卵石、石灰岩机制砂对水泥胶砂流动度和强度影响

用机制砂替代天然砂是目前缓解天然砂极度短缺的有效途径之一。为探索卵石、石灰岩机制砂应用潜力,本研究测试了两种机制砂的基本材料性能;并控制两种机制砂为相同且较低的石粉掺量,测试其对胶砂性能的影响;同时分别测试两种机制砂在不同石粉掺量下对胶砂性能的影响。结果表明:不同岩性机制砂的基本材料性能各不相同,其中石粉掺量和级配的差异较大;在石粉掺量相同的情况下,卵石机制砂砂浆的抗折强度与抗压强度均高于石灰岩机制砂,但二者相差不大,且随着龄期的增加增幅逐渐减小;随着石粉掺量的增加,两种机制砂的流动度、抗折强度和抗压强度都呈现先增加后下降的趋势,且在石粉掺量为5%时抗折强度达到峰值,均在石粉掺量为10%时抗压强度达到峰值,石粉掺量在5%~10%时为最佳。

Study on Influence of Gravel and Limestone Mechanism Sand on Fluidity and Strength of Cement Mortar

Replacing natural sand with manufactured sandis one of the effective ways to alleviate the shortage of natural sand. In order to explore the feasibility of the application of pebble and limestone manufactured sand in cement mortar, the basic material properties of the two manufactured sand were tested. The two types of manufactured sand, which had their dust contents set to be the same, were measured to evaluate their effects on the performance of mortar. Also, for both types of manufactured sand, the effect of dust content on the the performance of mortar was estimated. The results show that, for different types of manufactured sand, the basic material properties are different. With the same dust content, the flexural strength and compressive strength of mortar made with pebble manufactured sand are higher than that made with limestone manufactured sand. This difference is not significant. The rate of increase in strength decreased with the increase in age. For both types of manufactured sand, the flowability, flexural strength and compressive strength first increased and then decreased with the increase in dust content. The flexural strength reached the peak at a dust powder of 5%, while the compressive strength reached the peak at a dust powder of 10%. To conclude, the optimum dust content was 5%~10%.