Research on strength prediction model of manufactured sand‌ concrete during steam curing stage based on equivalent age

Abstract

Abstract To determine the optimal steam curing duration for precast manufactured sand‌ concrete components and the corresponding strength prediction model at this stage, this paper investigates the strength development law of manufactured sand‌ concrete with age under steam curing temperatures of 40 ℃, 50 ℃ and 60 ℃, and discusses the compressive strength prediction model of manufactured sand concrete at the steam curing stage based on the theory of maturity at the equivalent age of Arrhenius. The results show that steam curing can significantly shorten the time required for manufactured sand‌ concrete to reach the design strength, but the temperature effect of steam curing is limited and the curing duration should not be excessively long. Specifically, the steam curing duration at 60 ℃ should not exceed 12 h, at 50 ℃ should not exceed 24 h, and at 40 ℃ should not exceed 48 h. Among the prediction models based on equivalent age, the hyperbolic function prediction model has the highest accuracy, while the accuracy of the exponential function prediction model is the lowest. For the strength prediction of manufactured sand‌ concrete at steam curing temperatures of 50 ℃ or below, it is suitable to choose the hyperbolic function calculation model.