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 weatherrequires precise modelling of its maturity, strength and heat development. The existing engineering-orientedmodels are useful for Portland Cement Concretes, but their accuracy for LCC is still unclear. Moreover, study-ing the dependence of LCC maturity parameters on whether mechanical or heat tests are implemented is also ofinterest. 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 calorim-etry tests. Moreover, a novel Activation Energy (Ea) function was proposed, accounting for its hydrationdependence, here referred to as aging. The proposed models represent improvements for the evaluation of LCC assuggested by comparison against classical approaches. For instance, they better capture the extended dormantperiod of LCC. Furthermore, the aging of the Ea was found imperative to accurately predict the heat developmentof LCC independently of the type of heat test selected for calibration. The models also predicted more severecross-over effect on the tensile than the compressive strength for low water-to-binder ratio LCC, which is relevantto decide on cracking risk mitigation measures. In general, the modelling techniques developed here evidencedgood performance for LCC and are worth of further exploration by researchers and practitioners. Their appli-cation will contribute to incentive wider use of LCC in infrastructure projects by providing more accurate pre-dictions of their cracking risk.