本文選題：混凝土 + 納米改性�。� 參考：《哈爾濱工業(yè)大學(xué)》2015年碩士論文

【摘要】：利用納米材料對(duì)混凝土進(jìn)行改性以提高混凝土的性能,特別是抗鹽凍性能已被認(rèn)為具有可行性和廣泛前景。本文使用Si O2、納米Al2O3、納米Fe2O3以及納米Ti O2四種納米材料,摻量為水泥質(zhì)量的0.05%、0.1%、0.5%和1.0%,對(duì)水灰比為0.5的混凝土進(jìn)行改性,測(cè)試了納米改性混凝土的和易性、力學(xué)性能、抗?jié)B性以及抗鹽凍性能等,并且利用SEM和EDS等手段對(duì)其改性機(jī)理進(jìn)行了分析。試驗(yàn)采用先將納米材料在減水劑溶液中超聲分散后,再與干料一同拌合的方法制備混凝土。研究結(jié)果表明,當(dāng)摻量不大于1.0%時(shí),納米材料的摻入對(duì)混凝土的和易性,特別是流動(dòng)性無明顯影響。四種納米材料均可以提高混凝土的力學(xué)性能,且均呈現(xiàn)隨著摻量的增加,混凝土的力學(xué)性能隨之提高的趨勢(shì),當(dāng)摻量達(dá)到1.0%時(shí),四種納米改性混凝土的抗壓強(qiáng)度和抗折強(qiáng)度均提高10%以上。四種納米材料中,納米Si O2和納米Ti O2對(duì)混凝土力學(xué)性能的提升作用相對(duì)較強(qiáng),而納米Fe2O3對(duì)混凝土的力學(xué)性能的改善幅度最低。在Na Cl、CH3COOK和Ca Cl2三種鹽環(huán)境下對(duì)納米改性混凝土進(jìn)行凍融循環(huán)測(cè)試。發(fā)現(xiàn)在三種鹽凍環(huán)境下,納米改性混凝土均基本呈現(xiàn),隨著摻量的增加,混凝土的質(zhì)量損失率隨之降低,相對(duì)動(dòng)彈性模量隨之升高的趨勢(shì),既納米材料的摻量越大,混凝土的抗鹽凍性能越好,1%為抗鹽凍性能最佳摻量。對(duì)比四種納米材料對(duì)混凝土抗鹽凍性能的改善作用,納米Si O2所起作用較為明顯地高于其他三者,納米Ti O2次之,而剩余的納米Al2O3和納米Fe2O3兩者中,納米Al2O3的改善作用相對(duì)最弱。而利用電通量法測(cè)試納米改性混凝土的抗?jié)B性,也得到了與抗鹽凍性能相似的結(jié)果。納米改性混凝土的改性機(jī)理主要在于摻入納米材料后,提高了水化產(chǎn)物的數(shù)量和種類。水化產(chǎn)物數(shù)量的提升可以使混凝土更為致密。納米Si O2、納米Al2O3和納米Ti O2摻入后,出現(xiàn)的針狀水化產(chǎn)物,可以以原生納米纖維的形式起到阻礙混凝土內(nèi)部微裂紋的發(fā)展,使混凝土增強(qiáng)增韌的作用。而摻入納米Fe2O3后出現(xiàn)的球狀水化產(chǎn)物,由于其排列緊密,同樣起到了提升混凝土密實(shí)度的作用。這些納米材料的摻入引起的水化過程的優(yōu)化,最終使得混凝土在力學(xué)性能和耐久性方面得到了提升。
[Abstract]:In order to improve the properties of concrete, especially the salt freezing resistance, it is considered feasible and promising to modify concrete with nano-materials. In this paper, four kinds of nanomaterials, Sio _ 2, nano-Al _ 2O _ 3, nanometer Fe2O3 and nano TIO _ 2 were used to modify the concrete with water-cement ratio of 0.5% and 1.0% respectively. The properties of the concrete were tested. Impermeability and salt freezing resistance were analyzed by means of SEM and EDS. The concrete was prepared by ultrasonic dispersion of nanomaterials in water reducer solution and then mixing with dry materials. The results show that when the content of nano-materials is less than 1.0, the incorporation of nano-materials has no obvious effect on the workability of concrete, especially the fluidity of concrete. Four kinds of nanomaterials can improve the mechanical properties of concrete, and the mechanical properties of concrete increase with the increase of the content of concrete. The compressive strength and flexural strength of four kinds of nano-modified concrete are increased by more than 10%. Among the four kinds of nanomaterials, nano-SiO _ 2 and nano-TiO _ 2 can enhance the mechanical properties of concrete relatively strongly, while nano-SiO _ 2 can improve the mechanical properties of concrete by the least extent. The freeze-thaw cycling test of nanocrystalline modified concrete was carried out under three kinds of salt environments: NaClCl CH3COOK and Ca Cl2. It is found that under three kinds of salt freezing environment, nano-modified concrete is basically present, with the increase of content, the mass loss rate of concrete will decrease, and the relative dynamic elastic modulus will increase, that is, the content of nano-material will increase. The better the salt freezing resistance of concrete is, 1% is the best content of salt freezing resistance. Compared with the improvement of salt and freezing resistance of concrete by four kinds of nano-materials, nano-SiO _ 2 plays a more important role than the other three, nano TIO _ 2 takes the second place, while the remaining nano-sized Al2O3 and nanometer Fe2O3 are the second. The improvement of nanometer Al2O3 is the weakest. The permeability resistance of nano-modified concrete was measured by the method of electric flux, and the results were similar to those of salt freezing resistance. The modification mechanism of nano-modified concrete is mainly due to the increase of the quantity and variety of hydration products after the addition of nano-materials. Increasing the number of hydration products can make concrete denser. After the incorporation of nano-SiO _ 2, Al2O3 and TIO _ 2, the acicular hydration products can hinder the development of microcracks in concrete and strengthen and toughen the concrete in the form of primary nanofibers. However, the spherical hydration products after the addition of nanometer Fe2O3 can also enhance the compactness of concrete because of its compact arrangement. The hydration process caused by the addition of these nanomaterials improved the mechanical properties and durability of concrete.
【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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本文編號(hào)：1834649