Compressive strength estimates of adiabatically cured concretes using maturity methods

The strength development of standard and adiabatically cured concretes was determined. The concrete mixes were of 28-day cube strengths of 50 and 30 MPa and also had Portland cement (PC) replaced partially with fly ash (FA) and ground granulated blast-furnace slag (GGBS) at 30% and 50%, respectively. The peak adiabatic temperature was effectively reduced with GGBS addition but was only reduced with FA addition for the lower w/b concrete. Considerable early age strength enhancements resulted from the adiabatic curing regime. The Nurse-Saul and Arrhenius based maturity functions were used to estimate the increases in early age adiabatic strength. The Nurse-Saul function underestimated the effect of high early age curing temperature for all concretes but to a greater extent for those with GGBS and FA whilst the Arrhenius based, which allows for the consideration of an “apparent” activation energy, gave more accurate estimates. Strength estimates for adiabatically cured concretes and isothermally (50 °C) cured mortars were also compared indicating that the latter might have been affected by the detrimental effect of high curing temperatures starting from early age.