Using of Microsilica for Strength Improvement of Fiber Reinforced Cementitious Surface Compounds

Abstract

This study represents an extension work to investigate the role of ultra fine sand (UFS) in enhancing the mechanical properties of fiber reinforced cementitious compounds. The micro-structural origins were identified by scanning electron microscope (SEM). About 50% of UFS had a diameter of less than 20 m. Ordinary Portland Cement (OPC) was partially substituted by UFS at 3, 5, 7 and 10% by weight of binder. It was found that as UFS loadings increase, the flexural, compressive, and tensile strengths increased up to about 5% UFS loading by 12.9, 15.7 and 30.1%, respectively, thereafter, a decrease in these properties was observed. This can be attributed to the pozzolanic effect besides the filling effect of UFS resulting in enhancing the interfacial bonds between the sand grains and hydration products that makes the paste more homogeneous and dense. The effect of both short natural and artificial fiber loadings on the structural performance of compounds was also studied. Loadings of 2%, by weight, of short natural date palm leaves' midribs fibers (DP) and artificial polypropylene fibers (PP) were added to the 5% UFS blended mix. An increase in both flexural and tensile strength was achieved, while a decrease in the compressive strength was observed.

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

“…For flexure strengthincreasing trend were almost the same to compressive strength with different value as optimum percentage also 3%, as flexure strength increase by 25.3, 30 and 33% at 3, 7 and 28days, respectively as shown in figure (15). Workability clearly decreases with increasing nano silica percentage for all tested mixes as shown in figure (16).…”

“…An extensive research has been done all over the world in order to utilize and reuse the industry by-products in various construction applications. The addition of 10% silica fume has been found to increase the compressive strength of concrete cured at normal conditions [14], replacing cement by 5% marble dust could be a real energy and financial saving concept, in addition to saving part of the natural resources and alleviating the environmental [15], it can be replaced with sand to achieve adequate early compressive strength [16] , when cement is replaced with marble powder up to10% weight a high strength concrete was achieved [17,18]. impact imposed by the marble processing waste that the mix with nano-Silica from 1.5, 3, 5 or 7% or with nano-clay(by activated or inactivated phase) and Silica Fume 10%, increase in Compressive and flexure of concrete Strength and other properties [19,20] .…”