This paper reports the modeling of residual compressive strength of fired clay bricks submitted to elevated temperature. Five formulations were used and the explored temperatures were 95˚C, 200˚C, 550˚C, 700˚C and 950...This paper reports the modeling of residual compressive strength of fired clay bricks submitted to elevated temperature. Five formulations were used and the explored temperatures were 95˚C, 200˚C, 550˚C, 700˚C and 950˚C. The stress–strain relationships and the mechanical properties (including Young’s modulus and compressive strength) were assessed using a uniaxial compressive strength machine. A proposed model equation was established and found satisfying. The elastic modulus was evaluated and tested with one existing model together with two proposed models. The proposed model was both satisfying and even more precise than the existing one. The overall results show that the effect of temperature on the mechanical properties of clays can be accurately described through the definition of thermal damage using elastic modulus.展开更多
This article deals with the characterization of local materials used in insulation building heat. These materials are bricks of earth compressed and stabilized with rice husks. Thermal conductivity, the specific heat ...This article deals with the characterization of local materials used in insulation building heat. These materials are bricks of earth compressed and stabilized with rice husks. Thermal conductivity, the specific heat and the thermal diffusivity of materials based on clay incorporating rate of 0, 2%, 4%, 6%, 8% and 10% are determined. The results showed that the clay blocks + rice balls had better thermal insulators than simple clay blocks. However, these composite materials used for the envelope of the building must have sufficient mechanical resistance when used in construction. The measurement of mechanical properties such as compressive strength showed an improvement of 6% and beyond, a drop in resistance when increasing rice husks in clay is observed. These results allow to specify the optimal conditions of use of these materials for the building envelope.展开更多
Clay brick masonry unit(CBMU) walls are widely used in building structures,and its damage and protection under explosion loads have been a matter of concern in the field of engineering protection.In this paper,a serie...Clay brick masonry unit(CBMU) walls are widely used in building structures,and its damage and protection under explosion loads have been a matter of concern in the field of engineering protection.In this paper,a series of full-scale experiments of the response characteristics of 24 cm CMBU walls unreinforced and reinforced with polyurea elastomer subjected to blast loading were carried out.Through setting 5.0 kg TNT charges at different stand-off distances,the damage characteristics of masonry walls at different scaled distances were obtained.The reinforcement effect of different polyurea coating thicknesses and methods on the blast resistance performance of masonry walls under single and repeated loads were also explored.Five failure grades were summarized according to the dynamic response features of masonry walls.Based on the stress wave propagation pattern in multi-media composite structures,the internal stress distribution of masonry walls were analyzed,and the division basis of the masonry walls’ failure grades was then quantified.Combined with Scanning Electron Microscope(SEM)images,the deformation characteristics of soft and hard segments of polyurea and effects of detonation products on microstructures were revealed respectively,which provides an important reference for the design and application of polyurea in the blast resistance of clay brick masonry walls.展开更多
Coal is used as a traditional fuel for firing of clay bricks in kilns. The cost of coal is high and is increasing continuously. This paper describes the effect of alternate fuels on compressive strength, water absorpt...Coal is used as a traditional fuel for firing of clay bricks in kilns. The cost of coal is high and is increasing continuously. This paper describes the effect of alternate fuels on compressive strength, water absorption and density of fired clay bricks. The alternate fuels used in this study were 1) rapeseed husk (Type I), 2) combination of sugarcane-bagasse, rice husk and used clothes (Type II) and 3) coal (Type III). The results show that compressive strength of bricks fired using Type I and Type II fuels was decreased to 11% and 7%, respectively, compared to those fired with coal. However, the values of water absorption and density of bricks fired with Type I and Type II fuels were almost same as exhibited by those baked with coal. This study shows that a saving of 25%, and 18% could be achieved when the bricks were fired using Type I and Type II fuels, respectively, compared to those fired with coal.展开更多
This paper presents an experimental study of the characterisation of local materials used in the construction and thermal insulation of buildings. These materials are compressed earth bricks stabilised with cement and...This paper presents an experimental study of the characterisation of local materials used in the construction and thermal insulation of buildings. These materials are compressed earth bricks stabilised with cement and sawdust. The thermal conductivity, diffusivity, effusivity, and specific heat of earth-based materials containing cement or sawdust have been determined. The results show that the blocks with earth + sawdust are better thermal insulators than the blocks with simple earth. We observe an improvement in thermal efficiency depending on the presence of sawdust or cement stabilisers. For cement stabilisation, the thermal conductivity increases (λ: 1.04 to 1.36 W·m<sup>-1</sup>·K<sup>-1</sup>), the diffusivity increases (from 4.32 × 10<sup>-7</sup> to 9.82 × 10<sup>-7</sup> m<sup>2</sup>·s<sup>-1</sup>), and the effusivity decreases (1404 - 1096 J·m<sup>-2</sup>·K<sup>-1</sup>·s<sup>-1/2</sup>). For sawdust stabilisation, the thermal conductivity decreases (λ: 1.04 to 0.64 W·m<sup>-1</sup>·K<sup>-1</sup>), the diffusivity increases (from 4.32 × 10<sup>-7</sup> to 5.9 × 10<sup>-7</sup> m<sup>2</sup>·s<sup>-1</sup>), and the effusivity decreases (1404 - 906 J·m<sup>-2</sup>·K<sup>-1</sup>·s<sup>-1/2</sup>). Improving the structural and thermal efficiency of BTC via stabilisation with derived binders or cement is beneficial for the load-bearing capacity and thermal performance of buildings.展开更多
The scarcity of housing increases as population continues to rise all over the world. Despite government efforts at providing houses, yearly demand keeps on exceeding available houses and hence the hike in rent, the c...The scarcity of housing increases as population continues to rise all over the world. Despite government efforts at providing houses, yearly demand keeps on exceeding available houses and hence the hike in rent, the cost of erecting houses and the cost of building materials. This ultimately calls for a decisive solution. This study therefore applied compliance to cost ratio (C-CR) analysis in evaluating the optimum properties of fired ceramic bricks. The optimum mix proportions of waste glass (WG) and wood saw dust (WSD) in fired bricks, that will be suitable for housing constructions were hence determined. Fired clay brick samples which contained varied proportions of WG and WSD were examined for physical, mechanical and thermal properties in line with standard procedures. The results were compared with existing standards and property evaluation index, compliance level and C-CR were applied in analyzing the results obtained. It was observed that with increasing WG content, compliance level increased. Also, cost ratio and experimental cost of each brick sample trended upward. Sample with mix proportion;20 wt% WG, 5 wt% WSD and 75 wt% clay had compliance level of 94% and C-CR index of 7.81, hence chosen as optimum mix proportion for masonry bricks.展开更多
An evaluation of the effects of additives and firing temperatures on clay bricks characteristics was studied.The two(2)additives used were sawdust ash(SDA)and iron ore tailing wastes(IOTW),and the five(5)firing temper...An evaluation of the effects of additives and firing temperatures on clay bricks characteristics was studied.The two(2)additives used were sawdust ash(SDA)and iron ore tailing wastes(IOTW),and the five(5)firing temperatures of 400o C to 1200o C at intervals of 200o C were applied.The fired bricks were tested for linear shrinkage,water absorption,density,and compressive strength.The results of the investigations showed that firing temperature improved the clay brick characteristics across all replacement levels.However,the SDA additions increased the linear shrinkage and the water absorption but decreased the density and compressive strength.On the other hand,the addition of IOTW to the clay-SDA mixture,reduced both the linear shrinkage and water absorption of the clay bricks,and increased the density and compressive strength.The statistical values and the regression models derived on the experimental data using Minitab 18 Software were significant.展开更多
This study examines the benefits of incorporating passive techniques into multilayer hollow clay brick walls to improve their dynamic thermal performance.The finite element approach was used to solve the incompressibl...This study examines the benefits of incorporating passive techniques into multilayer hollow clay brick walls to improve their dynamic thermal performance.The finite element approach was used to solve the incompressible Navier-Stokes and energy equations to analyze the dynamic thermal response of walls exposed to real thermal excitations of the Marrakesh climate.The results show that increasing the emissivity from 0.1 to 0.9 significantly increases the total heat load over 24 h.Furthermore,filling 100% of the cavities with insulation materials delayed the temperature peak by about 2.3 h and lowered the decrement factor by roughly 43%,with a value smaller than 0.07.In addition,it is demonstrated that the total thermal load is reduced by approximately 28% for improved wall configurations(100% insulation filling cavities)compared to traditional wall configurations(100% air filling cavities),which aids in improving building energy efficiency.展开更多
文摘This paper reports the modeling of residual compressive strength of fired clay bricks submitted to elevated temperature. Five formulations were used and the explored temperatures were 95˚C, 200˚C, 550˚C, 700˚C and 950˚C. The stress–strain relationships and the mechanical properties (including Young’s modulus and compressive strength) were assessed using a uniaxial compressive strength machine. A proposed model equation was established and found satisfying. The elastic modulus was evaluated and tested with one existing model together with two proposed models. The proposed model was both satisfying and even more precise than the existing one. The overall results show that the effect of temperature on the mechanical properties of clays can be accurately described through the definition of thermal damage using elastic modulus.
文摘This article deals with the characterization of local materials used in insulation building heat. These materials are bricks of earth compressed and stabilized with rice husks. Thermal conductivity, the specific heat and the thermal diffusivity of materials based on clay incorporating rate of 0, 2%, 4%, 6%, 8% and 10% are determined. The results showed that the clay blocks + rice balls had better thermal insulators than simple clay blocks. However, these composite materials used for the envelope of the building must have sufficient mechanical resistance when used in construction. The measurement of mechanical properties such as compressive strength showed an improvement of 6% and beyond, a drop in resistance when increasing rice husks in clay is observed. These results allow to specify the optimal conditions of use of these materials for the building envelope.
基金supported by the National Natural Science Foundation of China nos.51978660。
文摘Clay brick masonry unit(CBMU) walls are widely used in building structures,and its damage and protection under explosion loads have been a matter of concern in the field of engineering protection.In this paper,a series of full-scale experiments of the response characteristics of 24 cm CMBU walls unreinforced and reinforced with polyurea elastomer subjected to blast loading were carried out.Through setting 5.0 kg TNT charges at different stand-off distances,the damage characteristics of masonry walls at different scaled distances were obtained.The reinforcement effect of different polyurea coating thicknesses and methods on the blast resistance performance of masonry walls under single and repeated loads were also explored.Five failure grades were summarized according to the dynamic response features of masonry walls.Based on the stress wave propagation pattern in multi-media composite structures,the internal stress distribution of masonry walls were analyzed,and the division basis of the masonry walls’ failure grades was then quantified.Combined with Scanning Electron Microscope(SEM)images,the deformation characteristics of soft and hard segments of polyurea and effects of detonation products on microstructures were revealed respectively,which provides an important reference for the design and application of polyurea in the blast resistance of clay brick masonry walls.
文摘Coal is used as a traditional fuel for firing of clay bricks in kilns. The cost of coal is high and is increasing continuously. This paper describes the effect of alternate fuels on compressive strength, water absorption and density of fired clay bricks. The alternate fuels used in this study were 1) rapeseed husk (Type I), 2) combination of sugarcane-bagasse, rice husk and used clothes (Type II) and 3) coal (Type III). The results show that compressive strength of bricks fired using Type I and Type II fuels was decreased to 11% and 7%, respectively, compared to those fired with coal. However, the values of water absorption and density of bricks fired with Type I and Type II fuels were almost same as exhibited by those baked with coal. This study shows that a saving of 25%, and 18% could be achieved when the bricks were fired using Type I and Type II fuels, respectively, compared to those fired with coal.
文摘This paper presents an experimental study of the characterisation of local materials used in the construction and thermal insulation of buildings. These materials are compressed earth bricks stabilised with cement and sawdust. The thermal conductivity, diffusivity, effusivity, and specific heat of earth-based materials containing cement or sawdust have been determined. The results show that the blocks with earth + sawdust are better thermal insulators than the blocks with simple earth. We observe an improvement in thermal efficiency depending on the presence of sawdust or cement stabilisers. For cement stabilisation, the thermal conductivity increases (λ: 1.04 to 1.36 W·m<sup>-1</sup>·K<sup>-1</sup>), the diffusivity increases (from 4.32 × 10<sup>-7</sup> to 9.82 × 10<sup>-7</sup> m<sup>2</sup>·s<sup>-1</sup>), and the effusivity decreases (1404 - 1096 J·m<sup>-2</sup>·K<sup>-1</sup>·s<sup>-1/2</sup>). For sawdust stabilisation, the thermal conductivity decreases (λ: 1.04 to 0.64 W·m<sup>-1</sup>·K<sup>-1</sup>), the diffusivity increases (from 4.32 × 10<sup>-7</sup> to 5.9 × 10<sup>-7</sup> m<sup>2</sup>·s<sup>-1</sup>), and the effusivity decreases (1404 - 906 J·m<sup>-2</sup>·K<sup>-1</sup>·s<sup>-1/2</sup>). Improving the structural and thermal efficiency of BTC via stabilisation with derived binders or cement is beneficial for the load-bearing capacity and thermal performance of buildings.
文摘The scarcity of housing increases as population continues to rise all over the world. Despite government efforts at providing houses, yearly demand keeps on exceeding available houses and hence the hike in rent, the cost of erecting houses and the cost of building materials. This ultimately calls for a decisive solution. This study therefore applied compliance to cost ratio (C-CR) analysis in evaluating the optimum properties of fired ceramic bricks. The optimum mix proportions of waste glass (WG) and wood saw dust (WSD) in fired bricks, that will be suitable for housing constructions were hence determined. Fired clay brick samples which contained varied proportions of WG and WSD were examined for physical, mechanical and thermal properties in line with standard procedures. The results were compared with existing standards and property evaluation index, compliance level and C-CR were applied in analyzing the results obtained. It was observed that with increasing WG content, compliance level increased. Also, cost ratio and experimental cost of each brick sample trended upward. Sample with mix proportion;20 wt% WG, 5 wt% WSD and 75 wt% clay had compliance level of 94% and C-CR index of 7.81, hence chosen as optimum mix proportion for masonry bricks.
文摘An evaluation of the effects of additives and firing temperatures on clay bricks characteristics was studied.The two(2)additives used were sawdust ash(SDA)and iron ore tailing wastes(IOTW),and the five(5)firing temperatures of 400o C to 1200o C at intervals of 200o C were applied.The fired bricks were tested for linear shrinkage,water absorption,density,and compressive strength.The results of the investigations showed that firing temperature improved the clay brick characteristics across all replacement levels.However,the SDA additions increased the linear shrinkage and the water absorption but decreased the density and compressive strength.On the other hand,the addition of IOTW to the clay-SDA mixture,reduced both the linear shrinkage and water absorption of the clay bricks,and increased the density and compressive strength.The statistical values and the regression models derived on the experimental data using Minitab 18 Software were significant.
文摘This study examines the benefits of incorporating passive techniques into multilayer hollow clay brick walls to improve their dynamic thermal performance.The finite element approach was used to solve the incompressible Navier-Stokes and energy equations to analyze the dynamic thermal response of walls exposed to real thermal excitations of the Marrakesh climate.The results show that increasing the emissivity from 0.1 to 0.9 significantly increases the total heat load over 24 h.Furthermore,filling 100% of the cavities with insulation materials delayed the temperature peak by about 2.3 h and lowered the decrement factor by roughly 43%,with a value smaller than 0.07.In addition,it is demonstrated that the total thermal load is reduced by approximately 28% for improved wall configurations(100% insulation filling cavities)compared to traditional wall configurations(100% air filling cavities),which aids in improving building energy efficiency.
