Temperature Rises in Low-Heat Cement Concrete

A frequent cause for concern in concrete structures today is cracking due to the fall in temperature following the liberation of the heat of hydration. Cements with low heat of hydration characteristics are preferred for massive members (which have the greatest temperature rise). Unfortuantely, however, it is now evident that the criteria which are at present specified in either ASTM standard C 150-66 or BS 1370:1958 are very largely irrelevant. Modern cements have much higher strengths than formerly, they tend to be more finely ground and more rapid hardening, so that the inadequacies of these specifications have become increasingly apparent. The paper describes in detail the temperatures which were obtained in the thick raft of high strength concrete for the office block of the ATV Paradise Center, Birmingham. The predicted and recorded temperatures are compared and a very clear warning is made in the conclusions.