Compressed earth blocks (CEB) are an alternative to cement blocks in the construction of wall masonry. However, the optimal architectural construction methods for adequate thermal comfort for occupants in hot and arid...Compressed earth blocks (CEB) are an alternative to cement blocks in the construction of wall masonry. However, the optimal architectural construction methods for adequate thermal comfort for occupants in hot and arid environments are not mastered. This article evaluates the influence of architectural and constructive modes of buildings made of CEB walls and concrete block walls, to optimize and compare their thermal comfort in the hot and dry tropical climate of Ouagadougou, Burkina Faso. Two identical pilot buildings whose envelopes are made of CEB and concrete blocks were monitored for this study. The thermal models of the pilot buildings were implemented in the SketchUp software using an extension of EnergyPlus. The models were empirically validated after calibration against measured thermal data from the buildings. The models were used to do a parametric analysis for optimization of the thermal performances by simulating plaster coatings on the exterior of walls, airtight openings and natural ventilation depending on external weather conditions. The results show that the CEB building displays 7016 hours of discomfort, equivalent to 80.1% of the time, and the concrete building displays 6948 hours of discomfort, equivalent to 79.3% of the time. The optimization by modifications reduced the discomfort to 2918 and 3125 hours respectively;i.e. equivalent to only 33.3% for the CEB building and 35.7% for the concrete building. More study should evaluate thermal optimizations in buildings in real time of usage such as residential buildings commonly used by the local middle class. The use of CEB as a construction material and passive means of improving thermal comfort is a suitable ecological and economical option to replace cementitious material.展开更多
Despite its low resistance to humidity, adobe remains the most widely used material for housing construction, particularly in developing countries. The present study aims to assess different modes of use of fermented ...Despite its low resistance to humidity, adobe remains the most widely used material for housing construction, particularly in developing countries. The present study aims to assess different modes of use of fermented RH and to evaluate their influence on the behavior of raw earth for application in plaster. The influences of two types of RH are evaluated: granular rice husk (RHg) and powdered RH (RHp). The clay mainly consists of clay (40%), silt (22%), and sand (38.4%), with a small proportion of gravel (0.24%). Its liquidity limit is 40% and the plasticity index is 26.5%. The mixtures were designed using earth and each of the two rice husks at the volumetric content of 10%, 15% and 20% of the total volume mixed with water 36.5%, 38.5% and 40.3% and fermented for three weeks. Each fermented mixture was added to the soil to form the paste, and 40 × 40 × 160 mm<sup>3</sup> test speciments were made for characterization. The results generally show an improvement in the physico-mechanical properties and water resistance of the mortars containing fermented RH, with an optimal content between 10% and 15%. The powdered RH improved the performance of the mortar better than granular RH.展开更多
This study focuses on the use of heavy fuel oil in construction material in Burkina Faso. Its mixture with silty or clayey soil is used as a coating to reinforce the walls of raw earth constructions which are very sen...This study focuses on the use of heavy fuel oil in construction material in Burkina Faso. Its mixture with silty or clayey soil is used as a coating to reinforce the walls of raw earth constructions which are very sensitive to water. The interest of this study is to determine erodibility, water content, while highlighting the influence of the porosity accessible by water on thermal diffusion in construction material containing heavy fuel oil. The heavy fuel oil was mixed with a silty-clayey soil, in different proportions, and water to make bricks samples on which tests were carried out. At the end of the experimental tests, it appears that the water content increases gradually, but not significantly with the addition of heavy fuel oil, which causes a slight increase in the speed of heat propagation through the material with reduced porosity, particularly those containing higher quantities of heavy fuel oil. Conversely, we note a good performance of heavy fuel oil in terms of water resistance properties such as porosity accessible by water and erodibility. This allows us to conclude that the mixture of heavy fuel oil and silty-clayey soil used as a coating material could greatly reduce water infiltration into the walls of housing constructions with raw earthen materials.展开更多
Oil Palm Shell (OPS) concrete can be used in different fields of construction. To determine more accurately the fields of application, it is important to know and understand the behaviour of OPS concrete over<span ...Oil Palm Shell (OPS) concrete can be used in different fields of construction. To determine more accurately the fields of application, it is important to know and understand the behaviour of OPS concrete over<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> long term and when it is in aggressive environments. This paper presents the results of studies conducted on the durability of OPS concrete. Water absorption capacity, electrical resistivity and apparent diffusion of chloride ions have been measured on different concrete samples. In addition, the behaviour of OPS concretes to carbonation was studied in an environment rich in carbon dioxide. Results show that OPS concrete ha</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> an absorptivity of 0.97 kg/m</span><sup><span style="font-family:Verdana;">2</span></sup></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">·</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">h</span><sup><span style="font-family:Verdana;">1/2</span></sup><span style="font-family:Verdana;">, an electrical resistivity of 64.37 Ω</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">·</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">m and an apparent diffusion coefficient of chloride ions of 3.84</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> × </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">10</span><sup><span style="font-family:Verdana;">-12</span></sup><span style="font-family:Verdana;"> m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/s after 90 days. All these results of OPS concrete are very close to those of concrete with normal aggregate and other lightweight concrete</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> which mean OPS concretes have globally good properties with regard to durability</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span>展开更多
This study focuses on the use of heavy fuel oil in construction in Burkina Faso.Mixed with silty and/or clay soil,it is used as a coating to reinforce the walls of raw soil constructions which are very sensitive to wa...This study focuses on the use of heavy fuel oil in construction in Burkina Faso.Mixed with silty and/or clay soil,it is used as a coating to reinforce the walls of raw soil constructions which are very sensitive to water.The interest of this paper is to shed light on the thermomechanical and above all water effects of heavy fuel oil on a sample of silty clayey soil.To achieve this,we used heavy fuel oil added in different proportions to silty clayey soil,to make sample of bricks on which tests were carried out.At the end of the experimental tests carried out on materials made(bricks)with our soil sample,it appears that heavy fuel oil moderately reduces the mechanical resistance of bricks and slightly increases thermal diffusion through them.On the contrary,we note a very good water resistance of the bricks thanks to the heavy fuel oil,in particular their water absorption by capillarity.This confirms that the mixture of heavy fuel oil and a silty-clayey soil used as a coating makes it possible to prevent the infiltration of water into the walls of raw soil constructions.However,its use as a construction material does not guarantee very good mechanical resistance,and slightly increases thermal diffusion.展开更多
This study specifically investigated the influence of the composition of aluminosilicate material <i>i.e.</span><span> </span></span><span><span><span style="font-fami...This study specifically investigated the influence of the composition of aluminosilicate material <i>i.e.</span><span> </span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"></i> the substitution of metakaolin by rice husk ash and the nature of alkaline activators (Na<sup>+</sup>/K<sup>+</sup>) on mineralogical, structural, physical and mechanical properties of geopolymer binders. This influence was evaluated based on X-ray diffraction (XRD), Fourier Transform InfraRed spectroscopy (FTIR) and Scanning Electron Microscope (SEM analyses, apparent density, water accessible porosity, compressive strength and thermal properties. Two types of geopolymer binder were synthesized according to the type of alkali activator used, the NaOH-based geopolymer and the KOH-based geopolymer. The results of characterization performed after 14 days of curing of geopolymer samples showed that the activation of the aluminosilicate powder using alkaline solution led to change in their micro</span><span style="font-family:Verdana;">structure. The highest compressive strength was obtained with the</span><span style="font-family:Verdana;"> NaOH-based geopolymer.展开更多
This study assesses the reactivity of four (04) different types of clayey earthen materials (Kamboinsé, Pabré, Saaba, and Kossodo) with Ca(OH)<sub>2</sub>, analytical lime (AL) versus lime residu...This study assesses the reactivity of four (04) different types of clayey earthen materials (Kamboinsé, Pabré, Saaba, and Kossodo) with Ca(OH)<sub>2</sub>, analytical lime (AL) versus lime residu (LR), in ambient conditions. The effect of the stabilization of the earth with the LR was also studied on the performances of compressed earth blocks (CEB). The lime content varied from 0% to 20% with respect to the mass of dry earth material. The analysis of the reactivity and physico-mechanical properties were respectively carried out on the solutions of the mixtures (earth + LR and earth + AL) and CEB (earth + LR). The mixtures were cured between 0 and 60 days at the ambient temperature of laboratory (30<span style="white-space:nowrap;">℃</span> ± 5<span style="white-space:nowrap;">℃</span>). The results showed that the reactivity of the clayey earth materials with AL is comparable to that with the LR. At the same time, this reactivity improved the physical and mechanical properties of stabilized CEB depending on the type of earth material, lime content and curing time. The maximum values of the dry compressive strength, observed for each material stabilized with 20% LR, are 6 and 7 MPa (Kamboinsé), 8.8 and 9.3 MPa (Pabré), 6 and 6.5 MPa (Saaba), 8.8 and 9.7 MPa (Kossodo) respectively at curing time of 28 and 45 days. The structural efficiency of CEB was also improved which implies that, in the current conditions, the stabilization of earth materials using LR allows to produce the CEB for potential applications in wall masonry.展开更多
文摘Compressed earth blocks (CEB) are an alternative to cement blocks in the construction of wall masonry. However, the optimal architectural construction methods for adequate thermal comfort for occupants in hot and arid environments are not mastered. This article evaluates the influence of architectural and constructive modes of buildings made of CEB walls and concrete block walls, to optimize and compare their thermal comfort in the hot and dry tropical climate of Ouagadougou, Burkina Faso. Two identical pilot buildings whose envelopes are made of CEB and concrete blocks were monitored for this study. The thermal models of the pilot buildings were implemented in the SketchUp software using an extension of EnergyPlus. The models were empirically validated after calibration against measured thermal data from the buildings. The models were used to do a parametric analysis for optimization of the thermal performances by simulating plaster coatings on the exterior of walls, airtight openings and natural ventilation depending on external weather conditions. The results show that the CEB building displays 7016 hours of discomfort, equivalent to 80.1% of the time, and the concrete building displays 6948 hours of discomfort, equivalent to 79.3% of the time. The optimization by modifications reduced the discomfort to 2918 and 3125 hours respectively;i.e. equivalent to only 33.3% for the CEB building and 35.7% for the concrete building. More study should evaluate thermal optimizations in buildings in real time of usage such as residential buildings commonly used by the local middle class. The use of CEB as a construction material and passive means of improving thermal comfort is a suitable ecological and economical option to replace cementitious material.
文摘Despite its low resistance to humidity, adobe remains the most widely used material for housing construction, particularly in developing countries. The present study aims to assess different modes of use of fermented RH and to evaluate their influence on the behavior of raw earth for application in plaster. The influences of two types of RH are evaluated: granular rice husk (RHg) and powdered RH (RHp). The clay mainly consists of clay (40%), silt (22%), and sand (38.4%), with a small proportion of gravel (0.24%). Its liquidity limit is 40% and the plasticity index is 26.5%. The mixtures were designed using earth and each of the two rice husks at the volumetric content of 10%, 15% and 20% of the total volume mixed with water 36.5%, 38.5% and 40.3% and fermented for three weeks. Each fermented mixture was added to the soil to form the paste, and 40 × 40 × 160 mm<sup>3</sup> test speciments were made for characterization. The results generally show an improvement in the physico-mechanical properties and water resistance of the mortars containing fermented RH, with an optimal content between 10% and 15%. The powdered RH improved the performance of the mortar better than granular RH.
文摘This study focuses on the use of heavy fuel oil in construction material in Burkina Faso. Its mixture with silty or clayey soil is used as a coating to reinforce the walls of raw earth constructions which are very sensitive to water. The interest of this study is to determine erodibility, water content, while highlighting the influence of the porosity accessible by water on thermal diffusion in construction material containing heavy fuel oil. The heavy fuel oil was mixed with a silty-clayey soil, in different proportions, and water to make bricks samples on which tests were carried out. At the end of the experimental tests, it appears that the water content increases gradually, but not significantly with the addition of heavy fuel oil, which causes a slight increase in the speed of heat propagation through the material with reduced porosity, particularly those containing higher quantities of heavy fuel oil. Conversely, we note a good performance of heavy fuel oil in terms of water resistance properties such as porosity accessible by water and erodibility. This allows us to conclude that the mixture of heavy fuel oil and silty-clayey soil used as a coating material could greatly reduce water infiltration into the walls of housing constructions with raw earthen materials.
文摘Oil Palm Shell (OPS) concrete can be used in different fields of construction. To determine more accurately the fields of application, it is important to know and understand the behaviour of OPS concrete over<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> long term and when it is in aggressive environments. This paper presents the results of studies conducted on the durability of OPS concrete. Water absorption capacity, electrical resistivity and apparent diffusion of chloride ions have been measured on different concrete samples. In addition, the behaviour of OPS concretes to carbonation was studied in an environment rich in carbon dioxide. Results show that OPS concrete ha</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> an absorptivity of 0.97 kg/m</span><sup><span style="font-family:Verdana;">2</span></sup></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">·</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">h</span><sup><span style="font-family:Verdana;">1/2</span></sup><span style="font-family:Verdana;">, an electrical resistivity of 64.37 Ω</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">·</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">m and an apparent diffusion coefficient of chloride ions of 3.84</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> × </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">10</span><sup><span style="font-family:Verdana;">-12</span></sup><span style="font-family:Verdana;"> m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/s after 90 days. All these results of OPS concrete are very close to those of concrete with normal aggregate and other lightweight concrete</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> which mean OPS concretes have globally good properties with regard to durability</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span>
文摘This study focuses on the use of heavy fuel oil in construction in Burkina Faso.Mixed with silty and/or clay soil,it is used as a coating to reinforce the walls of raw soil constructions which are very sensitive to water.The interest of this paper is to shed light on the thermomechanical and above all water effects of heavy fuel oil on a sample of silty clayey soil.To achieve this,we used heavy fuel oil added in different proportions to silty clayey soil,to make sample of bricks on which tests were carried out.At the end of the experimental tests carried out on materials made(bricks)with our soil sample,it appears that heavy fuel oil moderately reduces the mechanical resistance of bricks and slightly increases thermal diffusion through them.On the contrary,we note a very good water resistance of the bricks thanks to the heavy fuel oil,in particular their water absorption by capillarity.This confirms that the mixture of heavy fuel oil and a silty-clayey soil used as a coating makes it possible to prevent the infiltration of water into the walls of raw soil constructions.However,its use as a construction material does not guarantee very good mechanical resistance,and slightly increases thermal diffusion.
文摘This study specifically investigated the influence of the composition of aluminosilicate material <i>i.e.</span><span> </span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"></i> the substitution of metakaolin by rice husk ash and the nature of alkaline activators (Na<sup>+</sup>/K<sup>+</sup>) on mineralogical, structural, physical and mechanical properties of geopolymer binders. This influence was evaluated based on X-ray diffraction (XRD), Fourier Transform InfraRed spectroscopy (FTIR) and Scanning Electron Microscope (SEM analyses, apparent density, water accessible porosity, compressive strength and thermal properties. Two types of geopolymer binder were synthesized according to the type of alkali activator used, the NaOH-based geopolymer and the KOH-based geopolymer. The results of characterization performed after 14 days of curing of geopolymer samples showed that the activation of the aluminosilicate powder using alkaline solution led to change in their micro</span><span style="font-family:Verdana;">structure. The highest compressive strength was obtained with the</span><span style="font-family:Verdana;"> NaOH-based geopolymer.
文摘This study assesses the reactivity of four (04) different types of clayey earthen materials (Kamboinsé, Pabré, Saaba, and Kossodo) with Ca(OH)<sub>2</sub>, analytical lime (AL) versus lime residu (LR), in ambient conditions. The effect of the stabilization of the earth with the LR was also studied on the performances of compressed earth blocks (CEB). The lime content varied from 0% to 20% with respect to the mass of dry earth material. The analysis of the reactivity and physico-mechanical properties were respectively carried out on the solutions of the mixtures (earth + LR and earth + AL) and CEB (earth + LR). The mixtures were cured between 0 and 60 days at the ambient temperature of laboratory (30<span style="white-space:nowrap;">℃</span> ± 5<span style="white-space:nowrap;">℃</span>). The results showed that the reactivity of the clayey earth materials with AL is comparable to that with the LR. At the same time, this reactivity improved the physical and mechanical properties of stabilized CEB depending on the type of earth material, lime content and curing time. The maximum values of the dry compressive strength, observed for each material stabilized with 20% LR, are 6 and 7 MPa (Kamboinsé), 8.8 and 9.3 MPa (Pabré), 6 and 6.5 MPa (Saaba), 8.8 and 9.7 MPa (Kossodo) respectively at curing time of 28 and 45 days. The structural efficiency of CEB was also improved which implies that, in the current conditions, the stabilization of earth materials using LR allows to produce the CEB for potential applications in wall masonry.
