Temperature Control of Massive High-Strength Concrete Columns During Curing—A Case Study in Hong Kong

High-strength concrete generates a significant amount of heat during curing, which can cause delayed ettringite formation and early thermal cracking. Such problems are particularly acute in Hong Kong because of the local practice of designing concrete mixes to have rather high cementitious contents to avoid non-compliance with the stringent strength requirements. Moreover, in Hong Kong, there is still a lack of clear specifications of the temperature control limits to be imposed. Hence, the temperature control of curing high-strength concrete in massive columns/walls has, up to now, remained guess work. In this paper, temperature control limits are proposed, and a case study on temperature control of massive C80 concrete columns during curing is presented. Due to the high cementitious content and large column size, an internal water-cooling system, designed with the help of thermal analysis by the finite element method, was installed. In this system, each pipe was a double-pipe for both water inflow and outflow. It had successfully avoided exceedance of temperature control limits and formation of early thermal cracks. The lessons learned, as summarized in the Conclusions, should be useful for the optimum design of temperature control regimes for massive high-strength concrete members.