The working time principle was developed by the New South Wales Roads and Traffic Authority in the early 1990s to assist cement suppliers to predict in the laboratory, the time it will take for cementitious binders to set in the field before they can be successfully compacted. In NSW, the process have been developed as a research tool using density and UCS testing as a basis for estimating the duration that a cementitious binder could be mixed and left uncompacted in the field before performance is reduced. Until recently, no test method in NSW had emerged from the research work of the 1990s, and consequently there was limited opportunity to use a better binder by the contractor seeking an alternative tender bid for the project. Five years ago VicRoads published a test method based on their research work in Burwood East (Victoria). Whilst the outcomes of their research varied, this technique has since been used in NSW with some success. As both NSW and Victoria have different approaches to testing working time and each has their own limitations, a new approach based on tests carried out so far was required. This paper examines the current test methods and outlines a new approach for practitioners to consider. In addition, the paper explores whether this new approach may be applicable to all types of stabilisation binders. (a) For the covering entry of this conference, please see ITRD abstract no. 0612AR242E.
Samenvatting