The present study aims to analyzse alternative passive design solutions for enhancing building energy and hygrothermal efficiency in the Sahelian zone.To achieve this,a model representing a standard single-storey ceme...The present study aims to analyzse alternative passive design solutions for enhancing building energy and hygrothermal efficiency in the Sahelian zone.To achieve this,a model representing a standard single-storey cementhollow block dwelling building and its relevant parameters was input into EnergyPlus,combined with OpenStudio or SketchUp.Scenarios were then analyzed to evaluate the effects of roof solar reflectivity,wall external insulation,natural ventilation,and their combined options.First,the base case,serving as a reference model,was validated using measured and simulated temperatures by calculating the scientific criteria,such as the NBME and CVRMSE coefficients recommended by the ASHRAE and IPVM standards.Additionally,the numerical simulation was used to compare interior temperatures,discomfort hours,thermal parameters,and the hygrothermal index(IHT)across seven cases studied.The reference model simulation indicated that cement-based hollow blocks are less effective for building envelopes in the Sahelian climate,with 51.48%discomfort hours and an IHT of 1.6,as shown in the Givoni diagram.The results revealed that the wall external insulation was the most effective passive solution,with 56%of comfort hours and an IHT of 0.7,which indicates the expected position of the model within the hygrothermal comfort zone of the Sahelian climate.Combining passive strategies yields the best scenario,resulting in a 28.25%reduction in annual total discomfort hours compared to the base case.These simulations demonstrated the effectiveness of accessible passive design solutions applicable in dwelling construction for the sustainable development of countries in the Sahelian climate.展开更多
Current pavement design methods do not allow for the reduction of early deformation of the surface layers of bituminous pavements in the city of Ouagadougou. Weather conditions combined with traffic, particularly duri...Current pavement design methods do not allow for the reduction of early deformation of the surface layers of bituminous pavements in the city of Ouagadougou. Weather conditions combined with traffic, particularly during heat waves, are factors. The temperature at the surface of the bituminous pavement can reach 62˚C but the complex modulus associated with this temperature is not taken into account in the design, hence the interest in proposing laws of dependence of the complex moduli is taken into account in the maximum temperatures of the pavement surface. The objective of this paper is to propose an experimental method to determine the temperature dependence of the complex moduli of asphalt mixes for temperatures between 40˚C and 70˚C. This experimental method consists of performing axial compression tests on cylindrical asphalt specimens. It was applied to three different formulas of bituminous mixes, intended for the wearing course, obtained from mixes of crushed granites, granular classes 6/10, 4/6 and 0/4, pure bitumens of grade 50/70, 35/50 and modified bitumen of grade 10/65. The comparative study of the experimental results obtained with the results of a semi-empirical methodology revealed a root mean square deviation from the mean of between 6.58% and 14.8% of the norms of the complex moduli (modulus of rigidity) of the asphalt mixes for a fixed frequency of solicitations of 10 Hz. The consistency of these results with data from the literature led to the initial conclusion that asphalt mixes formulated with 35/50 and 10/65 bitumen would have better compressive strength than those formulated with 50/70 bitumen, for exposure temperatures between 40˚C and 70˚C. This experimental approach could be an alternative to the complex modulus test for determining the modulus of rigidity for design purposes under real pavement exposure conditions in the city of Ouagadougou during heat waves.展开更多
Sustainable building design in dry tropical areas recommends reducing exposure of buildings to solar radiation and/or designing efficient enclosures with satisfactory thermal inertia.We propose in this paper a study o...Sustainable building design in dry tropical areas recommends reducing exposure of buildings to solar radiation and/or designing efficient enclosures with satisfactory thermal inertia.We propose in this paper a study of the influence of the infiltration rate in the building and the coefficient of thermal transfer by convection of the walls, on the thermal comfort using TRNSYS software. All the models carried out were validated by recognized scientific criteria, namely correlation （R） and determination （R2） coefficients on the one hand and NBME and CVRMSE coefficients defined by ASHARE, 2002 on the other hand. The results obtained indicate that the modulation of the air infiltration rate allows the simulations on TRNSYS to be compared to in-situ measurements, with an annual average relative difference of 2.86% on the temperature difference. Furthermore, depending on the parameterization of the heat transfer coefficients by convection of the internal and external walls of walls used in the STD, the average annual difference can be reduced by 1% to 4% between the predictions and the measurements.展开更多
Despite the developments of sectors which aim at valorizing recyclable materials, landfills remain essential in integrated waste management. The construction of such infrastructures is an engineering challenge that mu...Despite the developments of sectors which aim at valorizing recyclable materials, landfills remain essential in integrated waste management. The construction of such infrastructures is an engineering challenge that must be proven over the long term. The purpose of this study is to understand the modification of the hydromechanical properties of bottom liners of landfills that may occur during their exploitation under leachate action. To do so, on the basis of its parameters of nature, a swelling clay from Burkina Faso is selected from soils of seven localities in Burkina Faso （West Africa）. Laboratory tests carried out with distilled water and then with a young synthetic leachate show a degradation of the permeability of this clay from 2.42 × 10^-10 m/s to 1.01 × 10^-9 m/s. In addition, leachate leads to an inhibition of the swelling and a remarkable increase of its compressibility, inducing significant settlement. With the increase in permeability, the primary consolidation settlement is increasing faster. Changes in the hydromechanical behavior can be attributed to the clays mineralogy, mainly cation exchange and the development of the diffuse double layer.展开更多
The present study focuses on the formulation of new composite consisting of plaster and raffia vinifera particle (RVP) with the purpose to reducing energy consumption. The aim of this study is to test this new compoun...The present study focuses on the formulation of new composite consisting of plaster and raffia vinifera particle (RVP) with the purpose to reducing energy consumption. The aim of this study is to test this new compound as an insulating eco-material in building in a tropical climate. The composites samples were developed by mixing plaster with raffia vinifera particles (RVP) using three different sizes (1.6 mm, 2.5 mm and 4 mm). The effects of four different RVP incorporations rates (i.e., 0wt%, 5wt%;10wt%;15wt%) on physical, thermal, mechanicals properties of the composites were investigated. In addition, the use of the raffia vinifera particles and plaster based composite material as building envelopes thermal insulation material is studied by the habitable cell thermal behavior instrumentation. The results indicate that the incorporation of raffia vinifera particle leads to improve the new composite physical, mechanical and thermal properties. And the parametric analysis reveals that the sampling rate and the size of raffia vinifera particles are the most decisive factor to impact these properties, and to decreases in the thermal conductivity which leads to an improvement to the thermal resistance and energy savings. The best improvement of plaster composite was obtained at the raffia vinifera particles size between 2.5 and 4.0 mm loading of 5wt% (C95P5R) with a good ratio of thermo-physical-mechanical properties. Additionally, the habitable cell experimental thermal behavior, with the new raffia vinifera particles and plaster-based composite as thermal insulating material for building walls, gives an average damping of 4°C and 5.8°C in the insulated house interior environment respectively for cold and hot cases compared to the outside environment and the uninsulated house interior environment. The current study highlights that this mixture gives the new composite thermal insulation properties applicable in the eco-construction of habitats in tropical environments.展开更多
Flexible pavements, whose surface layers are made from hot mix asphalt, may show rutting in some of these infrastructures during the first months of life. In the city of Ouagadougou, this rutting phenomenon is sometim...Flexible pavements, whose surface layers are made from hot mix asphalt, may show rutting in some of these infrastructures during the first months of life. In the city of Ouagadougou, this rutting phenomenon is sometimes observed. The objective of this article is to quantify the thermal response of the wearing course of national roads 1 and 2, when they are subjected to the braking of heavy trucks of 13 tons and 20 tons per axle. The meteorological conditions retained are those of the Burkinabe climate. The evaluation of the temperature was carried out by numerical simulation using the Comsol Multiphysics 5.2 software. This study showed that the thermal response of the pavement to the combined effects of surface temperature, overloading by a 20 tons heavy truck and braking during a heat wave increase in pavement surface temperature ranging from 1.09% for National Road 1 to 0.91% for National Road 2, particularly in the braking zone. This made it possible to establish the diagnosis according to which the nature of the bitumen used on the wearing course can reduce rigidity modulus. In predictive terms, they allowed us to deduce that an under-dimensioning of the wearing course, even if the bitumen was used is adequate.展开更多
The present study focuses on the design and choice of materials(steels S355 and 45SCD6)of a chassis of stirred tank(with a variable filling rate)for use in the manufacturing of cosmetic products.This tank or trough wi...The present study focuses on the design and choice of materials(steels S355 and 45SCD6)of a chassis of stirred tank(with a variable filling rate)for use in the manufacturing of cosmetic products.This tank or trough will be submitted to important mechanical and thermal loads and pressure according to the various manufacturing processes.The authors propose a model of thermal and mechanical loads which takes into account the operating conditions of the tank.The analysis of the first 10 modes of vibration of the frame shows that the frequencies are much higher when the filling rate is high.They are higher for steel 45SCD6 than for the$355.The simulation results show that for a selected type of steel,the equivalent Von Mises stress increases along with increase in fill rates and thermal gradient.It appears that the influence of the thermal gradient is predominant.For both steels,the Von Mises equivalent stress is maximum in the beam 32 when the thermal gradient is at its lowest stage,and in the beam 40 for the greatest thermal gradient.展开更多
文摘The present study aims to analyzse alternative passive design solutions for enhancing building energy and hygrothermal efficiency in the Sahelian zone.To achieve this,a model representing a standard single-storey cementhollow block dwelling building and its relevant parameters was input into EnergyPlus,combined with OpenStudio or SketchUp.Scenarios were then analyzed to evaluate the effects of roof solar reflectivity,wall external insulation,natural ventilation,and their combined options.First,the base case,serving as a reference model,was validated using measured and simulated temperatures by calculating the scientific criteria,such as the NBME and CVRMSE coefficients recommended by the ASHRAE and IPVM standards.Additionally,the numerical simulation was used to compare interior temperatures,discomfort hours,thermal parameters,and the hygrothermal index(IHT)across seven cases studied.The reference model simulation indicated that cement-based hollow blocks are less effective for building envelopes in the Sahelian climate,with 51.48%discomfort hours and an IHT of 1.6,as shown in the Givoni diagram.The results revealed that the wall external insulation was the most effective passive solution,with 56%of comfort hours and an IHT of 0.7,which indicates the expected position of the model within the hygrothermal comfort zone of the Sahelian climate.Combining passive strategies yields the best scenario,resulting in a 28.25%reduction in annual total discomfort hours compared to the base case.These simulations demonstrated the effectiveness of accessible passive design solutions applicable in dwelling construction for the sustainable development of countries in the Sahelian climate.
文摘Current pavement design methods do not allow for the reduction of early deformation of the surface layers of bituminous pavements in the city of Ouagadougou. Weather conditions combined with traffic, particularly during heat waves, are factors. The temperature at the surface of the bituminous pavement can reach 62˚C but the complex modulus associated with this temperature is not taken into account in the design, hence the interest in proposing laws of dependence of the complex moduli is taken into account in the maximum temperatures of the pavement surface. The objective of this paper is to propose an experimental method to determine the temperature dependence of the complex moduli of asphalt mixes for temperatures between 40˚C and 70˚C. This experimental method consists of performing axial compression tests on cylindrical asphalt specimens. It was applied to three different formulas of bituminous mixes, intended for the wearing course, obtained from mixes of crushed granites, granular classes 6/10, 4/6 and 0/4, pure bitumens of grade 50/70, 35/50 and modified bitumen of grade 10/65. The comparative study of the experimental results obtained with the results of a semi-empirical methodology revealed a root mean square deviation from the mean of between 6.58% and 14.8% of the norms of the complex moduli (modulus of rigidity) of the asphalt mixes for a fixed frequency of solicitations of 10 Hz. The consistency of these results with data from the literature led to the initial conclusion that asphalt mixes formulated with 35/50 and 10/65 bitumen would have better compressive strength than those formulated with 50/70 bitumen, for exposure temperatures between 40˚C and 70˚C. This experimental approach could be an alternative to the complex modulus test for determining the modulus of rigidity for design purposes under real pavement exposure conditions in the city of Ouagadougou during heat waves.
文摘Sustainable building design in dry tropical areas recommends reducing exposure of buildings to solar radiation and/or designing efficient enclosures with satisfactory thermal inertia.We propose in this paper a study of the influence of the infiltration rate in the building and the coefficient of thermal transfer by convection of the walls, on the thermal comfort using TRNSYS software. All the models carried out were validated by recognized scientific criteria, namely correlation （R） and determination （R2） coefficients on the one hand and NBME and CVRMSE coefficients defined by ASHARE, 2002 on the other hand. The results obtained indicate that the modulation of the air infiltration rate allows the simulations on TRNSYS to be compared to in-situ measurements, with an annual average relative difference of 2.86% on the temperature difference. Furthermore, depending on the parameterization of the heat transfer coefficients by convection of the internal and external walls of walls used in the STD, the average annual difference can be reduced by 1% to 4% between the predictions and the measurements.
文摘Despite the developments of sectors which aim at valorizing recyclable materials, landfills remain essential in integrated waste management. The construction of such infrastructures is an engineering challenge that must be proven over the long term. The purpose of this study is to understand the modification of the hydromechanical properties of bottom liners of landfills that may occur during their exploitation under leachate action. To do so, on the basis of its parameters of nature, a swelling clay from Burkina Faso is selected from soils of seven localities in Burkina Faso （West Africa）. Laboratory tests carried out with distilled water and then with a young synthetic leachate show a degradation of the permeability of this clay from 2.42 × 10^-10 m/s to 1.01 × 10^-9 m/s. In addition, leachate leads to an inhibition of the swelling and a remarkable increase of its compressibility, inducing significant settlement. With the increase in permeability, the primary consolidation settlement is increasing faster. Changes in the hydromechanical behavior can be attributed to the clays mineralogy, mainly cation exchange and the development of the diffuse double layer.
文摘The present study focuses on the formulation of new composite consisting of plaster and raffia vinifera particle (RVP) with the purpose to reducing energy consumption. The aim of this study is to test this new compound as an insulating eco-material in building in a tropical climate. The composites samples were developed by mixing plaster with raffia vinifera particles (RVP) using three different sizes (1.6 mm, 2.5 mm and 4 mm). The effects of four different RVP incorporations rates (i.e., 0wt%, 5wt%;10wt%;15wt%) on physical, thermal, mechanicals properties of the composites were investigated. In addition, the use of the raffia vinifera particles and plaster based composite material as building envelopes thermal insulation material is studied by the habitable cell thermal behavior instrumentation. The results indicate that the incorporation of raffia vinifera particle leads to improve the new composite physical, mechanical and thermal properties. And the parametric analysis reveals that the sampling rate and the size of raffia vinifera particles are the most decisive factor to impact these properties, and to decreases in the thermal conductivity which leads to an improvement to the thermal resistance and energy savings. The best improvement of plaster composite was obtained at the raffia vinifera particles size between 2.5 and 4.0 mm loading of 5wt% (C95P5R) with a good ratio of thermo-physical-mechanical properties. Additionally, the habitable cell experimental thermal behavior, with the new raffia vinifera particles and plaster-based composite as thermal insulating material for building walls, gives an average damping of 4°C and 5.8°C in the insulated house interior environment respectively for cold and hot cases compared to the outside environment and the uninsulated house interior environment. The current study highlights that this mixture gives the new composite thermal insulation properties applicable in the eco-construction of habitats in tropical environments.
文摘Flexible pavements, whose surface layers are made from hot mix asphalt, may show rutting in some of these infrastructures during the first months of life. In the city of Ouagadougou, this rutting phenomenon is sometimes observed. The objective of this article is to quantify the thermal response of the wearing course of national roads 1 and 2, when they are subjected to the braking of heavy trucks of 13 tons and 20 tons per axle. The meteorological conditions retained are those of the Burkinabe climate. The evaluation of the temperature was carried out by numerical simulation using the Comsol Multiphysics 5.2 software. This study showed that the thermal response of the pavement to the combined effects of surface temperature, overloading by a 20 tons heavy truck and braking during a heat wave increase in pavement surface temperature ranging from 1.09% for National Road 1 to 0.91% for National Road 2, particularly in the braking zone. This made it possible to establish the diagnosis according to which the nature of the bitumen used on the wearing course can reduce rigidity modulus. In predictive terms, they allowed us to deduce that an under-dimensioning of the wearing course, even if the bitumen was used is adequate.
文摘The present study focuses on the design and choice of materials(steels S355 and 45SCD6)of a chassis of stirred tank(with a variable filling rate)for use in the manufacturing of cosmetic products.This tank or trough will be submitted to important mechanical and thermal loads and pressure according to the various manufacturing processes.The authors propose a model of thermal and mechanical loads which takes into account the operating conditions of the tank.The analysis of the first 10 modes of vibration of the frame shows that the frequencies are much higher when the filling rate is high.They are higher for steel 45SCD6 than for the$355.The simulation results show that for a selected type of steel,the equivalent Von Mises stress increases along with increase in fill rates and thermal gradient.It appears that the influence of the thermal gradient is predominant.For both steels,the Von Mises equivalent stress is maximum in the beam 32 when the thermal gradient is at its lowest stage,and in the beam 40 for the greatest thermal gradient.
