本文選題：粉煤灰 + 負溫混凝土��； 參考：《重慶交通大學(xué)》2017年碩士論文

【摘要】：隨著工程行業(yè)的快速發(fā)展,大量水泥混凝土用于建筑結(jié)構(gòu)工程。水泥生產(chǎn)給環(huán)境造成了巨大破壞,大摻量粉煤灰混凝土能在有效減少水泥用量的同時將火電廠產(chǎn)生的廢渣—粉煤灰作為混凝土摻合料加以利用,降低對環(huán)境的污染,也節(jié)省工程造價,具有廣闊的應(yīng)用空間。近年來,由于工期等客觀條件限制,越來越多的大體積混凝土構(gòu)筑物需要在冬季施工,早期受凍對混凝土性能影響顯著。因此,亟待對大摻量粉煤灰混凝土在負溫下的性能進行研究,本文針對高寒地區(qū)用大摻量粉煤灰混凝土的力學(xué)性能與耐久性能進行了一系列研究,具有一定的價值。首先,本文針對大摻量粉煤灰混凝土力學(xué)性能,經(jīng)過初步探究,采用3種水膠比、5種粉煤灰摻量的15種不同配方的混凝土進行試驗,測試其不同齡期的抗壓強度、劈裂抗拉強度、抗折強度,并對其力學(xué)性能進行分析。結(jié)果表明:影響大摻量粉煤灰混凝土強度的主要因素是水膠比,同時粉煤灰摻量對抗壓強度的影響比其他力學(xué)性能更敏感;隨著粉煤灰摻量的增大,新拌混凝土早期力學(xué)性能顯著降低,但后期增長快速,粉煤灰摻量小于35%時,其90d力學(xué)性能不低于普通混凝土。其次,本文通過采用抗壓強度保證率的方式確定負溫混凝土抗凍臨界強度。采用水膠比0.4,粉煤灰摻量25%、35%、45%、55%的四種混凝土,標準養(yǎng)護混凝土分別測試其18h~48h、60d的抗壓強度;負溫混凝土早期成型后經(jīng)受不同的受凍制度,再轉(zhuǎn)標養(yǎng),以測試其60d抗壓強度能否達到標準養(yǎng)護混凝土對應(yīng)齡期抗壓強度的95%為依據(jù),并對預(yù)養(yǎng)護齡期與最終抗壓強度進行線性擬合,從而求出負溫混凝土各自的抗凍臨界強度,進而分析粉煤灰摻量與受凍制度對混凝土抗凍臨界強度的影響。結(jié)果表明:粉煤灰摻量增大,抗凍臨界強度值減小,達到抗凍臨界強度所必要的時間隨之增加;在凍害對其損害程度方面:恒負溫一次氣凍多次水凍水融一次水凍。最后,本文研究混凝土達到其抗凍臨界強度后經(jīng)受不同的受凍制度后對其耐久性的影響。采用快速凍融法和抗?jié)B透性試驗,測試負溫組混凝土的凍融循環(huán)次數(shù)與電通量能否達到標準養(yǎng)護組的95%。試驗結(jié)果表明:以抗壓強度保證率確定的抗凍臨界強度并不能使其抗凍性能達到未受凍混凝土的95%,對耐久性要求高的結(jié)構(gòu)物,應(yīng)適當延長其受凍前的預(yù)養(yǎng)護時間,冬季施工大體積構(gòu)筑物所用混凝土推薦粉煤灰摻量為35%。同時,本文還用氣泡間距系數(shù)分析儀對大摻量粉煤灰混凝土氣泡結(jié)構(gòu)進行微觀分析,發(fā)現(xiàn)其氣泡數(shù)量隨粉煤灰摻量的增加而增大,建議大摻量粉煤灰混凝土采用氣泡參數(shù)評價時其齡期應(yīng)在60d后。
[Abstract]:With the rapid development of engineering industry, a large number of cement concrete used in structural engineering. Cement production has caused great damage to the environment. Large amount of fly ash concrete can effectively reduce the amount of cement and use the waste slag-fly ash produced by thermal power plant as concrete admixture to reduce the pollution to the environment. Also saves the project cost, has the broad application space. In recent years, due to the limitation of time limit and other objective conditions, more and more mass concrete structures need to be constructed in winter. Therefore, it is urgent to study the performance of high-volume fly ash concrete under negative temperature. This paper has a series of research on mechanical properties and durability of high-volume fly ash concrete in high and cold regions, which has certain value. Firstly, according to the mechanical properties of fly ash concrete with large amount of fly ash, the concrete with 15 different formulations of 3 kinds of water-binder ratio and 5 kinds of fly ash are tested, and the compressive strength of concrete of different ages is tested. The splitting tensile strength and flexural strength are analyzed. The results show that the main factor affecting the strength of concrete with large amount of fly ash is water binder ratio, and the influence of fly ash content on compressive strength is more sensitive than that of other mechanical properties, and with the increase of fly ash content, The mechanical properties of fresh concrete decreased significantly in the early stage, but increased rapidly in the later stage. When the content of fly ash was less than 35%, the mechanical property of fresh concrete was not lower than that of ordinary concrete for 90 days. Secondly, the freezing critical strength of negative temperature concrete is determined by means of compressive strength guarantee rate. Four kinds of concrete with water / binder ratio of 0.4 and fly ash of 25% are used. The standard curing concrete is tested respectively for its compressive strength of 18 hours or 48 hours or 60 days, and the negative temperature concrete is subjected to different freezing systems after early forming, and then transferred to standard. On the basis of testing whether the compressive strength of 60 days can reach 95% of the corresponding age compressive strength of the standard curing concrete, and the linear fitting between the pre-curing age and the final compressive strength, the freezing critical strength of the negative temperature concrete is obtained. Furthermore, the influence of fly ash content and freezing system on the critical strength of concrete is analyzed. The results show that with the increase of fly ash content, the critical strength of freezing resistance decreases, and the necessary time to reach the critical strength of frost resistance increases, and the degree of damage caused by freezing injury is as follows: constant negative temperature, air freezing, water freezing and water thawing. Finally, the influence of different freezing systems on the durability of concrete is studied. Rapid freeze-thaw method and permeability test were used to test whether the freeze-thaw cycle times and electric flux of negative temperature group concrete could reach 95% of the standard curing group. The test results show that the critical strength determined by the compressive strength guarantee rate can not make the freezing resistance of unfrozen concrete up to 95% of that of unfrozen concrete. The pre-curing time before freezing should be appropriately prolonged for structures with high durability requirements. The recommended amount of fly ash for the construction of large-volume structures in winter is 35. At the same time, the bubble structure of concrete with large amount of fly ash is analyzed by using the bubble spacing coefficient analyzer. It is found that the number of bubbles increases with the increase of the amount of fly ash. It is suggested that the age of large fly ash concrete should be 60 days after the bubble parameter evaluation.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU528

【參考文獻】

相關(guān)期刊論文 前10條

1 崔健;張慶華;戴平;梁慧超;張曉明;;2016年中國水泥質(zhì)量分析報告[J];中國水泥;2017年03期

2 趙海軍;朱亞沖;葉金庫;李藝;;混凝土抗凍性與氣泡特征參數(shù)研究[J];低溫建筑技術(shù);2016年09期

3 曹浩鵬;袁芬;包美慧;劉繼濤;曾鑫;邵琦;;烏魯木齊地區(qū)摻加粉煤灰高性能混凝土抗凍性能的研究[J];粉煤灰;2016年04期

4 安國順;劉澤宇;李吉興;;粉煤灰對混凝土抗凍臨界強度的影響[J];低溫建筑技術(shù);2016年07期

5 黃聰;;大摻量粉煤灰混凝土力學(xué)性能試驗及應(yīng)用[J];人民長江;2015年S1期

6 魏強;謝劍;吳洪海;;超低溫凍融循環(huán)對混凝土材料性能的影響[J];工程力學(xué);2013年S1期

7 汪在芹;李家正;周世華;石妍;;凍融循環(huán)過程中混凝土內(nèi)部微觀結(jié)構(gòu)的演變[J];混凝土;2012年01期

8 王鵬;杜應(yīng)吉;;大摻量粉煤灰混凝土抗?jié)B抗凍耐久性研究[J];混凝土;2011年12期

9 劉軍;劉潤清;張冰;張云;;評價方法影響混凝土抗凍臨界強度作用機理的研究[J];混凝土;2011年09期

10 劉軍;;The Antifreeze Critical Strength of Low-temperature Concrete Effected by Index[J];Journal of Wuhan University of Technology(Materials Science Edition);2011年02期

相關(guān)碩士學(xué)位論文 前3條

1 杜森;負溫混凝土的抗凍臨界強度及其與耐久性的關(guān)系研究[D];哈爾濱工業(yè)大學(xué);2013年

2 馮仲偉;混凝土材料耐久性評價指標研究[D];鐵道部科學(xué)研究院;2007年

3 孟慶超;混凝土耐久性與孔結(jié)構(gòu)影響因素的研究[D];哈爾濱工業(yè)大學(xué);2006年

，

本文編號：1901366