Strength and heat development models including an aging activation energy for hardening Low-Carbon Concrete

Controlling early age thermal cracking in hardening Low-Carbon Concrete (LCC) casted in extreme weather requires precise modelling of its maturity, strength and heat development. The existing engineering-oriented models are useful for Portland Cement Concretes, but their accuracy for LCC is still unclear. Moreover, studying the dependence of LCC maturity parameters on whether mechanical or heat tests are implemented is also of interest. In response, this investigation proposed enhanced modelling techniques targeting a proper strength, heat, maturity, and cross-over effect assessment of LCC, including slag, limestone, superplasticizer, and air-entrainment. The models were calibrated using compressive, tensile, semi-adiabatic and isothermal calorimetry tests. Moreover, a novel Activation Energy (E a ) function was proposed, accounting for its hydration dependence, here referred to as aging. The proposed models represent improvements for the evaluation of LCC as suggested by comparison against classical approaches. For instance, they better capture the extended dormant period of LCC. Furthermore, the aging of the E a was found imperative to accurately predict the heat development of LCC independently of the type of heat test selected for calibration. The models also predicted more severe cross-over effect on the tensile than the compressive strength for low water-to-binder ratio LCC, which is relevant to decide on cracking risk mitigation measures. In general, the modelling techniques developed here evidenced good performance for LCC and are worth of further exploration by researchers and practitioners. Their application will contribute to incentive wider use of LCC in infrastructure projects by providing more accurate predictions of their cracking risk.