摘要
为改善氯氧镁水泥基材料的脆性和耐水性能,本试验基于微观力学设计原理,采用聚乙烯纤维作为增强材料,进行了超高韧性氯氧镁水泥基复合材料的研发。通过不同粉煤灰替代率(20%、30%、40%、60%)下复合材料的拉伸、压缩和单纤维拔出试验分析粉煤灰掺量对其基本力学性能、耐水性能的影响规律,并采用X射线衍射仪和扫描电镜分析了不同粉煤灰替代率下水化产物的物相组成和微观结构。结果表明,复合材料浸水前、后均具有稳定的应变硬化和多缝开裂特性,抗拉强度介于4~7 MPa之间,拉伸应变介于5%~8%之间;聚乙烯纤维和粉煤灰的加入改善了氯氧镁水泥基材料的耐水性能,抗拉和抗压强度软化系数分别大于0.70和0.80,拉伸应变能力在复合材料浸水后均有一定的提升。
To improve the inherent brittleness and poor water resistance of the magnesium oxychloride cement(MOC)based composites,ultra-high toughness MOC composites(MOC-UHTC)was developed with the help of specially treated polyethylene(PE)fibers under the guidance of micromechanical design principle.The tensile,compressive and single-fiber pullout tests of materials in the four replacement ratio of fly ash(20%,30%,40%and 60%)were conducted.The effect of the replacement ratio of fly ash on the mechanical properties,water resistance of the materials was analyzed.And the phase composition of hydration products and the microstructure of the composites in different replacement ratio of fly ash was analyzed by XRD and SEM,respectively.The results indicate that MOC-UHTC exhibits outstanding strain hardening behavior and multi-cracking response.The tensile strain capacity of MOC-UHTC ranged from 5%to 8%with the tensile strength from 4 MPa to 7 MPa.The tensile and compressive strength retention coefficient of the composites exceeded 0.7 and 0.8 respectively,indicating that the water resis-tance was improved due to the addition of fly ash and PE fibers.Moreover,the tensile strain capacity had a certain increase after the composites immersed in water.
作者
王义超
余江滔
魏琳卓
徐世烺
WANG Yichao;YU Jiangtao;WEI Linzhuo;XU Shilang(College of Civil Engineering,Tongji University,Shanghai 200092;Shanghai Key Laboratory of Engineering Structure Safety,Tongji University,Shanghai 200092;College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第16期2665-2670,共6页
Materials Reports
基金
国家自然科学基金(51478362
51778461)~~
关键词
氯氧镁水泥
粉煤灰
聚乙烯纤维
应变硬化
耐水性能
magnesium oxychloride cement
fly ash
polyethylene fiber
strain hardening
water resistance
