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

Abstract

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.

Physico-Mechanical and Hygro-Thermal Properties of Compressed Earth Blocks Stabilized with Industrial and Agro By-Product Binders

“…In fact, a simulation study [ 32 ] evidenced the thermal and energy efficiency of a building (wall) constructed using CCR stabilized CEBs compared to hollow cement blocks (HCB) based building. The CCR-CEBs-building allows to achieve lesser warm discomfort (400 h lesser) than HCB-building, only using natural ventilation systems.…”

Physico-chemical and mineralogical characterization of clay materials suitable for production of stabilized compressed earth blocks

“…This shows the structurally benefit of CCR˗stabilized CEBs which can provide similar or better mechanical performance and lower dead load than cement-stabilized CEBs. Furthermore, the decrease of the bulk density of CEBs stabilized with CCR would potentially decrease their thermal conductivity and possibly contribute to the improvement of the thermal comfort in the building [10,25]. It is noteworthy that denser and lesser porous CEBs are more likely to have better durability such as the resistance to water absorption and erosion [7].…”

“…The firing process is energy consuming and therefore not environmental-friendly, resulting in relative increase of the cost and embodied energy of the products [6][7][8]. Today, the awareness of the global warming and necessity for energy saving on the one hand and improved indoor comfort provided by unfired clay material on the other hand give this material the potential for construction of sustainable buildings [7,[9][10][11][12]. For centuries, unfired clay materials have been used in building construction, in various forms such as adobe (sun dried brick), rammed earth and recently compressed earth block (CEBs), and proved promising to provide affordable and comfortable housing [7][8][9][10].…”

“…Clay materials from this region are basically used for road pavement and in some cases for the artisanal production of adobe; although some small enterprises such as Zi-Matériau and CC3D offer services of production, commercialization and construction with CEBs in the major cities. In fact, current research on earth for building construction in Burkina Faso mainly reports on adobes and only a limited number of studies are reported on CEBs [10,11,14,[24][25][26].…”

“…CEBs are the most accepted form of unfired clay materials for the construction of modern building [7,10,15,]. This is basically related to their low (ambient) temperature of curing and other advantages such as improved mechanical and hygrothermal performances and durability, regular shape and size which allow to achieve various architectural designs contrary to the adobe and cement blocks [10,15,16,18]. Clay material used for production of CEBs should have a certain fraction of fine particles and plasticity for binding cohesion of coarser particles in order to ensure physical and mechanical stability of the matrix, i.e.…”