Using graphene oxide to improve the properties of ultra-high-performance concrete with fine recycled aggregate

Abstract

One of the most efficient methods for recycling construction and demolition (C&D) waste is to utilise the recycled aggregate (RA) obtained from the C&D waste to manufacture recycled aggregate concrete. However, the properties of the recycled aggregate concrete are inferior compared to normal concrete, owing to the use of the RA. Accordingly, this study examines the use of graphene oxide (GO) to enhance the properties of ultra-high-performance concrete (UHPC) with fine RA. An initial mixture of UHPC with fine RA was designed based on a modified Andreasen & Andersen particle packing model, and the effects of different contents of GO on the mechanical properties, volume stability, and durability of UHPC with fine RA were investigated. It was found that (1) the mechanical properties, volume stability, and durability properties of UHPC with fine RA were comparable to or even better than those of UHPC with natural river sand; (2) the optimal amount of GO was 0.06 wt%, considering the mechanical properties, durability properties, and pore structure of the UHPC; (3) the compressive strength, tensile strength, flexural strength, and elastic modulus of UHPC increased by 2.04%–16.04%, 7.36%–30.50%, 5.83%–23.40%, and 3.62%–12.95%, respectively, owing to the addition of GO; and (4) both the chloride penetration resistance and the freezing and thawing resistance of UHPC effectively improved owing to the addition of GO. These findings are conducive to the recycling of C&D waste.