Performance of multiscale, including nanoscale, fibres in concrete

Abstract

Engineered cementitious composites (ECCs) reinforced with macro-, micro- and nanoscale fibres are presented. Ten test groups, including a combination of the multiscale fibres, macroscale polypropylene (PP), microscale poly(vinyl alcohol) (PVA) and nanoscale carbon fibres in ECCs, are studied to determine experimentally the compressive, tensile and flexural strength as well as the impact toughness. Based on a repeated impact test performed in this study, ECCs reinforced with all three-scale hybrid fibres are approximately six and seven times more resilient to impact loading than ECCs singly reinforced with PP fibres and conventional plain concrete, respectively. Furthermore, multiscale fibre-reinforced concrete increases the tensile and flexural strength by more than 30% while maintaining the compressive strength. It is concluded that ECCs singly reinforced with carbon nanofibres (CNFs) have no significant advantage in increasing impact toughness, whereas CNFs provided in addition to a combination of PP and PVA fibres in ECCs significantly enhance the impact toughness or energy absorption capability by 20%.