This report deals mainly with the engineering properties of sand-sulphur-bitumen mixes for use as paving materials for road construction. Sand-sulphur-bitumen (SSB) mixes with different sulphur-bitumen ratios (17:3, 15:5 and 13:7) were manufactured together with control specimens of sand, limestone and bitumen (SLB). The influences of ageing and weathering on the mechanical properties were investigated by exposing specimens to natural weathering in an extreme environment and tested at six monthly intervals over a period of thirty months. The characteristics investigated included Marshall stability, tensile and flexural strengths, dynamic modulus of elasticity and fatigue properties. The severity of ageing with depth beneath the exposed top surface of the pavement was investigated by measuring the viscosity of bitumen. Other tests included permeability measurements and microscopic analysis of the mix structure. In contrast to the results of the various tests on the control samples, the results for the SSB mixes showed that weathering had little effect on the mechanical properties. Using multilayer elastic theory, a road pavement was designed for a million equivalent standard axles of loading. Compared with a conventional asphalt concrete pavement, savings in excess of 50 per cent were found to be feasible, depending on the local cost of sulphur. The hazards of using sulphur in this way and methods of reducing the risk of emitting potentially poisonous gases were reviewed. (A)

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