Preparation and characterization of cement treated road base material utilizing electrolytic manganese residue

摘要

The utilization of electrolytic manganese residue (EMR) in synergy with red mud (RM) and other solid wastes as road base materials (RBM) was investigated in this research. The chemical composition, mechanical properties, the hydration behavior, pore structure and environmental friendliness performance of the RBM with different Ca/Si ratios were investigated. The hydration characteristics were analyzed by XRD, FTIR, TG, Si-29 MAS-NMR and SEM-EDX technique; the pore structure was investigated by MIP, and environmental properties were texted by ICP. The results showed that the optimal proportion of Ca/Si is within the range of 0.91-1.17. After curing for 7 d, the unconfined compressive strength (UCS) of RBM can reach the highest strength requirement (class I) of 5-7 MPa for road base in Chinese standards. The best mechanical properties and polymerized structure were obtained for a Ca/Si ratio = 0.95 and the main hydration products are C-A-S-H gel, ettringite (AFt) and CaAl2Si2O8 center dot 4H(2)O, which promote the development of strength. The leaching test results indicated that the heavy metals can be efficiently solidified, and meet the Chinese groundwater standards GB14848-2017. This study provides a direction for the large-scale and effective utilization of EMR. (C) 2019 Elsevier Ltd. All rights reserved.