粉煤灰掺量对氯氧镁水泥混凝土物理力学性能的影响

为了拓展氯氧镁水泥(MOC)材料的应用领域,以盐湖提钾肥副产物水氯镁石、轻烧氧化镁和粉煤灰为胶凝材料,制备了不同粉煤灰掺量的氯氧镁水泥混凝土(MOCC).研究了粉煤灰掺量对MOCC抗压强度、物相组成、微观形貌和孔结构的影响.结果表明:随着粉煤灰掺量的增加,MOCC的抗压强度逐渐降低,当粉煤灰掺量为40％(质量分数)时,...

Influence of Fly ash Content on Physical and Mechanical Properties of Magnesium Oxychloride Cement Concrete

In order to expand the application fields of magnesium oxychloride cement (MOC) materials, magnesium oxychloride cement concrete (MOCC) with different fly ash content was prepared by using bischofite, light burned magnesia and fly ash as cementitious materials, in which bischofite is a by-product of potassium fertilizer extracted from salt lake. The influence of fly ash content on compressive strength, phase composition, micromorphology and pore structure of MOCC were studied. The results show that with the increase of fly ash content, the compressive strength of MOCC gradually decreases. When the content of fly ash is 40% (mass fraction), its 300 d compressive strength decreases to 39.99 MPa, which is a decrease of 22.52%. The main hydration products of MOCC are 5Mg(OH)₂·MgCl₂·8H₂O(5·1·8) and Mg(OH)₂. The addition of fly ash does not produce a new crystal phase. The addition of fly ash increases the porosity and harmful pore volume of MOCC, thereby reducing its compressive strength. Ordinary Portland cement concrete was prepared with the same water-cement ratio. The comparative test results of compressive strength show that although the compressive strength of MOCC with 40% fly ash is lower than that of MOCC without fly ash, it is still 19.66% higher than that of ordinary Portland cement concrete at 300 d age, indicating that MOCC has higher compressive strength than that of ordinary Portland cement concrete.