Evaluation of Thermal Conductivity of Concrete Using Finite Element Analysis

The thermal conductivity of concrete is an important parameter due to the concrete’s energy, thermal, and fire performance. It depends on the water–cement (w/c) ratio, coarse aggregate volume fraction, fine aggregate volume fraction, age, temperature, and concrete admixtures. Among these parameters mix proportions of cement and aggregate act as a crucial factor since concrete’s mechanical properties also depend on the mix proportions. Experimental methods such as steady and transient methods are available to measure the thermal conductivity of concrete. However, conducting experiments for every mix proportion used in the construction industry is not feasible. Therefore, this study develops a Finite Element (FE) model to determine the thermal conductivity of concrete with the known thermal conductivity values of mortar, aggregates and respective mix proportions. The developed FE model considers concrete as a two-phase model with mortar and coarse aggregates in the mesoscale concept. A two-dimensional model was developed with circular shape aggregates, and then the aggregate shapes were changed into two real shape aggregates such as elliptical and polygonal and validated with the experimental results from the literatures. The average difference percentage between the experimental results and FEM results is 4.30%. Hence the developed FE model was verified to predict the concrete’s thermal conductivity with known thermal conductivity values of coarse aggregates and mortar for any mix proportion.