Dynamic Splitting Tensile Strength of Precast Concrete Samples with Varying Moisture Contents

Abstract

In this work, we investigated the impact of moisture content on the dynamic mechanical properties of precast concrete members. The dynamic splitting impact test was applied to concrete specimens with different moisture contents using the split-Hopkinson pressure bar (SHPB) with a diameter of 75 mm. Further, variation laws of the waveform, stress–strain curve, damage pattern, dynamic splitting tensile strength (DSTS), strain rate, and damage evolution were analyzed. Experimental results indicate that specimen fragmentation degree increases with moisture content. The DSTS exhibited a “softening in the water” phenomenon when the moisture content was low, resulting in a decrease in strength. However, when the moisture content was high, the strength displayed a strengthening phenomenon, owing to the adhesion of internal pore water. The dynamic strength of the specimens is the macroscopic manifestation of the dynamic balance between the strain effect and moisture content. To model the effect of moisture content and strain rate, a viscoelastic damage constitutive model based on Weibull distribution was proposed and validated, considering the influence of water content and residual strength. The established model can reflect the damage stress–strain relationships of concrete with varying moisture contents under the impact load. The variation laws of associated parameters, such as Weibull distribution parameters, viscosity coefficient, and damage variables, were analyzed to explore the damage mechanism. From the experimental study, it can be concluded that moisture content is closely related to the specimens’ damage pattern, and the dynamic performance of concrete, both of which can be captured by the proposed viscoelastic damage model.