發(fā)布時(shí)間：2018-08-13 19:23

【摘要】：在海洋環(huán)境中,鋼筋混凝土因腐蝕破壞造成的經(jīng)濟(jì)損失難以估量,成為困擾全球海洋經(jīng)濟(jì)發(fā)展的難點(diǎn)問(wèn)題,使得各國(guó)政府和企業(yè)投入大量資金用于鋼筋混凝土耐久性與防護(hù)研究。在各類(lèi)耐久性提升技術(shù)中,混凝土滲透型防護(hù)劑具有滲透成膜、有效防護(hù)、應(yīng)用范圍廣等優(yōu)勢(shì),受到極大關(guān)注。目前對(duì)滲透型防護(hù)劑的研究主要集中于混凝土宏觀防護(hù)性能,在混凝土碳化、凍融及耐久性等方面作用機(jī)理仍不是十分完善,在實(shí)際應(yīng)用中占有較大市場(chǎng)份額的硅烷防護(hù)劑還存在揮發(fā)量大、成膜時(shí)間長(zhǎng)等問(wèn)題。所以,針對(duì)滲透型防護(hù)劑作用機(jī)理及新型防護(hù)劑的研制開(kāi)發(fā)顯得尤為重要。本課題在綜述海洋工程防腐技術(shù)及滲透型防護(hù)劑研究現(xiàn)狀的基礎(chǔ)上,首先通過(guò)混凝土濕度實(shí)驗(yàn)確定滲透型防護(hù)劑類(lèi)型及混凝土基材處理要求；然后通過(guò)加速碳化實(shí)驗(yàn)和快速凍融實(shí)驗(yàn)豐富防護(hù)劑滲透成膜作用機(jī)理,并結(jié)合滲透型防護(hù)劑在混凝土堿性環(huán)境耐久性能研究,提出新型滲透型防護(hù)劑的技術(shù)需求；最后通過(guò)對(duì)硅烷滲透型防護(hù)劑進(jìn)行溶膠凝膠酸堿兩步法納米改性,首次在混凝土防腐領(lǐng)域制備出快速成膜、有效防護(hù)的納米改性硅烷滲透型防護(hù)劑。本課題主要工作及研究結(jié)論如下：(1)系統(tǒng)研究了不同混凝土濕度條件下滲透型防護(hù)劑成膜性能、滲透能力及防護(hù)性能的變化規(guī)律,研究發(fā)現(xiàn)：混凝土烘干處理時(shí)間越久則濕度越低,防護(hù)劑在混凝土中滲透深度越深、成膜時(shí)間越短,防護(hù)劑處理后混凝土氯離子電通量越低；隨著烘干時(shí)間由6h延長(zhǎng)到48h,防護(hù)劑在混凝土中的滲透深度增加1.8mm,成膜時(shí)間可縮短近36h,經(jīng)防護(hù)劑處理混凝土的氯離子電通量值可以降低80%左右。(2)通過(guò)加速碳化實(shí)驗(yàn)研究了不同密實(shí)程度混凝土經(jīng)滲透型防護(hù)劑處理后碳化深度的變化規(guī)律,研究發(fā)現(xiàn)：當(dāng)混凝土密實(shí)程度較高時(shí),滲透型防護(hù)劑可提高混凝土抗碳化性能,防護(hù)劑處理后混凝土碳化深度小于未處理試件；當(dāng)密實(shí)程度較低時(shí),滲透型防護(hù)劑會(huì)加速碳化進(jìn)程,防護(hù)劑處理后混凝土碳化深度大于未處理試件。(3)通過(guò)快速凍融循環(huán)實(shí)驗(yàn)研究滲透型防護(hù)劑處理后混凝土質(zhì)量損失和動(dòng)彈性模量變化規(guī)律,研究發(fā)現(xiàn)：經(jīng)滲透型防護(hù)劑處理的混凝土?xí)?5次凍融循環(huán)時(shí)出現(xiàn)較大吸水增重過(guò)程,隨著循環(huán)次數(shù)的繼續(xù)增加,混凝土質(zhì)量損失率會(huì)快速上升,并在125次凍融循環(huán)后混凝土出現(xiàn)2.7%的最大質(zhì)量損失率；滲透型防護(hù)劑處理會(huì)加速混凝土相對(duì)動(dòng)彈性模量下降,在125次凍融循環(huán)后混凝土相對(duì)彈性模量下降最大,達(dá)到51.3%。(4)通過(guò)戶外服役實(shí)驗(yàn)研究了滲透型防護(hù)劑在早齡期混凝土上滲透深度和防護(hù)性能變化規(guī)律,研究發(fā)現(xiàn)：滲透型防護(hù)劑在早齡期混凝土堿性環(huán)境中滲透深度隨著服役時(shí)間延長(zhǎng)而小幅下降,其下降幅度會(huì)逐漸降低,最終使混凝土保持穩(wěn)定的滲透深度值；盡管滲透深度會(huì)出現(xiàn)下降,所有滲透型防護(hù)劑處理砂漿都具備優(yōu)異疏水效果,在整個(gè)戶外服役階段,24h表面吸水率都降低達(dá)90%以上。(5)采用溶膠凝膠酸堿兩步法開(kāi)展了納米改性滲透型防護(hù)劑的合成與性能研究,研究發(fā)現(xiàn)：通過(guò)溶膠凝膠酸堿兩步法實(shí)現(xiàn)酸性硅溶膠附著在堿性硅溶膠表面,制備出快速成膜、有效防護(hù)的納米改性滲透型防護(hù)劑；以30nm堿性硅溶膠為原料按酸堿20：1比例在20℃C復(fù)合制備的納米改性滲透型涂覆在混凝土試件4h后已基本成膜,比相同用量硅烷具有更好的降低氯離子電通量能力。
[Abstract]:In the marine environment, the economic loss of reinforced concrete caused by corrosion damage is hard to estimate, which has become a difficult problem to puzzle the development of the global marine economy. Many governments and enterprises have invested a lot of money in the durability and protection research of reinforced concrete. At present, the research on penetrating protective agent mainly focuses on the macro-protective performance of concrete. The mechanism of action in concrete carbonization, freeze-thaw and durability is still not perfect. Silane protective agent which occupies a large market share in practical application still has volatilization. Therefore, it is very important to study the mechanism of penetrating protective agent and the development of new type of protective agent. On the basis of reviewing the research status of marine engineering antiseptic technology and penetrating protective agent, the type of penetrating protective agent and concrete base material are determined by concrete humidity experiment. Physical requirements; then through accelerated carbonization experiments and rapid freeze-thaw experiments to enrich the mechanism of protective agent penetration film formation, and combined with the durability of permeable protective agent in alkaline environment of concrete durability study, put forward the technical requirements of new permeable protective agent; finally through the silane permeable protective agent sol-gel acid-base two-step method nanometer The main work and research conclusions of this subject are as follows: (1) The change rules of film-forming property, permeability and protective property of permeable protective agent under different concrete humidity conditions are systematically studied. The longer the soil drying time is, the lower the humidity is, the deeper the penetration depth of the protective agent in concrete, the shorter the film forming time is, and the lower the chloride ion electric flux of the concrete after the protective agent treatment is; with the drying time extending from 6 h to 48 h, the penetration depth of the protective agent in concrete increases by 1.8 mm, the film forming time can be shortened by 36 h, and the coagulation time after the protective agent treatment is shortened. The chloride ion electric flux of soil can be reduced by about 80%. (2) Through accelerated carbonization experiment, the change law of carbonization depth of concrete with different densities after treatment with penetrating protective agent is studied. It is found that penetrating protective agent can improve the carbonization resistance of concrete when the densities of concrete are high, and the concrete treated with protective agent can improve the carbonization resistance of concrete. Carbonation depth is less than untreated specimens; when the compactness is low, the permeable protective agent will accelerate the carbonization process, and the carbonization depth of concrete treated with protective agent is greater than untreated specimens. (3) The mass loss and dynamic elastic modulus of concrete treated with permeable protective agent are studied by rapid freeze-thaw cycles. The concrete treated with permeable protective agent will have a large water absorption and weight gain process during 25 freeze-thaw cycles. With the increase of the number of cycles, the mass loss rate of concrete will rise rapidly, and the maximum mass loss rate of concrete will be 2.7% after 125 freeze-thaw cycles. The permeable protective agent treatment will accelerate the relative dynamic elasticity of concrete. The relative elastic modulus of concrete decreases to 51.3% after 125 freeze-thaw cycles. (4) The penetration depth and protective performance of penetrating protective agent on early age concrete are studied by outdoor service experiments. The results show that penetrating depth of penetrating protective agent in alkaline environment of early age concrete changes with clothing. The decrease will gradually decrease with the prolongation of service time, and eventually the concrete will maintain a stable penetration depth. Although the penetration depth will decrease, all the penetration protective agents have excellent hydrophobic effect on the mortar. During the whole outdoor service period, the surface water absorption rate will be reduced by more than 90% after 24 hours. The synthesis and properties of nano-modified penetration protective agent were studied by two-step method of colloidal acid-base. The results showed that: acid silica sol was adhered to the surface of alkaline silica sol by two-step method of sol-gel acid-base, and nano-modified penetration protective agent was prepared quickly and effectively; 30 nm alkaline silica sol was used as raw material, and the acid-base ratio was 20:1. The nano-modified permeable coating prepared at 20 C for 4 hours has basically formed a film, which has better ability to reduce chloride ion flux than the same dosage of silane.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TV33

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本文編號(hào)：2181946