analytical Methods for Estimation of Early-Age Thermal-Shrinkage Stresses in RC Walls

Directory of Open Access Journals (Sweden)

Klemczak B.

2013-03-01

Full Text Available The volume changes caused by coupled temperature and moisture variations in early-age concrete elements lead to formation of stresses. If a restraint exists along the contact surface of mature concrete against which a new concrete element has been cast, generated stresses are mostly of a restraint origin. In engineering practice a wide range of externally restrained concrete elements can be distinguished such as tank walls or bridge abutments cast against an old set foundation, in which early-age cracking may endanger their durability or functionality. Therefore, for years methods were being developed to predict early-age stresses and cracking risk of externally restrained concrete elements subjected to early-age thermal-moisture effects. The paper presents the comparative study of the most recognised analytical approaches: the method proposed in EC2, the method proposed by ACI Committee 207 and the method developed at the Luleå University of Technology.

Building Of Training Program Of Non-Destructive Testing For Concrete Structures (Part 1: Radiographic testing; Ultrasonic pulse velocity measurement; Nuclear moisture-density gauge)

International Nuclear Information System (INIS)

Nguyen Le Son; Phan Chanh Vu; Pham The Hung; Vu Huy Thuc

2007-01-01

Non-destructive testing methods (NDT) have been identified as a strong candidate for remote sensing of concrete structures over recent years. This has accelerated the powerful development of the NDT techniques in Vietnam. Hence, there is an urgent need to promote the awareness of NDT methods which could give an improved estimate of the condition concrete. Building of training program of non-destructive testing for concrete structures is a necessary duty, in aiming to build a unified training program, possibly satisfying the requirements on training as well as researching. Under the framework of the basic VAEC project (CS/07/02-03), a training program for the first 03 NDT methods: 1. Radiographic testing; 2. Ultrasonic pulse velocity measurement; 3. Nuclear moisture- density gauge was prepared. The main products of this project include: 1. Set out 03 training notes for 03 methods; 2. Set out the practical exercises to train for 03 methods; 3. Editing a set of examination questions in aiming to familiarize with various questions in 03 trained methods; 4. Fabricating practical test specimens to demonstrate for 03 techniques. (author)

Moisture migration in concrete. Final report. Technical report C-75-1

International Nuclear Information System (INIS)

McDonald, J.E.

1975-05-01

In an effort to obtain information regarding the nature of moisture movement and rate of moisture loss in a prestressed concrete reactor vessel (PCRV), an experimental study of moisture migration in a pie-shaped specimen representing the flow path through a cylindrical wall of a PCRV was initiated. After casting of the test specimen, temperature distribution, shrinkage, and moisture distribution were monitored for approximately 510 days. After this initial monitoring, a temperature difference of 80 0 F was applied to the specimen, and the above-mentioned measurements were continued for an additional test period of one year. Results indicate that moisture migration in thick sections of concrete, such as a PCRV, is a slow process and is not likely to be a significant factor with temperature differences of 80 0 F or less. 15 references. (auth)

ASSESSMENT OF CRACKING RESISTANCE OF CELLULAR CONCRETE PRODUCTS UNDER MOISTURE AND CARBONISATION DEFORMATIONS WITH STRESS RELAXATION

Directory of Open Access Journals (Sweden)

Sh. I. Apkarov

2017-01-01

Full Text Available Objectives. On the basis of the experimental, theoretical and field studies, an engineering calculation method was developed for assessing the cracking resistance of external enclosing constructions made of cellular concrete, with the maximum gradient development of moisture and carbonisation forced deformations along their thickness, taking into account the relaxation of the shrinkage stresses. In this regard, the aim of the work is to provide technological measures at the manufacturing stage in order to increase the operational cracking resistance of the construction's outer surface layers by reducing the moisture and carbonation shrinkage of cellular concrete by introducing a large or fine porous aggregate in calculated amounts.Methods. A number of analytical equations were applied to establish the dependence of the shrinkage of heavy concrete of conventional hardness on the amount of aggregate introduced and its elasticity modulus, water-cement ratio and cement consumption, as well as the concrete's moisture content.Results. Knowing the volumes of the structural aggregate and the cellular concrete mass, as well as their modulus of elasticity, the shrinkage reduction factor of the cellular concrete was calculated with the addition of a lightweight porous aggregate. Subsequently, the shrinkage deformations of concrete in the surface layer of the outer enclosing construction, maximising crack resistance due to moisture exchange and carbonation influences under operating conditions, were defined, taking into account the relaxation of tensile stresses due to creep of concrete.Conclusion. Theoretical calculations, based on the recommended method of assessing the cracking resistance of cellular concrete enclosing constructions under moisture exchange and carbonisation processes, taking into account the relaxation of shrinkage stresses, showed that in order to exclude the appearance of cracks in wall panels 280 mm thick made of 700 kg/m3 gas ash

Moisture migration and shrinkage of hardened cement paste at elevated temperatures

International Nuclear Information System (INIS)

Numao, Tatsuya; Mihashi, Hirozo.

1991-01-01

The drying shrinkage of concrete is caused by the loss of water in the concrete. The moisture diffusion behavior influences the mechanical properties of concrete. When concrete is exposed to high temperature, the rate of moisture migration becomes fast, and moisture gradient is formed. This gradient causes cracks on the concrete surface. Accordingly, it is important to study on the relation between the drying shrinkage and the water diffusion in concrete when its mechanical properties at elevated temperature are discussed. In this paper, the results of the experiment which was carried out by using thin-walled cylinder specimens kept at different temperature and stress are reported. The specimens, the drying shrinkage of concrete and acoustic emission (AE), the thermal expansion of hardened cement paste, the influence that temperature change exerted to the drying shrinkage, and the influence that compressive stress and temperature exerted to water migration are described. The thin-walled cylinder specimens were useful for these experimental studies. (K.I.)

Moisture accumulation in a building envelope

Energy Technology Data Exchange (ETDEWEB)

Forest, T.W.; Checkwitch, K.

1988-09-01

In a large number of cases, the failure of a building envelope can be traced to the accumulation of moisture. In a cold winter climate, characteristic of the Canadian prairies, moisture is deposited in the structure by the movement of warm, moist air through the envelope. Tests on the moisture accumulation in a building envelope were initiated in a test house at an Alberta research facility during the 1987/88 heating season. The indoor moisture generation rate was measured and compared with the value inferred from the measured air infiltration rate. With the flue open, the moisture generation rate was approximately 5.5 kg/d of which 0.7 kg/d entered the building envelope; the remainder was exhausted through the flue. With the flue blocked, the moisture generation rate decreased to 3.4 kg/d, while the amount of moisture migrating through the envelope increased to 4.0 kg/d. The moisture accumulation in wall panels located on the north and south face of the test house was also monitored. Moisture was allowed to enter the wall cavity via a hole in the drywall. The fiberglass insulation remained dry throughout the test period. The moisture content of the exterior sheathing of the north panel increased to a maximum of 18% wt in the vicinity of the hole, but quickly dried when the ambient temperatures increased towards the end of the season. The south panel showed very little moisture accumlation due to the effects of solar radiation. 14 refs., 9 figs.

Masonry calendar 1989. A handbook on masonry, wall construction materials, sound, thermal and moisture insulation. Mauerwerk-Kalender 1989. Taschenbuch fuer Mauerwerk, Wandbaustoffe, Schall-, Waerme- und Feuchtigkeitsschutz

Energy Technology Data Exchange (ETDEWEB)

Funk, P [ed.

1989-01-01

The 1989 Masonry Calendar comprises the following sections and contibutions: Harmonisation of technical rules for brickwork construction on a European scale; fundamentals for brickwork dimensioning according to DIN 1053, part 2; exemplary calculations for the dimensioning of brick walls under compressive and shearing loads according to DIN 1053, part 2; calculation aids for brickwork dimensioning according to DIN 1053, part 2; dimensioning tables for reinforced brickwork of rectangular cross section; characteristic data of brickwork, bricks, and mortar; thermal insulation of brickwork; moisture protection problems in brickwork construction; noise abatement in brickwork construction; novel materials and designs in brickwork construction; characteristic data for calculating the thermal conductivity of building materials; regulations on construction, bricks, binders; further construction materials, testing standards, constructional physics, further standards and technical regulations for brickwork construction, with supplements; DGfM codes; work scaffolding; dwelling on brickwork construction; experiments on the seismic response of brickwork; supporting strength of brick walls under simultaneous horizontal and vertical stress; masonry cost calculation in the framework of overall construction cost calculation; bibliography and important addresses. (BR).

Characterization of fracture patterns and hygric properties for moisture flow modelling in cracked concrete

DEFF Research Database (Denmark)

Rouchier, Simon; Janssen, Hans; Rode, Carsten

2012-01-01

porous media. Digital Image Correlation was performed during the fracturing of concrete samples, in which moisture uptake was then monitored using X-ray radiography. Finite-element simulations were then performed based on the measurements of the fracture patterns, in order to recreate the measured......Several years after their installation, building materials such as concrete present signs of ageing in the form of fractures covering a wide range of sizes, from microscopic to macroscopic cracks. All sizes of fractures can have a strong influence on heat and moisture flow in the building envelope...

Use of geonics scientific positions for designing of building composites for protective (fortification) structures

Science.gov (United States)

Fediuk, R. S.; Yevdokimova, Yu G.; Smoliakov, A. K.; Stoyushko, N. Yu; Lesovik, V. S.

2017-07-01

The examples of the implementation of the geological (geomimetic) positions in construction materials science are given in the work. The wall materials obtained with this technology have a much more developed surface than traditional wall materials. The second example of using such approaches is the development of internal care systems that will create a more highly organized structure of cement stone at the macro-, micro- and nano-scale levels and concrete in general at all stages: the stage of mixing, hardening and exploitation of the material. The regularities of the structure formation processes are revealed and the principles for increasing the efficiency of non-autoclaved aerated concrete due to application of composite binders, process control in a three-phase disperse porous system and the development of technological methods for the production of protective (fortification) structures are developed.

A biomimic thermal fabric with high moisture permeability

Directory of Open Access Journals (Sweden)

Fan Jie

2013-01-01

Full Text Available Moisture comfort is an essential factor for functional property of thermal cloth, especially for thick thermal cloth, since thick cloth may hinder effective moisture permeation, and high moisture concentration in the micro-climate between skin and fabric would cause cold feeling. Here, we report a biomimic thermal fabric with excellent warm retention and moisture management properties. In this fabric, the warp yarn system constructs many tree-shaped channel nets in the thickness direction of the fabric. Experimental result indicates that the special hierarchic configuration of warp yarns endows the biomimic thermal fabric with a better warm retention and water vapor management properties compared with the traditional fabrics.

Moisture measurements in building materials with microwaves; Rakennusmateriaalien kosteusmittauksia mikroaalloilla

Energy Technology Data Exchange (ETDEWEB)

Kaeaeriaeinen, H.; Rudolph, M.; Schaurich, D.; Wiggenhauser, H. [VTT Building Technology, Espoo (Finland). Construction and Facility Management

1998-12-01

In order to assess the condition and evaluate the reliability of buildings and structures, it is essential to establish the moisture condition of the floor and other structural elements of the building. NDT-methods are increasingly being used for such moisture measurements because they do not cause any damage to the building under investigation. Microwave transmission is one of the NDT-methods and has been in use for several years. In this report, the applicability of the microwave method for measuring moisture in different building materials was investigated. This method has been successfully used at BAM for repeated moisture measurements in brick and sandstone material. This project also included other materials, such as concrete, sand, gravel, insulation and wood. At the same time, information was gathered about in situ moisture determination of building materials with a microwave moisture measuring system. The equipment used in this research has been developed at BAM over the last few years. The method requires two parallel boreholes in the specimen in which two microwave antennae can be moved. The moisture content in the material can be calculated from the microwave intensity transmitted between the two boreholes. Moisture profiles along the boreholes can be obtained by moving the antennae in steps along the length of the boreholes and taking measurements at each step. Special care must be taken while drilling the holes for the antennae, as this process must not affect the moisture condition in the specimen, and the boreholes must be made as parallel to each other as possible. The microwave frequencies used in the laboratory measurements ranged from 8 to 16,5 GHz in steps of 0,5 GHz. The diameters of the antennae were between 7 and 9 mm, and of the boreholes between 8 and 12 mm. Except for the concrete specimen, all the specimens were measured using plastic tubes in the boreholes. The moisture content measured by the microwave technique was verified by the

Calculation on cosmic-ray muon exposure rate in non-walled concrete buildings

International Nuclear Information System (INIS)

Fujitaka, Kazunobu; Abe, Siro

1984-01-01

Computer simulations on the exposure indoors from cosmic ray muons were practiced in the framework of non-scattering and non-cascade assumptions. The model buildings were two-dimensional, rectangular, and were made of a normal concrete. A stratified structure was assumed in each building, where no mezzanine was considered. Walls were not taken into account yet. The distributions of the exposure rates in 26-story buildings were illustrated in contour maps for various sets of parameters. All of them gave basically archlike patterns. Analyses of the results showed that the exposure rate is affected most largely by the floor board thickness. The ceiling height would be an insignificant factor for short buildings. The min/max ratio of the muon exposure rate in a moderate size building was estimated to be more than 0.7. (author)

1-Dimensional simulation of thermal annealing in a commercial nuclear power plant reactor pressure vessel wall section

International Nuclear Information System (INIS)

Nakos, J.T.; Rosinski, S.T.; Acton, R.U.

1994-11-01

The objective of this work was to provide experimental heat transfer boundary condition and reactor pressure vessel (RPV) section thermal response data that can be used to benchmark computer codes that simulate thermal annealing of RPVS. This specific protect was designed to provide the Electric Power Research Institute (EPRI) with experimental data that could be used to support the development of a thermal annealing model. A secondary benefit is to provide additional experimental data (e.g., thermal response of concrete reactor cavity wall) that could be of use in an annealing demonstration project. The setup comprised a heater assembly, a 1.2 in x 1.2 m x 17.1 cm thick [4 ft x 4 ft x 6.75 in] section of an RPV (A533B ferritic steel with stainless steel cladding), a mockup of the open-quotes mirrorclose quotes insulation between the RPV and the concrete reactor cavity wall, and a 25.4 cm [10 in] thick concrete wall, 2.1 in x 2.1 in [10 ft x 10 ft] square. Experiments were performed at temperature heat-up/cooldown rates of 7, 14, and 28 degrees C/hr [12.5, 25, and 50 degrees F/hr] as measured on the heated face. A peak temperature of 454 degrees C [850 degrees F] was maintained on the heated face until the concrete wall temperature reached equilibrium. Results are most representative of those RPV locations where the heat transfer would be 1-dimensional. Temperature was measured at multiple locations on the heated and unheated faces of the RPV section and the concrete wall. Incident heat flux was measured on the heated face, and absorbed heat flux estimates were generated from temperature measurements and an inverse heat conduction code. Through-wall temperature differences, concrete wall temperature response, heat flux absorbed into the RPV surface and incident on the surface are presented. All of these data are useful to modelers developing codes to simulate RPV annealing

The importance of moisture buffering for indoor climate and energy conditions of buildings

DEFF Research Database (Denmark)

Rode, Carsten; Grau, Karl

2007-01-01

A new Nordic test method specifies a test protocol for determination of the so-called Moisture Buffer Value (MBV) of building materials. But how important is moisture buffering to determine the indoor humidity condition of buildings? The paper will present the new MBV-definition. Although...... buffering to save energy by reducing the requirement for ventilation in periods, and still maintain the same quality of the indoor climate? The paper will outline some possibilities for analytical/numerical calculations, and will answer some of the posed questions on the probable benefit of taking moisture...

Thermal performance evaluation of a massive brick wall under real weather conditions via the Conduction Transfer function method

Directory of Open Access Journals (Sweden)

Emilio Sassine

2017-12-01

Full Text Available The reliable estimation of buildings energy needs for cooling and heating is essential for any eventual thermal improvement of the envelope or the HVAC equipment. This paper presents an interesting method to evaluate the thermal performance of a massive wall by using the frequency-domain regression (FDR method to calculate CTF coefficients by means of the Fourier transform. The method is based on the EN ISO 13786 (2007 procedure by using the Taylor expansion for the elements of the heat matrix. Numerical results were validated through an experimental heating box with stochastic boundary conditions on one side of the wall representing real weather conditions and constant temperature profile on the other side representing the inside ambiance in real cases. Finally, a frequency analysis was performed in order to assess the validity and accuracy of the method used. The results show that development to the second order is sufficient to predict the thermal behavior of the studied massive wall in the range of frequencies encountered in the building applications (one hour time step. This method is useful for thermal transfer analysis in real weather conditions where the outside temperature is stochastic; it also allows the evaluation of the thermal performance of a wall through a frequency analysis.

Two innovative solutions based on fibre concrete blocks designed for building substructure

Science.gov (United States)

Pazderka, J.; Hájek, P.

2017-09-01

Using of fibers in a high-strength concrete allows reduction of the dimensions of small precast concrete elements, which opens up new ways of solution for traditional construction details in buildings. The paper presents two innovative technical solutions for building substructure: The special shaped plinth block from fibre concrete and the fibre concrete elements for new technical solution of ventilated floor. The main advantages of plinth block from fibre concrete blocks (compared with standard plinth solutions) is: easier and faster assembly, higher durability and thanks to the air cavity between the vertical part of the block, the building substructure reduced moisture level of structures under the waterproofing layer and a comprehensive solution to the final surface of building plinth as well as the surface of adjacent terrain. The ventilated floor based on fibre concrete precast blocks is an attractive structural alternative for tackling the problem of increased moisture in masonry in older buildings, lacking a functional waterproof layer in the substructure.

Reliability and service life of wood structures and buildings

Directory of Open Access Journals (Sweden)

Zdeňka Havířová

2005-01-01

Full Text Available Service life of constructions and buildings of wood is dependent on temperature and moisture conditions in layers of the building cladding where the wood framework is built in. Temperature/moisture conditions or the corresponding equilibrium moisture content (EMC of the construction show considerable effects on the functional reliability of the whole building from the viewpoint of mechanical resistance and stability (ER1, energy savings and thermal protection (ER6 and hygiene, health and environment protection (ER3. To ensure the reliability of constructions and buildings for the period of their supposed service life a more profound analysis of constructions is necessary from the aspect of a global thermal/technical evaluation.

Moisture Durability Assessment of Selected Well-insulated Wall Assemblies

Energy Technology Data Exchange (ETDEWEB)

Pallin, Simon B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Boudreaux, Philip R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kehrer, Manfred [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hun, Diana E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jackson, Roderick K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Desjarlais, Andre Omer [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-12-01

This report presents the results from studying the hygrothermal performance of two well-insulated wall assemblies, both complying with and exceeding international building codes (IECC 2015 2014, IRC 2015). The hygrothermal performance of walls is affected by a large number of influential parameters (e.g., outdoor and indoor climates, workmanship, material properties). This study was based on a probabilistic risk assessment in which a number of these influential parameters were simulated with their natural variability. The purpose of this approach was to generate simulation results based on laboratory chamber measurements that represent a variety of performances and thus better mimic realistic conditions. In total, laboratory measurements and 6,000 simulations were completed for five different US climate zones. A mold growth indicator (MGI) was used to estimate the risk of mold which potentially can cause moisture durability problems in the selected wall assemblies. Analyzing the possible impact on the indoor climate due to mold was not part of this study. The following conclusions can be reached from analyzing the simulation results. In a hot-humid climate, a higher R-value increases the importance of the airtightness because interior wall materials are at lower temperatures. In a cold climate, indoor humidity levels increase with increased airtightness. Air leakage must be considered in a hygrothermal risk assessment, since air efficiently brings moisture into buildings from either the interior or exterior environment. The sensitivity analysis of this study identifies mitigation strategies. Again, it is important to remark that MGI is an indicator of mold, not an indicator of indoor air quality and that mold is the most conservative indicator for moisture durability issues.

Degradation tests for C 32/40 concrete used for perimetral wall, reactor base and components of Cernavoda NPP containment, under thermal stress conditions and liner degradation

International Nuclear Information System (INIS)

Carlan, P.; Paraschiv, I.; Dinu, A.; Stanciulescu, M.; Olteanu, A. M.; Voica, I.; Stelian, R.; Buc, G.

2016-01-01

In order to evaluate the effect of thermal degradation on C 32/40 concrete used in nuclear constructions at Cernavoda NPP, continuous thermal stress tests were performed at 65, 80 and 100°C and cyclic thermal stress tests at 65°C in dry conditions. This paper presents the macroscopic properties of concrete, obtained after these treatments and also the microstructural changes that occur in the cement paste from the concrete composition, which has been tested in the same conditions as the concrete samples. Determinations performed for macroscopic properties of concrete included: compressive strength, loss of density, permeability and modulus of elasticity. Cement paste samples were analysed by XRD (for mineralogical composition) and SEM (for morphology). The obtained results shown an appropriate behaviour of the concrete used in this study; changes are insignificant and follow the normal evolution process of concrete, proving that concrete will preserve its safety functions, as part of the containment structure. (authors)

Seismic Performance and Modeling of Reinforced Concrete and Post-Tensioned Precast Concrete Shear Walls

OpenAIRE

Tanyeri, Ahmet Can

2014-01-01

Past earthquakes have shown examples of unsatisfactory performance of buildings using reinforced concrete structural walls as the primary lateral-force-resisting system. In the 1994 Northridge earthquake, examples can be found where walls possessed too much overstrength, leading to unintended failure of collectors and floor systems, including precast and post-tensioned construction. In the 2010 Maule Chile earthquake, many structural wall buildings sustained severe damage. Although Chilean de...

Moisture dependence of radon transport in concrete : Measurements and modeling

NARCIS (Netherlands)

Cozmuta, [No Value; van der Graaf, ER; de Meijer, RJ

2003-01-01

The moisture dependence of the radon-release rate of concrete was measured under well controlled conditions. It was found that the radon-release rate almost linearly increases up to moisture contents of 50 to 60%. At 70 to 80% a maximum was found and for higher moisture contents the radon-release

Characterization and behaviour of Autoclaved Aerated Concrete before Autoclaving

NARCIS (Netherlands)

Straub, Chr.; Florea, M.V.A.; Brouwers, H.J.H.; Schmidt, Wolfram; Msinjili, Nsesheye Susan

In order to achieve a high quality Autoclaved Aerated Concrete (AAC) product, certain steps need to be ensured: the characterization of the raw materials, a proper mixing and correct slurry behaviour to achieve a good green body during green curing. In the current research the emphasis is on all of

Maintenance and Durability of the Concrete External Layer of Curtain Walls in Prefabricated Technological Poznan Large Panel System

Science.gov (United States)

Jasiczak, Józef; Girus, Krzysztof

2017-10-01

The issue of usability and durability of large-panel building constructed several decades ago is a subject of an in-depth analysis of many domestic and foreign investments. When considering the durability of specific large-panel system, one should consider, among others, the process of making external walls. The long-term and direct impact of weather conditions on the external layer of curtain walls is significant for the durability of large-panel buildings. For the needs of the presented paper, in 2016, the survey of cracks and a series of other tests of large-panel façade, residential building constructed in 1986, in Poland, in the PLP process system - Rataje was executed. Several hundred large-size, triple-layer curtain-wall slab with a 6-cm, concrete exterior cladding layer anchored using pins and hangers with the load-bearing layer, a 9-cm insulation layer made of mineral wool, and a 21-cm structural layer were surveyed. Significant deviations in thicknesses of particular wall layers were proven. Other significant damages and defects of external layers were found. At the second stage, many tests, both nondestructive and destructive, were conducted. They involved determining mechanical properties of an external layer. The concrete thickness was measured using with a type N Schmidt sclerometer and core samples were taken from this layer in order to mark concrete’s compressive strength. The range of carbonation (by phenolphthalein method) and the actual location and condition of reinforcement were estimated using a ferromagnetic device to determine the condition of the external layer. The diagnosis conducted in such a manner was the verification of necessary repair of the walls and their thermal efficiency improvement while ensuring safe conditions of their operation and modern functional and utility requirements. It should be also emphasized that the method of diagnosing the external walls presented in this paper may be popularized when evaluating such

Effects of moisture migration on shrinkage, pore pressure and other concrete properties

International Nuclear Information System (INIS)

Chapman, D.A.; England, G.L.

1977-01-01

This work investigates the uniaxial migration of moisture in long, upright, limestone concrete cylinders, sealed at the base and sides, and open at the top. The design represents a section through a concrete pressure vessel wall. The cylinders are subjected to a sustained temperature difference between their ends, with maximum temperatures between 105 0 C and 200 0 C. Readings of pore pressure, water content and temperature are taken at various positions along the axis of the cylinders. In one cylinder transverse and longitudinal shrinkage readings are also recorded. The results for the cylinders show that moisture migration is away from the hot face of the specimens, causing reduction in both pore pressure and water content values in this region. The moisture migration creates a drying front which moves slowly up the specimens. Evaporation drying takes place from the unsealed end of the specimen. A drying front moves into the concrete and considerable weight loss is recorded as moisture escapes to the atmosphere. The rate of movement of the drying front is slower than that of the hot front and is proportional to the temperature difference between the top of the specimen and the surrounding atmosphere. In the shrinkage specimen, values of transverse and longitudinal shrinkage reflect the water content results. The specimen indicates that shrinkage occurs in a concrete pressure vessel, in the regions where moisture is lost. The restraint of the mass of concrete surrounding these regions sets up a three dimensional state of internal tensile stress. The areas into which the moisture migrates tend to swell, creating an internal stress situation, which is this

The effect of moisture content within multilayer protective clothing on protection from radiation and steam.

Science.gov (United States)

Su, Yun; Li, Jun; Song, Guowen

2018-06-01

The moisture from skin sweat and atmospheric water affects the thermal protective performance provided by multilayer protective clothing. Four levels of moisture content were selected to evaluate the impact of moisture on thermal protection under dry (thermal radiation) and wet (thermal radiation and low-pressure steam) heat exposure. Also, the role of moisture and its relationship with exposure time were analyzed based on skin heat flux and Henriques integral value. The addition of moisture to a fabric system was found to result in differences in second-degree and third-degree skin burn times. When moisture is added to a fabric system, it both acts as a thermal conductor to present a negative effect and provides a positive effect owing to thermal storage of water and evaporative heat loss. The positive or negative effects of moisture are mainly dependent on the thermal exposure time, the moisture content and the presence of hot steam.

Impact of Moistened Bio-insulation on Whole Building Energy Use

Directory of Open Access Journals (Sweden)

Latif Eshrar

2017-01-01

Full Text Available One of the key properties of hemp insulation is its moisture adsorption capacity. Adsorption of moisture can increase both thermal conductivity and heat capacity of the insulation. The current study focuses on the effect of moisture induced thermal mass of installed hemp insulation on the whole building energy use. Hygrothermal and thermal simulations were performed using the CIBSE TRY weather data of Edinburgh and Birmingham with the aid of following simulation tools: WUFI and IES. Following simplified building types were considered: building-1 with dry hemp wall and loft insulations, building-2 with moistened hemp wall and loft insulation and building-3 with stone wool insulation. It was observed that the overall conditioning load of building-1 was 1.2 to 2.3% higher than building-2 and 3. However, during the summer season, the cooling load of building-2 was 3-7.5% lower than the other buildings. It implies that, moistened insulation can potentially mitigate the effect of increasing cooling degree days induced by global warming.

Equilibrium moisture content of wood at different temperature/moisture conditions in the cladding of wooden constructions and in the relation to their reliability and service life

Directory of Open Access Journals (Sweden)

Zdeňka Havířová

2010-01-01

Full Text Available One of the natural properties of wood and wood-based materials is their soaking capacity (hy­gro­sco­pi­ci­ty. The moisture content of wood and building constructions of wood and wood based materials significantly influences the service life and reliability of these constructions and buildings. The equilibrium weight moisture content of built-in wood corresponding to temperature/moisture conditions inside the cladding has therefore a decisive influence on the basic requirements placed on building constructions. The wood in wooden frame cladding changes its moisture content depending on temperature and moisture conditions of the environment it is built into. The water vapor condensation doesn’t necessarily have to occur right in the wooden framework of the cladding for the equilibrium moisture content to rise over the level permissible for the reliable function of a given construction. In spite of the fact that the common heat-technical assessment cannot be considered fully capable of detecting the effects of these factors on the functional reliability of wood-based constructions and buildings, an extension has been proposed of the present method of design an assessment of building constructions according to the ČSN 73 0540 standard regarding the interpretation of equilibrium moisture content in relation to the temperature/moisture conditions and their time behavior inside a construction.

Behaviours of reinforced concrete containment models under thermal gradient and internal pressure

International Nuclear Information System (INIS)

Aoyagi, Y.; Ohnuma, H.; Yoshioka, Y.; Okada, K.; Ueda, M.

1979-01-01

The provisions for design concepts in Japanese Technical Standard of Concrete Containments for Nuclear Power Plants require to take account of thermal effects into design. The provisions also propose that the thermal effects could be relieved according to the degree of crack formation and creep of concrete, and may be neglected in estimating the ultimate strength capacity in extreme environmental loading conditions. This experimental study was carried out to clarify the above provisions by investigating the crack and deformation behaviours of two identical reinforced cylindrical models with dome and basement (wall outer diameter 160 cm, and wall thickness 10 cm). One of these models was hydraulically pressurized up to failure at room temperature and the other was subjected to similar internal pressure combined with the thermal gradient of approximately 40 to 50 0 C across the wall. Initial visual cracks were recognized when the stress induced by the thermal gradient reached at about 85% of bending strength of concrete used. The thermal stress of reinforcement calculated with the methods proposed by the authors using an average flexural rigidity considering the contribution of concrete showed good agreement with test results. The method based on the fully cracked section, however, was recognized to underestimate the measured stress. These cracks considerably reduced the initial deformation caused by subsequent internal pressure. (orig.)

Damage Detection of Reinforced Concrete Shear Walls Using Mathematical Transformations

Directory of Open Access Journals (Sweden)

Hosein Naderpour

2017-02-01

Full Text Available Structural health monitoring is a procedure to provide accurate and immediate information on the condition and efficiency of structures. There is variety of damage factors and the unpredictability of future damage, is a necessity for the use of structural health monitoring. Structural health monitoring and damage detection in early stages is one of the most interesting topics that had been paid attention because the majority of damages can be repaired and reformed by initial evaluation ,thus the spread of damage to the structures, building collapse and rising of costs can be avoided .Detection of concrete shear wall damages are designed to withstand the lateral load on the structure is critical .Because failures and  malfunctions of shear walls can lead to serious damage or even progressive dilapidation of concrete structures .Change in stiffness and frequency can clearly show the damage occurrence. Mathematical transformation is also a tool to detect damage. In this article, with non- linear time history analysis, the finite element model of structures with concrete shear walls subject to four earthquakes have extracted and using Fourier and wavelet transform, the presence of shear walls is detected at the time of damage.

Wall Painting Investigation by Means of Non-invasive Terahertz Time-Domain Imaging (THz-TDI): Inspection of Subsurface Structures Buried in Historical Plasters

Science.gov (United States)

Dandolo, Corinna Ludovica Koch; Jepsen, Peter Uhd

2016-02-01

Characterization of subsurface features of wall paintings is important in conservation and technical art history as well as in building archaeology and architecture fields. In this study, an area of the apsidal wall painting of Nebbelunde Church (Rødby, Denmark) has been investigated by means of terahertz time-domain imaging (THz-TDI). Subsurface structures have been detected at different depths inside the lime-based plaster of the wall painting until approximately 1 cm from the surface. The surface morphology of the buried structures has been 3D imaged in detail, providing a substantial contribution in their characterization.

Effects of moisture migration on shrinkage, pore pressure and other concrete properties

International Nuclear Information System (INIS)

Chapman, D.A.; England, G.L.

1977-01-01

This work investigates the uniaxial migration of moisture in long, upright, limestone concrete cylinders, sealed at the base and sides, and open at the top. The design represents a section through a concrete pressure vessel wall. The cylinders are subjected to a sustained temperature difference between their ends, with maximum temperatures between 105 0 C and 200 0 C. Readings of pore pressure, water content and temperature are taken at various positions along the axis of the cylinders. In one cylinder, transverse and longitudinal shrinkage readings are also recorded. The results for the cylinders show that moisture migration is away from the hot face of the specimens causing reduction in both pore pressure and water content values in this region. The moisture migration creates a drying front which moves slowly up the specimens. The rate at which this drying front, moves is influenced by the base temperature, the magnitude of temperature and pressure gradients and the coefficient of permeability of the concrete. Samples taken from the hot side of the drying front show a considerable increase in the coefficient of permeability, and Scanning Electron Microscope photographs of the microstructure show both a break-up and reduction in size of the hydration products. The experiments reported indicate that when the hot inner face temperature of a concrete pressure vessel is increased above 100 0 C, the drying rate inside the wall increases considerably, However, it is unlikely pressure vessels of the size currently in use will ever completely dry out. (Auth.)

A metric for characterizing the effectiveness of thermal mass in building materials

International Nuclear Information System (INIS)

Talyor, Robert A.; Miner, Mark

2014-01-01

Highlights: • Proposes a metric for interior thermal mass materials (floors, walls, counters). • Simple, yet effective, metric composed of easily calculated ‘local’ and ‘global’ variables. • Like Energy Star, the proposed metric gives a single number to aid consumer choice. • The metric is calculated and compared for selected, readily available data. • Drywall, concrete flooring, and wood paneling are quite effective thermal mass. - Abstract: Building energy use represents approximately 25% of the average total global energy consumption (for both residential and commercial buildings). Heating, ventilation, and air conditioning (HVAC) – in most climates – embodies the single largest draw inside our buildings. In many countries around the world a concerted effort is being made towards retrofitting existing buildings to improve energy efficiency. Better windows, insulation, and ducting can make drastic differences in the energy consumption of a building HVAC system. Even with these improvements, HVAC systems are still required to compensate for daily and seasonal temperature swings of the surrounding environment. Thermal mass inside the thermal envelope can help to alleviate these swings. While it is possible to add specialty thermal mass products to buildings for this purpose, commercial uptake of these products is low. Common building interior building materials (e.g. flooring, walls, countertops) are often overlooked as thermal mass products, but herein we propose and analyze non-dimensional metrics for the ‘benefit’ of selected commonly available products. It was found that location-specific variables (climate, electricity price, material price, insolation) can have more than an order of magnitude influence in the calculated metrics for the same building material. Overall, this paper provides guidance on the most significant contributors to indoor thermal mass, and presents a builder- and consumer-friendly metric to inform decisions about

Microencapsulated phase change materials for enhancing the thermal performance of Portland cement concrete and geopolymer concrete for passive building applications

International Nuclear Information System (INIS)

Cao, Vinh Duy; Pilehvar, Shima; Salas-Bringas, Carlos; Szczotok, Anna M.; Rodriguez, Juan F.; Carmona, Manuel; Al-Manasir, Nodar; Kjøniksen, Anna-Lena

2017-01-01

Highlights: • Microencapsulated phase change materials give high energy storage capacity concrete. • Microcapsule addition increases the porosity of concrete. • Thermal and mechanical properties are linked to the enhanced concrete porosity. • Agglomerated microcapsules have strong impact on the concrete properties. • Microcapsules caused geopolymer to become more energy efficient than Portland cement. - Abstract: Concretes with a high thermal energy storage capacity were fabricated by mixing microencapsulated phase change materials (MPCM) into Portland cement concrete (PCC) and geopolymer concrete (GPC). The effect of MPCM on thermal performance and compressive strength of PCC and GPC were investigated. It was found that the replacement of sand by MPCM resulted in lower thermal conductivity and higher thermal energy storage, while the specific heat capacity of concrete remained practically stable when the phase change material (PCM) was in the liquid or solid phase. Furthermore, the thermal conductivity of GPC as function of MPCM concentration was reduced at a higher rate than that of PCC. The power consumption needed to stabilize a simulated indoor temperature of 23 °C was reduced after the addition of MPCM. GPC exhibited better energy saving properties than PCC at the same conditions. A significant loss in compressive strength was observed due to the addition of MPCM to concrete. However, the compressive strength still satisfies the mechanical European regulation (EN 206-1, compressive strength class C20/25) for concrete applications. Finally, MPCM-concrete provided a good thermal stability after subjecting the samples to 100 thermal cycles at high heating/cooling rates.

Application of glass recycling by-products in Autoclaved Aerated Concrete

NARCIS (Netherlands)

Straub, Chr.; Florea, M.V.A.; Brouwers, H.J.H.; Schmidt, Wolfram; Msinjili, Nsesheye Susan

Autoclaved Aerated Concrete (AAC) is a construction material with a large range of applications. In order to generate more sustainable materials, the possibility of the incorporation of by-products and left-over-materials from various processes is investigated. The focus of this research is the

Investigation into the behaviour of concrete anchored diaphragm walls under earthquake condition

International Nuclear Information System (INIS)

Saba, H. R.; Rahaii, A. R.

2003-01-01

Diaphragm walls are frequently used in civil Engineering projects. Considering the variety and important volume of consumed materials (concrete, anchors and soil), one of the important factors for design and construction of these walls, are their behaviour under different executive, and loading conditions. In this paper, various models of concrete diaphragms with different number of anchors and soil parameters under static and dynamic loading have been investigated using finite element method with nonlinear models. Results including the internal forces in diaphragm walls, variation of forces in the anchors, shape of the sliding surface and variation of pressure in soil are obtained and compared. An experimental tool with suitable measurement systems for determining the pressure and internal forces was designed and realised. Also with similitude and dimensional analyses, diaphragms with different number of anchors were built and set on the shaking table test and experimented under different accelograms. Finally results of nonlinear dynamic analysis were compared with experimental results

Dynamic thermal reaction analysis of wall structures in various cooling operation conditions

International Nuclear Information System (INIS)

Yan, Biao; Long, Enshen; Meng, Xi

2015-01-01

Highlights: • Four different envelop structures are separately built in the same test building. • Cooling temperature and operation time were chosen as perturbations. • State Space Method is used to analyze the influence of wall sequence order. • The numerical models are validated by the comparisons of theory and test results. • The contrast of temperature change of different envelop structures was stark. - Abstract: This paper proposes a methodology of performance assessing of envelops under different cooling operation conditions, by focusing on indoor temperature change and dynamic thermal behavior performance of walls. To obtain a general relationship between the thermal environment change and the reaction of envelop, variously insulated walls made with the same insulation material are separately built in the same wall of a testing building with the four different structures, namely self-heat insulation (full insulation material), exterior insulation, internal insulation and intermediate insulation. The advantage of this setting is that the test targets are exposed to the same environmental variables, and the tests results are thus comparable. The target responses to two types of perturbations, cooling temperature and operation time were chosen as the important variations in the tests. Parameters of cooling set temperature of 22 °C and 18 °C, operation and restoring time 10 min and 15 min are set in the test models, and discussed with simulation results respectively. The results reveal that the exterior insulation and internal insulation are more sensitive to thermal environment change than self-heat insulation and intermediate insulation.

Thermal and Hygric Expansion of High Performance Concrete

OpenAIRE

J. Toman; R. Černý

2001-01-01

The linear thermal expansion coefficient of two types of high performance concrete was measured in the temperature range from 20 °C to 1000 °C, and the linear hygric expansion coefficient was determined in the moisture range from dry material to saturation water content. Comparative methods were applied for measurements of both coefficients. The experimental results show that both the effect of temperature on the values of linear thermal expansion coefficients and the effect of moisture on th...

PCM-enhanced lime plasters for vernacular and contemporary architecture

Science.gov (United States)

Theodoridou, Magdalini; Kyriakou, Loucas; Ioannou, Ioannis

2016-04-01

have significantly lower (by 55%) thermal conductivity and increased (by almost 20%) specific heat capacity at 90 days after laboratory production. At the same time, even though porosity values are higher for the PCM-enhanced renders, compared to the reference mixtures, their capillary absorption coefficient is significantly reduced (up to 60%). This is of great importance in the case of renders and may well be an indication for better expected durability in the long-term. Regarding the mechanical properties of the laboratory composites, PCM addition seems to have a negative effect on the hydraulic plasters. In contrast, when PCM is added to the hydrated lime-based plaster, no change is observed for the flexural strength, while the compressive strength is notably improved (up to 36%). The apparently improved properties of the PCM-enhanced plasters render them particularly appropriate for application in southern European climatic conditions. Due to their compatibility with traditional substrate materials (e.g. natural stone), the aforementioned composites may be used not only in new contemporary structures, but also for the renovation and retrofitting of existing buildings. The lime-based nature of their matrix and their physico-mechanical properties further extend their applicability to listed and monumental buildings.

Cracked reinforced concrete walls of chimneys, silos and cooling towers as result of using formworks

Directory of Open Access Journals (Sweden)

Maj Marek

2018-01-01

Full Text Available There are presented in this paper some problems connected with reinforced concrete shell objects operation in the aggressive environment and built in method of formworks. Reinforced concrete chimneys, cooling towers, silos and other shells were built for decades. Durability of cracked shells are one of the most important parameters during process of designing, construction and exploitation of shells. Some reasons of appearance of horizontal and vertical cracks as temperature, pressure of stored material, live loads e.g. dynamic character of wind, moisture, influence of construction joints, thermal insulation, chemistry active environmental etc. reduce the carrying capacity of the walls. Formworks, as is occurred recently, are the reason for technological joints with leaking connection, imperfections of flexible formworks slabs and as result can initiate cracks. Cracked surface of this constructions causes decreasing capacity and lower the state of reliability. Horizontal, vertical cracks can caused corrosion of concrete and steel bars, decreasing stiffness of contraction, increasing of deflection and carbonation of concrete cover. Local and global imperfactions of concrete shells are increasing according to greater number of cracks...

Studies on irradiation resisting paints for concrete structures in nuclear power plant, 4

International Nuclear Information System (INIS)

Kita, Daizo; Sumino, Masahiro; Goto, Tomoaki.

1978-01-01

It is necessary for irradiation resisting paints to adhere tightly to concrete in order to exhibit superior effects. Adhesion of paints to concrete is greatly affected by moisture content and the form of moisture in concrete. Further, adhesion will probably be affected by differences in concrete surface conditions between floors, walls and ceilings. Therefore, experiments were conducted with concrete to make clear allowable moisture conditions and the influence of these concrete surfaces. The following results were obtained. (1) Adhesion of paint becomes stronger as pF-value increases, that is, as moisture content falls. (2) The allowable pF-values and moisture contents were respectively 5.5 over and 4.5% under at floor, 4.4 over and 4.9% under at wall, and 4.3 over and 5% under at ceiling. (3) Fractures of paint films under these allowable conditions occurred in paint-concrete composites, and the fractured concrete thickness than was 0.5-0.8 mm and measured adhesion strength was 33 kg/cm 2 . (auth.)

Thermal denaturation of sunflower globulins in low moisture conditions

International Nuclear Information System (INIS)

Rouilly, A.; Orliac, O.; Silvestre, F.; Rigal, L.

2003-01-01

DSC analysis in pressure resisting pans of sunflower oil cake makes appear the endothermic peak of sunflower globulins denaturation. Its temperature decreases from 189.5 to 119.9 deg. C while the corresponding enthalpy increases from 2.6 to 3.3 J/g of sample, or from 6.7 to 12.2 J/g of dry protein, when the samples moisture content varies from 0 to 30.0% of the total weight. The plot of the denaturation temperature versus the moisture content is not linear but has a rounded global shape and seems to follow the hydration behavior of the proteins, modeled with the sorption isotherm. As it can be seen on scanning electron microscopy (SEM) micrographs, protein corpuscles 'melt' after such a thermal treatment and large aggregates form by coagulation. Moisture dependence of the 'fusion' temperature of native proteic organization, in low moisture conditions, offers so a new characterization method for the use of vegetable proteins in agro-materials

Thermal denaturation of sunflower globulins in low moisture conditions

Energy Technology Data Exchange (ETDEWEB)

Rouilly, A.; Orliac, O.; Silvestre, F.; Rigal, L

2003-03-05

DSC analysis in pressure resisting pans of sunflower oil cake makes appear the endothermic peak of sunflower globulins denaturation. Its temperature decreases from 189.5 to 119.9 deg. C while the corresponding enthalpy increases from 2.6 to 3.3 J/g of sample, or from 6.7 to 12.2 J/g of dry protein, when the samples moisture content varies from 0 to 30.0% of the total weight. The plot of the denaturation temperature versus the moisture content is not linear but has a rounded global shape and seems to follow the hydration behavior of the proteins, modeled with the sorption isotherm. As it can be seen on scanning electron microscopy (SEM) micrographs, protein corpuscles 'melt' after such a thermal treatment and large aggregates form by coagulation. Moisture dependence of the 'fusion' temperature of native proteic organization, in low moisture conditions, offers so a new characterization method for the use of vegetable proteins in agro-materials.

Reliability and service life of wood structures and buildings

OpenAIRE

Zdeňka Havířová; Pavel Kubů

2005-01-01

Service life of constructions and buildings of wood is dependent on temperature and moisture conditions in layers of the building cladding where the wood framework is built in. Temperature/moisture conditions or the corresponding equilibrium moisture content (EMC) of the construction show considerable effects on the functional reliability of the whole building from the viewpoint of mechanical resistance and stability (ER1), energy savings and thermal protection (ER6) and hygiene, health and e...

Bio-susceptibility of materials and thermal insulation systems used for historical buildings

Science.gov (United States)

Sterflinger, Katja; Ettenauer, Joerg; Pinar, Guadalupe

2013-04-01

In historical buildings of Northern countries high levels of energy are necessary to reach comfortable temperatures especially during the cold season. For this reason historical buildings are now also included in country specific regulations and ordinances to enhance the "energy - efficiency". Since an exterior insulation - as it is commonly used for modern architecture - is incompatible with monument protection, several indoor insulation systems based on historical and ecological materials, are on the market that should improve the thermic performance of a historical building. However, using organic materials as cellulose, loam, weed or wood, bears the risk of fungal growth and thus may lead to health problems in indoor environments. For this reason 5 different ecological indoor insulations systems were tested for their bio-susceptibility against various fungi both under natural conditions - after 2 years of installation in an historical building - and under laboratory conditions with high levels of relative humidity. Fungal growth was evaluated by classical isolation and cultivation as well as by molecular methods. The materials turned out to have a quite different susceptibility towards fungal contamination. Whereas insulations made of bloated Perlite (plaster and board) did not show any fungal growth after 2 years of exposition, the historical insulation made of loam and weed had high cell counts of various fungi. In laboratory experiments wooden softboard represented the best environment for fungal growth. As a result from this study, plaster and board made of bloated Perlite are presented as being the most appropriate materials for thermal insulation at least from the microbiological and hygienic point of view. For future investigations and for the monitoring of fungi in insulation and other building materials we suggest a molecular biology approach with a common protocol for quantitative DNA-extraction and amplification.

On the Effects of Variation of Thermal Conductivity in Buildings in the Italian Construction Sector

Directory of Open Access Journals (Sweden)

Umberto Berardi

2018-04-01

Full Text Available Stationary and dynamic heat and mass transfer analyses of building components are an essential part of energy efficient design of new and retrofitted buildings. Generally, a single constant thermal conductivity value is assumed for each material layer in construction components. However, the variability of thermal conductivity may depend on many factors; temperature and moisture content are among the most relevant ones. A linear temperature dependence of thermal conductivity has been found experimentally for materials made of inorganic fibers such as rockwool or fiberglass, showing lower thermal conductivities at lower temperatures. On the contrary, a nonlinear temperature dependence has been found for foamed insulation materials like polyisocyanurate, with a significant deviation from linear behavior. For this reason, thermal conductivity assumptions used in thermal calculations of construction components and in whole-building performance simulations have to be critically questioned. This study aims to evaluate how temperature affects thermal conductivity of materials in building components such as exterior walls and flat roofs in different climate conditions. Therefore, experimental conductivities measured for four common insulation materials have been used as a basis to simulate the behavior of typical construction components in three different Italian climate conditions, corresponding to the cities of Turin, Rome, and Palermo.

Measurement of Moisture in Wood for Application in the Restoration of Old Buildings.

Science.gov (United States)

Moron, Carlos; Garcia-Fuentevilla, Luisa; Garcia, Alfonso; Moron, Alberto

2016-05-14

There are many historic buildings whose construction is based on timber frame walls. Most buildings built during the nineteenth and early twentieth centuries were based on timber frame walls with vertical support elements. These timber frame elements are affected by their moisture content and by the passage of time. If the interaction of the timber frame walls with hygrothermal fluctuations were known, the maintenance of these buildings could be improved significantly. To determine the moisture content of wood there are two types of meters on the market: on the one hand, capacitance meters which consist of two side ends and where the moisture content is measured locally between two peaks. On the other hand, there are meters based on the variation of electromagnetic transmittance of timber, which depends on the moisture of timber. The second ones are very expensive and difficult to handle. This work presents a new non-intrusive capacitive sensor that measures the global moisture content in a section of the timber frame walls and therefore its accuracy is similar to the accuracy that can be obtained with electromagnetic transmittance meters. Additionally, as it is a capacitive sensor, it is low cost and easy to operate.

Dynamic Heat Storage and Cooling Capacity of a Concrete Deck with PCM and Thermally Activated Building System

DEFF Research Database (Denmark)

Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

2012-01-01

This paper presents a heat storage and cooling concept that utilizes a phase change material (PCM) and a thermally activated building system (TABS) implemented in a hollow core concrete deck. Numerical calculations of the dynamic heat storage capacity of the hollow core concrete deck element...... in the article highlight the potential of using TABS and PCM in a prefabricated concrete deck element....

Parametric Investigation of Optimum Thermal Insulation Thickness for External Walls

Directory of Open Access Journals (Sweden)

Omer Kaynakli

2011-06-01

Full Text Available Numerous studies have estimated the optimum thickness of thermal insulation materials used in building walls for different climate conditions. The economic parameters (inflation rate, discount rate, lifetime and energy costs, the heating/cooling loads of the building, the wall structure and the properties of the insulation material all affect the optimum insulation thickness. This study focused on the investigation of these parameters that affect the optimum thermal insulation thickness for building walls. To determine the optimum thickness and payback period, an economic model based on life-cycle cost analysis was used. As a result, the optimum thermal insulation thickness increased with increasing the heating and cooling energy requirements, the lifetime of the building, the inflation rate, energy costs and thermal conductivity of insulation. However, the thickness decreased with increasing the discount rate, the insulation material cost, the total wall resistance, the coefficient of performance (COP of the cooling system and the solar radiation incident on a wall. In addition, the effects of these parameters on the total life-cycle cost, payback periods and energy savings were also investigated.

Sasol Coal`s `better brick` for colliery ventilation walls

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-12-01

Sasol coal has developed a better brick for construction of ventilation walls underground. It has proven to be a speedy and cost-saving alternative to the standard concrete block used for the purpose. The brick has an interlocking design ensuring that it is laid correctly. Unlike the conventional concrete block, the ventilation walls built for the new brick do not have to be plastered to achieve airtightness. The skills required to build such walls are minimal as the design of the brick makes it virtually impossible to lay it badly or unevenly - further facilitated by the absence of mortar. While introducing the new method Sasol Coal took the opportunity to introduce a purpose-made trailer for transporting the bricks, with the trailer doubling as a building platform on site. This has further contributed to the efficiency and speed of the operation. It has also reduced to a minimum the number of times the bricks are handled, thus cutting down on breakages. 1 fig.

The impact of thermal bridges on the energy demand of buildings with double brick wall constructions

Energy Technology Data Exchange (ETDEWEB)

Theodosiou, T.G. [Department of Engineering and Management of Energy Resources, University of Western Macedonia, GR-50100 Kozani (Greece); Papadopoulos, A.M. [Laboratory of Heat Transfer and Environmental Engineering, Department of Mechanical Engineering, Aristotle University Thessaloniki, GR-54124 Thessaloniki (Greece)

2008-07-01

The implementation of the European Directive on the Energy Performance of Buildings (EPBD) is a milestone towards the improvement of energy efficiency in the building sector. However, even in cases where impressive measures can be implemented in the densely built urban environment, the less glamorous measure of building's envelope thermal insulation remains a prerequisite towards the improvement of the building's energy efficiency. Despite the insulation requirements specified by national regulations, thermal bridges in the building's envelope remain a weak spot in the constructions. Moreover, in many countries construction practices tend to implement only partially the insulation measures foreseen by regulations. As a result, thermal losses are in practice greater than those predicted during the design stage. This paper presents a study on representative wall thermal insulation configurations used in Greek buildings, in order to investigate the impact of the thermal bridges on the energy consumption. The double wall construction, used widely in Greece and not only there, is rather susceptible to the occurrence of thermal bridges, in contrast to a typical thermal insulating facade, like the one applied in Central Europe. The analysis of the thermal bridges' impact will in that sense also highlight the potential for energy renovation measures in older buildings. (author)

Heat Conductivity Resistance of Concrete Wall Panel by Water Flowing in Different Orientations of Internal PVC pipe

Science.gov (United States)

Umi, N. N.; Norazman, M. N.; Daud, N. M.; Yusof, M. A.; Yahya, M. A.; Othman, M.

2018-04-01

Green building technology and sustainability development is current focus in the world nowadays. In Malaysia and most tropical countries the maximum temperature recorded typically at 35°C. Air-conditioning system has become a necessity in occupied buildings, thereby increasing the cost of electric consumption. The aim of this study is to find out the solution in minimizing heat transfer from the external environment and intentions towards going green. In this study, the experimental work includes testing three types of concrete wall panels. The main heat intervention material in this research is 2 inch diameter Polyvinyl Chloride (PVC) pipe embedded at the center of the concrete wall panel, while the EPS foam beads were added to the cement content in the concrete mix forming the outer layer of the wall panel. Water from the rainwater harvesting system is regulated in the PVC pipe to intervene with the heat conductivity through the wall panel. Results from the experimental works show that the internal surface temperature of these heat resistance wall panels is to 3□C lower than control wall panel from plain interlocking bricks.

Experiments on moisture form of concrete and adhesion of paints

International Nuclear Information System (INIS)

Kita, Daizo; Sumino, Masahiro

1975-01-01

It is necessary for radiation-resisting paints to adhere tightly to concrete in order to exhibit superior effects. As adhesion of paints to concrete is greatly affected by moisture content of concrete, this content is checked severely in the field. However, it may be considered that adhesion will be affected by the form of the moisture in the concrete also. Therefore, experiments were conducted with mortar to investigate the interrelations between pF-moisture content, moisture form and adhesion of paint. The following results were obtained: 1) Adhesion of paint becomes stronger as moisture content falls. 2) Adhesion strength of paint rises sharply until moisture content falls to a pF-value of 5.5 after which the strength is increased gradually until moisture content reaches pF of 7.0. 3) The pF-moisture content of 5.5 varies greatly depending on the mix proportions of mortar, but the form of moisture in such cases remains fixed and unchanged. (auth.)

Construction solutions for the exterior walls in the process of increasing the width of residential buildings of brownfield construction in seismic hazardousand dry hot conditions of Central Asia

Directory of Open Access Journals (Sweden)

Usmonov Shukhrat Zaurovich

2014-02-01

Full Text Available The main object of this study is the reconstruction, renovation and modernization of the housing built in the period 1975—1985. These buildings have low energy efficiency due to the poor thermal insulation properties of the walls. These apartments do not meet the necessary requirements for year round warmth and comfort.Reconstruction is more preferable, than new-build, because of the cost saving for the land acquisition. Reconstruction is generally 1.5 times cheaper than new-build with 25—40 % reduced cost on building materials and engineering infrastructure.Increasing the width of the apartment blocks from 12 to 15 m can save 9—10 % on the consumption of thermal energy for heating and reduce the m2 construction cost by 5.5—7.0 %. In—5-9 storey high-rise buildings the savings are 3—5 %.Therefore, the width of the apartment block should preferably be between 9—12 m but could be extended to 18 m. The depth of the apartments themselves will be 5.4 — 6.0 —7.2 or 9.0 m. During the reconstruction of 5-storey residential buildings (Building Type105 in a seismic zone, an increase in the width of the block and the lateral stiffness of the building is achieved by building a new reinforced concrete (RC frame on both sides of the building with a depth of between 2 and 6 m. This technique is especially effective in increasing the seismic resistance of the building. Self-supporting walls of cellular concrete blocks (density 600 kg/m3 and a thickness of 300 mm are constructed on the outside of the frame, taking care to avoid cold bridges.Model studies have shown that in the conditions of hot-arid climate the thickness of the air gap in a ventilated facade does not significantly change the cooling-energy consumption of the building, and heating consumption is significantly increased. The building's energy consumption is most influenced by the volume of the air in the air gap. By increasing the ventilation rate in the air gap, the energy

Pore structure modification of cement concretes by impregnation with sulfur-containing compounds

Directory of Open Access Journals (Sweden)

YANAKHMETOV Marat Rafisovich

2015-02-01

Full Text Available The authors study how the impregnation with sulfur-containing compounds changes the concrete pore structure and how it influences on the water absorption and watertightness. The results of this research indicate that impregnation of cement concrete with water-based solution of polysulphide modifies pore structure of cement concrete in such a way that it decreases total and effective porosity, reduces water absorption and increases watertightness. The proposed impregnation based on mineral helps to protect for a long time the most vulnerable parts of buildings – basements, foundations, as well as places on the facades of buildings exposed to rain, snow and groundwater. Application of the new product in the construction industry can increase the durability of materials, preventing the destruction processes caused by weathering, remove excess moisture in damp basements. The surfaces treated by protective compounds acquire antisoiling properties for a long time, and due to reduced thermal conductivity the cost of heating buildings is decreased. The effectiveness of the actions and the relatively low cost of proposed hydrophobizator makes it possible to spread widely the proposed protection method for building structures.

Remedial measures in Czech houses with high radium content in building material

International Nuclear Information System (INIS)

Hulka, J.; Thomas, J.

1999-01-01

Three groups of houses built from materials having elevated natural radioactivity content were found in the Czech republic. These are: 1) about hundred old houses in Jachymov (Joachimstal) in Northern Bohemia, where residues from factory producing uranium paints were used as plaster and mortar before the World War II (radium concentration up to 1 MBq/kg, indoor gamma dose rate up to 10-100 μGy/h); 2) some 20 000 family houses built from highly emanating aerated concrete with radium content 500-1000 Bq/kg (produced from flying ash) in the period 1963-1980; 3) more than 2000 family houses from slag concrete of radium content about 3 kBq/kg in average (indoor gamma dose rate up to 2 μGy/h) made in the period 1972-83. Remedy measures were undertaken with state financial support. Intervention levels were laid down 200 Bq/m 3 for EEC (equivalent equilibrium radon concentration - it is equivalent to radon gas concentration 500 Bq/m 3 ), 2 μGy/h for indoor gamma dose rate. Weighted sum of indoor radon and indoor gamma dose rate was used if the latter was above 0,5 μGy/h. The central heat recovery ventilation units were used largely as the remedy measures. Some houses were demolished, in some houses local contamination of plasters was removed. Other tested measures (removal of the contaminated building material in great amount, gamma shielding, wall coating, etc.) proved to be not effective or not acceptable in practice. (author)

Seismic behavior of reinforced concrete shear walls

International Nuclear Information System (INIS)

Wang, F.; Gantenbein, F.

1989-01-01

Reinforced concrete shear walls have an important contribution to building stiffness. So, it is necessary to know their behavior under seismic loads. The ultimate behavior study of shear walls subjected to dynamic loadings includes: - a description of the nonlinear global model based on cyclic static tests, - nonlinear time history calculations for various forcing functions. The comparison of linear and nonlinear results shows important margins related to the ductility when the bandwidth of the forcing function is narrow and centred on the wall natural frequency

History of the Development of Liquid-Applied Coatings for Protection of Reinforced Concrete

Science.gov (United States)

Curran, Joseph J.; Hansen, marlin H.

2005-01-01

Corrosion of reinforcing steel in concrete is an insidious problem for structures at Kennedy Space Center (KSC). KSC is located on the coast of Florida in a highly corrosive atmosphere. Launch pads, highway bridge infrastructure, and buildings are strongly affected. To mitigate these problems, NASA initiated a development program for a Galvanic Liquid-Applied Coating System (GLACS). A breakthrough in this area would have great commercial value in transportation, marine and construction industry infrastructures. The patented NASA GLACS system has undergone considerable testing to meet the needs of commercialization. A moisture-cure coating gives excellent adhesion with ease of application compared to existing galvanic products on the market. The latest development, GalvaCori; can be sprayed or hand applied to almost any structure shape. A self-adhesive conductive tape system has been devised to simplify current collection within the coating areas. In testing programs, millivolt potential and milliamp output per square foot of anode have been closely studied at actual test sites. These two parameters are probably the most challenging items of a resin-based, room-temperature-applied, galvanic coating. Extensive re-formulation has resulted in a system that provides the needed polarization for catholic protection of reinforcing steel in concrete in a variety of structure environments. The rate of corrosion of rebar in concrete is greatly affected by the environment of the structure. In addition to this, for any given concrete structure; moisture level, carbonization, and chloride contamination influences the rate of rebar corrosion. Similarly, the cathodic protection level of galvanic systems is also dependent on the moisture level of the concrete. GalvaCorr is formulated to maintain galvanic activity as the moisture level of the structure declines. GalvaCorr is available as a three-part kit. The mixing step requires about ten minutes. The viscosity can be easily

Measurement of Moisture in Wood for Application in the Restoration of Old Buildings

Science.gov (United States)

Moron, Carlos; Garcia-Fuentevilla, Luisa; Garcia, Alfonso; Moron, Alberto

2016-01-01

There are many historic buildings whose construction is based on timber frame walls. Most buildings built during the nineteenth and early twentieth centuries were based on timber frame walls with vertical support elements. These timber frame elements are affected by their moisture content and by the passage of time. If the interaction of the timber frame walls with hygrothermal fluctuations were known, the maintenance of these buildings could be improved significantly. To determine the moisture content of wood there are two types of meters on the market: on the one hand, capacitance meters which consist of two side ends and where the moisture content is measured locally between two peaks. On the other hand, there are meters based on the variation of electromagnetic transmittance of timber, which depends on the moisture of timber. The second ones are very expensive and difficult to handle. This work presents a new non-intrusive capacitive sensor that measures the global moisture content in a section of the timber frame walls and therefore its accuracy is similar to the accuracy that can be obtained with electromagnetic transmittance meters. Additionally, as it is a capacitive sensor, it is low cost and easy to operate. PMID:27187410

Quality evaluation of carbonaceous industrial by-products and its effect on properties of autoclave aerated concrete

Science.gov (United States)

Fomina, E. V.; Lesovik, V. S.; Fomin, A. E.; Kozhukhova, N. I.; Lebedev, M. S.

2018-03-01

Argillite is a carbonaceous industrial by-product that is a potential source in environmentally friendly and source-saving construction industry. In this research, chemical and mineral composition as well as particle size distribution of argillite were studied and used to develop autoclave aerated concrete as partial substitute of quartz sand. Effect of the argillite as a mineral admixture in autoclave aerated concrete was investigated in terms of compressive and tensile strength, density, heat conductivity etc. The obtained results demonstrated an efficiency of argillite as an energy-saving material in autoclave construction composites.

Measurement of thermal transmittance of opaque facade wall relationship with meteorological conditions

Directory of Open Access Journals (Sweden)

Antunović Biljana S.

2015-01-01

Full Text Available This paper presents the results of measurements of thermal transmittance or as otherwise called U-value [W/m2⋅K] of opaque facade wall of preschool institution built in 1977. The building has an incomplete technical documentation according to which considered wall was built of brick and masonry mortar. Thermal characteristics of the incorporated materials have not been specified. Considering that in the period of building construction JUS standards was used, a possible range of calculated U-vales was obtained (1,241-1,404 W/m2·K. Measurements were performed in accordance with ISO 9869 during three time periods with the resulting U-values (1,269±0,276 W/m2·K; 1,025±0,175 W/m2·K; 1,200±0,212 W/m2·K that do not differ from each other within experimental uncertainty. Furthermore, the correlation of the measured U-values and meteorological conditions that prevailed during the measurements was analyzed. In the second measurement period, the average values of the total cloud cover and low cloud cover were less, and the average duration of sunshine was longer than in the other two measurement periods.

Moisture Dynamics in Building Envelopes

DEFF Research Database (Denmark)

Peuhkuri, Ruut Hannele

2003-01-01

The overall scope of this Thesis "Moisture dynamics in building envelopes" has been to characterise how the various porous insulation materials investigated performed hygrothermally under conditions similar to those in a typical building envelope. As a result of the changing temperature...... part of the Thesis consists of a theory and literature review on the moisture storage and transport processes (Chapter 2), on the non-Fickian moisture transport (Chapter 3)and on the methods for determining the moisture properties (Chapter 4). In the second part, the conducted experimental work...

Heat-insulating mortars for older buildings. Problem solutions for all kinds of building materials. Waermedaemmputze in der Altbausanierung. Problemloesungen auf allen Untergruenden

Energy Technology Data Exchange (ETDEWEB)

Bresch, C M

1988-01-01

The book is a guideline for the renovation and sanitation of outer walls with improved thermal insulation. Heat-insulating mortars are described, and machines and equipment for efficient roughcasting are listed. Subjects: Heat-insulating mortars; protective cover and thermal insulation; surfaces to be plastered (old brick walls, house fronts, wall cracks); renovation or sanitation; colours and structures; manual and mechanized roughcasting; calculations; an exemplary case of sanitation, solutions for constructional details; light-weight mortar; heat-insulating mortars in Austria. (HWJ).

A new aspects for project of subsequent thermal resistance extension at old-timer timbering constructions of wood

Directory of Open Access Journals (Sweden)

Zdeňka Havířová

2006-01-01

Full Text Available To ensure the reliability of subsequent thermal resistance extension at old-timer timbering constructions of wood for the period of their supposed service life a more profound analysis of construction is necessary from the aspect of a global thermal/technical evaluation. Service life of these buildings is dependent on temperature and moisture conditions in layers of the building cladding where the wood framework is built in. Temperature/moisture conditions or the corresponding equilibrium moisture content (EMC of the construction show considerable effects on the functional reliability of the whole building from the viewpoint of mechanical resistance and stability, energy savings and thermal protection and hygiene, health and environment protection.

A numerical study of external building walls containing phase change materials (PCM)

International Nuclear Information System (INIS)

Izquierdo-Barrientos, M.A.; Belmonte, J.F.; Rodríguez-Sánchez, D.; Molina, A.E.; Almendros-Ibáñez, J.A.

2012-01-01

Phase Change Materials (PCMs) have been receiving increased attention, due to their capacity to store large amounts of thermal energy in narrow temperature ranges. This property makes them ideal for passive heat storage in the envelopes of buildings. To study the influence of PCMs in external building walls, a one-dimensional transient heat transfer model has been developed and solved numerically using a finite difference technique. Different external building wall configurations were analyzed for a typical building wall by varying the location of the PCM layer, the orientation of the wall, the ambient conditions and the phase transition temperature of the PCM. The integration of a PCM layer into a building wall diminished the amplitude of the instantaneous heat flux through the wall when the melting temperature of the PCM was properly selected according to the season and wall orientation. Conversely, the results of the work show that there is no significant reduction in the total heat lost during winter regardless of the wall orientation or PCM transition temperature. Higher differences were observed in the heat gained during the summer period, due to the elevated solar radiation fluxes. The high thermal inertia of the wall implies that the inclusion of a PCM layer increases the thermal load during the day while decreasing the thermal load during the night. - Highlights: ► A comparative simulation of a building wall with and without PCMs has been conducted. ► PCM is selected according with the season, the wall orientation and the melting temperature. ► PCM in a building wall help to diminish the internal air temperature swings and to regulate the heat transfer.

IMPACT ON THE APPLICATION OF INSULATION IN BUILDINGS TO ACHIEVE THERMAL COMFORT (A CASE STUDY: LAUSER OFFICE BUILDING IN BANDA ACEH

Directory of Open Access Journals (Sweden)

Nova Purnama Lisa

2014-12-01

Full Text Available From the results of research studies on the impact of the use of insulation in buildings, reducing solar radiation on buildings to improve indoor comfort by applying the Principles of radiation reduction in buildings naturally using insulation application that serves as an insulator against the building materials, use of thermal insulation in particular mounted on the roof of the building and the walls are located on second floor and the third floor Lauser office building, Calculate the cooling load for each room that was on second floor and the third floor based on the geographical location or position of the building, climate data, building material data , and the intensity of the spatial characteristics which include lighting, solar radiation, user activity and electrical appliances being used. The calculation is done with the help of Ecotech v.5, 2011. The location and position on the third floor of a building with a flat roof cast concrete, so that the heat absorbed by the platform, and two times greater than the amount of heat radiation is absorbed by the material in the direction of the light falling the sun is at an angle <30°C. The simulation results on the building with the addition of thermal insulation on all walls and the roof of the inside of the foam material ultrafolmadehid, without changing the model building and similar activities in accordance with the existing condition and the condition of the room using the air conditioner at a temperature of 18-26°C, indicating a decrease in cooling load signifinikan in any space reaches 40% of the total cooling load required on the lauser office building. Comparing the simulation results Ecotech temperature v.5 2011 with field measurements as a validation of the simulation results in order to achieve thermal comfort in buildings and can menggurangi use energy consumption in buildings and can be used as a reference in planning space-based conditioning systems energy efficient.

Modeling of shear wall buildings