海洋工程鋼筋混凝土滲透型防護劑作用機理及納米改性研究
發(fā)布時間：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)濟損失難以估量,成為困擾全球海洋經(jīng)濟發(fā)展的難點問題,使得各國政府和企業(yè)投入大量資金用于鋼筋混凝土耐久性與防護研究。在各類耐久性提升技術(shù)中,混凝土滲透型防護劑具有滲透成膜、有效防護、應(yīng)用范圍廣等優(yōu)勢,受到極大關(guān)注。目前對滲透型防護劑的研究主要集中于混凝土宏觀防護性能,在混凝土碳化、凍融及耐久性等方面作用機理仍不是十分完善,在實際應(yīng)用中占有較大市場份額的硅烷防護劑還存在揮發(fā)量大、成膜時間長等問題。所以,針對滲透型防護劑作用機理及新型防護劑的研制開發(fā)顯得尤為重要。本課題在綜述海洋工程防腐技術(shù)及滲透型防護劑研究現(xiàn)狀的基礎(chǔ)上,首先通過混凝土濕度實驗確定滲透型防護劑類型及混凝土基材處理要求；然后通過加速碳化實驗和快速凍融實驗豐富防護劑滲透成膜作用機理,并結(jié)合滲透型防護劑在混凝土堿性環(huán)境耐久性能研究,提出新型滲透型防護劑的技術(shù)需求；最后通過對硅烷滲透型防護劑進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、有效防護的納米改性硅烷滲透型防護劑。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劑成膜性能、滲透能力及防護性能的變化規(guī)律,研究發(fā)現(xiàn)：混凝土烘干處理時間越久則濕度越低,防護劑在混凝土中滲透深度越深、成膜時間越短,防護劑處理后混凝土氯離子電通量越低；隨著烘干時間由6h延長到48h,防護劑在混凝土中的滲透深度增加1.8mm,成膜時間可縮短近36h,經(jīng)防護劑處理混凝土的氯離子電通量值可以降低80%左右。(2)通過加速碳化實驗研究了不同密實程度混凝土經(jīng)滲透型防護劑處理后碳化深度的變化規(guī)律,研究發(fā)現(xiàn)：當(dāng)混凝土密實程度較高時,滲透型防護劑可提高混凝土抗碳化性能,防護劑處理后混凝土碳化深度小于未處理試件；當(dāng)密實程度較低時,滲透型防護劑會加速碳化進程,防護劑處理后混凝土碳化深度大于未處理試件。(3)通過快速凍融循環(huán)實驗研究滲透型防護劑處理后混凝土質(zhì)量損失和動彈性模量變化規(guī)律,研究發(fā)現(xiàn)：經(jīng)滲透型防護劑處理的混凝土?xí)?5次凍融循環(huán)時出現(xiàn)較大吸水增重過程,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；滲透型防護劑處理會加速混凝土相對動彈性模量下降,在125次凍融循環(huán)后混凝土相對彈性模量下降最大,達到51.3%。(4)通過戶外服役實驗研究了滲透型防護劑在早齡期混凝土上滲透深度和防護性能變化規(guī)律,研究發(fā)現(xiàn)：滲透型防護劑在早齡期混凝土堿性環(huán)境中滲透深度隨著服役時間延長而小幅下降,其下降幅度會逐漸降低,最終使混凝土保持穩(wěn)定的滲透深度值；盡管滲透深度會出現(xiàn)下降,所有滲透型防護劑處理砂漿都具備優(yōu)異疏水效果,在整個戶外服役階段,24h表面吸水率都降低達90%以上。(5)采用溶膠凝膠酸堿兩步法開展了納米改性滲透型防護劑的合成與性能研究,研究發(fā)現(xiàn)：通過溶膠凝膠酸堿兩步法實現(xiàn)酸性硅溶膠附著在堿性硅溶膠表面,制備出快速成膜、有效防護的納米改性滲透型防護劑；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)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TV33
本文編號：2181946
[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)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TV33
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1 孔綱;張雙紅;孫子文;車淳山;盧錦堂;;二氧化硅粉體粒度對硅酸鹽轉(zhuǎn)化膜制備的影響[J];材料研究學(xué)報;2014年06期
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1 王華;海水凍融循環(huán)作用下活性粉末混凝土的耐久性研究[D];北京交通大學(xué);2014年
，本文編號：2181946
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