Effect of materials and age on the coefficient of thermal expansion of concrete paving mixture

This study examined the effect of the materials and age on the coefficient of thermal expansion (CTE) of concrete paving mixtures at 28 and 120 days. Concrete specimens were prepared in the laboratory by varying the mix design variables with different types of aggregate to produce different mixes using Portland cement. The microstructures of the concrete mixtures were also observed by scanning electron microscopy to determine the relationship between the volume change in concrete and the formation of microcracks. Statistical analyses of the experimental data suggested that the CTEs measured at 120 days are significantly lower than those measured at 28 days. An analysis of variance indicated that the mixture with granite results in significantly higher CTE reduction with time than the mixture with dolomite. The larger volume change with a higher CTE may be due to the formation of microcracks in concrete.