Factors affecting air-entrainment and performance of roller compacted concrete

The study reported in this paper aims at assessing the key factors affecting the air-entrainment in roller compacted concrete (RCC). The effects of binder content, air-entraining agent (AEA) dosage, workability level, and compaction method on the air-void system and frost resistance of RCC were evaluated. The mixtures were tested to evaluate compressive strength, splitting tensile strength, modulus of elasticity, as well as frost resistance of RCC including freeze-thaw resistance, de-icing salt scaling resistance, and air-void system. The performance of the RCC was compared to that of reference air-entrained and non-air-entrained concrete mixtures. Test results indicated that RCC mixtures with air contents of 5% to 7% and spacing factors lower than 230 mu m can be achieved even in relatively dry mixtures with Vebe consistency of 90 s. The air-void network of RCC was found to depend primarily on the consistency level of the concrete and to a lesser extent on the binder content and compaction method. The 28-d compressive strength ranged between 36 and 58 MPa even in the mixtures with a low binder content of 255 kg/m(3). Despite the adequate air-void system, the RCC mixtures exhibited low to marginal freeze-thaw resistance. However, the air-entrained RCC mixtures exhibited high durability to deicing salt-scaling with mass loss lower than 400 g/m(2) after 50 freeze-thaw cycles. (C) 2020 Elsevier Ltd. All rights reserved.