Effect of Styrene–Butadiene Rubber Latex Dosage on the Workability and Compressive Strength of Concrete Incorporating Manufactured Sand as Fine Aggregate

Abstract

The scarcity of natural river sand has encouraged interest in the use of manufactured sand (M-sand) as a fine aggregate in structural concrete. Additionally, the addition of polymers to the concrete mix can improve the engineering properties of the resultant concrete. M20 grade concrete is prepared using M-sand as the fine aggregate and styrene-butadiene rubber (SBR) latex at replacement levels of 2%, 4%, 6% and 8% of the mass of the cement. The mix is designed according to Indian Standard methods with a water-cement ratio of 0.50 and a cement content of 394 kg/m³. The slump of the mix increases from 85 mm for the control mix to a maximum of 110 mm for 6% SBR latex content before decreasing to 95 mm for 8% latex replacement. The 28-day compressive strength of concrete with 6% SBR latex replacement has the highest strength values (21.14 MPa at 7 days and 27.03 MPa at 28 days) while the 8% replacement level gives the lowest strength (18.74 MPa at 7 days and 25.28 MPa at 28 days). All the tested concrete had a 28 day compressive strength greater than the 20 MPa characteristic strength required for M20 grade concrete. These results show that 6% SBR latex replacement in M20 grade concrete with M-sand as fine aggregate gives the highest strength and hence can be considered the optimum dosage of polymer in this type of concrete. A framework for using machine learning to model the properties of such concrete is proposed.