养护方式对氯氧镁水泥力学性能的影响

Influence of Curing Regimes on Mechanical Properties of Magnesium Oxychloride Cement

通过控制水分子的传输过程设置了6种不同的养护方式,研究了不同养护方式对氯氧镁水泥(magnesium oxychloride cement,MOC)力学性能的影响。采用X射线衍射、微孔参数法和扫描电子显微镜分析了不同养护方式对MOC物相组成、孔结构及微观形貌的影响。研究表明:在不同的养护方式下MOC水泥的主要物相未发生变化。在敞开形式的养护下MOC力学性能较差;在密封形式的养护下可获得较高的力学性能。在微观形态上表现为:在敞开形式的养护下,长短不一的晶体搭接生长,结构疏松;在密封形式的养护下,MOC硬化体微观形貌呈密集交织的短棒状晶体存在,结构致密;尤其在M5方式养护下,晶体水化物有向凝胶状晶型转化的趋势。其作用机理主要为:密封养护有利于5相的形成与生长,在封闭保水的条件下,H2O分子可以充分参与518晶相的形成。

Six different curing regimes were set up through controlling the transport process of moisture.The influence of different curing regimes on mechanical properties of magnesium oxychloride cement was studied.X-ray diffraction,pore parameters method and scanning electron microscopy were adopted to analysis the effect of different curing regimes on the MOC phase composition,microstructure and morphology.The results show that the main phase of MOC cement does not change under different curing regimes;poor mechanical properties appeared when adopting the open form of curing;however,samples could get a better densification and higher mechanical properties arose under the condition of the seal curing.As for microcosmic morphology,under the open form of conservation,the length of the crystal lap grows,the structure is loose;in the form of sealed microstructure is dense intertwined short rod-like crystals exist,being dense structure.Especially in the M5 curing,crystalline hydrates trend to the gellike crystalline transformation.Its mechanism can be explained that H20 molecules could participate in the formation of 518 crystal abundantly under the seal curing condition,this lead to a higher mechanical performance of MOC.