Effect of lime mud under wet grinding on the compressive strength and hydration of cement mortar

Lime mud, an alkaline solid waste used to cause environmental problems now is a potential mineral additive in building material. In this paper, sodium hexametaphosphate (SH) and sodium stearate (SDS) were used to pretreat lime mud during wet grinding to make two modified lime muds, respectively. Incorporation of the 10% lime mud (not pretreated or pretreated by wet grinding without modifiers) reduced the fluidity of cement mortar, but the mortar containing 10% modified lime mud show a similar fluidity with the reference. The effect of modified lime mud on the compressive strength and hydration of cement mortar was evaluated by X-Ray Diffraction (XRD), Fourier transform infrared spectrometer (FTIR), Thermogravimeter (TG-DTG) and Scanning electron micrograph-energy dispersive spectrometry (SEM-EDS). The results showed that the lime mud pretreated by wet grinding with 1% SH had the great bonding property with hydration products, and the optimal replacement ratio was 10% in cement mortar.