Investigation of external sulphate attacks and moisture effects on roller-compacted concrete pavement mixes containing micro silica sand powder

Abstract

Abstract External sulphate attacks (ESA) and water movement tend to produce the most deleterious effects on concrete. This study therefore aimed to investigate the durability of a roller compacted concrete (RCC) mix created with better engineering properties to be suitable for road paving. This RCC concrete has a dry consistency and low cementitious materials (cms) content. Slabs were prepared in dimensions of 380 × 380 × 100 mm by taking sulphate resistant Portland cement and replacing various proportions with silica sand powder (SSP) (5%, 10%, and 20%) on a weight-to-weight basis. Additionally, crushed stone, M-sand, filler, and water were added in appropriate proportions. The slabs were subjected to normal curing for 28 days, then sawed into prisms of 380 × 100 × 100 mm and cubes of 100 × 100 × 100 mm. Cyclic wetting at 23 ± 2°C once in 5% MgSO4 solution and then in water, followed by drying at 60°C for 30 and 60 cycles was then used to investigate the durability of the RCC specimens. Mixes with 5% SSP achieved the best results with increases of 5.46% and 35.24% for compressive (f’c) and flexural (fr) strengths, respectively, while absorption and volume of voids was decreased by 57.3% & 52.29%, respectively, after 60 cycles of MgSO4 wetting and drying, as compared to the control mix.