内蒙古砒砂岩的性能及其对水泥力学性能影响的研究

Properties of Pisha Sandstone in Inner Mongolia and Its Influence to Mechanical Properties of Cement

砒砂岩地区是黄河泥沙的主要来源地之一。为了实现对砒砂岩的资源化利用,对砒砂岩基本物理化学性质进行了研究,并探讨了其作为混凝土掺合料的可行性。通过X射线荧光光谱分析(XRF)、X射线衍射分析(XRD)和扫描电镜(SEM)研究发现,红色、白色砒砂岩的矿物成分差别不大,主要包含石英、长石、蒙脱石、高岭土、方解石等,还含有一定量活性的Si O2、Al2O3和Ca O(能够促进水泥水化)。砒砂岩作为水泥掺合料对水泥胶砂性能影响的研究试验结果表明,掺入砒砂岩会缩短水泥的初凝时间,掺量30%时初凝时间会缩短69%;当砒砂岩掺量不多于20%时水泥胶砂的28 d抗压强度和抗冻性能会提高,当掺量大于20%时水泥胶砂的抗压强度和抗冻性能(冻融循环后抗压强度)会显著降低。同时,研究还发现掺入砒砂岩会显著提高水泥胶砂28 d抗折强度。

Pisha sandstone is the main source of the Yellow River sediment. In order to achieve the resources utilization of Pisha sandstone,the paper studied the basic physical and chemical properties of Pisha sandstone and discussed the feasibility of using it as concrete admixture. The results of XRD,XRF and SEM show that the difference of mineral composition in red and white is not much,mainly containing quartz,feldspar,montmorillonite,kaolin clay and calcite and also containing some active SiO 2,Al2O3 and CaO which can promote the cement hydration. The outcomes of the study on influence of using Pisha sandstone as cement admixture to the cement mortar properties show that a) the initial setting time of cement will decrease with the increasing of Pisha sandstone powders dosage and when the amount of admixture of Pisha sandstone powders is 30%,the initial setting time of cement will be shortened by 69% and; b) when the admixture of Pisha sandstone powders is less than 20%,the 28-day compressive strength and frost resistance of cement mortar can be increased. But when the admixture of Pisha sandstone powder is greater than 20%,the compressive strength and frost resistance of mortar will be significantly reduced. In the meanwhile,it also finds out that the Pisha sandstone powders can remarkably increase the flexural strength of cement mortar.