Interfacial fracture toughness between aggregates and injected quick-hardening mortar

Abstract

This study investigated the interfacial fracture toughness (IFT) between injected quick-hardening mortar and coarse aggregate to increase the strength of quick-converting track concrete. The effects of different maximum grain size of sand and different additives (two types of polymer, silica fume, ground granulated blast-furnace slag and fly ash) on the IFT were investigated by using three-point fracture toughness tests to suggest an effective method to omit the cleaning process of contaminated aggregates in the quick-converting track concrete. The silica sand with the maximum grain size of 0.5 mm produced higher IFT than that with smaller particle size; consequently, the strength of quick-converting track concrete using silica sand with coarser particle size was 43.3 MPa, while the IFT was 10.10 MPa.mm(1/2). Silica fume among the various additives produced the highest strength of quick-converting track concrete (51.9 MPa). Furthermore, the effect of abraded fine particles (attached to aggregates) on IFT was evaluated. As the content of abraded fine particles increased from 0.00 to 0.10 wt%, the value of IFT decreased from 10.39 to 9.29 MPa.mm(1/2). The experimental findings suggest that the use of silica sand with the maximum grain size of 0.5 mm and silica fume enables an efficient quick-converting track method without a thorough cleaning process of contaminated aggregates.