A new mix design method for steel fibre-reinforced, roller compacted and polymer modified bonded concrete overlays

For roller compacted concrete used in pavements, optimal water content is one of main concerns for mix design. However the mix design method aiming at achieving both high bond strength and roller compactability is not available so far. The modified Proctor compaction method and modified Vebe method were investigated and found to be inappropriate to the type of mixes in terms of durability. In this paper a method for determining optimal water content is proposed for steel fibre-reinforced, roller compacted and polymer modified bonded concrete overlays. Two types of mixes suitable for asphalt paver placement and roller compaction were developed: They were the SBR and the SBR-PVA hybrid polymer modified cement concrete mixes with the optimal water contents determined by the proposed method. Both mixes achieved good bond with the old concrete substrate.