Physical, Water Diffusion and Micro-Structural Analysis of “Canarium Schweinfurthii Engl”

The purpose of this study is to determine the morphological, microstructural characteristics and water diffusion parameters of the Canarium schweinfurthii (CS) shellnut. This work is part of a vast project to valorize the above-mentioned cores for possible industrial use as charges in composites or abrasives materials. The study was based on the characterization of intrinsic physical characteristics of the coreshells scanning electron microscopic (SEM) observations desorption, adsorption and absorption kinetics. The water diffusion phenomenon was modeled and it appears that the Page model well predicted the kinetic of drying, absorption and adsorption. The effective diffusion coefficient and the energy of activation were calculated at three isothermal temperatures (50°C, 70°C and 90°C). There was a tendency for hysteresis in the sorption-desorption cycles. These results strongly predicted the possibility of using these products as a filler in composites, clay building materials and cement because of their high water diffusion stability on a macroscopic scale.

Comparative Study of Thermal Comfort Induced from Masonry Made of Stabilized Compressed Earth Block vs Conventional Cementitious Material

This paper investigates the stabilization effect on compressed earth blocks (CEB) produced from quartz-kaolinite rich earthen material stabilized with 0% - 25% calcium carbide residue (CCR). The paper evaluated various physico-thermal properties of the stabilized CEB and thermal comfort in the model building made of CEB masonry. The optical properties of CEB were evaluated from the mineral composition of the earthen material and CCR and apparent density of the CEB. A simulation was carried out on naturally ventilated model building whose masonry is made of CCR stabilized CEB comparing to the so-called conventional cementitious materials such as cement blocks and concrete. The results showed a decrease of the apparent density of the CEB from 2100 kg·m–3 for unstabilized CEB (0% CCR) to 1600 kg·m–3 for 25% CCR stabilized CEB. The thermal conductivity and depth of penetration of the heat flux on a 24 hours period of CEB respectively decreased from 1 W·m–1·K–1 and 12.7 cm for 0% CCR-CEB to 0.5 W·m–1·K–1 and 10.2 cm for 25% CCR-CEB. The emissivity, solar absorptivity and visible absorptivity of the CEB respectively decreased from 0.82, 0.82 and 0.82 for 0% CCR-CEB to 0.80, 0.64 and 0.64 for 25% CCR-CEB. The number of hours of warm and humid thermal discomfort was impacted for stabilized CEB based masonry in comparison with cement based masonry. The warm discomfort in building made of 20% CCR-CEB masonry was 400 hours lesser than that in building made of hollow cement blocks masonry. If air conditioning system is used to keep the indoor temperature below 28°C, the economy of 310,000 CFA francs (535 USD) is made every year on energy consumption for cooling in the model building made of 20% CCR-CEB masonry, corresponding to 9.6% less, with respect to that made of hollow cement blocks masonry.

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

The 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.

Comparative Study of the Reactivity of Clay Earth Materials for the Production of Compressed Earth Blocks in Ambient Conditions: Effect on Their Physico-Mechanical Performances

This study assesses the reactivity of four (04) different types of clayey earthen materials (Kamboinsé, Pabré, Saaba, and Kossodo) with Ca(OH)2, 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℃ ± 5℃). 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.

Using nature in architecture： Building a living house with mycelium and trees

This study proposed the development of a house with the following characteristics： grows, builds, and repairs itself; changes with the seasons; uses the forces of nature and is in harmony with its environment; favors biodiversity and natural equilibrium; Low cost and does not require considerable workforce or industrial material; carbon free and waste free; returns to nature when no longer in use; enables sustainable and balanced mankind development. The use of Living architecture to decrease or nullify the environmental costs of structure materials was also investigated. Furthermore, the use of Living architecture techniques to comply with the current Living and construction style with as Little change as possible was analyzed. A new envelope material with Little to no carbon impact was scientifically explored, and the use of this material to create a sustainable house was technically examined. Findings demonstrate that such a house is not only feasible but also rational and beneficial from the economic and environmental perspectives.