Influence of Finely Ground Recycled Concrete on Microstructure of Cement-Based Composite Material

Abstract

This article deals with using recycled concrete in cement-based composite materials. The recent studies were mostly focused on utilization of recycled concrete in the form of an aggregate filler. In this study we are investigating the possibility of using finely ground recycled concrete as microfiller or partial substitution for binder. In particular, we focus on changes in microstructure of the cement paste which differed in amount of finely ground recycled concrete (FGRC). We used four mixtures of cement pastes containing 0, 33, 50 and 67 wt. % of FGRC, respectively. For the examination of their microstructure, phase distinction and determination of FGRC influence, the images obtained using optical and electron microscope were used. The first results indicate that cement paste with 33 wt. % of FGRC has similar mechanical properties as reference cement paste. Partial replacement of cement by finely ground recycled concrete leads to a cost reduction of cement-based composites and also can reduce environmental impacts of construction waste disposal and cement production.