Effect of Adding Sawdust to Cement on its Thermal Conductivity and Compressive Strength

In this practical study, the thermal conductivity and compressive strength of a number of cement mortar and sawdust mixtures were measured. This study aims to analyze the possibility of using these mixtures as thermal insulators in the building parts. The materials used in the study were ordinary Portland cement available in the local Iraqi market, sand, and sawdust. Samples were prepared according to American standards. Sawdust in two different sizes (greater than 50 mm and less than 1.4 mm) was added to the cement. The study results showed that adding sawdust caused an apparent decrease in the mixture's thermal conductivity, which means an improvement in the thermal insulation of the mixtures. The decrease in conductivity also raised with the sawdust mass fraction increase. The thermal conductivity of sawdust and cement mixtures increased when using small sawdust (less than 1.4 mm) compared to the second case (sawdust of large size above 5 mm). The mixture's thermal conductivity decreased with the increase in the water curing period, and the decrease in conductivity increased with this period. Increasing the sawdust mass fraction resulted in a decrease in the studied mixtures' compressive strength, and this resistance decreased more when using sawdust of smaller sizes (less than 1.4 mm). The compressibility strength of all the studied products increases with the increase in the treatment time with water due to the cement's properties.