Improving the Building Energy Efficiency and Thermal Comfort through the Design of Walls in Compressed Earth Blocks of Agricultural and Biopolymer Residues Masonry: A Recent Study

editorial reviewedThe impact of wall construction materials on dwelling hygrothermal behavior and energy efficiency is investigated in this research. Most people want to live in a sophisticated ambiance in this modern age and spend massive investment on improving their buildings’ inside condition. The building design was created in the Design Builder interface using three types of construction materials for the wall: CSEB of fonio straw and Shea butter cakes, cement blocks, and cut laterite blocks. Dynamic modeling with Energy Plus software was used to calculate the thermal comfort and overall amount of energy required for building cooling. The simulation was done using the meteorological characteristics of Ouagadougou city, and we discovered that the thermal behavior of the housing is influenced by the wall in earth-based simulations. The findings demonstrate that in housing with a CSEB of fonio straw and Shea butter cakes masonry wall, the number of warm thermal discomfort hours and cooling energy loads are reduced by an average of 10.60 percent and 93.86 percent, respectively, when compared to housing with a cement or cut laterite blocks masonry wall. In terms of the inside environment, the earth-based impact of this wall allows for an average internal temperature and indoor operating temperature of 28.64°C and 25.82°C, respectively. 6.54°C is attained as the average indoor temperature peaks dampening (i.e. 22.83 percent). As a result, these CSEB walls offer an effective contribution to the development of sustainable dwellings in a hot climate.11. Sustainable cities and communitie

An Experimental Study on the Use of Fonio Straw and Shea Butter Residue for Improving the Thermophysical and Mechanical Properties of Compressed Earth Blocks

peer reviewedThe efficient use of building materials is one of the responses to increasing urbanization and building energy consumption. Soil as a building material has been used for several thousand years due to its availability and its usual properties improving and stabilization techniques used. Thus, fonio straws and shea butter residues are incorporated into tow soil matrix. The objective of this study is to develop a construction eco-material by recycling agricultural and biopolymer by-products in compressed earth blocks (CEB) stabilization and analyze these by-products’ influence on CEB usual properties. To do this, compressed stabilized earth blocks (CSEB) composed of clay and varying proportion (3% to 10%) of fonio straw and shea butter residue incorporated were subjected to thermophysical, flexural, compressive, and durability tests. The results obtained show that the addition of fonio straw and shea butter residues as stabilizers improves compressed stabilized earth blocks thermophysical and mechanical performance and durability. Two different clay materials were studied. Indeed, for these CEB incorporating 3% fonio straw and 3% - 10% shea butter residue, the average compressive strength and three-point bending strength values after 28 days old are respectively 3.478 MPa and 1.062 MPa. In terms of CSEB thermal properties, the average thermal conductivity is 0.549 W/m·K with 3% fonio straw and from 0.667 to 0.798 W/m. K is with 3% - 10% shea butter residue and the average thermal diffusivity is 1.665.10-7 m2/s with 3% FF and 2.24.10-7 m2/s with 3.055.10-7 m2/s with 3% - 10% shea butter residue, while the average specific heat mass is between 1.508 and 1.584 kJ/kg·K. In addition, the shea butter residue incorporated at 3% - 10% improves CSEB water repellency, with capillary coefficient values between 31 and 68 [g/m2·s]1/2 and a contact angle between 43.63°C and 86.4°C. Analysis of the results shows that, it is possible to use these CSEB for single-storey housing construction.SERAMA program for Secondary Resources valuation for Sustainable Constructio

Lois d’ecoulement des suspensions de boues residuaires de la station d’epuration des eaux de ziga (Burkina Faso)

L’étude porte sur le comportement thixotrope des boues de la station d’épuration des eaux de Ziga. La rhéologie de suspensions aqueuses plus ou moins concentrées est étudiée à l’aide du rhéomètre Physica MCR (Anton-Paar) doté des géométries « cône-plan » ou « cylindres de Couette ». La gamme des concentrations (ou siccité) explorée va de 6% à 47%, pour des températures de bain allant de 25°C à 45°C. L’étude met en évidence que les suspensions de boue se comportent comme un fluide newtonien pour une siccité W inférieure à 6,25%, et comme un fluide à seuil thixotrope pour les grandes valeurs de W. La contrainte seuil de déclenchement des écoulements a été analysée et une corrélation est proposée.Mots clés: Contrainte seuil, thixotropie, rhéologie, fluide newtonien, siccitéEnglish AbstractThe study focuses on the thixotropic behavior of the sludge treatment plant water Ziga. The rheology of aqueous suspensions of varying concentration is studied using the Physica MCR rheometer (Anton Paar) with geometries « cône-plan » or « cylindres de Couette ». The range of concentrations (solids content) explored ranges from 6% to 47%, for bath temperatures ranging from 25 ° C to 45 ° C. The study shows that the mud suspensions behave as a Newtonian fluid to a solids content less than 6.25% W, and as a thixotropic fluid line for large values of W. The stress threshold flow was analyzed and a correlation is proposed.Keywords: Yield stress, thixotropy, rheology, Newtonian fluid, drynes

Multicriteria analysis of the components of ecological paving stones made from plastic and glass waste, and granular reinforcements

The use of plastic waste as a resource in construction applications is an opportunity for environmental protection, conservation of natural resources and reduction of pollution. Unfortunately, they don't always withstand the stresses to which they are subjected, leading to subsidence and collapsing. An analysis of the causes using the Pareto curve shows that 74.47 % of the causes of this collapse are due to poorly formulated mixes and poor choice of raw materials for the composite. The compressive test carried out on the first sample of pavers studied showed a maximum compressive strength value of 4.6 MPa, which is below the standard requirements. As a result, the pavers were considered unsuitable for use on a T5 road. Through the use of the SUPERDECISION software, we were able to identify two favourable constituent materials - glass/glass waste and gravel - for the production of composite paving stones. By adding low-density plastic waste, collected, cleaned and crushed in the form of aggregates, we obtain a compressive strength of 7 MPa with gravel and 8 MPa with glass waste. These values are below the recommendations of the NF EN 1339 standard (Rc ≥ 20 MPa) for T5 traffic. The best composition for ecological paving is therefore (PET/PP/PEBD) + sand + glass (50/12.5/37.5). Analyzing these results shows that the raw materials used for ecological paving should be adapted to the loads

Numerical Simulation of Hygrothermomechanical Deformations of Bituminous Pavements in the City of Ouagadougou Subjected to Tropical Dry Showers

International audienceThe waters of the torrential rains in the city of Ouagadougou lead to the appearance or amplification of damage to the surface of asphalt pavements during the rainy season. Road infrastructure maintenance campaigns follow one another almost every rainy season to fill potholes and cracks observed on the pavements. Several hypotheses can be put forward as to the origin of the action of water on the surface of pavements: the pressure of runoff water, infiltration, thermal expansion during the rainy episode, etc. These various reasons reveal the need to take rainwater into account when designing pavements. A previous study on the effect of heat waves on pavement design made some recommendations for better design. It has raised the interest to observe the impact of rain on pavement deformability. The objective of this article is to estimate, as a first approach, the effect of tropical rains on the Thermomechanical behaviour of bituminous pavements formulated with pure grade 35/50 bitumen and grade 10/65 modified bitumen without trafic. The properties of the road materials and the data from the statistical treatment of rainfall in the city of Ouagadougou were determined. The software based on the finite element method was used to model the phenomena coupling the meteorological conditions to the mechanical structure of the pavement for the quantification of hygrothermal and mechanical deformations. The bituminous pavements studied were subjected to maximum rainfall intensities of 53.06 mm/h, and 99 mm/h with respective frequencies of occurrence of 2 years and 15 years. The comparison of the temperature profiles at the surface of the studied pavements, allowed to highlight the viscous character of the asphalt subjected (35/50 bitumen and grade 10/65 modified bitumen) to the rains of maximum intensity of 99 mm/h. The maximum deformations simulated during these rains are about 1.2 times greater in the wearing course than in the base course, which does not disrupt the classical order of temperature evolution in the different pavement layers under dry tropical conditions. These deformations obtained also respect the admissibility criteria in terms of pavement design for T2 trafic (151 to 300 Heavy Truck/day). This study could be expanded to include the permeability of bituminous surfaces and runoff phenomena that could provide information on the origin of the observed deterioration

Study of Local Construction and Technique: Adequacy of an Existing Nubian Vaulted Building with the "Bioclimatic" Concept Including the Performance of Its Envelope in Sahelian Climate of Ouagadougou

This study permitted to evaluate the adequacy of an existing Nubian vaulted building with the "bioclimatic" concept including the performance of its envelope. In that purpose, we needed to analyze its architectural concept and to measure parameters such as the temperature of the internal and external surfaces of all the façades (walls, roof and floor) of the study building. The measurement campaign took place over three (03) days in the month of January 2018 with a one-hour step for temperatures. Out of eleven (11) bioclimatic principles identified, six (06) were respected in the design of the building. In addition, we obtained thermal amplitudes of the interior surfaces lower than 1.5°C for the walls and 5°C for the roof, a decrement factor lower than 12% for the walls and 17% for the roof and a thermal time lag of 6 to 8 hours on in average for the walls and 4 to 6 hours in average for the roof. Finally, after evaluation of the thermal loads, with the Nubian vault building a reduction of a bit more than one third (1/3) of the thermal loads is achieved comparatively to a building of the same size made of cinder blocks for the walls and aluminum roofing sheet. However, this comfort offered by the Nubian vault can be improved with more bioclimatic provisions which we have recommended

Highlighting of a local non-equilibrium thermodynamics during the transfer of trichlorethylene (TCE) in the superficial layers of arid soils

International audienceIn this paper, we analyze and model the mass transfer of trichloroethylene in the surface layer of a soil. Our study essentially focuses on arid soils taking into account the phase change liquid-vapor. We have then examined the validity of the assumption of local equilibrium by comparing the values of the instantaneous pressure of the trichloroethylene vapor and the equilibrium vapor pressure during the transfer process. It appears that the assumption of local equilibrium during the transfer of trichloroethylene cannot be admitted