Cooling Concrete with Embedded Pipes

Post-cooling concrete using pipes embedded in a mass concrete structure can often be a cost-effective alternative to pre-cooling in hot weather construction. This article explains the post-cooling procedure and describes a recent case study using the method. In post-cooling, cool water is circulated through small-diameter pipes embedded in concrete sections. The water can reduce the differential temperature between the core and surface. These post-cooling systems can also control the subsequent heat removal and accompanying volume changes during early ages, when the concrete’s elastic modulus and tensile strength are relatively low. Heat removed during the first several days following placement depends on the location, size and number of pipes, volume of water circulated and the temperature of the cool water. The post-cooling systems are advantageous when high-performance concrete is specified for use in large structural members, such as piers, drilled shafts or mat foundations. The post-cooling method was successfully used in a project in Florida that involved the construction of a large cross beam between two bridge piers.