Cement stabilization of road pavement materials: laboratory testing programme phase 1

Abstract

The introduction of the SABS EN 197-1 (SANS 50197-1) specification for cements in South Africa resulted in a change in the range of cements available for material stabilization for road layers. An investigation was carried out to assess the impact of seven of the available cements on two typical South African construction materials. Chemical analyses of the two materials showed no incidences of unusual components that would lead to specific problems during cement stabilization of the materials. There is no doubt that both conditioning time and material temperature during the early stages of hydration of the cement affect the compacted density and unconfined compressive strength and indirect tensile strength (these three are obviously interrelated) negatively. However, comparison with one documented example indicates that the current cements probably have an equal or even lesser effect in this regard than the older cements. No dominant trends relating to the behaviour of the different cements could be isolated during the project. It is clear, however, that the combination of cement type and material under the expected construction conditions will affect the density and strength of material obtained in the field. On this basis, all potential construction materials that are to be stabilized should be tested with the cements likely to be used on the proposed project and under the expected ambient conditions to identify the expected allowable construction time and the combination which provides the longest workability/ construction time should be selected