Influence mechanism of mineral composition ratios on the early anchorage properties for cement anchoring agents

Abstract

The utilization of cement anchoring agents has attracted significant attention in engineering applications such as tunnel support, primarily due to its high early strength and cost-effectiveness. Three different mineral composition ratios of cement anchoring agents were prepared in this paper for enhancing anchoring properties. The effects of mineral composition ratios on setting time, compressive strength, and early tensile pull-out properties of cement anchoring agents were thoroughly investigated. Based on hydration heat, hydration products composition and content, and microstructural evolution, the influence mechanism of mineral composition ratios on cement anchoring agents were discussed. Results show that the mineral composition ratios significantly affect the setting time and mechanical properties of cement anchoring agents. Excess alumina and filler content delays the setting time of cement anchoring agents, which is not conducive to the development of early strength. MC (the mass ratio of calcium oxide to alumina is 11.06) demonstrates a tensile pull-out strength that is 18% greater than MA (the mass ratio of calcium oxide to alumina is 5.67) and 55% higher than MB (the mass ratio of calcium oxide to alumina is 5.55). Moreover, its compressive strength is 6.88% higher than MA and 25.17% higher than MB after casting one day. MC boasts elevated hydration heat and a higher content of hydration products. These hydration products effectively bind together, thereby improving the interface adhesion between the steel bar and the cement anchoring agents. This study enhances our comprehension on how mineral composition ratios influence the early fundamental properties of cement anchoring agents, which also provides new avenues for designing high-performance cement anchoring agents.