天然沸石粉对氯氧镁水泥耐水性影响研究

氯氧镁水泥(MOC)具有轻质、高强、耐磨等优势,但耐水性差制约了其在建筑行业的发展。为制备高耐水性MOC,以天然沸石粉(NZOP)为掺合料,分析了天然沸石粉对MOC凝结时间、抗压强度、耐水性的影响。同时,利用X射线衍射仪、扫描电镜、压汞仪分析了改性后MOC的相组成、微观形貌和孔结构的变化。此外,利用离子色谱仪检测了MOC浸水后溶液中的Cl^-浓度。结果表明,合适掺量的天然沸石粉可以有效提高MOC的抗压强度和耐水性,缩短MOC的凝结时间。掺入30%(质量分数)天然沸石粉和0.5%(质量分数)磷酸后,MOC的28 d抗压强度和浸水28 d软化系数分别可达75.8 MPa和0.91,氯离子浓度低至9.0 mmol/L。此外,溶液中Cl^-浓度随着MOC软化系数的降低而提高。

Effect of Natural Zeolite Powder on Water Resistance ofMagnesium Oxychloride Cement

Magnesium oxychloride cement (MOC) has the advantages of light weight,high strength and high wear resistance,however,its poor water resistance restricts its development in the construction industry.To prepare high water resistance of MOC,natural zeolite powder (NZOP) was used as admixture.The effect of NZOP on the setting time,compressive strength and water resistance of MOC was investigated.Meanwhile,X-ray diffractometer,scanning electron microscope and mercury intrusion porosimetry were used to analyze the change of phase composition,microstructure and pore structure of modified MOC.In addition,the concentration of Cl^- in immersing solution was measured by ion chromatograph.The results show that NZOP effectively improves the compressive strength and water resistance of MOC and reduces the initial and final setting time of MOC.After adding 30% (mass fraction) NZOP and 0.5% (mass fraction) phosphoric acid,the 28 d compressive strength and 28 d softening coefficient of MOC reach up to 75.8 MPa and 0.91,respectively,and the concentration of Cl^- in immersing solution is as low as 9.0 mmol/L.In addition,the concentration of Cl^- in immersing solution increases with the decrease of the softening coefficient of MOC.