Enhanced Impact Properties of Concrete Modified with Nanofiller Inclusions

Abstract

This paper investigated the impact properties of reactive powder concrete modified with different types (nano-SiO2, nano-TiO2, and nano-ZrO2) and dosages (1.0% and 3.0%) of nanofillers. Three mechanical parameters (dynamic compressive strength, dynamic ultimate strain, and dynamic peak strain) and two toughness indicators (impact toughness and specific energy absorption) were used as the evaluation indexes of impact properties. Experimental results show that the incorporation of nanofillers significantly improves the impact properties of concrete. Composites with nano-SiO2 present the largest dynamic peak strain, whereas composites containing nano-ZrO2 and nano-TiO2 present higher dynamic ultimate strain and dynamic compressive strength. With the incorporation of nanofillers, the impact toughness of nanocomposites increased by 23.2%–39.9%, and the specific energy absorption increased by as high as 159.7%–246.9%. Among the three types of nanofillers, nano-SiO2 shows an obvious advantage on the toughening enhancement for concrete. The reinforcement mechanisms of nanofillers are attributed to three main aspects: (1) the small size effect and gap filling effect of nanofillers reduce the initial defects of concrete and increases the compactness; (2) the nucleation effect and core effect of nanofillers inhibit the crack propagation and improve the weak interface of concrete; and (3) the pozzolanic effect of nanofillers enhances the structural performance of concrete.