Characterization on a cementitious material composed of red mud and coal industry byproducts

This research was to investigate the possibility of incorporating red mud and coal industry byproducts as the raw material for producing cementitious material. Systematic mechanical strength tests were conducted to evaluate the performance of this cementitious material. Results showed that the designed red mud-coal industry byproducts based cementitious material had higher strength in the middle to late curing age (47.5 MPa in 180 days and 48.7 MPa in 360 days) than the OPC control group. The series of durability tests indicated that the cementitious material met with the ASTM requirement. Moreover, the toxicity characteristic leaching tests demonstrated that this cementitious material had good stabilization/solidification ability to bind the heavy metal in the red mud as raw material. Microanalysis revealed that the amorphous gel was the dominant structure of the material at the middle to late curing age, which possibly played a significant role on the heavy metal binding properties through the polymerization during the hydration process of this cementitious material. In essence, this designed red mud-coal industry byproducts based cementitious material not only meet with the physical and mechanical requirements of the ASTM standards, but also meet with the EPA regulation on the environmental heavy metal leaching limitation. This proves the designed material can possibly be used as a clean technology to recycle the red mud from alumina industries and byproduct from coal industries.