A pilot study has been conducted in Tanzania to investigate the possibility of using naturally occurring pozzolan materials as a sand stabilizing agent for road base and subbase construction. The pozzolan material investigated was to be used in the coastal area of Tanzania, which lacks good road construction materials that meet material specification requirements. The coastal area produces mainly sand and some poor-quality limestones that are not particularly suitable for road construction. Pozzolan samples collected from different parts of Tanzania were investigated. The collected pozzolan samples were mixed with lime to stabilize sand that could be used in a base or subbase course. Laboratory tests were done to determine properties of individual pozzolans and lime-pozzolan-sand mixtures. The compressive strength and split tensile tests were performed to determine the pozzolan mixtures' strength development and their suitability for road construction. Tanzanian experience with natural pozzolanic materials resulting from the Dar-Mlandizi road project will be discussed. The Dar-Mlandizi road was constructed by using sand stabilized with blast furnace slag as the base course material. The paper highlights the availability and preliminary testing of natural pozzolans in Tanzania, which resulted in follow-up testing of natural pozzolans in Denmark and the construction of a test road section in Tanzania. The pilot study can be considered an example of successful research in investigating the use of local materials for low-volume road construction.
Abstract