Compressive strength development of concrete with different curing time and temperature

In this experimental and analytic research, the strength development for va rious curing histories was investigated with particular regard to the influ ences of curing time points with given temperatures. For this purpose, four different points of curing time were considered with an individual interva l of, 24 h. Two different temperatures of 5 degrees C and 40 degrees C were applied for the selective intervals, whereas the rest period days were und er the reference curing condition of 20 degrees C. A new model for the stre ngth prediction was suggested based on the rate constant model. In this mod el, the equivalent ages introduced in the Saul and Arrhenius models were mo dified to show the effects of curing temperature at different ages. Test re sults show that the concrete subjected to a high temperature at an early ag e attains higher early-age strength but eventually attains lower later-age strength. The concrete subjected to a low temperature at an early age leads to lower early-age strength but almost the same later-age strength. Moreov er, the proposed model showed better agreement with the test results than t he existing models. (C) 1998 Elsevier Science Ltd.