摘要
通过中子成像试验、吸水试验和氯离子侵蚀试验,研究无裂缝和带裂缝情况下硅烷改性混凝土的防水和抗氯离子侵蚀性能。试验结果表明,中子成像能够清晰观测未掺硅烷试件的快速吸水过程,而掺加硅烷后在毛细孔隙壁上形成的憎水膜能够有效抑制液态水分侵入,中子成像观测不到肉眼可见的水分前锋,吸水量降为未掺硅烷时的13%,显示出良好的防水性能。硅烷在水泥基体中的水解缩合反应并不堵塞毛细孔隙,保持"可呼吸性"。未改性试件一旦开裂,水在瞬间充满裂缝继而向裂缝两侧入侵,而硅烷改性试件即使开裂宽度达0.3mm,也无明显水分运动,裂缝在0.1mm～0.4mm扩展时不削弱其整体防水效果。良好的防水性能决定了硅烷改性混凝土无论是在无裂缝还是带裂缝情况下都具有良好的抗氯离子侵蚀能力。掺加硅烷改性是提高混凝土材料防水和抗氯离子侵蚀能力,进而提高其耐久性的有效途径。
The water repellency and chloride resistance of modified concrete with silane without and with cracks have been investigated through neutron radiography test,water absorption test and chloride penetration test.The results indicate that the process of water penetration into mortar specimens without silane can be visualized distinctly by means of neutron radiography,while water in the modified mortar with silane cannot be observed by naked eyes.The hydrophobic films formed in the capillary pores from the added silane effectively restrain liquid water from penetrating into mortar,and consequently it results in decreasing water absorption to be only 13% of mortar without silane.The hydrolysis and polymerization reaction of silane in cementitious materials do not block the respirability of the capillary pores.Cracks are instantaneously filled with water once specimens without silane crack,and after that water will penetrate into the adjacent areas around the cracks.However,even when the modified specimens with silane crack up to 0.3mm,there is no obvious water movement observed.The cracks from 0.1mm to 0.4mm hardly decrease the integral water repellency of modified concrete with silane.Due to the high water repellency of the modified concrete with silane it thus also has high resistance to chloride penetration with or without cracks.It is an effective method to improve the water repellency and chloride resistance and thus the durability of cement-based materials by modifying concrete with silane.
出处
《土木工程学报》
EI
CSCD
北大核心
2011年第3期72-78,共7页
China Civil Engineering Journal
基金
国家973资助项目(2009CB623203)
国家自然科学基金(507390015
1008165)
山东省自然科学基金(ZR2009FQ014)
关键词
硅烷
吸水
中子成像
氯离子侵蚀
裂缝
silane
water absorption
neutron radiography
chloride penetration
cracks
