Shrinkage Properties of Hybrid Fiber Reinforced Recycled Aggregate Concrete

Abstract

Recycled aggregate concrete (RAC), which is made by recycled coarse and fine aggregate, is of great significance in improving the recycling rate of construction materials, reducing carbon emissions from construction materials, and alleviating the ecological degradation problems currently faced. Due to its low strength and large shrinkage and deformation problems, RAC is limited in its application. In order to improve the performance and expand the application of RAC, research was conducted on the effect of fiber type, fiber content, and fiber hybrid on mechanical properties and shrinkage of RAC. Test results indicate that the shrinkage of RAC decreases with the increase in fiber content, and steel fiber (SF) reinforced effect is better than that of polypropylene fiber (PF). The shrinkage deformation of hybrid fiber group is smaller than that of the single fiber group, and the shrinkage deformation is smallest when the steel fiber content is 0.5% and the polypropylene fiber content is 1.5 kg/m3. Based on the experimental data, three theoretical calculation models of shrinkage applicable to single and hybrid fiber reinforced RAC were established by considering the characteristics of fiber type and content.

Keywords: Recycled concrete, shrinkage, Steel fiber, Polypropylene fiber, hybrid fiber