Carbon nanofibers and PVA fiber hybrid concrete: Abrasion and impact resistance

Abstract

This study investigated the effects of carbon nanofibers (CNFs) and PVA fibers on the mechanical properties, impact resistance, abrasion resistance, and microstructure of ultrafine fly ash (UFA) high-performance concrete when used alone and in blends. CNFs and PVA fibers were incorporated at 0.1 %, 0.2 %, and 0.3 %, respectively. The results of the study revealed that CNFs and PVA fibers significantly enhanced the mechanical strength and cracking toughness of concrete, whether added individually or in blends. The enhancement of cracking toughness was more prominent in the mixed systems with higher fiber additions. Notably, the combined use of CNFs and PVA fibers can also significantly enhance the impact resistance and abrasion resistance of concrete. When the fiber addition is appropriate, the impact energy consumption is significantly increased. The optimal incorporation ratio was 0.1 % by volume of PVA fibers and 0.3 wt% by mass of CNFs. at this ratio, the impact resistance of concrete was improved by 128.24 % and the abrasion resistance was improved by 18.17 % compared to the control group. Further scanning electron microscopy (SEM) and mercury-in-pressure (MIP) tests revealed that the mixing of CNFs and PVA fibers effectively enhanced the densification of the concrete matrix, increased the amount of its hydration products, and strengthened the bonding of the fibers to the matrix.