Micromechanical investigation of plasticity-damage coupling of concrete reinforced by shape memory alloy fibers

摘要

Although concrete is an extremely popular material in the building industry, it is very weak in tension, as compared to its strength in compression. Smart prestressing of concrete with shape memory alloy fibers is a promising solution to this limitation. To this end, already stretched shape memory alloy fibers are embedded in a concrete matrix at a relatively low temperature which corresponds to that of the shape memory effect. Upon heating (activating) the resulting composite, the shape memory alloy fibers regain their original shape, and compressive stresses are transmitted to the concrete. In the present study, a robust micromechanical framework is proposed to analyze the concrete that has been prestressed by shape memory alloy fibers. The offered methodology accounts for the evolution of plastic strains in the concrete phase, in addition to the coupled evolving damage. Initial yield surfaces of the SMA/concrete composite are obtained for several loading cases. These surfaces are further generalized to incorporate the effect of the activation temperature change. The relation between the residual macroscopic plastic strain and the activation temperature change, as well as the macroscopic stress-strain response of the activated composite are presented.