冻融循环下隧道防火涂料粘结退化与损伤机理

发布时间：2018-01-08 23:11

本文关键词：冻融循环下隧道防火涂料粘结退化与损伤机理　出处：《福州大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着国家基础建设的加强,快速铁路的发展,人们在使用隧道时安全意识的增强,市场对隧道防火涂料的性能,尤其是对冻融循环条件下粘结性能和损伤提出了更高的要求。在宏观方面,研究了冻融循环对隧道防火涂料质量、粘结强度、横向基频和超声声速的影响规律；在微观方面,结合氮吸附法和MATLAB图像处理技术对涂料宏观、微观孔结构进行了研究。对冻融循环下可再分散乳胶粉、聚丙烯纤维和引气剂对隧道防火涂料性能影响机理,以及涂料的损伤进行了研究。研究结果表明：1.可再分散乳胶粉掺量增大时,涂料初始粘结强度增大,涂料初始微观孔累计孔体积和宏观孔平均直径均减小。在不同的冻融循环中,可再分散乳胶粉对微观孔作用明显；相同冻融循环下,随着其掺量增加,涂料微观孔累计孔体积、分类孔体积和宏观孔平均直径均减小,无害孔比例增大,涂料抗冻融性能提高。2.聚丙烯纤维掺量由0%、0.2%、0.4%增大时,涂料初始粘结强度分别为0.314 MPa、0.353 MPa、0.336 MPa,涂料微观孔累计孔体积和宏观孔平均直径增大。相同冻融循环下,随着聚丙烯纤维掺量的增加,涂料微观孔累计孔体积和宏观孔平均直径均减小；其掺量大于0.2%时,涂料抗冻融性能没有提高。冻融循环达30次时,聚丙烯纤维对微观孔作用不明显,但仍可有效抑制宏观孔的恶化。3.引气剂掺量增大时,涂料初始粘结强度减小,涂料微观孔体积减小,宏观孔隙平均直径和孔隙率均增大。相同冻融循环下,随着引气剂掺量增加,涂料微观孔体积和宏观孔平均直径减小；其掺量大于0.015%时,涂料抗冻融性能提高不明显。4.随着冻融循环的进行,涂料粘结强度、横向基频和超声声速的损失增大。引气剂对减少涂料损伤的有利作用要比可再分散乳胶粉和聚丙烯纤维的都要明显。采用横向基频和超声声速二者对涂料损伤评价的结果吻合。5.理论推导的剩余强度模型中的涂料冻融循环次数和粘结强度经试验数据拟合表明有较好相关性。拟合得到了剩余粘结强度与损伤度关系,可以对实际工程中涂料剩余粘结强度进行估算,并给出了工程应用算例。
[Abstract]:With the strengthening of the national infrastructure and the development of the rapid railway, the safety consciousness of people in the use of the tunnel has been enhanced, and the performance of the anti-fire coating for the tunnel has been improved by the market. In macroscopical aspect, the influence of freeze-thaw cycle on the quality, bond strength, transverse fundamental frequency and ultrasonic velocity of anti-fire coating for tunnel is studied. In microscopic aspect, the macroscopical and micro-pore structures of coatings were studied by nitrogen adsorption method and MATLAB image processing technology. The redispersible latex powder under freeze-thaw cycle was studied. The influence mechanism of polypropylene fiber and air entraining agent on the properties of tunnel fire resistant coating and the damage of the coating were studied. The results showed that the initial bond strength of the coating increased with the increase of the content of redispersible latex powder. The accumulative pore volume and the average diameter of macroscopic pore in the initial micropore of the coating decreased. In different freeze-thaw cycles, the redispersible latex powder had obvious effect on the micropore. Under the same freeze-thaw cycle, the accumulative pore volume, the classified pore volume and the macro pore average diameter of the coating micropore decreased with the increase of its content, and the harmless pore ratio increased. When the content of polypropylene fiber increased from 0% to 0.2%, the initial bond strength of the coating was 0.314 MPA / 0.353 MPa, respectively. At 0.336 MPA, the accumulative pore volume and the average diameter of macroscopic pore increased. Under the same freeze-thaw cycle, the content of polypropylene fiber increased. The accumulative pore volume and the average diameter of macroscopic pore in coatings were decreased. The freeze-thaw resistance of the coating was not improved when the dosage was more than 0.2. When the freeze-thaw cycle reached 30 times, the effect of polypropylene fiber on the micropore was not obvious. However, it can effectively restrain the deterioration of macro pore. When the amount of air entraining agent increases, the initial bond strength decreases, the micro pore volume decreases, the average pore diameter and porosity increase under the same freezing and thawing cycle. With the increase of the amount of air entraining agent, the micropore volume and the average diameter of macroscopic pore decrease. When the content of the coating is more than 0.015, the freeze-thaw resistance of the coating is not improved obviously. 4. With the freeze-thaw cycle, the coating bond strength. The loss of transverse fundamental frequency and ultrasonic sound velocity is increased. The beneficial effect of air entraining agent on reducing paint damage is more obvious than that of redispersible latex powder and polypropylene fiber. Evaluation of paint damage with transverse fundamental frequency and ultrasonic sound velocity. The results are in good agreement. 5. The number of freeze-thaw cycles and bond strength of coating in the theoretical model of residual strength are fitted to show a good correlation. The relationship between residual bond strength and damage degree is obtained by fitting. The residual bond strength of coating in practical engineering can be estimated, and an example of engineering application is given.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U454

【相似文献】