Effect of Adding (SBR) on Concrete Properties and Bond Between Old and New Concrete

Abstract

The effect of adding cempatch SBR ( Styrene- Butadiene – Rubber) emulsion to the following was studied: Cement mortar with different dosages of SBR ( 10 %, 25%, 35% ) by volume of water. Compressive strength of this mortar was tested at ages ( 7, 28, 60 ) days. Initial and final setting time were also recorded. SBR also added to concrete mix 1 : 2 : 4 with 0.45 water to cement ratio by weight, and SBR in dosages of ( 10 %, 2 5%, 35 % )by volume of water . Compressive strength in ages ( 7, 28, 60 ) days was tested, also absorption, slump loss with time and flexural strength were also measured. And SBR was also used as bonding mortar layer between old and new concrete layers, the compressive strength and flexural strength of bonded samples were tested. The results of adding SBR emulsion to cement mortar affects compressive strength negatively at all age. Initial and final setting time decrease with increasing the dosage of SBR. The using of SBR emulsion as admixture for concrete mix affects compressive strength negatively at early ages ( 7 days ) and positively at later ages. It also reduces; the absorption of concrete and slump loss with time and increase the flexural strength. The use of SBR as bonding layer showed increasing in compressive and flexural strength of the bonded samples compared with samples having old and new concrete without bond layer.