On the efficiency of induced prestressing in SMA mortar beams through different thermal stimuli

Abstract

This paper investigates the efficiency of prestressing effect on the flexural performance of reinforced mortar beams through different heating methods. To this end, different specimens reinforced by 1.0% and 1.5% volume fractions crimped shape memory alloy fibers as well as diverse internal and external heating sources are employed. Time-deflection relationships during heating and cooling of specimens are extracted to evaluate the amount of induced prestressing force in each specimen via different heating process. Upon developing prestressing force in the reinforced mortar beams, we carry out several three-point bending tests to study the flexural behavior of mortar beams and compare the material parameters with the reinforced specimens in the absent of prestressing force. The results show that internal heating source using electric current in comparison with external heating via heat gun could be faster and more uniform across the beams cross section contributing to a higher potential capacity in terms of stimulating recovery stress and subsequently boosting ductility and toughness of the composites.