Effects of different silica fume dosages on early-age behavior and cracking resistance of high strength concrete under restrained condition

Abstract

High strength concrete (HSC) containing silica fume (SF) is widely utilized in construction practices, and its cracking resistance attracts considerable attentions. Previous studies mostly focus on the single parameter of concrete, however, the evaluation of early-age cracking resistance of HSC containing different SF dosages considering different early-age parameters is limited. The present study investigated the effect of different SF dosages on the temperature process, autogenous shrinkage, restrained stress, and creep by utilizing Temperature Stress Test Machine to evaluate the cracking resistance of early-age HSC containing SF. Four concrete mixtures with a 0.33 water/binder ratio were prepared at different replacement levels of SF (0%, 5%, 10%, and 15% of cement by weight). The analysis and experimental results indicated that, when the SF dosage in the HSC increased, (1) the cracking resistance of HSC decreased at early age; (2) the temperature drop, cracking time, cracking stress, and ratio of cracking stress to axial tensile strength decreased; (3) the autogenous shrinkage as well as restrained stress rate increased; (4) the basic tensile creep, specific tensile creep, and creep-shrinkage ratio increased.