Effect of graphene oxide on the microscopic, physical and mechanical characteristics of rubberized concrete

摘要

Exhausted rubber tires are a big problem for a sustainable environment. Sustainable construction practices can be achieved with the inclusion of rubber aggregate (RA) in the concrete. The rubberized concrete (RC) was made with RA as a partial substitution of 5, 10, and 15 by weight to manufactured sand (MS). Graphene oxide (GO) was added and mixed in the proportions of 0.01, 0.03, 0.05, and 0.1 as a partial replacement of cement by GO by weight. Two series of concrete mixes based on water-cement ratios, having 16 concrete samples each, were evaluated. It was observed that the inclusion of RA makes significant changes in the microscopic, physical, and mechanical properties of concrete. Incorporating RA in the concrete leads to increased voids, which can be easily detected with microscopic images through field emission scanning electron microscopy (FESEM). Workability and density of the concrete mixes were decreased up to 14.85 and 4.76, respectively, and an increment of 2.8 was observed in air content at a 15 MS substitution level. After the inclusion of RA in the concrete, decrements of up to 27.16, 24.85, and 26.26 were observed in compressive, tensile, and flexural strengths, respectively, at 28 days of testing. The application of GO as a partial replacement for cement was found very effective in mitigating the losses in the concrete properties caused earlier by the inclusion of RA. FESEM images revealed the presence of fewer voids and more compact microstructures in GO-induced RC. Although workability was still reduced after the application of GO, density and air content improved by up to 1.13 and 1.3, respectively. Compressive, tensile, and flexural strengths showed increments of 13.45, 15.19, and 8, respectively, at 28 days of testing for GO-induced RC samples.