Utilization of Nano Clay, Marble Powder and Silica Fume Waste as Hybrid Addition for Enhancing the Properties of Concrete

The main objective of this research is to investigate the effect of utilizing Nano Clay (NC) particles and Marble Powder (MP) in Normal Strength Concrete (NSC) and in High Strength Concrete (HSC) on its physical/mechanical properties and microstructure configuration. For obtaining economically feasible concrete mix, the amount of NC particles in the mix was reduced by MP as a cheap waste material. This reduction of NC particles also facilitated its dispersion in partial amount of mixing water and superplasticizer by practical techniques such as, stirring and sprinkling. At first, concrete samples were prepared with hybrid additions of NC and MP; NC and MP replacement ratios were 3% and 5% of cement and 5%, 10% and 15% of sand by weight, respectively. After that, concrete physical properties; permeability, and mechanical properties; compressive, flexural, splitting and bond strength were investigated. Moreover, stressstrain response of optimum performance mixes was monitored. Finally, the microstructure of these mixes was studied using Scanning Electron Microscopy analysis (SEM) and Thermogravimetric Analysis (TGA). It can be concluded from this work that the best physical/mechanical performance of concrete mixes can be achieved by using 3% NC and 10% MP additives ratios by weight of cement and sand, respectively. Also, the microstructure of these mixes shows less voids due to filling effects of MP and the share of NC in the hydration process. KeywordsNano clay, marble powder, silica fume, hybrid additions, waste, sprinkling, dispersion.