硅酸盐水泥—硫铝酸盐水泥基修补材料及防腐抗渗性能研究

发布时间：2018-07-28 17:02

【摘要】：硫铝酸盐水泥(SAC)具有良好的防腐抗渗性能,作为修补材料可以很好被应用于混凝土建筑物的修补及海洋建筑的防腐抗渗等工程。然而,硫铝酸盐水泥的生产成本高,使其在实际工程中的推广应用受到限制。因此,为了满足混凝土结构工程的防腐抗渗需求并降低修补成本,本实验研究了硅酸盐-硫铝酸盐水泥复合为胶凝材料的基本性能,同时利用超细粉煤灰取代水泥,丁苯乳液(SBR)对复合水泥进行改性,采用机制砂为骨料,制备具有优良防腐抗渗性能且成本较低的修补材料。主要的研究结果如下:(1)SAC可以促进硅酸盐水泥的水化,缩短水泥凝结时间;SAC水化可以产生微膨胀,降低复合水泥的孔隙率,提高水泥的力学性能,减小干燥收缩。当SAC掺量为6%时,复合水泥砂浆后期的抗折强度和抗压强度达到最大值,其28d抗折强度为9.2MPa和55.2MPa,干燥收缩值最小。当掺量超过6%时,SAC水化产生过大的微膨胀,导致硬化水泥浆体产生微裂纹,增大孔隙率,力学性能逐渐降低,干燥收缩值达到平衡。利用超声波测试技术可以对复合水泥体系的微观裂纹进行表征。(2)粉煤灰具有“球体效应”可以改善水泥浆体的流动度,然而过多掺量超细粉煤灰可以降低水泥浆体的流动度。此外,粉煤灰在碱性条件下可以发生火山灰反应,趋向生成的C-S-H凝胶数量增大,可进一步降低水泥浆体的孔隙率,提高水泥力学性能。掺入10%的粉煤灰可显著改善水泥浆体的流动度;当掺入20%超细粉煤灰时,水泥的抗折和抗压强度达到最大值,28d抗压强度为59.9MPa,抗折强度10.0MPa。利用20%超细粉煤灰的水泥浆体的最可几孔径尺寸最低。因此,20%超细粉煤灰取代复合水泥可以作为混凝土的修补抗渗材料。(3)引入的气体可以改善水泥浆体的流动度,当水灰比分别为0.4和0.5时,聚灰比(P/C)为15%的SBR改性水泥净浆的流动度分别增大37.4%和39.6%。此外,SBR改性水泥浆体的含气量与流动度具有良好的线性关系,相关性为R2=0.988。SBR可以降低水的表面张力且改善其在水中的分布规律。这主要是由于为了溶液体系能量最低,SBR乳液在溶液表面的溶度大于本体溶液的浓度,使SBR分子趋向在水溶液表面存在,并且极性的憎水基团指向空气。因此SBR与水泥浆体在搅拌的过程中增强引气作用。(4)SBR在水泥水化过程中可以形成连续的膜结构,有效的降低硬化水泥孔隙率,然而其引气作用可以增大浆体的孔隙率。养护3d试样,随着P/C的增大,水泥浆体的孔隙率增加。养护28d的试样,随着水泥水化进行,总孔隙率相比3d降低。当P/C=2%和4%时,水泥浆体的孔隙率降低;当P/C超过4%时,水泥浆体的孔隙率增大,其10μm-200μm的大孔数量减少明显;0.003μm-0.01μm的大孔数量明显增多。因此,丁苯乳液主要影响10μm-200μm和0.003μm-0.01μm范围的孔分布。因此,当P/C=2%-4%时,SBR乳液改性水泥砂浆孔隙率最低,适合作为修补防水材料。(5)水泥砂浆随着SBR掺量增大,其抗压强度逐渐降低,抗折强度先降低后增大。此外,压折比逐渐降低,即SBR改善水泥砂浆的韧性。养护28d时,SBR改性水泥砂浆的防水性及耐久性得到改善。当P/C为2%和4%时,SBR改性水泥砂浆试样的吸水率明显低于OPC试样,P/C=4%时吸水率达到最低值;此外,P/C为2%和4%的水泥试样,其抗冻性能,抗氯离子渗透性能及抗硫铝酸侵蚀性能达到最佳。因此,当P/C=2%-4%时,SBR乳液改性水泥砂浆适合作为防腐的修补材料。(6)SBR可以提高水泥砂浆的粘结强度,相比空白试样,当P/C=15%时,养护3d,7d和28d的砂浆试样的粘结强度分别提高70%,50%和58%。在水化过程中,SBR可以形成具有憎水作用的膜结构,可以降低水分在基体与界面的传输,有效的降低界面孔隙率,减小干燥收缩,提高“有效的粘结面积”。此外,SBR降低Ca(OH)2的定向生长和阻止界面过渡区裂缝形成。
[Abstract]:Sulphoaluminate cement (SAC) has good anti-corrosion and anti permeability properties. As a repair material, it can be well applied to repair of concrete buildings and anticorrosion and anti-seepage engineering of marine buildings. However, the production cost of sulphoaluminate cement is high and its application in practical engineering is limited. Therefore, in order to meet the structure of concrete construction, In this experiment, the basic properties of silicate sulphoaluminate cement composite cementitious material are studied in this experiment. At the same time, superfine fly ash is used to replace cement and styrene butadiene emulsion (SBR) is used to modify the composite cement. The mechanism sand is used as aggregate to make the repair with excellent anti-corrosion and permeability and low cost. The main research results are as follows: (1) SAC can promote the hydration of Portland cement and shorten the setting time of cement; SAC hydration can produce micro expansion, reduce the porosity of composite cement, improve the mechanical properties of cement and reduce the drying shrinkage. When the content of SAC is 6%, the flexural strength and compressive strength of the later cement mortar reach the maximum. The flexural strength of 28d is 9.2MPa and 55.2MPa, and the drying shrinkage value is the smallest. When the dosage is more than 6%, the hydration of SAC produces a large micro expansion, which causes the hardening cement paste to produce micro cracks, increase the porosity, the mechanical properties gradually decrease, and the drying shrinkage value reaches the balance. The micro crack of the composite cement system can be cracked by ultrasonic wave testing technology. (2) the fluidity of cement slurry can be improved by the "ball effect" of fly ash. However, the fluidity of cement slurry can be reduced by the excess of superfine fly ash. In addition, the ash can occur in the alkaline condition, and the amount of C-S-H gel tends to increase, which can further reduce the porosity of cement slurry. To improve the mechanical properties of cement, adding 10% fly ash can significantly improve the fluidity of cement paste; when adding 20% ultrafine fly ash, the flexural and compressive strength of cement reaches the maximum, the compressive strength of 28d is 59.9MPa, and the maximum size of the cement slurry with 20% superfine fly ash is the lowest. Therefore, 20% superfine powder The mixed cement can be used as a mending anti seepage material for concrete. (3) the flow degree of cement slurry can be improved by the gas introduced. When the ratio of water to cement ratio is 0.4 and 0.5, the flow degree of SBR modified cement paste with ash ratio (P/C) is increased by 37.4% and 39.6%. respectively, and the gas content and fluidity of the SBR modified cement paste are good. The good linear relation is that R2=0.988.SBR can reduce the surface tension of water and improve its distribution in water. This is mainly because the solubility of the SBR emulsion on the solution surface is greater than the concentration of the bulk solution for the lowest energy of the solution system, so that the SBR molecules tend to exist on the surface of water solution, and the polar hydrophobic group points to the air. Gas. Therefore, SBR and cement slurry can enhance the air entraining effect during the mixing process. (4) SBR can form continuous membrane structure during the hydration process of cement, effectively reducing the porosity of hardened cement, but its air entraining effect can increase the porosity of the slurry. The porosity of the cement paste will be cured with the increase of the P/C, the test of the porosity of the cement paste is increased. The test of the curing of the 28d With the hydration of cement, the total porosity decreased compared with 3D. When P/C=2% and 4%, the porosity of cement slurry decreased; when P/C exceeded 4%, the porosity of cement slurry increased, the number of macropores of its 10 mu M-200 m decreased obviously; the number of large pores in 0.003 mu m-0.01 m increased obviously. Therefore, the styrene butadiene emulsion mainly affected 10 u M-200 mu m and 0.003 micron m-0.0. The pore distribution of 1 mu m range. Therefore, when P/C=2%-4%, the porosity of SBR emulsion modified cement mortar is the lowest, it is suitable for repairing waterproof material. (5) the compressive strength of cement mortar decreases gradually with the increase of the content of SBR, and the flexural strength decreases first and then increases. In addition, the compression ratio decreases gradually, that is, SBR improves the toughness of cement mortar. SBR modification when 28d is cured. The waterproof and durability of the cement mortar are improved. When P/C is 2% and 4%, the water absorption of the SBR modified cement mortar is obviously lower than that of the OPC sample, and the water absorbency reaches the lowest value at P/C=4%. In addition, the P/C is 2% and 4% of the cement sample, and its frost resistance, the chloride permeability and the corrosion resistance of sulphoaluminate are best. Therefore, when P/C=2% When -4%, SBR emulsion modified cement mortar is suitable as an anticorrosion repair material. (6) SBR can improve the bond strength of cement mortar. When compared to blank sample, when P/C=15%, the bond strength of the mortar specimens cured by 3D, 7d and 28d is increased by 70%, 50% and 58%. in the hydration process, SBR can form a hydrophobic membrane structure, which can be reduced. The transport of water in the matrix and interface effectively reduces the porosity of the interface, reduces the drying shrinkage and increases the "effective bond area". In addition, SBR reduces the directional growth of Ca (OH) 2 and prevents the formation of cracks in the interface transition zone.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ172.7

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