A mix design method has been developed for Emulsified BitumenMacadam materials (EBMs) used in trench reinstatement operationsas wearing and base course layers in flexible pavement constructions.The method considers the effect of mixing, compaction, curing,strength development and moisture sensitivity. The influence ofpolymer-modified emulsions on the stiffness and permanent deformationcharacteristics of the EBMs has been investigated. EVA and SBScopolymers have been incorporated into a conventional 100 penemulsion at various levels in the investigation, and the resultingEBM properties were compared to the specifications advocated bythe Highway Authorities and Utilities Committee (HAUC) to arriveat suitable mixes that are capable of performing adequately inservice.

The conventional and selected modified EBMs were then usedin a laboratory study to evaluate their fatigue behaviour, togetherwith an equivalent hot-applied mix containing 200 penetrationgrade bitumen. Controlled stress three-point bending fatigue testswere conducted to arrive at strain/fatigue life relationshipsfor the hot and cold-lay mixes. Linear elastic theory was thenapplied to evaluate the response of the materials to traffic loadingin a typical flexible pavement model using BISAR-PC Program developedby Shell. The calculated strains were used to determine the lifeof the pavements with candidate mixes from the developed fatiguerelationships. Structural equivalency factors for the cold-laymaterials in conjunction with the hot-applied mixes were computedfrom the resulting fatigue lives. The fatigue analysis revealedthat certain modified EBMs have the potential to perform equallyto, or even better than, the equivalent hot-applied material.