Comparative analysis of time dependent temperature profiles of hydrating mass concretes of different mix ratios

Abstract

In mass concrete, heat due to cement hydration in most cases is not easily released and is otherwise confined within its core. Consequently, mass concrete may exhibit quite remarkable increase in temperatures internally depending on majorly the vicinity temperature and the proportion of cement in mixture ratio. When the surface tensile stresses resulting from temperature difference between its core and surface exceeds the strength of the concrete, cracks could develop at the surface. Two mass concrete blocks of dimensions 1.10 m × 1.10 m × 1.10 m each and mixes of 1: 2: 4 and 1: 3: 6 with constant water cement ratio (w/c) of 0.60 were used in the study. Type-K thermocouples were used to monitor the temperature variance in mass concretes. BK Precision 710 temperature meter dual input was used to determine the temperature readings at time intervals. Thermometer was used to measure the environment temperatures within the vicinity of the mass concretes. Generally, the trends of the temperature profiles exhibit an initial uniform temperature which rises to peak values at 24 hours of concrete placement and then declined to constant temperature at mostly 120 hours and beyond. The sole source of heat in hydrating concrete is the cement paste, and higher cement content leads to higher quantity of heat release. Therefore, the mass concrete block of mix ratio 1:2:4 exhibited higher quantity of heat release than that of 1:3:6 especially at the core.