Temperature variation in concrete samples due to cement hydration

Abstract

Large structures of massive concrete are an engineering problem due to cracking created by thermal stresses. Nowadays, many constructions use large amount of concrete, like dams, tall buildings and infrastructure solutions. In big concrete structures, the temperature gradient is mainly caused by cement hydration heat. Concrete properties also directly affect the temperature gradient. To prevent cracking in concrete structures, some technical approaches can be done, such as choosing cooler raw materials or precooling (ice) or pipe cooling, or applying superficial thermal insulation. Cracks will reduce the safety, integrity and durability of the structure. Besides, repairing a crack is very difficult. This paper focus on identifying which properties influence the concrete temperature and on how raw materials affect the thermal characteristics. Experimental tests have been done to analyze how the precooling technique and cement type reduce the temperature’s gradient. The numerical simulation contributed to the understanding of the temperature behavior in several points in the specimen. There was a reasonable agreement between the experimental results and those obtained by numerical simulation. The use of cement with low hydration heat, the concrete in lower height layers and the use of ice were the main properties evaluated, and they all caused a reduction in temperature. However, the biggest difference was noticed in lower height layers of concrete. The use of concrete in several layers was the best option for decreasing temperature.