Strength development and drying shrinkage of high-strength concretes

Ten high to very high strength concretes with total cementitious contents of 550 and 600 kg/m(3) were made. The concretes consisted of plain cement, 5 and 10% condensed silica fume (CSF) and 10% silica fume with 20% fly ash or 20% ground granulated blast furnace slag. The specimens were either continuously fog cured or 3 or 7 days initially cured and then exposed to 40% R.H. drying regime. The results suggest that all laboratory made specimens irrespective of their composition (with or without cement replacement materials) give lower strength when inadequately cured and exposed to drying regimes for a long period of time. However; concretes made with 5 and 10% CSF resulted in the least loss in strength and drying shrinkage and had a superior quality cover concrete as indicated by the 24 h water sorption rest. (C) 1996 Elsevier Science Limited.