Application of bottom ash as pavement material

Abstract

Nowadays, Thailand has an increasing electricity demand and coal-fired power plants require a lot of coal-fired fuel. The material obtained from coal is called coal ash. Most of Thailand’s sources of coal ash come from the Mae Moh power plant. The coal ash from the power generating process consists of 75–80% fly ash and 20–25% bottom ash per year. Fly ash can be widely used, while bottom ash is a waste material managed by landfills. If bottom ash can be applied to engineering work, it will increase its value and reduce its environmental impact. The bottom ash particles have a rough texture, sharp edges, and are larger than fly ash. In dry conditions, it is like dust without any bonding between particles. However, particle friction can increase the strength of material used for road construction. Suitable and quality materials for construction in some areas are difficult to come by. It is necessary to spend on transportation, which is the cause of increasing construction costs. Ground improvement with materials that can be increased strength enough to be used as the pavement is one option. Then, this study shows the improvement in laterite when replaced with bottom ash and treated with cement. Experiments consisted of unconfined compressive strength (UCS), splitting tensile strength (STT), and California bearing ratio (CBR). The result of this study shows that 20% of bottom ash content is appropriate for all cement content and curing time. Moreover, it can be applied as a material for soil-cement base pavement according to standard, DH-S 204/2556, Department of Highway, Thailand.