Experimental studies were carried out in aiming for utilization of fusion slag manufactured by melting ash produced in high-temperature incineration of common waste materials as fine aggregate for concrete. Results obtained in the studies were ascertainment that there is no problem about safety of the fusion slag, that physical qualities as fine aggregate are approximately the same as those of ordinary sand, that there is little scatter in quality when manufactured, and that quality is stable. Furthermore it was verified that the quality of concrete using the slag as fine aggregate, when replacement ratio is not more than 40%, is roughly the same as with concrete using ordinary fine aggregate, both when fresh and when hardened. There is no problem about durability when water cement ratio is not more than 50%, and the fusion slag can be used as fine aggregate for concrete.
