本文關(guān)鍵詞： 石灰石粉-粉煤灰混凝土 硫酸鎂侵蝕 SEM XRD　出處：《中國礦業(yè)大學》2014年碩士論文　論文類型：學位論文

【摘要】：石灰石粉和粉煤灰作為混凝土的摻合料已經(jīng)越來越多的出現(xiàn)在工程實踐中，但在使用中仍存在力學性能及耐久性能等多方面的問題。硫酸鹽侵蝕作為混凝土耐久性研究的重要組成部分，一直倍受關(guān)注。本文對復合摻入石灰石粉和粉煤灰的混凝土經(jīng)受硫酸鎂侵蝕后，其性能退化情況進行了分析研究。 對石灰石粉-粉煤灰膠砂受硫酸鎂侵蝕后，質(zhì)量變化率、吸水率、抗折強度、抗壓強度及抗蝕系數(shù)變化規(guī)律進行研究。結(jié)果表明，粉煤灰單獨摻入有利于提高膠砂抗硫酸鹽侵蝕性能；石灰石粉、粉煤灰復合摻入，相對用量配制合理情況下所制膠砂具有優(yōu)良的抗硫酸鹽侵蝕性能。 石灰石粉-粉煤灰混凝土受硫酸鎂侵蝕后，研究其峰值應力、峰值應變、彈性模量及抗蝕系數(shù)的變化規(guī)律。結(jié)果表明，粉煤灰的摻入能改善混凝土抗硫酸鹽侵蝕性能，同粉煤灰相比，石灰石粉的單獨摻入，，對混凝土抗硫酸鹽侵蝕十分不利；石灰石粉與粉煤灰復合摻入形成的混凝土試件具有較高的抗蝕能力；水膠比越小，混凝土抗硫酸鹽侵蝕能力越高；與長期浸泡侵蝕環(huán)境，浸烘循環(huán)加劇了混凝土在硫酸鹽中的損傷程度。 本文利用XRD技術(shù)定量分析長期浸泡和浸烘循環(huán)兩種侵蝕環(huán)境下試件侵蝕產(chǎn)物物相組成演變，并利用SEM分析其微觀結(jié)構(gòu)。研究表明，長期浸泡侵蝕120d后，純水泥凈漿的侵蝕產(chǎn)物主要是CaSO4·2H2O。浸烘循環(huán)侵蝕方式加劇了試件的侵蝕破壞。
[Abstract]:Limestone powder and fly ash have been more and more used as admixtures of concrete in engineering practice. However, there are still many problems in use, such as mechanical properties and durability. Sulfate erosion is an important part of concrete durability research. The performance degradation of concrete mixed with limestone powder and fly ash after magnesium sulfate erosion has been studied in this paper. The changes of mass change rate, water absorption rate, flexural strength, compressive strength and corrosion resistance coefficient of limestone powder-fly ash cement sand after being eroded by magnesium sulfate are studied. The addition of fly ash alone is beneficial to the improvement of sulfate corrosion resistance of cemented sand, and the composite mixing of limestone powder and fly ash has excellent sulphate resistance when the relative dosage of fly ash is reasonable. The changes of peak stress, peak strain, elastic modulus and corrosion resistance coefficient of limestone powder-fly ash concrete after being eroded by magnesium sulfate are studied. The results show that the addition of fly ash can improve the corrosion resistance of concrete to sulfate. Compared with fly ash, the addition of limestone powder alone is very disadvantageous to the sulphate resistance of concrete, and the concrete specimen mixed with limestone powder and fly ash has higher corrosion resistance, and the smaller the water-binder ratio, the lower the ratio of water to binder. The higher the resistance of concrete to sulfate erosion is, the more severe the damage of concrete in sulphate is due to the immersion cycle in the environment of long-term soaking erosion. In this paper, XRD technique was used to quantitatively analyze the evolution of the phase composition of the corrosion products in two erosive environments, I. e., long-term immersion and drying cycle, and the microstructure of the samples was analyzed by SEM. The results showed that after 120 days of long-term immersion erosion, the microstructure of the samples was analyzed. The erosion product of pure cement slurry is mainly CaSO4 路2H _ 2O.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU528

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