The early age thermal cracking in concrete structures

• Main Author: Tajik, Nosratollah
• Published: University of Westminster 2008
• Subjects: 620.1
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502220

Investigations on the assumptions, the limitations and the factors influencing the development of early age thermal cracking in concrete have been carried out for many decades, but there is a better understanding of these phenomena in the recent years. Review of the literature on the early age thermal cracking (EATC) of concrete structures has shown that this phenomenon is very important and has significant influence on the durability, serviceability and aesthetically aspects of concrete structures, however despite this its mechanisms are still not well understood. Furthermore, most efforts to control this type of cracking have been by specifically designing distribution reinforcement, but this is proving uneconomic and is not a failsafe technique. The experimental technique carried out in this research investigation is an improvement on the past research on early age cracking. The experiments were carried out successfully and the effects of internal and external restraints were studied. Further methods of assessing the risk of early age thermal cracking in mass concrete under natural environmental conditions developed and the results were compared with those recorded under laboratory conditions. It has been shown that the early age· thermal cracking in concrete resulted from either internal restraint caused by differential expansion within concrete member during heating due to larger temperatures gradient between the core, and that the adjacent media or by external restraint to contract on cooling from a temperature peak of the concrete specimen are the critical factors in developing early age thermal cracking. It has been found that the temperature differential that causes early age thermal cracking . in concrete is greater than that figure found previous research. Other factors influencing the development of the thermal cracking were investigated and recommendations on controlling the early age thermal cracking were given.