Research on Dynamic Mechanical Properties of Silicon Carbide-Modified Concrete.

Abstract

This research investigates the dynamic mechanical properties of silicon carbide-modified concrete using a ∅ 100 mm large-diameter split Hopkinson pressure bar (SHPB). The effects of silicon carbide content, particle size, and strain rate on dynamic compressive strength, deformation, and energy dissipation characteristics were examined. The results indicate that both ordinary concrete and silicon carbide-modified concrete exhibit significant strain rate effects, with peak stress, impact toughness, and fracture degree progressively increasing as strain rate rises. The peak strain and ultimate strain of ordinary concrete decreased with increasing strain rate, while those of silicon carbide-modified concrete decreased initially before increasing again. At a strain rate of 180 s^-1, the concrete fracture morphology showed almost no occurrence of cement paste connecting adjacent aggregates. The addition of silicon carbide directly increased the strength of aggregates at the micron scale, thereby enhancing the concrete's load-bearing ability under high-velocity impact loads. Therefore, the modifying effect of coarse-fineness high-strength silicon carbide particles on the strength and deformation characteristics of concrete was more evident under high strain rate conditions.