The effect of coarse aggregate gradation on the properties of self-compacting concrete

The aim of this paper is to assess the effect of coarse aggregate gradation (A/B ratio, size 5–10 mm coarse aggregate weight/size 10–20 mm coarse aggregate weight) on the properties of self-compacting concrete (SCC). For this purpose, four SCC mixtures with A/B ratio for 4/6, 5/5, 6/4, 7/3 were prepared, the bulk density of aggregate with various A/B ratios was investigated, the effect of A/B ratio on the fresh properties, mechanical properties, porosity and durability properties of SCC was studied. The test results indicated that aggregate with A/B ratio for 6/4 has a maximum bulk density of aggregate, with the change in A/B ratio from 4/6 to 7/3, the initial slump flow, blocking and segregation ratio are decreasing, while the wet density of fresh SCC are increasing. SCC with A/B ratio for 6/4 had a maximum mechanical properties, least porosity, carbonation depth, chloride ion diffusion coefficient. Moreover, the damage of SCC under drying–wetting cycles was evaluated, it was found that SCC with various A/B ratios has a resemble behavior on resistance damage against drying–wetting cycles.

► The A/B ratio in SCC effect on the fresh, mechanical and durability properties of SCC.
► More size 5–10 mm coarse aggregates added into SCC enhance fresh properties, the wet density of SCC.
► SCC with A/B ratio for 6/4 has maximum mechanical properties and higher durability properties.
► SCC with various A/B ratios has a resemble behavior under drying–wetting cycles.