Development and Calibration of Method for Thermal Property Measurement of Nonhomogeneous Masonry Materials

Abstract

Existing thermal conductivity or R-value data for masonry building materials are very limited and quite dated. Additionally, very little data on heat capacity are available. A convective heat transfer device was designed and built for the purpose of measuring the thermal performance of nonhomogeneous masonry materials that are not well suited for other testing methods. The device is similar to the hot box apparatus described in the standard ASTM C1363, Standard Test Method for Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus, and it uses heat flux sensors to measure heat flows. This modified hot box apparatus is capable of measuring steady-state properties such as thermal conductivity or R-value. The modified hot box can also measure non-steady-state heat capacity that is traditionally measured by laser/light flash apparatuses. The heat capacity measurements can be used to calculate the thermal diffusivity when the density and thermal conductivity are known. The modified hot box instrumentation was calibrated to acquire data on building materials such as brick, concrete, and other nonhomogeneous materials that were large in size and mass.