Incorporation of reduced graphene oxide in waste-based concrete including lead smelter slag and recycled coarse aggregate
Mohammad Valizadeh Kiamahalleh, Aliakbar Gholampour, Youhong Tang, Tuan Ngo
Abstract
Waste-based concrete stands as an environmentally friendly and sustainable option compared to conventional concrete. The waste-based concrete holds the potential to lessen the unfavorable ecological effects associated with the concrete construction. In this research, along with ground granulated blast furnace slag (GGBS) and fly ash (FA) as alternative binders to cement, lead smelter slag (LSS) as sand and recycled coarse aggregate (RCA) have been utilized in the production of the waste-based concrete. The influence of reduced graphene oxide (rGO) on mechanical and durability characteristics of the waste-based concrete has been assessed. Four rGO dosages of 0%, 0.05%, 0.1% and 0.3% by weight of binder were incorporated. Scanning electron microscopy and thermogravimetric analysis were conducted to assess the rGO-reinforced concrete's microstructure. The findings indicate that rGO improved the characteristics of the waste-based concrete. 0.1% is the optimum dosage of rGO to increase the compressive strength (47%), splitting tensile strength (44%), and flexural strength (42%) and decrease the water absorption (45%) and drying shrinkage (35%) of the concrete. Further dosage leads to reduced properties of the concrete. In addition, the waste-based concrete incorporating 20% FA, 50% GGBS, 100% LSS, and 100% RCA reinforced with 0.1% rGO exhibits similar mechanical and durability properties to the conventional concrete. The enhanced performance of the waste-based concrete can be related to the reduced porosity, refined pore structure, densified hydration products and increased hydration degree of the concrete by incorporating rGO.