本文選題：滲透性 + 抗凍性　； 參考：《哈爾濱工業(yè)大學(xué)》2015年碩士論文

【摘要】：凍融破壞是混凝土最常見的破壞現(xiàn)象之一,尤其是在凍融交替的地區(qū)。在引氣劑與防水劑單獨(dú)或者綜合作用下,混凝土的抗凍及抗?jié)B性能會(huì)得到很大的改善。國內(nèi)外學(xué)者研究的大部分為引氣劑或者防水劑單獨(dú)作用的情況,因此,本文旨在研究它們的復(fù)合作用效果。選取典型配合比的混凝土,采用電通量法和表面氣體滲透儀分析其抗?jié)B性;利用快速凍融試驗(yàn)評(píng)價(jià)其抗凍性能。最后分析了硬化混凝土的氣泡參數(shù)、孔結(jié)構(gòu)與孔徑分布及界面過渡區(qū)結(jié)構(gòu)。首先,研究分析了蒸汽養(yǎng)護(hù)和常溫養(yǎng)護(hù)兩種制度下,引氣劑對(duì)混凝土的抗凍及抗?jié)B性能的影響規(guī)律。研究結(jié)果表明:無論蒸汽養(yǎng)護(hù)還是常溫養(yǎng)護(hù),引氣劑摻量大的混凝土的抗凍性及抗?jié)B性較好,但其初始強(qiáng)度相對(duì)較低。從微觀角度分析,在引氣劑摻量相同的前提下,蒸養(yǎng)混凝土的氣泡間距系數(shù)大于常溫養(yǎng)護(hù)的,但是其最可幾孔徑卻小于常溫養(yǎng)護(hù)的,蒸養(yǎng)混凝土中含有較多的大孔隙(1000nm)和小孔隙(10nm),而常溫養(yǎng)護(hù)混凝土中則含有較多的對(duì)混凝土抗凍及抗?jié)B性能有利的10nm~100nm的孔隙;蒸養(yǎng)混凝土的界面過渡區(qū)晶體含量相對(duì)較多,未受凍時(shí)其界面區(qū)或者漿體中已經(jīng)有少許的小裂縫存在,蒸養(yǎng)混凝土的凍融破壞可能同時(shí)發(fā)生在界面過渡區(qū)和漿體,而常溫養(yǎng)護(hù)混凝土的破壞主要集中在界面過渡區(qū)。其次,研究了常溫養(yǎng)護(hù)制度下,引氣與防水組分對(duì)混凝土的復(fù)合作用。研究結(jié)果發(fā)現(xiàn):引氣劑和防水劑的加入都會(huì)使混凝土的強(qiáng)度有所下降,但是它們對(duì)混凝土的抗凍及抗?jié)B性能改善效果明顯;有機(jī)硅防水劑及引氣劑均可以顯著改善混凝土的抗水、氯離子滲透能力,滲透結(jié)晶型防水劑則可以全面改善的混凝土的抗?jié)B性,凍融循環(huán)200次時(shí),滲透結(jié)晶型防水劑的加入使得引氣量相同的混凝土的表面氣體滲透深度最多下降了19.18%,其滲透結(jié)晶型產(chǎn)物主要為鈣礬石(Aft)、氫氧化鈣(CH)、水化硅酸鈣(C-S-H)及碳酸鈣(Ca CO3),其滲透深度約為8~12mm;防水劑的加入使混凝土的氣泡間距系數(shù)有減小的趨勢(shì),抗凍性及抗?jié)B性優(yōu)異的未凍混凝土的氣泡間距系數(shù)僅為138μm,比空白混凝土低257μm;防水劑的摻入使得混凝土中10~100nm的孔隙的比例大大,使得混凝土的最可幾孔徑有減小的趨勢(shì),使得混凝土的界面及漿體結(jié)構(gòu)更加均勻、連續(xù)、密實(shí),其中滲透結(jié)晶型防水劑的作用效果尤為明顯。最后,確定了混凝土的最佳外加劑組成為:摻1.5?引氣劑+1.0%有機(jī)硅防水劑+外涂0.8~1.0mm滲透結(jié)晶防水劑。經(jīng)過300次凍融循環(huán)后,其質(zhì)量損失僅為0.81%,其抗凍等級(jí)達(dá)到了DF300。
[Abstract]:Freeze-thaw failure is one of the most common failure phenomena in concrete, especially in the regions where freeze-thaw alternate. Under the action of air-entraining agent and water-repellent agent alone or synthetically, the frost resistance and impermeability of concrete will be greatly improved. Scholars at home and abroad mostly study the situation of air-entraining agent or water-repellent acting alone, therefore, the purpose of this paper is to study their compound effect. The concrete with typical mix ratio was selected to analyze its impermeability by electric flux method and surface gas permeation instrument, and its frost resistance was evaluated by rapid freeze-thaw test. Finally, the bubble parameters, pore structure, pore size distribution and interface transition zone structure of hardened concrete are analyzed. Firstly, the influence of air entraining agent on the frost resistance and impermeability of concrete under steam curing and normal temperature curing is studied. The results show that the concrete with large amount of air entraining agent has good frost resistance and impermeability, but its initial strength is relatively low, regardless of steam curing or normal temperature curing. From the microscopic point of view, on the premise of the same air entraining agent content, the bubble spacing coefficient of steaming concrete is larger than that of room temperature curing, but the most suitable pore size is smaller than that of room temperature curing. The steaming concrete contains more macropores (1000 nm) and small pores (10 nm), while the curing concrete at room temperature contains more 10nm~100nm pores which are favorable to the frost resistance and impermeability of concrete, and the interfacial transition zone of steaming concrete contains relatively more crystals. There are a few cracks in the interface zone or the slurry body when the concrete is not frozen. The freeze-thaw failure of the steaming concrete may occur in the interfacial transition zone and the slurry at the same time, while the damage of the curing concrete at room temperature is mainly concentrated in the interfacial transition zone. Secondly, the compound action of air entrainment and waterproof component on concrete under normal temperature curing system is studied. The results show that both air-entraining agent and water-repellent agent can decrease the strength of concrete, but they can improve the frost resistance and impermeability of concrete obviously. Both silicone water-repellent and air-entraining agent can significantly improve the water resistance of concrete. The permeable capacity of chloride ion can be improved significantly. The permeability of concrete with permeable crystalline waterproof agent can be improved completely, and when freeze-thaw cycles are 200 times, The penetration depth of the surface gas of concrete with the same amount of air entraining decreased by 19.18% with the addition of permeable crystalline water-repellent agent. The main products of permeation crystallized were ettringite, calcium hydroxide, calcium silicate (C-S-H), calcium carbonate and calcium carbonate. The permeation depth is about 812 mm, and the air bubble spacing coefficient of concrete decreases with the addition of water-repellent. The bubble spacing coefficient of unfrozen concrete with excellent frost resistance and impermeability is only 138 渭 m, which is 257 渭 m lower than that of blank concrete. The interface and slurry structure of concrete are more uniform, continuous and dense, and the effect of permeable crystalline waterproof agent is especially obvious. Finally, the optimum admixture composition of concrete is determined as follows: 1.5? Air entraining agent 1.0% silicone water repellent was coated with 0.8~1.0mm permeable crystalline waterproof agent. After 300 freeze-thaw cycles, the mass loss was only 0.81%, and the frost resistance grade reached DF300.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU528

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