Influence of polypropylene fibres and silica fume on the mechanical and fracture properties of ultra-high-performance geopolymer concrete

摘要

This study intends to assess the effect of polypropylene fibres (PPF) and silica fume (SF) on the mechanical behaviour and fracture mechanics of ultra-high performance geopolymer concrete (UHPGC). A total of 20 concrete mixes were produced and the workability, compressive, splitting tensile and flexural strengths, load-displacement behaviour, equivalent flexural strength, energy absorption, load-crack mouth opening displacement, fracture energy and fracture resistance of the specimens were experimentally evaluated. To produce the mixes, PPF were used at four volume contents: 0%, 1%, 2% and 3%. In addition, five SF contents were used in terms of total binder's mass: 0%, 5%, 10%, 20% and 30%. The results were also compared with current standards and models proposed in previous investigations. Subsequently, new models were developed to predict the mechanical and fracture properties of UHPGC. The experiments showed that the mechanical and fracture properties of UHPGC considerably declined with the use of 10% SF and then improved for more than 10% SF incorporation. Moreover, PPF plays an important role to improve the mechanical and fracture of UHPGC containing SF and adding 3% PPF prevents a high reduction in the properties of UHPGC when 10% SF is used. (C) 2021 Published by Elsevier Ltd.