Drying shrinkage of waste-based concrete reinforced with pristine graphene (PRG) nanomaterial

Abstract

Drying shrinkage because of moisture loss is one of the main concerns in construction, as it can result in the creation of early cracking in concrete. This study presents the results of an experimental study on the use of pristine graphene (PRG) nanomaterial to improve drying shrinkage properties of waste-based concrete. In this study, the conventional materials of concrete are completely replaced with waste-based materials and industrial by-products including: 20 % fly ash and 80 % ground granulated blast furnace slag as binder, 100% recycled concrete aggregate as coarse aggregate, and 100% lead smelter slag as fine aggregate. Four different mixes were prepared with PRG contents of 0% (control mix), 0.05%. 0.1%, and 0.3% by the weight of binders. Drying shrinkage test (up to 28 days of curing) and scanning electron micrography (SEM) were carried out on the concrete specimens to examine the influence of the PRG concentration on the drying shrinkage properties of the concretes. The results show that increasing the PRG dosage decreases the drying shrinkage of the concrete to a minimum value which is achieved by 0.1% PRG dosage. However, it is found that beyond the 0.1% dosage the drying shrinkage increases. According to SEM analysis, this increased shrinkage is because of the agglomeration of the PRG nanomaterials at higher concentrations.