Waste concrete powder generated during the process of recycling waste concrete into aggregate has a low recycling rate. This is because fine particles of waste concrete powder and cement components are present. Therefore, in this study, waste concrete powder is used as a raw material for centrifugal concrete. Experimental results show that waste concrete powder has cement and aggregate composition, SEM image has irregular shape, C-S-H and Ettringite exist inside. Waste concrete powder showed the same strength, up to 5% in terms of strength by age according to the substitution rate. Also, as the strength characteristics varied according to the centrifugal forming force, the substitution rate of siliceous matter increased by 5% and the strength decreased by substitution rate of 5%. Because of this study, it is considered difficult to use waste concrete powder as a substitute for silica sand because of the resulting characteristics of centrifugal concrete. It is recommended that economic and environmental concerns be considered when some substitution is made for silica sand.

The amount of ferro-nickel slag powder produced by the Fe-Ni industry has grown in conjunction with the increase in demand for stainless steel materials. In this study, we investigated the effects of ferro-nickel slag powder on the flow, strength, and microstructure of polymer mortar. Ferro-nickel slag powder was used to replace CaCO3 at ratios of 0%, 25%, 50%, 75%, and 100% by volume. The flow and the compressive and flexural strength of the polymer mortar were measured, and both scanning electron microscopy (SEM) and hot resistance testing were performed. The test results indicate that the flow of the polymer mortar with more than 25% CaCO3 replacement decreased as the ferro-nickel slag powder content increased. The compressive strength of the polymer mortar mixes with ferro-nickel slag powder was relatively higher than that of the control mix. From the results of the hot resistance test, the strength improved compared with that before the test and increased as the powder replacement ratio was increased.