Influence of Coarse Aggregate Type on the Mechanical Strengths and Durability of Cement Concrete

Abstract

In this paper, the influence of coarse aggregate on the slump flow and the following mechanical strengths (flexural and compressive strengths), the shrinkage rate, the chloride penetration resistance, and the freeze–thaw resistance were investigated. Water–binder ratios in this study were 0.22, 0.30, 0.34, and 0.45. Sand ratio in this study was 0.45. All samples were cured for 7 d, 14 d, 28 d, and 56 d, respectively. Results indicated that the fluidity of cement concrete with different coarse aggregate increased in this order: gneiss < limestone < basalt < diabase. The mechanical strengths and shrinkage rate increased obviously with the increasing curing age when the curing age ranged from 7 days to 28 days. However, the mechanical strengths and shrinkage rate trended to a stable value when the increasing curing age increased from 28 days to 56 days. The mechanical strengths with different coarse aggregate increased in this order: diabase < basalt < limestone < gneiss. Meanwhile, the shrinkage rate demonstrated this trend of development: diabase < basalt < limestone < gneiss. The resistance to freeze–thaw cycles of cement concrete decreased with the increasing water–binder ratio. Meanwhile, the resistance to freeze–thaw cycles was closely related to the types of coarse aggregate.