沙粒粒径及掺量对氯氧镁水泥性能的影响研究

氯氧镁水泥是由氯化镁溶液调和轻烧氧化镁粉制成的气硬性胶凝材料,是固废再利用的重要手段,但其成本高、耐水性较差等问题限制其大规模应用。天然沙粒作为掺料制备氯氧镁水泥,可以大幅降低成本,但其沙粒粒级及掺料如何影响氯氧镁水泥的性能还不清楚。以不同粒径(80~120目、40~80目、0.5~1 mm)天然沙粒作为掺料,并进行不同配比(沙漠沙∶氯氧镁水泥=1∶1、1∶3、1∶5、1∶7)后的材料性能分析。结果表明,掺入不同粒径与掺量的沙漠沙能够改善氯氧镁水泥的力学性能,当粒径为0.5~1 mm,掺入量为1∶1时,其抗压强度可达281.04 MPa,总体提升较高;将天然沙漠沙加入氯氧镁水泥中,能够明显改善氯氧镁水泥的微观形貌,有效填充孔隙,提高密实性,进一步提高材料的力学性能;在氯氧镁水泥中加入天然沙漠沙产生新的物相,并且加入天然沙漠沙可有效地提升氯氧镁水泥的凝固速度和抗压强度。

Magnesium oxychloride cement is a kind of air-hard cementitious material made from magnesium chloride solution mixed with lightly burned magnesia powder.It is an important means of solid waste reuse,but its large-scale application is limited by its high cost and poor water resistance.The preparation of magnesium oxychloride cement with natural sand as admixture can greatly reduce the cost,but how the sand particle size and admixture affect the performance of magnesium oxychloride cement is not clear.The material properties were analyzed after different proportions(desert sand∶magnesium oxychloride cement=1∶1,1∶3,1∶5,1∶7)with different particle sizes(80~120 mesh,40~80 mesh,0.5~1 mm).The results show that the mechanical properties of magnesium oxychloride cement can be improved by adding different particle size and content of desert sand,and the compressive strength can reach 281.04 MPa when the particle size is 0.5~1 mm and the content is 1∶1.The addition of natural desert sand to magnesium oxychloride cement can obviously improve the micro-morphology of magnesium oxychloride cement,effectively fill pores,improve the compactness and further improve the mechanical properties of the material.Natural desert sand is added to magnesium oxychloride cement to produce a new phase,and natural desert sand is added to effectively improve the solidification rate and compressive strength of magnesium oxychloride cement.