Exploratory use of Rigden Voids as Design Criteria for the Design of Sand Treated with Emulsion

ABSTRACT Soil/sand treated with emulsion (STE) sections were constructed experimentally by labour intensive and plant intensive means on sections at Marracuene, close to Maputo, Mozambique. No cement or lime was added as is standard practice in South Africa with emulsion treatment of gravels, but only bitumen emulsion. It was determined that the characteristics of the filler sized material (smaller than 75μm) in the soil/sand had significant influence on the performance of the sand asphalt pavements in the past. A laboratory study was launched to quantify the influence of the filler sized material in the STE mixes. Various Rigden voids determined filler binder ratios of mastic mixes were tested to determine the effect on Brookfield viscosity, Wilhelmi and normal ring and ball and ductility measurements. Rigden void filler-binder ratios were used in a reversal of criteria normally used with hot mix asphalt to determine stiffening of the mix. In a STE mix stiffening is due to the filler and binder combination as only emulsion is added to the sand or soil.