Contribution of Economic Nano-materials and Industry By-Products to the Fresh and Hardened Properties of Cement Mortars

Abstract

This study aims at evaluating the influence of low cost nano materials including; nano silica (NS) and nano clay (NC) and various industry by-products including; silica fume (SF), Fly ash (FA), and fine Air-Cooled Slag (FACS) as cement replacements on the compressive strength, flexural strength and rheological properties of cement mortars. The results revealed that, the investigated industrial by-products contribute to the strength development by various ratios at various replacement percentages. The best mechanical performance was obtained for the mortar incorporating 15 wt. % SF; remarkable enhancements by about 30.8 and 26.8 were obtained for the compressive and flexural strengths respectively as compared with the plain ordinary mortar. FACS showed insignificant contribution to both compressive and flexural strengths. Even at low levels of replacement; the nano-materials provide better enhancements of the mechanical strength. Incorporation of 3 wt. % NS into the cement mortar has increased the compressive strength by about 38.5%; while, the incorporation of 5 wt.% of activated NC has considerably increased the flexural strength by 59% as compared to the ordinary cement mortar at 28 days of hydration. The workability of the blended mortars decreases with the loading of silica fume, fine air cooled slag nano-silica and nano-clay while increases with using fly ash and marble dust. The nano materials showed noticeable improvement of the structural integrity and microstructure, confirming the enhanced durability characteristics.