【摘要】：大摻量礦渣水泥基材料已經(jīng)在土木工程中得到了廣泛運(yùn)用，其耐久性問(wèn)題越來(lái)越受到重視�？紫督Y(jié)構(gòu)是決定材料耐久性的重要因素，而滲透性是表征其耐久性的重要指標(biāo)，研究大摻量礦渣水泥基材料孔隙結(jié)構(gòu)及其滲透性對(duì)準(zhǔn)確預(yù)測(cè)結(jié)構(gòu)全壽命周期的耐久性、降低結(jié)構(gòu)使用成本具有重要意義。 論文選用水膠比分別為0.3、0.4以及0.5的摻加70%礦渣的凈漿及砂漿材料為研究對(duì)象，選用相同配合比但不摻礦渣材料作為對(duì)照組，，通過(guò)MIP孔隙結(jié)構(gòu)測(cè)試方法研究不同因素對(duì)水泥基材料孔隙結(jié)構(gòu)的影響，并聯(lián)系工程實(shí)際情況，研究了在不同養(yǎng)護(hù)條件下水泥基材料孔隙結(jié)構(gòu)的變化；同時(shí)采用基于CEMBUREAU氣體滲透測(cè)試方法的改進(jìn)方法，選用水膠比為0.28，摻加30%礦渣以及水膠比為0.4，摻加70%礦渣的砂漿及混凝土材料進(jìn)行氣體滲透性研究，并選擇絕干、20%、40%、60%以及80%等五個(gè)飽水度狀態(tài)測(cè)試了不同飽水度對(duì)水泥基材料氣體滲透性的影響。 研究結(jié)果表明摻加70%礦渣會(huì)使材料10nm以上孔隙體積減少而10nm以下孔隙體積大幅增加，材料孔隙率、比表面積上升，平均孔徑降低，并且水膠比越低，小于10nm孔隙占總孔隙比例越高；養(yǎng)護(hù)過(guò)程中水分不足會(huì)導(dǎo)致材料水化過(guò)程中出現(xiàn)自干燥現(xiàn)象，在100~1000nm孔徑范圍出現(xiàn)大量孔隙，同時(shí)削弱1000nm以下孔隙數(shù)量，材料孔隙率升高，孔隙曲折度增大；不摻礦渣材料比表面積增大，而摻加礦渣比表面積降低。材料氣體滲透性受材料組成影響很大，試驗(yàn)中發(fā)現(xiàn)模具過(guò)高或者振搗過(guò)度會(huì)導(dǎo)致材料出現(xiàn)分層，從而導(dǎo)致同一試件上下部分氣體滲透測(cè)試結(jié)果相差較大；砂漿試件孔隙率φ和平均孔徑D的乘積φD2與本征滲透系數(shù)成線性關(guān)系，但是孔隙率降低到一定程度時(shí)氣體滲透系數(shù)就會(huì)降至0，混凝土試件孔隙結(jié)構(gòu)與氣體滲透系數(shù)之間的關(guān)系則不明顯；滲透系數(shù)與飽水度之間的關(guān)系大致符合Kr=(1-Sw)η(1-Sw1/m)2m的關(guān)系，不同材料滲透系數(shù)隨飽水度變化的規(guī)律不同，所得到的擬合參數(shù)也會(huì)有所不同。 論文最后提出了一種專(zhuān)用于高整體容器混凝土材料氣體滲透測(cè)試的試件預(yù)處理方法。
[Abstract]:Large amount of slag cement-based materials have been widely used in civil engineering, and its durability has been paid more and more attention. Pore structure is an important factor to determine the durability of materials, and permeability is an important index to characterize its durability. The study on pore structure and permeability of cement-based materials with large amount of slag can accurately predict the durability of the whole life cycle of the structure. It is of great significance to reduce the cost of structural use. In this paper, the water-binder ratio is 0.3, 0.4 and 0.5 respectively with 70% slag and mortar materials as the research object, and the same mix ratio but no slag material as the control group. The influence of different factors on the pore structure of cement-based materials was studied by means of MIP pore structure test method, and the change of pore structure of cement-based materials under different curing conditions was studied. At the same time, the modified method based on CEMBUREAU gas permeability test method is adopted. The gas permeability of mortar and concrete with 30% slag, 0.4% slag and 70% slag is studied. The ratio of water to binder is 0.28, the ratio of water to binder is 0.4, and the ratio of slag to cement is 0.4, and 70% slag, respectively. The effects of different saturation degrees on the gas permeability of cement-based materials were tested in five saturation states: absolute dry, 20%, 40%, 60% and 80%. The results show that when 70% slag is added, the pore volume above 10nm decreases and the pore volume below 10nm increases greatly. The porosity, specific surface area and average pore size decrease, and the lower the ratio of water to binder is, the higher the pore volume is, and the lower the pore volume is below 10nm. The ratio of pores smaller than 10nm to total pores is higher; The lack of moisture in the curing process will lead to self-drying phenomenon in the hydration process of the material, a large number of pores appear in the 100~1000nm pore size range, and at the same time weaken the number of pores below 1000nm, the porosity of the material increases, the porosity of the material increases and the porosity curvature increases. The specific surface area of slag-free material increases, while the specific surface area of slag-free material decreases. The gas permeability of the material is greatly affected by the composition of the material. It is found in the experiment that too high mold or excessive vibration will lead to the delamination of the material, which leads to a great difference in the gas permeability test results between the upper and lower parts of the same test piece. The product of porosity 蠁 and average pore diameter D of mortar specimens 蠁 D2 has a linear relationship with intrinsic permeability coefficient, but the gas permeability coefficient will decrease to 0 when porosity decreases to a certain extent. The relationship between pore structure and gas permeability coefficient of concrete specimens is not obvious. The relationship between permeability coefficient and saturation is in accordance with the relation of Kr= (1-Sw) 畏 (1-Sw1/m) 2m. The variation of permeability coefficient with saturation degree is different, and the fitting parameters are also different. At the end of the paper, a pre-treatment method for testing gas permeability of high integral container concrete materials is presented.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類(lèi)號(hào)】：TU528

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