Performance Evaluation of Road Pavements Stabilized In Situ

This chapter introduces in situ stabilization technology as applicable to rehabilitation of degraded granular road pavements. The method essentially involves the fragmentation of the old road and recompaction after mixing with a certain percentage of a binder. The main binder types used for in situ stabilization are cementitious and/or bituminous. This chapter highlights the benefits of this technology for environmental sustainability in the areas of recycling of old materials and the use of blends of waste products such as alkali activated slag as stabilization binders. On the basis of work undertaken in Australia, the evaluation of the pavement performance using accelerated loading and complementary laboratory testing is presented. Two trials of in situ stabilization known as the Cooma trial and the Dandenong trial are presented. The first is a deep-lift trial involving layer thickness up to 360. mm, whereas the second involves layer thickness of 200. mm. The host pavement materials stabilized included traditional crushed rock and marginal materials, sandstone, and gravel. Both trials used blast furnace slag and lime blends as the binder, and they concluded that in situ stabilization can be effectively used for roads carrying low, medium, or heavy traffic, particularly in rural settings. The case studies presented have contributed to advancement of the technology and to the identification of areas that require further understanding. These areas include the development of reliable mix design methodologies, rational design of stabilized pavement bases taking into account the traffic and environmental loading, and the issues of construction practices. A brief discussion of research results and thinking is also presented.