关键词: 耐久性;抗折强度;碱式硫酸镁水泥;微观机理;玻璃纤维

Abstract: In order to study the long-term strength of glass fiber reinforced basic magnesium sulfate cement composite and evaluate its durability,SIC (Strand In Cement) test method was used to determine the flexural strength of glass fiber reinforced basic magnesium sulfate cement composite sheet at 50 ℃,80 ℃ hot water accelerated aging test conditions.The hydrothermal product was characterized by XRD and SEM,and the corrosion characteristics of glass fiber in basic magnesium sulfate cement matrix were observed.The results show that the flexural strength of the composite sheet decreases obviously with the increase of the time in the aging condition,because the 517 phase of the needle-like magnesium sulfate cement is decomposed into the sheet-like cementation-free Mg(OH)2;it needed 12 d when the strength retention rate of sheet material reached 50％ at 80 ℃ aging condition,while the magnesium oxide cement sample failure time is only 3 d,so the glass fiber reinforced alkaline magnesium sulfate cement material aging life of a long time,more suitable for the application in the actual project.

Key words: durability;flexural strength;basic magnesium sulfate cement;microscopic mechanism;glass fiber