Effects of Using Nano-Silica Particles, Fly Ash and Waste Water Sludge on Properties of Cement Mortar

Wastewater sludge has been widely applied to cementitious materials. In this paper, the influence of nano-SiO2, wastewater sludge and fly ash addition as cement replacement has been studied. In all cases, two sludge contents of 0 and 7.5 percent by weight of cement were introduced to the mortar mixes. Moreover, 0 and 1 percent of nano-SiO2 was added to the mixture. The fly ash replacement level of 20% by weight of the cementitious material was used for all the mortar mixes. This high level of replacement was selected such that the effect of the fly ash replacement could be detected. The water-binding ratio of 0.54 was assigned to the mix. Tests were carried out on mortar specimens cured at 7, 14 and 28 days. From the results of compressive strength, setting time, SEM and XRD tests can be concluded that adding nano-SiO2 and fly ash to environmentally friendly cement mortar containing sewage sludge can improve it properties.

Keywords:

Nano-SiO2 , Wastewater sludge , Fly Ash , Cement mortar , Sustainable development