【作者】 王曦林；

【导师】 余剑英；

【作者基本信息】 武汉理工大学 ， 建筑材料与工程， 2008， 博士

【摘要】 裂缝是沥青路面的主要病害之一,裂缝的存在不仅影响行车的舒适性和安全性,而且路表雨水通过裂缝渗入基层,还将大大削弱路基的强度和稳定性,使沥青路面受到更严重的破坏。目前通常采用聚合物改性沥青灌缝材料对裂缝进行修补,但是现有的裂缝修补材料与旧油面之间的低温粘结力较低、低温柔性和耐久性较差,在路面低温收缩时容易出现修补材料与旧路面剥离脱落,重新产生裂缝,特别是在气候寒冷、紫外线强的地区,沥青路面的裂缝需要年年修补。本文通过对SBS接枝改性显著提高了SBS改性沥青的粘结性、低温柔韧性,并借助于有机化蒙脱土进一步改善了SBS改性沥青的耐老化性能,制备出了性能优良的SBS改性沥青灌缝材料。主要研究成果如下:采用溶液聚合法制备了不同接枝率(GD)的马来酸酐接枝SBS(MAH-g-SBS)、丙烯酸接枝SBS(AA-g-SBS)和甲基丙烯酸甲酯接枝SBS(MMA-g-SBS)改性剂,通过傅立叶红外光谱仪(FTIR)对接枝产物结构进行表征。以接枝SBS作为改性剂,制得了不同接枝率的接枝SBS改性沥青灌缝材料,研究了接枝率对接枝SBS改性沥青灌缝材料的物理性能、力学性能、微观结构以及老化性能的影响。研究结果表明,随着接枝率的增大,三种接枝SBS改性沥青灌缝材料的低温柔韧性和弹性恢复都得到显著的提高。同时,MAH-g-SBS提高了改性沥青灌缝材料的软化点、粘度及针入度,MMA-g-SBS和AA-g-SBS改性沥青灌缝材料随接枝率的增大,软化点和粘度稍有下降。力学性能测试表明MAH、AA、MMA对SBS接枝后,均能显著提高SBS改性沥青灌缝材料与旧路面之间的粘结强度,拉伸强度和低温柔韧性也得到不同程度的提高。长期热氧老化试验、薄膜烘箱老化试验(TFOT)、压力老化试验(PAV)和长期紫外老化试验(UV)对接枝SBS改性沥青灌缝材料抗老化性能的研究结果表明,三种接枝SBS改性沥青的抗老化性能均有一定程度的改善,其中MAH-g-SBS改性沥青灌缝材料抗老化性能最好。这是由于接枝过程中,MAH、AA、MMA与SBS中的双键发生化学反应,减少了SBS中的C=C双键数量,避免了SBS在热氧作用下的断链降解,因而提高了接枝SBS改性沥青灌缝材料的耐老化性;而MAH在SBS分子链上以单分子接枝为主,相同接枝率时MAH-g-SBS中的双键最少,故其耐老化性最好。以物理性能和抗老化性优良的MAH-g-SBS改性沥青灌缝材料为基础,分别加入抗氧化剂、紫外吸收剂和有机化蒙脱土来进一步提高灌缝材料的耐热氧和光氧老化性能,结果表明抗氧化剂和紫外线吸收剂对耐老化性有一定的改善作用,而有机化蒙脱土的改善作用最为有效。X射线衍射(XRD)测试结果表明,有机化蒙脱土与SBS改性沥青形成了剥离结构的纳米复合材料。剥离的有机化蒙脱土片层均匀地分散在SBS改性沥青中,有效地阻止或减缓了氧气在沥青中的扩散,减少了SBS和沥青分子链受攻击的几率,从而改善了SBS改性沥青灌缝材料的耐热氧和光氧老化性能。参照国外试验规范和国内相关的试验方法对制备的高性能SBS改性沥青灌缝材料的性能进行了评价,试验结果和实际工程应用均表明所制备的灌缝材料具有优良的粘结性、低温柔韧性和耐老化性。更多还原

【Abstract】 Crack is one of major disasters of asphalt pavement. Crack has effect on suitability and safty of driving and water on the surface may infiltrate into roadbase through the cracks, which greatly weakens the strength and stability of the road, and will cause the asphalt pavement suffer more severe damage. At present, polymer modified asphalt and polymer modified asphalt emulsion are widely used as the crack filling materials (CFM). However, most of the CFMs show low adhesive strength, poor low temperature flexibility and durability. The stripping of the CFM from cracks often occurs, when the pavements shrinkage under low temperature conditions, which leads to the formation of new cracks. In order to overcome shortcomings of currently existing CFMs, the SBS modified crack filling materials with good performance were prepared by means of grafting modification of SBS and organo-montmorillonite (OMMT) in this paper. The results of this paper are as follows:1. Methyl methacrylate grafted SBS (MMA-g-SBS)> acrylic acid grafted SBS () and maleic anhydride grafted SBS (MAH-g-SBS) with different grafting degree (GD) were prepared by solution graft polymerization. The GD of grafted SBS modifiers were investigated by means of chemical analysis and the structure of the grafted SBS modifiers were characterized by Fourier transform infrared spectroscopy (FTIR). CFMs were prepared by asphalt and MMA-g-SBS, AA-g-SBS and MAH-g-SBS, respectively. The effects of GD on physical properties, microstructure, mechanical properties and ageing resistance properties of CFM with grafted SBS modifiers were studied. The results showed that, with the increase of GD of grafted SBS, the ductility and elastic recovery of all CFM with grafted SBS modifiers obviously enhanced. The softening point, viscosity and penetration of MAH-g-SBS modified asphalt CFM also increased, but the softening point and viscosity of MMA-g-SBS and AA-g-SBS modified asphalt CFMs decreased slightly. Mechanical properties testing showed that the adhesive strength of all CFM with grafted SBS modifiers was greatly enhanced due to the grafting of MMA, AA and MAH to SBS. Meanwhile, the tensile strength, elongation at break and flexibility at low temperatures of the CFM were also improved to some extent.2. The ageing resistance properties of the grafted SBS modified asphalt CFM were evaluated by the long-term heat ageing, thin film oven test (TFOT), the pressure ageing vessel (PAV) and long-term ultraviolet(LTUV) ageing. The results showed that the thermo-oxidative ageing of SBS modified asphalt CFM was delayed remarkably after MMA, AA and MAH grafted to SBS, which means that the ageing resistance properties of grafted SBS modified asphalt CFMs were improved obviously. The improvement of grafted SBS modified asphalt CFM in ageing resistance can be attributed to the grafted structure of SBS. During the grafted process, the MMA, AA and MAH monomers are easily reacted with C=C double bonds functional group in SBS, accompanied by the formation of graft copolymer, that leads to the decrease of C=C double bonds, and finally reducing the heat degradation of SBS molecular chains. However, compared with the MMA-g-SBS and AA-g-SBS CFM, the MAH-g-SBS modified asphalt CFM exhibits better aging resistance properties. This is because MAH was grafted to SBS by single molecule grafted way during the grafted process. Under the conditions of same grafting degree, the numbers of C=C double bonds of MAH-g-SBS are less than that of the MMA-g-SBS and AA-g-SBS. So it exhibits the best aging resistance properties.3. The effects of antioxidant, UV absorber and organo-montmorillonite (OMMT) on the thermal-oxidative ageing of MAH-g-SBS modified asphalt CFM were investigated. The results showed that the aging resistance properties of MAH-g-SBS modified asphalt CFM were enhanced to some degree by introduction of a small amount of antioxidant and UV absorber. Compared with the antioxidant and UV absorber, the OMMT displays better improving effectiveness for aging resistance of MAH-g-SBS modified asphalt CFM. It can be attributed to form of exfoliated structures in OMMT/MAH-g-SBS modified asphalt CFM, and the silicate layer of OMMT which uniformly dispersed among asphalt at nanometer-scale can efficiently prevent permeation or pervasion of oxygen in the CFM Therefore, the attacking of the oxygen to SBS and asphalt molecular chains is restricted evidently, and the aging resistance properties of OMMT/MAH-g-SBS modified asphalt CFM are improved significantly.4. XRD analysis indicated that the interlayer spacing of OMMT in SBS modified asphalt crack filling materials was widened and an exfoliated structure was formed, which can obstruct oxygen penetrating into material. The improvement of aging resistance of OMMT/SBS modified asphalt crack filling materials can be abscribed to the barrier of peeled OMMT layer to penetration of oxygen.5. On the basis of reviewing foreign test regulations and domestic test methods, the performance of OMMT/MAH-g-SBS modified asphalt CFM was tested. All the results suggested that the OMMT/MAH-g-SBS modified asphalt CFM exhibited good low temperature flexibility and aging resistance properties.更多还原