On the relationship between morphology and thermal conductivity of cement-based composites

The present work discloses the factors related to the morphology of the matrix that affect the thermal conductivity of cement-based composites. For this purpose, we investigated three mortar mixes with cement and hydrated lime (1:3, 1:1:6 and 1:2:9); and three types of aggregates (river sand, iron ore tailings, friable quartzite). We studied how the chemical composition and particle characteristics of the aggregates affect the overall properties of the mortars. In this sense, physical and chemical characterisation of the aggregates were performed; along with the physical, thermal and morphological evaluation of the resulting mortars. It is concluded that the morphology of the matrix is more relevant to the thermal conductivity of mortars than the chemical composition of its components. Also, the pore system generated by the aggregates in the mortar is more correlated to its thermal conductivity than its total porosity and specific gravity.