Effect of Shape Memory on the Mechanical Properties of Concrete Reinforced with Short Shape Memory Alloy Fibers

Abstract

To enhance the mechanical properties of concrete and inhibit the development of cracks, this study designed and prepared four kinds of shape memory alloy fiber–reinforced concrete (SMAFRC) with different volume contents (0%, 0.3%, 0.6%, and 0.9%), and carried out cube compression, splitting tensile, and bending tests at two temperatures (20°C and 100°C). The SMAFRC failure samples were analyzed by scanning electron microscopy (SEM) and the failure mechanism was explored. The results showed that the SMAFRC specimen with 0.9% SMA fiber content (S-0.9) had the best mechanical properties at 20°C, and the cube compressive strength, splitting tensile strength, and bending strength were increased by 18.22%, 32.34%, and 33.20%, respectively, compared with the pure specimen (S-0). At 100°C, the strength of concrete decreased compared with that at 20°C and the SMAFRC sample with an SMA fiber content of 0.6% (S-0.6) decreased slightly at 100°C, indicating stable mechanical properties. SEM shows that the presence of SMA fibers not only acts as a bridge in concrete, but also blocks the generation and development of microcracks.