热带海洋气候下聚羧酸高性能减水剂对混凝土抗蚀性的影响研究

发布时间：2018-01-20 13:32

本文关键词： 聚羧酸减水剂热带海洋性气候抗氯离子渗透性抗硫酸盐侵蚀性　出处：《海南大学》2015年硕士论文　论文类型：学位论文

【摘要】：如何建造更加耐久的混凝土建筑,成为当今混凝土行业面临的主要问题。由于地处热带海洋气候地区,海南省同时处于热带和海洋两种恶劣的自然环境中：高温高湿高辐射；海水蒸发量大；空气中氯离子相对含量高；氧气、水汽、紫外线照射等腐蚀性介质活跃。因此,海南省的混凝土建筑的抗氯离子渗透性及抗硫酸盐侵蚀性更需要受到重视。聚羧酸(PCE)是目前研究和应用最广泛的混凝土减水剂,其分子结构对混凝土耐久性的影响机理研究鲜有报道。本文通过合成不同羧酸根系列、磺酸根系列及支链系列的PCE,从分子结构层面研究PCE对水泥净浆性能、热带海洋性气候下混凝土抗氯离子渗透性和抗硫酸盐侵蚀性能的影响,进一步初探其作用机理。对于不同羧酸根系列PCE,研究了酯型短侧链、醚型短侧链以及醚型长侧链三个不同侧链类型的PCE,结果表明：掺酯型和醚型短侧链PCE净浆均在酸酯比为2.5：1时得到最优净浆流动度和最小损失率,而掺醚型长侧链PCE净浆在3.5：1时达到最优净浆流动度,在2.5：1时得到最小损失率；20℃净浆表观粘度测试结果与流动度结果一致,但随着温度升高到40℃,掺高酸醚(酯)比PCE净浆表现出表观粘度出先升高后降低的现象；就抗硫酸盐侵蚀性而言,掺短侧链PCE混凝土在酸酯(醚)比较小的情况下抗硫酸盐侵蚀性能更差,掺醚型长侧链PCE混凝土抗硫酸盐侵蚀性则随着羧酸根密度增加而减小；对于抗氯离子渗透性来说,酯型短侧链PCE酸酯比的变化对混凝土抗氯离子渗透性能没有明显的影响,而醚型PCE无论侧链长短,都在较高酸醚比下获得较好的混凝土抗氯离子渗透性能；从混凝土内部孔结构的结果可知,酸酯比对掺酯型短侧链PCE的混凝土孔结构参数的变化没有明显的规律,掺长侧链醚型PCE混凝土随着PCE酸醚比增加,孔隙率减小,毛细孔含量没有明显变化,掺短侧链醚型PCE混凝土随酸醚比增加,孔隙率增大,毛细孔含量减小。对于不同磺酸根根系列PCE研究了甲基丙烯磺酸钠(MAS)用量对醚型长侧链PCE性能的影响,结果表明：随着甲基丙烯磺酸钠(MAS)加入量的增多,其净浆流动度、流动度损失以及表观粘度均是先增加后减小,均在MAS含量为0.32时达到最优值；随着温度升高,掺高MAS含量的PCE净浆表观粘度增加值是小于掺低MAS含量PCE的；MAS加入量的增加对混凝土抗硫酸盐侵蚀性能没有太大的影响,但会降低混凝土抗氯离子渗透性能。对于不同侧链系列PCE,研究了不同酯基取代,不同长短侧链,不同侧链长度及PO嵌段长侧链PCE性能的差异,结果表明：掺不同酯基取代的PCE净浆在10%酯基取代的羧酸根的情况下可提高净浆流动度并减少损失率；掺长短侧链的PCE净浆无论是流动度还是表观粘度变化均介于掺单长侧链PCE净浆和单短侧链PCE净浆之间；侧链长度增长,净浆流动度增大、损失率和表观粘度减小,特别是掺PO嵌段的长侧链PCE净浆,变化效果最明显；净浆表观粘度会随着温度升高而升高,但当所掺PCE存在高含量的酯键时,无论是酯基取代还是醚酯型长短侧链PCE,其净浆粘度均会在高温下有一定程度的降低；抗蚀性结果表明,掺醚型PCE混凝土,随着PCE侧链长度变短,混凝土孔隙率减小,混凝土抗蚀性能变好；部分酯基取代和引入侧链分子上含有PO嵌段的结构PCE,有利于混凝土抗氯离子渗透性能的提高,但酯类基团的引入会因和易性不好而降低混凝土抗硫酸盐侵蚀性能；对于长短侧链,无论是醚酯型还是醚醚型,其混凝土孔隙率都比掺单侧链种类PCE的混凝土要大一些,因此长短侧链对于抗蚀性能的提高是没有帮助的。联系净浆结果与混凝土抗蚀性结果发现,净浆表观粘度与混凝土抗硫酸盐侵蚀性存在着一定的内在联系,随着对应PCE净浆表观粘度增加,混凝土抗硫酸盐侵蚀性也会变好。
[Abstract]:How to build a more durable concrete building, become the main problem facing concrete industry. Due to the tropical marine climate area is located in Hainan Province, at the same time in the tropical and marine two kinds of harsh natural environment, high radiation, high temperature and high humidity; evaporation; high relative content of chloride ions in the air; oxygen, water vapor, ultraviolet exposure to corrosive medium active. Therefore, concrete construction in Hainan Province, the anti chloride ion permeability and sulfate resistance need more attention.
Poly carboxylic acid (PCE) is currently the most widely research and application of concrete superplasticizer, the effect of molecular structure on the durability of concrete mechanism has not been studied. Through the synthesis of different carboxylic acid series, sulfonic acid series and branched PCE series, from the molecular structure of the level of PCE on the properties of cement paste, resistance to chloride ion penetration effect of sulfate resistance of concrete tropical marine climate, further research on its mechanism.
For different series of carboxylic acid ester type PCE, the short side chain is studied, and the short side chain polyether ether type long side chain side chain of three different types of PCE, the results show that the mixed ester and ether type short side chain of PCE paste in ester ratio to obtain the optimal paste fluidity and minimum loss the rate of 2.5:1, and with long side chain ether type PCE paste in 3.5:1 to achieve optimal fluidity, get the minimum loss rate in 2.5:1 is 20 DEG C; paste apparent viscosity test results and fluidity results, but with the increase of temperature to 40 degrees Celsius, with high acid (ester ether) than PCE the paste showed apparent viscosity increased first and then decreased; on the sulfate resistance, with short side chain PCE (ester ether) in concrete under the condition of small resistance to sulfate attack is even worse, with long side chain ether type PCE sulphate resistance of concrete decreases with increasing density of carboxylic acid but for; The resistance to chloride ion permeability, change of ester type short side chain PCE esters than the chloride penetration resistance of concrete has not obvious effect on the length of the side chain of both ether type PCE, are higher than under the acid ether to obtain better resistance of concrete to chloride ion penetration; it can be seen from the internal pore structure of concrete results. The change of pore structure parameters on the mixed ester ester short side chain PCE has no obvious regularity, with long side chain ether type PCE concrete with PCE acid ether ratio increases, the porosity decreases, the pores content did not change significantly, with short side chain ether type PCE concrete with acid ether ratio increases, the porosity increases the pores, reduce the content.
For different PCE series of methyl sulfonic acid by sodium allyl sulfonate (MAS), the amount of ether type long side chain PCE performance results show that with sodium methylacrylsulfonate (MAS) content increased, the fluidity, fluidity loss and apparent viscosity were increased first and then decreased. In the content of MAS is to achieve the optimal value of 0.32; with the increase of temperature, with high content of MAS PCE paste increased the apparent viscosity value is less than PCE with low MAS content; the increase of the amount of MAS had no impact on the sulfate resistance of concrete, but will reduce the chloride permeability of concrete.
For the different side chain of PCE, study the different ester substituted, different length of side chain, difference, different side chain length and PO block long side chain PCE performance. The results showed that the carboxylic acid ester substituted with different PCE paste in 10% case of ester substituted can improve the fluidity of cement paste and to reduce the loss rate; the length of the side chain of PCE doped paste both between fluidity or apparent viscosity change between doped single long side chain of PCE paste and PCE paste single short side chain; side chain length increases, the fluidity loss rate increases, and the apparent viscosity decreased, especially with PO block the long side chain of PCE paste, the most obvious change effect; paste viscosity increases with the increase of temperature, but when the ester bond of PCE doped high contents, either ester substituted or ether ester side chain length PCE, the paste viscosity will be decreased to a certain degree the resistance at high temperature; The results show that the corrosion resistance of concrete, mixed with ether type PCE, with the PCE side chain length, concrete porosity, corrosion resistance of concrete is better; the structure of PCE part and the introduction of ester substituted side chain molecules containing PO block, is conducive to the chloride permeability of concrete increases, but the introduction of ester groups because of bad workability and reduce concrete sulfate resistance; for the length of the side chain, either ether ester or ether ether type, the porosity of concrete than with unilateral PCE chain concrete ones, thus improving the length of side chain for corrosion resistance is not helpful. Contact paste the results of corrosion and concrete results showed that the apparent viscosity of paste and concrete sulfate resistance there exists a certain relationship, with the increase of the apparent viscosity of corresponding PCE paste, concrete sulfate resistance will become better.

【学位授予单位】：海南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528.042.2

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