Research on a multivariate non-linear regression model of dynamic mechanical properties for the alkali-activated slag mortar with rubber tire crumb

As the inappropriate disposal of used tires will cause various environmental problems, rubber tire crumb (RTC) can be processed to replace fine aggregate in mortar. The content and particle size of RTC in mortar are the main influencing factors for the strength of rubber concrete. Alkali-activated slag mortar (AASM) can be used to replace ordinary Portland cement, which can improve the early strength and environmental friendliness of engineering. For this reason, the separating Hopkinson pressure bar (SHPB) test system was used to explore the effect of multi-factor coupling on the dynamic compressive strength of AASM. Besides, the significance analysis and multivariate non-linear regression analysis were carried out on the experimental results to determine the significance of each factor to the dynamic compressive strength of mortar. On this basis, The multivariate non-linear regression model was established for AASM dynamic compressive strength. The microstructure characterization and Statistics of chord length distribution of pore of AASM specimens were performed to explore the mechanism of strength deterioration experienced by rubber aggregate mortar. According to the experimental results, the surface of RTC can be modified in high alkaline environment, and the dynamic compressive strength of mortar would decline gradually with the increase of aggregate replacement ratio. In the optimal test group, the dynamic compressive strength of AASM is higher than that of the control group.