Influence of initial curing on the properties of concrete containing limestone blended cement

This paper describes the effect of duration of initial curing on the mechanical properties (compressive strength, tensile strength, and modulus of elasticity) and the chloride penetration of concretes containing limestone blended cements. Three concrete mixtures (water/cementitious = 0.5) containing a portland and two limestone blended cements were subjected to three different initial curing regimens (full, wet, and air curing). Results show that mechanical properties of concrete containing limestone blended cement are less affected by the cessation of moist curing at early ages. This is attributed to the hydration acceleration owing to limestone presence and the increase of fineness in the clinker fraction of the blended cement. A prolonged initial moist curing reduces this advantage of limestone blended cements and the dilution effect produced by limestone addition impairs the potential mechanical properties. For concretes cured for an initial 7 days, there was no substantial difference in mechanical properties and chloride penetration resistance of cements with and without limestone filler. (C) 2000 Elsevier Science Ltd. All rights reserved.