In situ stabilisation using cementitious binders has become a common activity for rehabilitation of degraded road pavements in Australia and worldwide. Sometimes, traditional cementitious binders such as general purpose Portland cement and limes, are blended with industrial waste products such as fly ash and blast furnace slag. Although the microstructure of concrete using such binders has been studied, similar studies have not been reported for cementitiously stabilised pavement materials. Investigations were carried out to examine the microstructural changes that occur during hardening of the paste consisting of binders and fines portion of the aggregates. Attempts were made to relate the microstructural development of the pastes to the development of mechanical properties. Tests carried out included determination of pore structure by mercury porosimetry and scanning electron microscopy; and determination of unconfined compressive strength and drying shrinkage. Detailed test results are presented in this paper. Generally the degree of hydration in binder paste increased with time resulting in decrease in porosity and in increase in strength and shrinkage. Most of the shrinkage took place due to water loss from the mesopores of the pore structure. (a).
Abstract