Designing high impact-resistance self-compacting concrete by addition of asphalt-coated coarse aggregate

The brittle fracture characteristic of conventional cement-based concrete poses a great challenge to the security of concrete structures under impact loads. In this study, a new design method is proposed to optimize the impact resistance of self-compacting concrete (SCC) by precoating coarse aggregates with an asphalt-based energy-absorbing layer. The dynamic mechanical properties of SCC with asphalt-coated coarse aggregate (ACCA) were investigated with a 75-mm-diameter split Hopkinson pressure bar. The impact toughness index is defined to evaluate SCC's impact-resistance performance. Results show that the dynamic increase factor of compressive strength (DIFc) increases linearly with decimal logarithm of strain rate, indicating remarkable strain rate effect. The incorporation of ACCA significantly increases the impact toughness index of SCC, showing a significantly optimized impact resistance. The optimal thickness of asphalt layer is 120 mu m, in which the average increase rates of impact toughness index is about 20%. (C) 2020 Elsevier Ltd. All rights reserved.