Effect of Silica Fume and Polymers on Absorption and Some Mechanical Properties of Concrete Contains Waste Aggregates

This research aims to study the effect of silica fume and liquid polymers (Styrene Butadiene Rubber (SBR)) on absorption and some mechanical properties of concrete like compressive strength, tensile strength and flexural strength of concrete containing waste aggregates. The reference mixes having waste aggregates (crushed glass) as coarse aggregates to decrease the cost of concrete and also increase strength. The aim for using silica fume powder is to increase strength of concrete by reaction of this material with silicates hydroxide that liberate from hydration of cement and this reaction give additional cement gel that fill the pores inside cement paste and that give higher strength and less absorption concrete, and that also give more durable concrete. The using of liquid polymer (SBR) can give additional bond between cement particles or gel with external silica of aggregates and also decreasing voids inside concrete. So, the using of both silica fume and polymers can give extra bond and strength and less voids concrete and these are the main aims of using both materials in this study. Using the waste aggregates in this study have two benefits firstly is the decrease for cost of concrete and secondly is higher mechanical properties by using glass aggregates because of its properties that have zero absorption compared with normal aggregates and also higher strength of glass, that give concrete additional strength and durability. The effect of silica fume only on concrete was given 61% increment in compressive strength, but with polymers together give about 72% increment, flexural strength increased from 3.8 MPa for reference mixes to 10.5 MPa for silica fume mixes and 12.3 MPa for polymer-silica mixes. The absorption decreases from 6.01% to 2.85% for silica mixes and to 1.5% for polymer-silica mixes.