冻融—盐分侵蚀作用下沥青混凝土疲劳性能试验与分析

发布时间：2018-01-07 15:09

本文关键词：冻融—盐分侵蚀作用下沥青混凝土疲劳性能试验与分析　出处：《安徽理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：路面疲劳损伤是水、温度和荷载共同作用的结果,在此过程水的存在和温度的反复变化改变了无水情况下对路面的单一破坏作用,使整个疲劳破坏过程变得更加复杂；另一方面,反复的疲劳荷载、冬季喷洒的除冰盐也加速了沥青路面的水温损害。多年来,沥青路面的疲劳性能一直是道路工程研究的重点。本文根据华东地区的冬季气温,在总结国内外学者研究的基础上,采用间接拉伸疲劳试验探究沥青混凝土的疲劳寿命的规律。通过室内试验从以下五方面进行研究：1.沥青混凝土试件在不同冻融次数下疲劳寿命；2.盐分侵蚀对沥青混凝土疲劳寿命的影响；3.不同冻融温度下沥青混凝土的疲劳寿命；4.不同类型沥青混凝土在相同条件下的疲劳寿命；5.通过超声波检测,预测沥青混凝土的劈裂强度。分别分析了冻融次数,氯盐侵蚀,沥青类型,冻融温度对沥青混凝土疲劳寿命的影响。主要结论如下： (1)随着冻融次数的增加,沥青混凝土的疲劳寿命呈下降趋势。在-5℃-15℃冻融温度区间,经清水浸泡的AH-70号基质沥青混凝土经过2、4、6、8次冻融循环后,疲劳寿命分别为未冻融循环试件的75.1%,62.8%,49.6%,40.4%。 (2)在盐冻作用下,沥青混凝土表面出现剥落,掉粒现象。在氯盐侵蚀和冻融破坏的双重影响下,沥青混凝土的疲劳寿命呈明显下降趋势。在相同的冻融温度和相同的冻融次数下,被盐分侵蚀的沥青混凝土试件的疲劳寿命低于经清水浸泡的沥青混凝土试件。在-5℃～15℃冻融温度区间,经盐水浸泡的AH-70号基质沥青混凝土经过2、4、6、8次冻融循环后,疲劳寿命分别为未冻融循环试件的72.9%,58.1%,47.0%,28.1%。 (3)分别在-5℃-15℃、-10℃-10℃、-15℃C-5℃三个温度区间对沥青混凝土进行冻融循环后,对其进行间接拉伸疲劳试验,发现温度越低,造成的盐冻破坏越大；低温持续的时间越长,也会加大盐冻的破坏程度。 (4)在相同的冻融次数和冻融温度下,SBS改性沥青混凝土的疲劳寿命高于AH-70号基质沥青混凝土疲劳寿命,并且随着冻融次数的增加,SBS改性沥青混凝土的疲劳寿命的降低速度低于AH-70号基质沥青混凝土。在-5℃-15℃冻融温度区间,经清水浸泡后AH-70号基质沥青混凝土经过2、4、6、8次冻融循环后,疲劳寿命分别为未冻融循环试件的75.1%,62.8%,49.6%,40.4%。SBS改性沥青混凝土经过2、4、6、8次冻融循环后,疲劳寿命分别为未冻融循环试件的80.0%,71.8%,65.9%,56.0%。 (5)对不同试验条件下的沥青混凝土试件进行超声波检测,根据试验数据得到AH-70号基质沥青混凝土和SBS改性沥青混凝土在冻融循环后波速和劈裂强度的回归方程,分别为fc=0.1507e(0.0005v),R2=0.9196, fc=0.2594e0.0004v,R2=0.9297。利用该回归方程可以预测未进行劈裂试验试件的劈裂强度。综上所述,冻融循环和盐分侵蚀对沥青混凝土的疲劳寿命有明显影响,采用SBS改性沥青混凝土可以减小冻融损害和盐分侵蚀对疲劳寿命的影响。在基质沥青中掺入SBS改性剂后,提高了沥青的软化点,降低了其脆点。工程应用中,应进一步加强对SBS改性沥青的研究,以减少冻融循环对沥青路面的损害。
[Abstract]:The pavement fatigue damage is water, the combined effect of temperature and load the results of repeated changes in the process of the existence of water and temperature change of the single damage to the pavement without water, the fatigue failure process becomes more complex; on the other hand, the fatigue load repeatedly, spraying winter deicing salt also accelerated temperature the damage of asphalt pavement. For many years, the fatigue performance of asphalt pavement has been the focus of road engineering research. According to the East China winter temperature, summarizes the domestic and foreign scholars, the fatigue life of the indirect tensile fatigue test of asphalt concrete law.
Study from the following five aspects: 1. through the laboratory test of asphalt concrete specimens under different freeze-thaw cycles fatigue life; 2. the erosion of salt effect on fatigue life of asphalt concrete; 3. different freeze-thaw fatigue life of asphalt concrete temperature; fatigue life of 4. different types of asphalt concrete under the same conditions; 5. by ultrasonic detection and the prediction of asphalt concrete splitting strength were analyzed. The freeze-thaw cycles and chloride corrosion, asphalt type, effect of freeze-thaw temperature on fatigue life of asphalt concrete. The main conclusions are as follows:
(1) increase with the number of freeze-thaw cycles, the fatigue life of asphalt concrete is decreased. At -5 DEG -15 DEG freeze-thaw temperature range, the AH-70 asphalt concrete water soaking after 2,4,6,8 freeze-thaw cycles, the fatigue life were not freeze-thaw cycle samples of 75.1%, 62.8%, 49.6%, 40.4%.
(2) in salt freezing under the action of the asphalt concrete surface spalling, dropped phenomenon. In chlorine salt erosion and freezing thawing damage under the double impact, the fatigue life of asphalt concrete was significantly decreased. In the same freeze-thaw temperature and the same number of freeze-thaw, by the fatigue life of asphalt salt erosion the concrete specimen is below the water soaked asphalt concrete specimens. In the -5 to 15 DEG C freeze-thaw temperature range, the AH-70 matrix asphalt concrete brine after 2,4,6,8 freeze-thaw cycles, the fatigue life were not freeze-thaw cycle samples of 72.9%, 58.1%, 47%, 28.1%.
(3) at -5 DEG -15 DEG -10 DEG C, -10, -15 three C-5 DEG C temperature range of asphalt concrete after freeze-thaw cycles, indirect tensile fatigue test on it, found that the lower the temperature, the greater the damage caused by salt freezing at low temperature; the longer the duration, will also increase the salt freeze damage.
(4) in the same number of freeze-thaw cycles and freeze-thaw temperature, the fatigue life of SBS modified asphalt concrete is higher than that of the fatigue life of AH-70 asphalt concrete, and with the increase in the number of freezing and thawing, the fatigue life of SBS modified asphalt concrete and the decrease rate of less than AH-70, the matrix asphalt concrete at -5 DEG -15 DEG. The freeze-thaw temperature interval, the water soaked AH-70 matrix asphalt concrete after 2,4,6,8 freeze-thaw cycles, the fatigue life were not freeze-thaw cycle samples of 75.1%, 62.8%, 49.6%, 40.4%.SBS modified asphalt concrete after 2,4,6,8 times of freeze-thaw cycles, the fatigue life was not the freeze-thaw cycle test piece 80%, 71.8%, 65.9%, 56.0%.
(5) of the asphalt concrete under different test conditions were ultrasonic testing, according to the test data of AH-70 asphalt concrete and SBS modified asphalt concrete under cyclic freezing and thawing velocity and splitting the regression equation of the fracture strength, respectively fc=0.1507e (0.0005v) 0.9196, R2=, fc=0.2594e0.0004v, R2=0.9297. by using the regression equation prediction without splitting test specimen splitting strength.
In summary, freeze-thaw and salt erosion fatigue life of asphalt concrete has been significantly affected by SBS modified asphalt concrete can reduce the freeze-thaw damage and erosion of salt effect on fatigue life. The incorporation of SBS in the asphalt modifier, improve the softening point of asphalt, reduce the brittle point. In the application, should strengthen the research on SBS modified asphalt, freeze-thaw cycle to reduce the damage of the asphalt pavement.

【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U414

【参考文献】