长期低温环境对氯氧镁水泥微观结构及力学性能的影响

Effect of Long-Term Low Temperature Environment on Microstructure and Mechanical Properties of Magnesium Oxychloride Cement

为揭示氯氧镁水泥(MOC)在长期低温环境下的耐久性能,采用SEM、MIP、XRD、TG-DSC、FT-IR以及微机电液伺服压力试验机考察了冷冻时间对MOC试样微观结构、物相组成以及力学性能的影响。结果表明:MOC试样具有良好的长期低温抗冻性能,经过12个月的冷冻处理后,MOC试样的质量仅增加了0.9%;微观形貌由较细的针棒状与凝胶状转变为较粗的针棒状与凝胶块状,微孔孔径为38~48 nm,0.01~0.1μm的微孔体积比例为70%~80%;相组成无明显变化,主要强度相5Mg(OH)_(2)·MgCl_(2)·8H_(2)O(5·1·8相)含量仅减少了3%;力学性能仅略有降低,其中抗压和抗折强度分别降低了3.4和2.6 MPa。

In order to reveal the durability of magnesium oxychloride cement(MOC)under long-term low temperature environment,the effect of freezing time on microstructure,phase composition and mechanical properties of MOC samples were investigated by SEM,MIP,XRD,TG-DSC,FT-IR and microcomputer electro-hydraulic servo pressure testing machine.The results show that MOC samples have good long-term low temperature frost resistance.After 12 months of long-term low temperature freezing experiment,the weight of MOC samples only increases by 0.9%.The microscopic morphology changes from fine needle-like and gel-like to thicker needle-like and gel-like block.The microporous structure does not change significantly,with the average pore diameter varying between 38 and 48 nm and the pore volume distribution(0.01μm to 0.1μm)fluctuating from 70%to 80%.The phase composition does not change significantly,and the content of the main strength phase 5Mg(OH)_(2)·MgCl_(2)·8H_(2)O(5·1·8 phase)only decreases by 3%.The mechanical properties decrease slightly,in which the compressive strength decreases by 3.4 MPa and the flexural strength decreases by only 2.6 MPa.