玄武岩纤维-砒砂岩水泥土力学特性试验研究

为了降低黄河流域泥沙治理成本,提高砒砂岩的利用价值,在砒砂岩中掺入适量水泥和纤维改善其力学性质及功能性.借助玄武岩纤维(BF)的加筋效应,配制玄武岩纤维掺量为0.2%,0.5%,0.7%的BF-砒砂岩水泥土试块,进行无侧限抗压强度和SEM扫描电镜试验.探究BF掺量、龄期对BF-砒砂岩水泥土强度影响以及BF-砒砂岩水泥土强度形成机理; 建立了玄武岩纤维参与下砒砂岩水泥土应力-应变曲线方程.结果表明:纤维掺入有效提高了砒砂岩水泥土的强度,其强度随玄武岩纤维掺量的增加呈先增大后减小的趋势,掺量为0.2%时达到峰值强度; BF-砒砂岩水泥土后期强度同比砒砂岩水泥土强度提高更明显; BF-砒砂岩水泥土的龄期与无侧限抗压强度表现为正相关,而与其强度增长速率表现为负相关; 水泥掺量10%、纤维掺量0.2%的砒砂岩水泥土在强度指标上完全可以替代水泥掺量15%的砒砂岩水泥土; 建立龄期28 d时,BF掺量0~0.7%的BF-砒砂岩水泥土应力-应变曲线方程,反映了各纤维掺量下应力-应变变化及破坏情况.

Experimental study on mechanical properties of basalt fiber- Pisha-sandstone cement soil

The property of Pisha-sandstone to be easily collapsed in water brings obstacles to water and soil treatment in the Yellow River Basin. In order to increase the utilization value of Pisha-sandstone, and reduce the cost of sediment treatment, an appropriate amount of cement and fiber was added to the Pisha-sandstone to improve its mechanical properties and functionality. Based on the reinforcement effect of basalt fiber(BF), the test block with 0.2%, 0.5% and 0.7% basalt fiber content was prepared. Unconfined compressive strength and SEM scanning electron microscope test were carried out. The effect of BF content and age on the strength of BF- Pisha-sandstone cement soil, and the formation mechanism of BF-Pisha-sandstone cement soil′s strength were explored and the stress-strain curve equation of BF participating in Pisha-sandstone cement soil was established. The results show that the incorporation of fiber effectively increases the strength of Pisha-sandstone cement soil, and its strength increases first and then decreases with the increase of BF. The peak strength is reached when the content is 0.2%; the later strength of BF- Pisha-sandstone cement soil is more obvious than that of Pisha-sandstone cement soil; the age of BF-Pisha-sandstone cement soil is positively correlated with the unconfined compressive strength, but is negatively correlated with its strength growth rate; Pisha-sandstone cement soil with a cement content of 10% and a fiber content of 0.2% can completely replace that with a cement content of 15%. At 28 days of age, the stress-strain curve equation of BF- Pisha-sandstone cement soil with BF content between 0 and 0.7% is established, which is convenient to reflect the stress-strain changes and failure conditions of each fiber content.