Evaluation of Asphalt Mixture Containing Coal Ash

As the first time in Korea, bottom ash which is by-product of coal ash in power plant was recycled as fine aggregates in hot mix asphalt (HMA) mixtures. The bottom ash was used to replace the fine aggregate of HMA by various portions of fine aggregate which is passing 4.75 mm sieve, at the ratio of 10%, 20%, and 30%. Leaching test was performed to measure the concentration of toxicity in the bottom ash. The optimum asphalt content was measured for each portion of bottom ash used as fine aggregate using by Marshall mix design method. Stability, flow value, and mixture volumetric properties were compared to verify the applicability of bottom ash as fine aggregate in HMA. The moisture susceptibility and fatigue cracking resistance of asphalt mixture containing bottom ash and fly ash was investigated. It is concluded that coal ash can be efficiently used as fine aggregates in asphalt mixture.