Design and Microstructure Analysis of Alkali-activated Zinc Slag Cementitious Materials

Taking zinc slag as raw material, this work prepared alkali-activated zinc slag cementitious material, based on the reuse of zinc slag solid waste. The orthogonal test was adopted to study the influence of ratio of liquid to solid, water glass modulus and cement content on the mechanical properties of alkali-activated zinc slag cementitious material system. And then, we analyzed the microstructure of alkali-activated zinc slag cementitious materials with different mixing ratios and explored the effects of temperature and specific surface area based on the optimal ratio by XRD and SEM. Finally, we tested the curing ability of alkali-activated zinc slag cementitious material to the zinc ion. The results show that the compressive strength of alkali-activated zinc slag cementitious material system is most affected by cement content, followed by ratio of liquid to solid and water glass modulus. In this study, under the condition of the cement content 10%, the ratio of liquid to solid 0.2, and the water glass modulus 0.8, the optimum mixing ratio is obtained, and the 28 d compressive strength can reach 56.5 MPa. In addition, the physical methods of steam curing and increasing the specific surface area of zinc slag powder can improve the early strength. The hydrated product of alkali-activated zinc slag cementitious materials is an amorphous gel phase mainly composed of C-(A)-S-H gel, which belongs to α-C-S-H gel. Its dense three-dimensional structure not only provides a positive effect for strength, but also has a good ability to solidify Zn2+, which provides a new way for the second utilization of zinc slag. © 2022 Cailiao Daobaoshe/ Materials Review. All rights reserved.