目的: 研究超细矿物掺合料对水泥砂浆力学性能的影响。方法: 分别测试了不同掺量超细矿物掺合料替代水泥的胶砂抗压强度以及抗折强度, 并进行了水化热测试, 利用XRD与SEM测试分析了掺入超细矿物掺合料后微观结构特征的变化。结果: 掺入5%超细矿物掺合料后水泥净浆流动度下降了25. 3%, 在加入超细掺合料后, 各龄期的抗压强度稳步提升, 随后逐渐降低, 当超细矿物掺合料掺量为20%时胶砂28d强度达到最大值, 与不掺加掺合料试块相比提高了23. 76%。超细矿物掺合料的掺入使得胶砂的3d、7d的抗折强度有所减弱, 胶砂28d的抗折强度随着超细掺合料的掺入缓慢增大, 至掺量为25%时抗折强度值达到最大。水化热及微观结构分析表明, 掺入超细矿物掺合料后胶砂体系产生了更多的水化硅酸钙凝胶填充到胶砂的体系结构当中。结论: 一定掺量的超细矿物掺合料对于砂浆的抗压强度有良好的提升效果, 对3d以及7d的抗折强度有一定的减弱效果, 增大28d抗折强度。
Objective: The effect of ultrafine mineral admixtures on the mechanical properties of grouting mortar was studied. Methods: In this paper, the compressive strength and flexural strength of the mortar with different contents of ultrafine mineral admixture replacing cement were tested respectively, and the heat of hydration was tested. XRD and SEM were used to analyze the changes in the microstructure characteristics after the addition of ultrafine mineral admixture. Results: after the addition of 5% ultrafine mineral admixture, the fluidity of cement slurry decreased by 25. 3%, and the fluidity gradually decreased with the gradual increase of ultrafine mineral admixture. With the addition of superfine mineral addition, The compressive strength increased steadily and gradually decreased thereafter, while the content of superfine mineral added was 20%, the strength of rubber sand reached the maximum value at 28 days, which increased by 23. 76% compared with the test block without admixture. The flexural strength of 3d and 7d of rubber sand was weakened by the incorporation of ultrafine mineral admixture, and the flexural strength of 28d increased slowly with the incorporation of ultrafine admixture, and the flexural strength value reached the maximum when the dosage was 25%. The heat of hydration and microstructure analysis showed that the sand system produced more hydrated calcium silicate gel filling into the structure of the sand after the addition of ultrafine mineral admixture. Conclusion: a certain amount of ultrafine mineral admixture has remarkable influence on the compression strength of rubber sand, and the flexural strength of 3d and 7d is weakened, and increases the flexural strength of 28d.