Abstract:

To enhance the resource utilization rate of industrial solid waste， this study systematically investigated the synergistic regulation of ground granulated blast furnace slag （GGBFS）， steel slag （SS）， and desulfurization gypsum （FGD） on the workability and mechanical performance of all-solid waste cementitious materials， based on the Mixture-Optimal （Custom） Design method in the Design-Expert software. The results indicate that the ternary solid waste system exhibits significant regulation of fluidity and setting performance. When the content of GGBFS is 50.75% （mass fraction， the same below）， SS content is 40.00% and FGD content is 9.25%， the mortar fluidity reaches a maximum of 205 mm， while the initial setting time and final setting time shorten to 170 and 490 min， respectively. This effect is primarily attributed to the synergistic action between the skeletal effect of SS particles and the setting acceleration of \mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-} in FGD. Furthermore， when GGBFS content is not less than 70%， the SS content is controlled below 30%， and FGD content is maintained within 4%~5%， the 28 d compressive and flexural strength reach maximum value of 45.3 and 8.6 MPa， respectively， This validates the performance enhancement mechanism of “ground granulated blast furnace slag dominant，steel slag synergy gypsum， and desulfurization gypsum activation”. Through response surface model optimization analysis reveal that an optimal balance of material properties is achieved when the content of ground granulated blast furance slag， steel slag， and desulfurization gypsum are 63.6%， 34.9%， and 1.5%， respectively， the comprehensive performance of materials achieve the optimal balance， the measured value of each response indicator deviate from their predicted value by less than 5%， confirming the accuracy and reliability of the established regression model. In addition， the carbon emission and economic analysis reveal that， compared with ordinary Portland cement， the optimized all-solid waste cementitious materials reduce the global warming potential （GWP） by approximately 86% and save about 100 yuan/t， highlighting its application potential in promoting low-carbon building materials and sustainable development.

Key words: industrial solid waste, cementitious material, response surface methodology, mix proportion optimization, mechanical performance