Dynamic splitting tensile bond behavior of new-to-old concrete interfaces

New-to-old concrete interfaces, which widely exist in concrete structures, are commonly regarded as weak links. Hence, many researchers have studied the splitting tensile bond behavior of concrete interfaces. However, these studies were focused on the behavior under quasi-static loading. Concrete interfaces may suffer blast and/or impact loading during their service lives. Therefore, this paper experimentally investigated the dynamic splitting tensile bond behavior of concrete interfaces. For comparison, a quasi-static splitting tensile test was also carried out. A total of 46 splitting tensile cylinders were tested. Test parameters included three strain rates (10(-6), 0.63 and 1.58/s), two levels of average roughness (1.2 and 2.4 mm) and two interface ages (60 and 120 days). Experimental results show that influences of the strain rate on failure modes, compressive load-deformation curves, absorption energy and splitting tensile bond strength of specimens are significant. The surface roughness and interface age have little effects on splitting tensile bond strength. Existing formulas for the dynamic increase factor of the tensile strength of concrete-like materials cannot be used for concrete interfaces. Consequently, a new formula for the dynamic increase factor of the splitting tensile bond strength of concrete interfaces is finally proposed. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study found that strain rate has a significant influence on the failure modes, compressive load-deformation curves, absorption energy, and splitting tensile bond strength of concrete interfaces, while surface roughness and interface age have minimal effects on the splitting tensile bond strength. Existing formulas for the dynamic increase factor of tensile strength of concrete-like materials cannot be applied to concrete interfaces, leading to the proposal of a new formula for the dynamic increase factor of the splitting tensile bond strength of concrete interfaces.