Reusing coal ash of thermal power plant in a pavement base course

Nowadays, the disposing of coal bottom ash from thermal power plants is increasing day by day and creates serious environmental problems, especially in Vietnam. The utilization of coal ash from Vietnam’s thermal power plants in a pavement base course has been attempted in this study. A total of 345 specimens in California bearing ratio, proctor compaction, compressive strength, resilient modulus, and splitting tensile strength test of bottom ash–cement, coarse aggregate–fly ash–cement, and local soil–fly ash–cement mixtures are investigated to find the mixtures that meet the technical requirements of the pavement base course. First, bottom ash was mixed with (3, 5, 7, 9, 11, and 13)% cement by weight. Second, coarse aggregates were mixed with 3% cement and (5, 10, 15, and 20)% fly ash by weight. Last, local soil was mixed with 5% cement and (5, 10, 15, and 20)% fly ash. Test results show that the optimal mixtures that have qualified properties for a pavement base course are mixtures of bottom ash + 11% cement, coarse aggregates + 20% fly ash + 3% cement, and local soil + 10% fly ash + 5% cement. These results demonstrate that Vietnam’s coal ash can be reused in a base course pavement