本文選題：偏高嶺土改性混凝土 + 水化過(guò)程　； 參考：《武漢理工大學(xué)》2014年博士論文

【摘要】：混凝土材料與結(jié)構(gòu)都處于特定的環(huán)境中，諸如城市環(huán)境、海洋環(huán)境、寒冷環(huán)境、鹽堿侵蝕環(huán)境等，，隨著混凝土應(yīng)用的日益廣泛，混凝土耐久性的問(wèn)題受到越來(lái)越多專家學(xué)者和行業(yè)人員的關(guān)注。近年來(lái)，隨著海洋開發(fā)的不斷深入，海洋混凝土用量大增，其耐久性問(wèn)題受到更高的重視。海工混凝土結(jié)構(gòu)長(zhǎng)期浸泡在海水環(huán)境中，結(jié)構(gòu)受到海水中有害物質(zhì)的侵蝕，混凝土結(jié)構(gòu)極易劣化，表面產(chǎn)生裂縫、體積膨脹、剝落、破洞等損壞現(xiàn)象，現(xiàn)有研究表明將偏高嶺土作為摻合料加入混凝土能夠提高其力學(xué)性能和耐久性，加之遠(yuǎn)海施工中原材料拌和水與細(xì)骨料的取材存在運(yùn)輸困難，因此深入研究海水環(huán)境下混凝土結(jié)構(gòu)與性能的關(guān)系對(duì)于海洋工程意義重大。 本文以低摻量偏高嶺土體系為基礎(chǔ)，與不同原材料相配合，分別組成不同的海工混凝土體系，這些體系包括普通粗骨料-河砂-淡水-偏高嶺土改性體系、普通粗骨料-河砂-人工海水-偏高嶺土改性體系、普通粗骨料-海砂-淡水-偏高嶺土改性體系，研究上述三類體系分別在標(biāo)準(zhǔn)條件、氯化鈉溶液、硫酸鈉溶液、硫酸鎂溶液養(yǎng)護(hù)下水泥基材料體系的顯微結(jié)構(gòu)特征、強(qiáng)度發(fā)展規(guī)律、耐久性能與改善機(jī)理，以期將研究結(jié)果應(yīng)用于海洋工程。 論文進(jìn)行的主要工作和取得的主要成果如下： (1)三大體系在標(biāo)準(zhǔn)養(yǎng)護(hù)下的力學(xué)性能測(cè)試表明，對(duì)于各體系，當(dāng)偏高嶺土摻量為5wt%時(shí)，偏高嶺土對(duì)凈漿、砂漿、混凝土強(qiáng)度活性指數(shù)最高。 (2)淡水-偏高嶺土和人工海水-偏高嶺土水泥體系的水化量熱分析表明，淡水體系偏高嶺土的加入使得72小時(shí)總放熱量降低，人工海水的加入使得水化放熱總量有不同程度的提高。兩種體系水化放熱速率在偏高嶺土摻量為3wt%時(shí)高于基準(zhǔn)樣，而偏高嶺土摻量為5wt%和6wt%時(shí)低于基準(zhǔn)試樣。 (3)水化產(chǎn)物的礦物組成研究發(fā)現(xiàn)，淡水拌合的情況下的水化產(chǎn)物為C-S-H凝膠、氫氧化鈣(CH)、鈣礬石(ettringite)、單硫型硫鋁酸鈣及類水滑石(hydrotalcite，HT，Mg4Al2(OH)12CO3(H2O)3)。人工海水拌合的情況下的水化產(chǎn)物種類與淡水拌合情況下類似，類水滑石生成量降低，并增加生成新的礦物水鋁鈣石(hydrocalumite，HC，Ca8Al4(OH)24(CO3)Cl2(H2O)1.6(H2O)8)。 (4)水化產(chǎn)物氫氧化鈣含量的分析表明，未摻入偏高嶺土的凈漿基準(zhǔn)試樣中氫氧化鈣的含量隨著齡期增長(zhǎng)而增加，而摻入偏高嶺土的凈漿，氫氧化鈣的含量從3天到7天增加，而從7天到28天齡期的含量下降，這說(shuō)明在后期偏高嶺土與氫氧化鈣產(chǎn)生火山灰反應(yīng)。相同偏高嶺土摻量下，海水拌合體系的氫氧化鈣含量始終高于同摻量同齡期的淡水拌合體系，這說(shuō)明人工海水拌合對(duì)水化有促進(jìn)作用。 (5)對(duì)抗氯離子侵蝕性能的研究結(jié)果表明，各系列中，摻入5wt%偏高嶺土能夠有效提高混凝土的抗壓強(qiáng)度和抗氯離子滲透性能，其原因是漿體致密度的提高以及固化侵蝕溶液中的氯離子生成Friedel鹽。海水拌和體系中偏高嶺土的加入同樣使體系表現(xiàn)出一致的抗氯離子侵蝕性能。對(duì)于所有系列，氯離子侵蝕后的水化產(chǎn)物為碳酸鈣、氫氧化鈣及Friedel鹽。原有的水化產(chǎn)物中的鈣礬石及類水滑石或水鋁鈣石均轉(zhuǎn)變?yōu)樘妓徕}和Friedel’s salt，起到固化氯離子的作用。 (6)對(duì)抗硫酸鹽侵蝕性能的研究表明，各體系中5wt%偏高嶺土體系在硫酸鈉和硫酸鎂溶液侵蝕后的抗壓強(qiáng)度較其他體系更佳。含5wt%偏高嶺土的人工海水拌和體系經(jīng)硫酸鹽侵蝕后強(qiáng)度與任一試樣相比均為最高，這說(shuō)明使用人工海水拌合并摻入5wt%偏高嶺土能夠增強(qiáng)混凝土的抗硫酸鹽侵蝕性能。硫酸根離子侵蝕深度的結(jié)果表明，偏高嶺土的加入使體系尤其是混凝土有更好的抗硫酸鹽侵蝕性能，表現(xiàn)出良好的抗?jié)B性。
[Abstract]:Concrete materials and structures are in a specific environment, such as urban environment, marine environment, cold environment, saline alkali erosion environment, and so on. With the increasing application of concrete, the problem of concrete durability has been paid more and more attention by experts and scholars and industry personnel. In recent years, with the continuous development of marine development, marine concrete The durability problem of the sea workers has been paid more attention to. The structure of the marine concrete is soaked in the seawater environment for a long time, the structure is eroded by the harmful substances in the sea water, the concrete structure is very easy to deteriorate, the surface produces cracks, the volume expansion, the exfoliation, the broken hole and so on. The existing research shows that the high ridge soil is used as the admixture to add the coagulation. Soil can improve its mechanical properties and durability. In addition, there is a transport difficulty in the material of raw materials mixed with water and fine aggregate in the offshore construction. Therefore, it is of great significance to study the relationship between the structure and properties of concrete under seawater environment for marine engineering.
Based on the low content of the metakaolin system, different raw materials are combined to form different marine concrete systems. These systems include ordinary coarse aggregate - river sand - freshwater - metakaolin system, ordinary coarse aggregate - river sand - artificial sea water - high ridge soil modified body system, ordinary coarse aggregate - sea sand fresh water and high ridge soil modification In this system, the microstructure characteristics, strength development law, durability and improvement mechanism of the above three kinds of systems under the standard conditions, Sodium Chloride Solution, sodium sulfate solution and Magnesium Sulfate solution are studied in order to apply the results to marine engineering.
The main work and main achievements of the paper are as follows:
(1) the mechanical properties test of the three major systems under the standard maintenance showed that, when the content of kaolin was 5wt%, the strength activity index of the ridge to the pulp, mortar and concrete was the highest.
(2) the hydration heat analysis of the fresh water - metakaolin and the artificial sea water - metakaolin cement system shows that the addition of the metakaolin in the freshwater system makes the total amount of heat reduced in 72 hours. The addition of artificial sea water makes the total amount of hydrated exothermic increase in varying degrees. The hydration heat rate of the two systems is higher than that of the base of 3wt%. The content of meta kaolin is lower than that of reference sample when 5wt% and 6wt% are added.
(3) a study of the mineral composition of the hydration products found that the hydration products of fresh water are C-S-H gel, calcium hydroxide (CH), ettringite (ettringite), single sulphur type calcium aluminate and hydrotalcite like (hydrotalcite, HT, Mg4Al2 (OH) 12CO3 (H2O) 3). The types of hydration products under artificial seawater are similar to those of fresh water. The amount of hydrotalcite decreased and the formation of new mineral alcalite (hydrocalumite, HC, Ca8Al4 (OH) 24 (CO3) Cl2 (H2O) 1.6 (H2O) 8) increased.
(4) the analysis of the content of calcium hydroxide in the hydration products showed that the content of calcium hydroxide increased with the age increase, and the content of calcium hydroxide was increased from 3 days to 7 days, while the content of calcium hydroxide was increased from 7 days to 28 days, which indicated that in the later period the metakaolin and hydrogen oxidation were oxidized. Calcium produced the reaction of volcanic ash. Under the same amount of kaolin, the content of calcium hydroxide in the seawater mixing system is always higher than the fresh water mixing system with the same age at the same age, which indicates that the artificial seawater mixing can promote the hydration.
(5) the results of the study on the corrosion resistance of chlorine ion show that the addition of 5wt% to high ridge soil can effectively improve the compressive strength and the permeability resistance of the chloride ion, which is due to the increase of the density of the slurry and the formation of the chloride ion in the solidified solution of the Friedel salt. For all series, the hydrated products after chlorine ion erosion are calcium carbonate, calcium hydroxide and Friedel salt. The ettringite and hydrotalcite or alalite in the original hydration products all change into calcium carbonate and Friedel 's salt, which play the role of curing chlorine ions.
(6) the study of resistance to sulfate erosion shows that the compressive strength of the 5wt% metakaolin system after erosion of sodium sulfate and Magnesium Sulfate solution is better than that of the other systems. The strength of the artificial seawater mixing system containing 5wt% metakaolin is the highest after sulfate attack, which indicates the combination of artificial seawater mixing. The addition of 5wt% to the high ridge soil can enhance the corrosion resistance of the concrete. The result of the depth of sulfate ion erosion shows that the addition of the metakaolin makes the system especially the concrete have better resistance to sulphate erosion, and shows good impermeability.

【學(xué)位授予單位】：武漢理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV431

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