利用快速碳化试验方法,测定了普通和改性玻璃纤维增强氯氧镁水泥(GRMC)在碳化前后的弯曲应力-挠度曲线,运用XRD分析其碳化产物组成,用SEM观察其显微结构特征与玻璃纤维的腐蚀状况.结果表明:在快速碳化28 d后,普通GRMC的水化产物5Mg(OH)2·MgCl2·8H2O(简称5·1·8)碳化为Mg(OH)2·MgCl2·2MgCO3·6H2O(简称1·1·2·6),Mg(OH)2碳化为MgCO3,碳化后的部分MgCl2溶出和流失导致材料基体孔洞较多,结构松散,从而引起普通GRMC的初裂强度降低,极限挠度变大,极易变形；而改性GRMC的水化产物5·1·8在快速碳化条件下保持基本稳定,微观结构未发生显著变化,显示出较强的抗碳化能力,其初裂强度增大,初裂挠度和极限挠度几乎不降低,不易开裂.此外,碳化作用不会导致玻璃纤维的腐蚀,纤维与水泥基体粘结良好,结构致密.%The curves of bending stress-deflection about common and modified glass fiber reinforced magnesium oxychloride cement (GRMC) were determined though rapid carbonation method.Carbonation product components was analyzed by XRD,microstructure characteristics and corrosion of glass fiber were observed by SEM.The results indicate that hydration product 5Mg(OH)2 · MgCl2 · 8H2O (5 · 1 · 8) of common GRMC is carbonated to Mg(OH)2 ·MgCl2 · 2MgCO3 · 6H2O (1 · 1 · 2 · 6) and Mg(OH)2 carbonated to MgCO3 after 28 d rapid carbonation.Partially leaching and draining of MgCl2 lead to more holes in matrix,looseness of structure that cause initial cracking strength decrease,limited deflection increase,and deformation easily of common GRMC.Hydration product 5 · 1 · 8 and its microstructure characteristics of modified GRMC remain stable within rapid carbonation.Modified GRMC reveals better carbonation resistance,initial deflection and limited deflection reduce little,initial cracking strength increase and cracking difficult.Moreover,carbonation do not lead to corrosion of glass fiber,fiber with cement matrix bond well,with dense structure.
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