Temperature regime in mass concrete during the cooling phase

Abstract

A numerical simulation study has been conducted to investigate temperature regime in mass concrete during the cooling phase. The analysis of the thermal-stress field in mass concrete has been performed using the thermal flow analysis tool of the Midas/Civil software. The reliability and accuracy of the proposed numerical method are demonstrated by comparing the numerical analysis results with experimental data. The research results show that controlling thermal cracking in mass concrete during the cooling phase is essential. With the mix design and boundary conditions as simulated, the heating phase occurs over a short period, approximately 80 hours, while the cooling phase lasts significantly longer, about 1400 hours, before the temperature within the entire concrete mass reaches a stable state, close to the ambient temperature. During this phase, the thermal cracking index at the center of mass concrete decreases significantly, although it remains greater than 1.0. However, there is a clear trend toward reaching 1.0, indicating a potential risk of thermal cracking at the core during the cooling phase. If the standard cracking index of 1.85, which corresponds to a thermal cracking probability of ≤ 5%, is considered, as in some countries, the mass concrete may have already experienced through-cracking.