Development and Field Validation of Engineered Volcanic-Ash Materials for Sustainable Road Pavements in Uganda

There is an ongoing depletion of materials to be used on Ugandan raods. Key among these materials is gravel that meets the required specifications for road use in both gravel and paed roads. Volcanic ash is a material which is formed on the earth surface or in the water, from a great amount of lava scraps and dust which are ejected together with the lava in the volcanic eruption and is loose or is lightly cementitious, having a certain activity. Volcanic ash is abundantly available in the Eastern and South-western districts of Mbale and Kisoro respectively. Even though its use would substantially reduce road construction costs in those areas, volcanic ash is not fully utilized at a large scale because it tends to be deficient in fine material and does not conform to the generally accepted grading specifications. With the ever-increasing depletion of good quality gravel materials and hence increased haulage distances, there is need to promote use of locally available marginal materials in roadway construction in order to preserve non-renewable natural resources and lower energy costs. This fits in with the global objective of sustainable development by the prudent use of natural resources.