Experimental investigation on the tensile behavior of hybrid steel-PVA fiber reinforced concrete containing fly ash and slag powder

A series of direct tensile tests are performed to investigate the tensile behavior of hybrid steel-PVA fiber reinforced concrete containing fly ash and slag powder. Digital image correlation (DIC) measurement is also utilized to capture the formation and propagation of cracks during the test. Different hybrid ratios (steel: PVA = 1:3 similar to 3:1) and fiber volume contents (1%-3%) are investigated to highlight their effects on the tensile behavior. The test results reveal the following: (i) the tensile strength of hybrid fiber reinforced concrete (HFRC) increases with the increase in steel fiber content, while it decreases as the PVA fiber content increases; (ii) the engineering tensile strength (tensile stress at a crack width of 0.2 mm) and the toughness, T-0.5 and T-1.0, are introduced and proved to be more suitable to describe the tensile behavior of HFRC during the post-peak stage; (iii) adding fly ash and slag powder has no effect on the hybridization of the steel and PVA fibers and their enhanced effects on tensile behavior when compared with HFRC containing different kinds of cementitious material; and (iv) the tensile behavior of HFRC is a combined result of the PVA fiber effect and the steel fiber effect, and their contributions vary with loading. (C) 2020 Elsevier Ltd. All rights reserved.