本文選題：快速碳化 + 水灰比��； 參考：《浙江科技學(xué)院》2017年碩士論文

【摘要】：鋼筋銹蝕一直是各國鋼筋混凝土建筑結(jié)構(gòu)安全的最大隱患,鋼筋混凝土中的鋼筋表面有一層鈍化膜可以阻礙其銹蝕,但包裹鋼筋的混凝土若是失去堿性后發(fā)生碳化時,會導(dǎo)致鋼筋表面鈍化膜破壞,從而使鋼筋發(fā)生銹蝕。鋼筋銹蝕主要是由于混凝土碳化、氯離子引起鋼筋去鈍化和酸性介質(zhì)引起的,而混凝土是否碳化關(guān)系到氯離子及酸性介質(zhì)進(jìn)入的關(guān)鍵,所以研究混凝土碳化尤為重要。要研究混凝土碳化緣由,水泥是混凝土組成材料中最易發(fā)生碳化的成分,因此最終解決水泥試塊的碳化是解決鋼筋混凝土結(jié)構(gòu)破壞的關(guān)鍵所在。本論文研究中法兩國常用水泥的抗碳化性能,目的在于了解兩國用于實(shí)際工程建筑的水泥對鋼筋混凝土建筑的耐久性的影響,并研究了水灰比、CO_2濃度、有無防水劑、預(yù)處理(碳化試驗前)和水泥成分等因素對水泥試塊的碳化的影響。得出以下結(jié)論:1)實(shí)驗分別對0.45、0.50和0.55三組水灰比的試塊進(jìn)行抗碳化性能比較,實(shí)驗結(jié)果顯示,隨著水灰比的增大,碳化程度增加。2)實(shí)驗選用CO_2濃度為10%和20%,結(jié)果表明CO_2濃度越高,碳化越快。3)實(shí)驗選用一組試塊添加表面有機(jī)硅防水劑與不添加防水劑的試塊進(jìn)行碳化程度的比較,發(fā)現(xiàn)有防水劑的試塊前7天碳化速度明顯小于無防水劑的試塊,且總的碳化深度也較低。4)預(yù)處理對于水泥膠砂試塊碳化性能影響較為明顯:一組試塊成型后在60℃的烘干箱中干燥48h,另一組試塊成型后在45℃的烘干箱中干燥14天,進(jìn)行加速碳化。前者較后者碳化速度慢。5)中國和法國常用水泥成分不同,中國的常用水泥的碳化速度比法國常用水泥碳化速度更快。法國所用水泥中,CaO含量的成分相對較多,水化后的堿性物質(zhì)更多,單位體積消耗的CO_2更多,所以碳化速度更慢。
[Abstract]:The corrosion of steel bars has always been the biggest hidden danger to the safety of reinforced concrete buildings in various countries. A passivation film on the surface of reinforced concrete bars can hinder its corrosion. However, if the reinforced concrete is carbonized after losing its alkalinity,This will lead to the destruction of the passivation film on the steel bar surface, which will lead to the corrosion of the steel bar.The corrosion of steel bar is mainly caused by carbonation of concrete, deactivation of steel bar by chloride ion and acid medium, and the carbonation of concrete is related to the key of chloride ion and acid medium, so it is very important to study the carbonation of concrete.In order to study the cause of concrete carbonation, cement is the most easily carbonated component of concrete. Therefore, the key to solve the structural damage of reinforced concrete is to solve the carbonation of concrete specimen.In this paper, the carbonation resistance of cement used in China and France is studied. The purpose of this paper is to understand the influence of cement used in practical construction on the durability of reinforced concrete buildings, and to study the concentration of water cement ratio of COSP 2 and the availability of water repellent.Effects of pretreatment (before carbonization test) and cement composition on carbonation of cement test blocks.The following conclusions are drawn: (1) the carbonization resistance of the three groups of water-cement ratio of 0.45 and 0.55 is compared with the ratio of water to cement. The experimental results show that with the increase of water-cement ratio, the carbonization degree increases with the increase of water-cement ratio.) the concentration of CO_2 is 10% and 20% respectively. The results show that the higher the concentration of CO_2 is, the higher the carbonization degree is.The faster the carbonization was, the faster the carbonization degree was compared between a group of test blocks with surface silicone water-repellent and those without water repellent. It was found that the carbonation rate of the sample with water repellent was obviously lower than that without water repellent in the first 7 days.The total carbonation depth was also lower. 4) Pretreatment had a significant effect on the carbonization properties of cement mortar sand. One group of samples was dried in oven at 60 鈩，

本文編號：1766180