Previous work has shown that the use of binders modified by the addition of EVA (ethylene vinyl acetate co-polymer) enhance the properties of bituminous materials. The behaviour of roadbase macadams containing 5 per cent by weight of EVA modified binders was compared with that of control lengths of conventional roadbase macadam in four motorway and trunk road contracts. The production, laying and compaction characteristics of the test materials were assessed together with the structural properties of samples measured in the laboratory. At frequencies and temperatures typical of conditions in the roadbase, the load spreading ability of the modified materials was similar to the control materials. The incorporation of EVA in roadbase materials would result in a 15 to 20 per cent increase in production cost and would therefore be uneconomic for use in the roadbase. (Author/publisher)
Samenvatting