Thermal Resistance of Polystyrene-Seeded Concrete for Better Insulative Value

This paper details the experimentally-measured thermal conductivity, k, of concrete composite samples consisting of various mixtures of extruded polystyrene waste chips and concrete for the purpose of better insulative value and lighter weight. A “hot box” apparatus was designed based on the parameters of ASTM C1363, and was constructed primarily out of 4” rigid polystyrene insulation and designed to force the majority of the heat generated in the enclosure through the test samples. The design allowed for the indirect measurement of thermal conductivity, k, by directly measuring the internal and external surface temperatures of the samples and heat input required to maintain a steady state internal temperature. Several samples with well documented k values were first tested to calibrate the hot box apparatus. Prototype samples were made in sheets and also in cylindrical format to test for thermal conductivity and also compression testing, respectively. Results showed that although the insulative values of the concrete composite increased with additional polystyrene aggregate, as would be expected, at some point there is a rapid fall-off in compressive strength.