Effect of lithium slag on the performance of cement mortar
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Lithium slag-cement composite mortar (LSCCM) was prepared by replacing part of 42.5 Ordinary Portland cement withlithium slag (LS). The effects of LS on the properties of cement mortar and its mechanism of action were analyzed by X-raydiffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), heat of hydrationmethod, nuclear magnetic resonance (NMR) technique and mercury intrusion porosity (MIP). The results showed that LSreplacing part of the cement would reduce the fluidity of the system, shorten the setting time, lower the strength in thepreperiod, increase the strength in the postperiod, change the pore size distribution, and would not cause changes in thehydration products. In the early stage, LS just plays a filling role, the hydration reaction rate of the LSCCM decreases, andthe pores in the system become larger, resulting in a lower compressive strength than the cement mortar at 3d and 7d. Inthe later stage, the LS undergoes pozzolanic reaction, which makes the LSCCM become denser, and when the replacementamount of lithium slag is 20% of the cement mass, the 28d compressive strength of the LSCCM can reach 50.2 MPa, whichis 9.4% higher than that of the cement mortar specimen.
Abstract
Lithium slag-cement composite mortar (LSCCM) was prepared by replacing part of 42.5 Ordinary Portland cement withlithium slag (LS). The effects of LS on the properties of cement mortar and its mechanism of action were analyzed by X-raydiffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), heat of hydrationmethod, nuclear magnetic resonance (NMR) technique and mercury intrusion porosity (MIP). The results showed that LSreplacing part of the cement would reduce the fluidity of the system, shorten the setting time, lower the strength in thepreperiod, increase the strength in the postperiod, change the pore size distribution, and would not cause changes in thehydration products. In the early stage, LS just plays a filling role, the hydration reaction rate of the LSCCM decreases, andthe pores in the system become larger, resulting in a lower compressive strength than the cement mortar at 3d and 7d. Inthe later stage, the LS undergoes pozzolanic reaction, which makes the LSCCM become denser, and when the replacementamount of lithium slag is 20% of the cement mass, the 28d compressive strength of the LSCCM can reach 50.2 MPa, whichis 9.4% higher than that of the cement mortar specimen.