Tensile behavior of recycled-glass-UHPC under direct tensile loading

This paper analyzes the ductility parameters of the uniaxial tensile behavior of 52 different UHPC test series using an eco-friendly and cost-effective recycled-glass cementitious matrix. The focus was made on investigating the suitability of this material for the seismic retrofitting application. The commercially available in the Colombian market fibers assessed involved five steel plus three synthetic ones. The series analyzed encompassed mono-fiber and binary multi-scale fiber-reinforcement systems. Experimental results of mono-fiber-reinforced UHPC with a fiber volume fraction of 2.0% of high-strength smooth steel fibers with a slenderness of 65 showed strain values at peak stress in tension (εpc) similar to those from other researchers, notwithstanding the reduction in cement and silica fume by 35% and 50%, respectively, of the low-cost and sustainable cementitious matrix used. Nonetheless, a significant drop in the energy absorption capacity (g) values are observed, which can be explained by the decrease in cement and silica fume. Outcomes also pointed out the relevant synergy between the hooked end fibers and the high-strength smooth ones. The results indicated that only the hybrid blend of high-strength smooth fibers (lf/df =65) and hooked end fibers achieved the required ductility parameters (g≥50 kJ/m3 and εpc≥0.3%) for seismic retrofitting applications.