Effect of insulation materials and cavity layout on heat transfer of concrete masonry hollow blocks

The aim of this research was to reduce the demand for air conditioning in buildings by minimizing the heat flow from outdoor environment to the interior of building envelopes (walls and roofs). Hence, a finite element model (FEM) was developed to find out the optimum geometry of cavities and their layout in masonry concrete blocks in order to reduce the thermal flow of heat and the results were compared with that of hollow blocks available in the market in terms of thermal insulation. Results of the simulation were promising and indicated that the new “optimum” designed geometry of hollow blocks was much better than the hollow blocks available in the market. Thereafter, some insulation materials were utilized in the concrete mixtures to produce hollow masonry concrete blocks to reduce the thermal conductivity through wall elements. Experimentally, the results of the new block with optimum geometry without the insulation materials showed improved thermal insulation by as much as 71% compared to other designs of hollow blocks including those available in the market. The thermal resistance of concrete and masonry blocks with the insulation materials (perlite, rubber and polyethylene) was enticing and significant. The newly developed optimum design of masonry concrete block with and without the insulation materials satisfied the ASTM C129 requirements for non-load bearing walls in terms of strength and absorption and was considered as medium weight (without insulation material) and as lightweight (with insulation materials) masonry hollow blocks. Results of this comprehensive investigation also indicated that the thermal conductivity could be reduced by up to 40% compared to that of the conventional blocks available in the market. Therefore, it is recommended that these optimum designed blocks be utilized by the construction industry in order to reduce the amount of energy used for the air conditioning as well as the carbon footprrint.