LAUSR

Abstract The present study was designed to prepare and characterize an eco-friendly road base material using mainly red mud in terms of mechanical properties, hydration and leaching characteristics. The microstructure was characterized by using scanning electron microscopy, X-ray diffractometer, Fourier transform infrared spectroscopy, electron probe microanalysis, Magnetic angle spinning Nuclear magnetic resonance and mercury intrusion porosimetry while inductively coupled plasma emission spectrometer was adopted to characterize the leaching behavior of hazardous compounds. The results showed that the strength of the optimum proportion reached 5.92 MPa and 6.66 MPa after curing for 7 and 28 days respectively and meet the highest strength requirement (class I) of 5–7 MPa for road base in Chinese standards. The results also showed that the strength increased with long term soaking which implies a good durability of RBM against water. The microstructure analysis indicated that predominant hydration products are C-S-H, C-A-S-H, N-A-S-H gels, ettringite and are responsible for strength development in the road base. The leaching results showed that all parameters in specimens cured for 7d and 28d are lower than drinking water GB 5749-2006 standard limits. Therefore, based on strength and environmental performance, red mud-flue gas desulfurization fly ash mix can be used as a road base material. This process is believed to reduce environmental pollution related to red mud and flue gas desulfurization fly ash, lower the road base cost and also save huge disposal fees that is used for safe disposal of these wastes.