POLYMER-MODIFIED CEMENT ASPHALT MORTAR AS INTERLAYER IN THE NON-BALLASTED TRACK OF HIGH-SPEED TRAIN

Abstract

Non-ballasted track consists of a concrete slab bonded firmly to the concrete base by a cement asphalt mortar (CAM) as an interlayer for damping. In practice, interface bonding failure occurs on CAM. Styrene-butadiene rubber (SBR) polymer is proposed as a modifying material to increase the interface bonding strength of CAM. The problem of polymer modification in CAM is probably related to poor compatibility and workability. This study aims to investigate the effect of the SBR polymer pH value on the compatibility and workability in CAM. Compatibility is determined by separation rate. Zeta potential value describes polymer-modified asphalt emulsion (PMAE) activity. Workability is determined by funnel fluidity time and slump flow time. Results showed that increasing the SBR polymer pH value decreased the zeta potential of PMAE. Decreasing zeta potential to be value-neutral results in destabilized asphalt droplets, demulsified, separated water, and asphalt coalescence. Finally, the asphalt coalescence is covered by polymer and forms a binding film on cement. It is affecting the compatibility between PMAE and cement hydration. It results in a low separation rate. Compatibility is achieved by SBR polymer pH 10.0 doses ranging from 1% to 6%. SBR polymer dosage of 1% to 3% led to a deceleration in funnel fluidity time and slump flow time associated with elevated demulsification. Their 4% to 6% dose accelerates funnel fluidity time and slump flow time associated with delaying demulsification. Acceptance of compatibility and workability in CAM is proposed using SBR polymer pH 10.0 dosage of 4% to 6%.