An Experimental Investigation on Thermal Properties of immature Concrete

Abstract

Since the heat of hydration of cement is highly temperature dependent, variation of thermal properties of concrete at early ages is essential to predict the temperature rise and distribution due to heat of hydration of cement in concrete. Experimental investigation was carried out to obtain the temperature response of fresh concrete sample of 150mm cube with time under known thermal boundary condition. The specific heat capacity of fresh concrete was estimated based on the specific heat capacities of cement and products of cement hydration using Dulong - Petit Rule (DPR) and Neumann- Kopp Rule (NKR). The thermal conductivity (X) was determined by fitting the temperature response curve of the cube with the temperature history predicted by transient heat conduction analysis based on the estimated specific heat capacity of concrete using ANSYS software. Tests were conducted for concrete at early age, i.e. from one hour to 1 day, for several mix proportions. It was found that thermal conductivity increases rapidly within the first 5 to 12 hours and reached a constant value which depends on the mix proportion.