Impact of partial substitution of sand by compost on the mechanical and thermal parameters of concrete

The study investigates recycling organic waste in Algeria due to the rising use of natural resources and energy in concrete production and the large amount of organic waste discarded. The aim is to use compost as a partial replacement for sand, reducing the use of natural aggregates in the concrete industry while also reusing previously discarded waste as part of a circular economy. An experimental study was carried out on concrete’s thermal and mechanical properties to determine the effect of partial compost replacement on these properties. Five mixtures were created by replacing sand with compost in different proportions: 0, 5, 10, 15, and 20%. Slump and density were assessed in the formulations’ original state. Mechanical tests were performed on the hardened concrete to determine porosity, compressive strength, and flexural strength. Thermal tests were also conducted on various types of concrete to determine thermal conductivity. The findings show that the texture of the compost reduced the slump, highlighting the importance of incorporating an admixture to achieve the desired workability. While meeting normal-weight concrete standards, concrete density was reduced. The mechanical properties of concrete with small amounts of compost were similar to regular concrete; instead, waste porosity improved insulation.