改性黄河砒砂岩筑坝材料性能试验

为改变砒砂岩遇水溃散的特性,满足砒砂岩区淤地坝建设对建筑材料的需求,研究了砒砂岩改性技术。通过试样固结体积观测、抗剪强度测试、X射线衍射(XRD)、热重(TG-DTG)分析和扫描电子显微镜(SEM)分析,探讨了不同浓度改性剂对砒砂岩固结体积、抗剪强度、矿物组成和微观结构形貌的影响。试验结果表明,改性后砒砂岩的膨胀性得到显著抑制,材料体积稳定性及抗剪强度得到提高,试样的体积减小率及抗剪强度最大值分别为50%和138 kPa;改性后试样中蒙脱石晶层间距和试样质量损失明显减小,试样的水化膨胀特性得到有效控制;改性后试样的孔隙结构得到改善,裂隙数量及尺寸显著减小,试样更加均匀密实。

Research on properties of modified Yellow River Pisha sandstone dam construction materials

To change the collapsing property of Pisha sandstone in water and to meet the needs for construction materials of check dams, Pisha sandstone property modification technologies were investigated. The effects of modifier with different concentrations on the swelling volume, shear strength, mineral composition and microstructure were studied by using consolidation volume and mechanical tests, XRD, TG-DTG and SEM. It shows that after property modification, the swelling of Pisha sandstone was evidently controlled and both the volume stability and the shear strength were improved. The maximum value of the volume reduction and the shear strength can be 50% and 138 kPa respectively. After modification, the spacing of the crystal layers of montmorillonite and the mass loss of the test specimen showed a significant decrease, and the hydration swelling inhibition was controlled effectively. In addition, the fracture and pore structure of the modified specimen was significantly reduced with much less cracks and smaller scales, which was more homogeneous.