Investigation on Effectiveness of the Top Down Nanotechnology in Mechanical Activation of High Calcium Fly Ash in Mortar

Background/Objectives: Many synthetic additives have been using for improve cement mortar and concrete characteristics, but natural additive is a friendly environment option.In this work, the attempt is made to study, to reduce the pollution from cement production and other materials used in the construction by replacing of Secondary Cementitious Materials. Methods: In this study, the effects of cementitious materials like Ultra-Fine Fly Ash (UFFA) and Nano Silica (NS) on strength development, water permeability of mortar and the optimum use of UFFA and NS in mortars are investigated. Class C Fly Ash which is used as partial replacement of cement was subjected to ball milling for a total duration of 2 hours to obtain UFFA. The NS is a by product obtains from the silicon industries are also used as a replacement material of cement. Cement was partially replaced with four percentages (15%, 30%, 45% and 60%) of UFFA and NS by weight. The specimens used to determine the compressive strength and split tensile strength at the age of 3, 7, 14 and 28 days. Crystallite phase and grain size of UFFA and NS were determined by using X-ray diffraction test and the shape and texture was studied using SEM analysis. Findings: The test results show that strength increases with increase of secondary cementitious materials up to 30% of replacements of cement. Test results indicates that the physical, chemical, mechanical and durability properties of the cement are also enhanced with the influence of the secondary cementitious material. Application/Improvements: Increase in use of fly ash in cement mortar in the construction industry reduces the consumptions of cement as well as the cost of construction.