Influence of shape memory alloy and rice husk ash on the mechanical behavior of concrete

The increase in population and high demand for construction have prompted engineers to propose innovative solutions to meet these needs. Concrete, as a highly consumed material that contributes to significant environmental pollution, can be modified using various additives to improve its mechanical properties and reduce its environmental impact. In this research, the shape memory alloy (SMA) fiber and rice husk ash (RHA) were applied as two reinforcement materials in the concrete structure. The compressive strength, splitting tensile strength, flexural strength, ultrasonic pulse velocity, and secondary compressive strength tests were examined. The results indicated that replacing 5% of RHA by the weight of Portland cement led to a 1.5% increase in compressive strength, a 2.5% increase in tensile strength, and a nearly 8.5% increase in flexural strength. SMA also contributed to the improvement of strength parameters, and using 0.3% of this fiber enhanced compressive strength by 2%, tensile strength by 5.5%, and flexural strength by 10% compared to control specimen. Additionally, this material had a noticeable impact on the results of the secondary compressive strength test. Furthermore, the simultaneous use of SMA and RHA in the concrete structure was evaluated as highly beneficial.