The purpose of this research is to observe the strength of asphalt concrete using solidified coal waste or geopolymer. The use of geopolymer is known in enhancing concrete mixture strength. More detail in this study is to acquire the comparison rate of stability and flow of mixture using geopolymer and the one with ordinary filler. The stability and melting rate of this mixture will determine whether the use of geopolymer as a filler material in flexible pavement is applicable. In this research, the first stage is to find the initial mix design, which is not including the geopolymer filler. From this research, it is found that the use of geopolymer increases the stability in asphalt mixture but reduce the flow rate and increase the void in the mixture. Although the flow rate decreases and the voids increases, the result acquired still fulfills the minimum specification of asphalt concrete for the high level of traffic load.