红色砒砂岩水泥土干湿循环下力学性能试验研究

为有效利用砒砂岩资源,通过简单加工降低治理成本,达到利用价值,在红色砒砂岩中加入不同掺量的硅酸盐水泥制成砒砂岩水泥土,在不同龄期下进行干湿循环、无侧限抗压强度试验和超景深微观结构观测.结果表明:掺量仅为5%砒砂岩水泥土就可以有效改善砒砂岩遇水溃散的特性;干湿循环5次砒砂岩水泥土抗压强度达到最大,然后趋于平缓,可见干湿循环对无掺水泥砒砂岩有破坏作用,对砒砂岩水泥土却提供了有效养护;不论是早期还是后期强度,掺量为5%的抗压强度最低,然后逐渐增加,掺量20%及以上的强度几乎相等且最大,可见水泥最优掺量为20%;通过微观结构观察,龄期的增加,掺量小的砒砂岩水泥土表面凹凸起伏程度大,孔洞多,最优掺量为20%的砒砂岩水泥土结构整体性紧密,表面平整、孔洞少,密实性更好,且抗压强度可以满足砖和砌块的强度要求.

Experimental study on mechanical properties of red Pisha-Sandstone Cement Soil under wetting-drying cycles

In order to solve the problem of breaking loose and reducing strength of Pisha-sandstone in case of water, through simple processing, to achieve the effective use of the Pisha-sandstone, reduce the cost of governance, by adding different amounts of silicate cement form red Pisha-Sandstone and name Pisha-Sandstone Cement Soil,experiment on wetting-drying cycle, and unconfined compressive strength, and microstructure observation of hyperdepth at different ages of Pisha-Sandstone Cement Soil was made.The results show that: only 5% dosage Pisha-Sandstone Cement Soil can effectively improve the Pisha-sandstone water collapsibility. The 5 times wetting-drying cycle Pisha-Sandstone Cement Soil reaches the maximum compressive strength, then it tends to be gentle. The wetting-drying cycle has damaging effects on non-cement Pisha-sandstone. It provides effective curing for Pisha-Sandstone Cement Soil. Whether at early strength or at late strength,the compressive strength of 5% is the lowest and then gradually increased. The strength of 20% and above is almost equal and maximum. It can be seen that the optimum cement content is 20%. By observing the microstructure, feldsparthic Pisha-Sandstone Cement Soil, with the increase of age, and small admixture has uneven surface fluctuation, and holes. The feldsparthic Pisha-Sandstone Cement Soil structure of the aptimas dosage of 20% is wholly close,smooth, with surface,less holes,better compactness,and the compressive strength can reach the strength requirement of bricks and blocks.