High strength mortar using coal gasification slag fine aggregate were examined. As a result, the higher the replacement rate of the coal gasified slag fine aggregate, the slightly higher the flow value of the mortar. And, due to the increase in the replacement rate of coal gasified slag fine aggregate, the compressive strength of mortar decreased in the high-strength region and increased in the general strength region. Furthermore, even under the condition that the replacement rate of coal gasified slag fine aggregate was 100%, it was possible to obtain a compressive strength exceeding 100 N/mm2.
