Unconfined mechanical properties and micromechanism of short-age recycled aggregate from road solid waste modified by waterborne polyurethane

Abstract

In recent years, road waste treatment has become a hot topic, and how to solve and utilize these solid wastes is becoming an interesting research field. In order to explore the mechanical modification effect of waterborne polyurethane (PU) on short age road solid waste recycled aggregate, unconfined compression test and scanning electron microscope test were carried out on samples with different dry density and PU content. The dry density was 1.6 g cm−3, 1.7 g cm−3 and 1.8 g cm−3, and the PU content was 0%, 3%, 4%, 5% and 6%, respectively. The tested results show that, the strength of recycled aggregate (RA) increases with the increase of dry density. PU improves the strength and ductility of recycled aggregate (RA), and the residual strength and peak strength of RA increase with the increase of PU content. The peak strength and residual strength of waterborne polyurethane improved recycled aggregate (WPRA) increase with the increase of dry density, too. Polyurethane forms a three-dimensional network structure by film shape and linear shape, and its network structure can provide cohesion and effectively inhibit the crack propagation of the sample. The results demonstrate that adding appropriate amount of PU can effectively improve the mechanical properties of RA, which provides a technical reference for the recycling of RA.