A Relationship for Effective Thermal Conductivity of Reinforced Concrete Structures

Abstract

Thermal conductivity is an important parameter in predicting the temperature distribution of large reinforced concrete structures. To accurately predict the temperature gradients, the effect of the steel rebar must be considered. An overall effective thermal conductivity was proposed to account for the steel reinforcement to eliminate the need to consider the complicated geometry of the rebar. In this study, the thermal conductivity of concrete cylinders embedded with 4% and 8% steel reinforcement was measured following industry standards. The effective thermal conductivity was calculated and shown to increase with the reinforcement ratio. Finite-element analysis (FEA) was conducted to model the experimental tests, and an equation was proposed to estimate the effective thermal conductivity. Additionally, FEA was used to model a concrete pier cap using the effective thermal conductivity. It was concluded that the simple effective thermal conductivity could be used to simulate the complicated steel reinforcement in the concrete.