多尺度纳米材料对沥青流变和老化性能的影响

采用布氏旋转黏度、动态剪切流变和弯曲梁流变试验,同时结合红外光谱试验对比研究了多尺度纳米材料对不同老化状态下4种沥青——SK-70和Alfa-70基质沥青、SBR和SBS改性沥青(SBRMA, SBSMA)流变性能的影响.结果表明:4种沥青经多尺度纳米材料改性后,布氏旋转黏度、复数模量及车辙因子均得到不同程度的提高;长期热氧和光氧老化后的疲劳因子降低,即抗疲劳性能得到改善,且对SBRMA的改善最明显.相比未改性沥青,多尺度纳米材料改性后4种沥青在各种老化方式下的复数模量老化指数均降低,而且SBSMA和SBRMA这2种聚合物改性沥青老化前后的丁二烯指数差值也降低,即4种沥青的耐热氧和耐光氧老化性能同时得到有效改善,且对SBRMA的改善效果最好.多尺度纳米材料提高了2种基质沥青的低温连续等级温度,但同时在一定程度上降低了2种聚合物改性沥青的低温连续等级温度.     

不同旧沥青掺量下高胶再生沥青的力学性能评价

以老化后的基质沥青为旧沥青,采用梯度比例将不同老化程度的旧沥青与高胶沥青进行调和再生,通过动态剪切流变仪（DSR）对高胶再生沥青试样进行PG分级试验、多应力蠕变恢复试验、线性振幅扫描试验和频率扫描试验,测定了Jnr、R、2.5%应变水平下的疲劳寿命、G-R常数等参数,研究旧沥青掺量对高胶再生沥青性能的影响。研究结果显示,随着高胶沥青掺量的增加,再生沥青的Jnr、疲劳寿命、G-R常数等参数均有所增大,表明高胶沥青的掺入能够较全面地提高再生沥青的力学性能。     

基于DSR试验的生物重油再生沥青流变性能评价

为研究生物重油再生沥青的流变性能,将生物重油掺入经旋转薄膜烘箱试验（RTFOT）老化的70^#沥青和SBS改性沥青中制备生物重油再生沥青,通过动态剪切流变（DSR）试验研究了沥青的流变性能.结果表明：生物重油的掺入提高了老化沥青的抗疲劳性能、低温抗裂能力和黏性比例,降低了高温抗车辙性能;低频加载易使沥青产生不可恢复的永久性变形;生物重油对70^#老化沥青的再生效果优于老化SBS改性沥青;建议生物重油掺量宜为4%,该掺量下再生沥青的性能可恢复至原样沥青.     

老化对基质沥青阻燃抑烟性能的影响

为探究不同条件老化后沥青阻燃抑烟性能的变化规律,采用旋转薄膜烘箱（RTFOT）对基质沥青进行85 min短期老化、270 min长期老化以及湿热老化。利用氧指数试验（LOI）和锥形量热试验研究老化沥青火灾安全性能,同时结合红外光谱分析技术（FTIR）以及热重-质谱联用技术(TG-MS)分析沥青（BA）成分与气态产物释放特性的变化规律。试验结果表明：基质沥青在经历热氧老化后轻质组分减少,重质组分增加,导致氧指数提升。而湿热老化中由于水蒸气分压力的作用使沥青氧指数略有下降。在热释放方面,热氧老化后沥青燃烧热释放速率峰值下降,峰值对应时间提前,有效燃烧热降低;而湿热老化后热释放速率基本不变。在烟气释放方面,热氧老化后沥青燃烧的炭烟、CO、CO2释放量更低,SO2释放量增加;湿热老化后炭烟、CO、CO2释放量变化不大,而SO2释放量明显增多。     

生物油对再生沥青流变性能影响的研究

为评价生物油对再生沥青胶结料流变性能的影响规律,以餐饮废油制备得到的生物油和老化沥青为原材料,通过高速剪切试验分别配制出了不同生物油掺量的再生沥青.对比分析同等条件下试样的流变性能变化规律后认为:掺入生物油后,其对再生沥青的MSCR流变性能水平恢复有限,并且远未恢复至基质沥青的流变性能水平;当生物油掺量为5％时,再生沥...     

高掺量橡胶沥青再生混合料性能的室内试验分析研究

为研究高掺量橡胶沥青再生混合料AC-13试验段性能,对再生料回收沥青老化指标和掺再生剂后指标进行评价。通过橡胶粉掺量试验和再生混合料室内试验评价,研究高掺量橡胶沥青再生混合料路用性能。研究结果表明:再生剂掺量7%、胶粉掺量25%的橡胶沥青再生AC-13混合料具有优异的高温性能,综合指标符合技术要求,且明显优于普通沥青路面,推荐采用。     

有机蛭石与纳米二氧化钛复配改性沥青的抗老化性能研究

研究了有机蛭石与纳米TiO2复配改性剂对沥青物理性能和流变性能的影响,并分析不同老化方式下复配改性剂对沥青抗老化性能的改善效果。结果表明,复配改性剂对沥青的物理性能和流变性能影响较小。复配改性剂的加入可以达到同时改善沥青耐热氧和紫外光老化性能的目的,但是改善效果受复配掺量的影响较大,不同掺量的复配改性剂对沥青的短期和长期热氧老化性能都有改善效果,而耐紫外光老化性能的改善只在特定的复配改性剂掺量下才能体现。综合热氧老化和紫外光老化性能数据,复配改性剂的最佳掺量为1%的有机蛭石和3%的纳米TiO2。     

RAP掺量对温拌再生沥青混合料路用性能的影响

为了评价RAP（Reclaimed Asphalt Pavement）对再生沥青混合料路用性能的影响,选取了2种不同来源的RAP,对其进行了性能评价后,并以不同的掺量（0%、20%、30%和45%）分别添加在不同类型的热拌及温拌再生沥青混合料（AC-13F和SMA-13）中,进行高温车辙试验、低温弯曲试验、浸水马歇尔和冻融劈裂试验。根据试验结果分别评价了热拌及温拌再生沥青混合料的高温性能、低温性能以及水稳定性能,分析了不同类型RAP及其掺量对热拌及温拌再生沥青混合料路用性能的影响规律,确定了RAP在热拌及温拌再生沥青混合料中的最佳掺量。     

基质沥青对自粘聚合物改性沥青防水卷材耐老化性能的影响研究

基于4种不同的90#基质沥青,分别制得4种自粘聚合物改性沥青防水卷材,探讨了基质沥青对卷材耐老化性能的影响,重点研究了热老化前后卷材低温柔性的变化。结果表明,常规的软化点、针入度和延度不能直接反映基质沥青对卷材耐老化性能的影响;基质沥青的胶体指数（CI指数）与卷材的耐老化性能表现出一定的相关性：CI指数越低,制得的卷材具有更优的耐老化性能。     

温拌再生沥青混合料性能试验

按照热拌再生设计方法配制了废旧沥青混合料（RAP）掺量分别为20%,30%和45%（质量分数）的AC 13F热拌再生沥青混合料.在此基础上,采用干拌法和湿拌法两种制备工艺分别配制温拌再生沥青混合料.利用车辙试验、冻融劈裂试验、低温弯曲和弯曲蠕变试验来评价热拌及温拌再生沥青混合料的高温性能、低温抗裂性能和水稳定性能.结果表明：温拌再生沥青混合料除高温性能优于热拌再生沥青混合料外,其低温抗裂性能和水稳定性能均低于热拌再生沥青混合料;随着RAP掺量的增加,热拌及温拌再生沥青混合料的路用性能除高温性能有所提高外,低温抗裂性能和水稳定性能均有不同程度的降低;制备工艺对温拌再生沥青混合料的性能有一定程度的影响.     

Characterization of warm mix asphalt binders containing artificially long-term aged binders

Reclaimed asphalt pavement (RAP) comprises one of the largest recycled materials, and warm mix asphalt (WMA) technologies become more commonly used due to their promising advantages in the United States and Europe. This paper addresses the laboratory investigation of performance properties of WMA binders containing aged binders. The recycled binders with the additives were produced using two (i.e., zeolite Aspha-min^® and wax Sasobit^®) of the available warm asphalt processes. The recycled WMA binders were artificially short-term and then long-term aged through the rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were carried out on the binders through the rotational viscometer, the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). In general, the results of this study indicated that (1) the additives and aged binders played an important role in determination of the binder properties; (2) the use of lower PG grade as a virgin binder (PG 58-28 in this study) was critical on offsetting the increase of binder stiffness caused by the addition of WMA additives and aged binders; and (3) even at the low recycling percentage of 15%, the lower PG grade was needed to get the results meeting current Superpave binder requirements.     

Effect of organo-montmorillonite on aging properties of asphalt

Effects of organo-montmorillonite (OMMT) on thermo-oxidative and ultraviolet (UV) aging properties of asphalt were investigated. The results show that the viscosity aging index (VAI) and softening point increment (ΔS) of OMMT modified asphalt decrease significantly due to introduction of OMMT, and the ductility retention rate of the modified asphalt is also evidently higher than that of the pristine asphalt after thin-film oven test (TFOT) and pressure aging vessel (PAV) aging. In the meantime, both VAI and ΔS of the modified asphalt are obviously lower than that of the pristine asphalt after UV aging. Furthermore, compared with the pristine asphalt, the results of dynamic shear rheometer (DSR) testing exhibit smaller changes in rut factor (G*/sin δ) after TFOT and lower fatigue factor (G*sin δ) after PAV for the modified asphalt, which suggests that the effect of thermo-oxidative aging on dynamic rheological behaviors of the modified asphalt is restrained due to introduction of OMMT.     

基于MSCR试验的石墨烯复合橡胶改性沥青抗老化性能研究

为了评价石墨烯复合橡胶改性沥青(GRS)的高温抗变形能力随老化时间的变化规律,分别选取SBS改性沥青、橡胶复合改性沥青及石墨烯复合橡胶改性沥青,进行原样及热氧老化20h(TFOT5h+PAV20h)、40h(TFOT5h+PAV40h)和60h(TFOT5h+PAV60h)的多应力重复蠕变试验(MSCR).结果表明,在...     

耐老化弹性体改性沥青的制备与性能研究

采用熔融共混法制备了层状双羟基复合金属氢氧化物(LDHs)/弹性体改性沥青,研究了LDHs对弹性体改性沥青耐紫外光老化和耐热氧老化性能的影响.结果表明,LDHs可显著提高弹性体改性沥青的耐光热老化性能.     

Influence of aging on the evolution of structure,morphology and rheology of base and SBS modified bitumen

The influence of aging on the evolution of structure, morphology and rheology of base bitumen and SBS modified binders was investigated by Fourier transform infrared (FTIR), atomic force microscopy (AFM) and dynamic shear rheometer (DSR), respectively. Two laboratory simulation aging methods, named standard rolling thin film oven (RTFO) test and pressure aging vessel (PAV) test were applied in this study. The aging temperature of PAV was selected at 60 °C, which is considered to be consistent with the real high temperature within an asphalt pavement in the field. After aging, it was found that more carbonyl and sulphoxide groups but less chain segments of butadiene were available. With the oxidation of base bitumen and the degradation of SBS segments, obvious asphaltene micelles appeared in both binders, consistent with the changes of softening point and rheology of base bitumen and SBS modified binders.     

废机油底渣再生剂对老化沥青低温性能影响

为准确评估废机油底渣(WEOB)作为沥青再生剂时对老化沥青低温性能的影响,通过室内旋转薄膜烘箱老化(RTFOT)和40h长期老化(PAV)试验制备老化沥青,然后采用双边缺口拉伸(DENT)试验、扩展弯曲梁流变(Ex-BBR)试验分别研究了原样沥青、老化沥青和添加废机油底渣再生沥青的抗延性断裂性能,以及物理硬化对这3种沥青低温极限分级的影响;采用原子力显微镜研究了原样沥青、老化沥青和再生沥青的微观结构.结果表明:使用废机油底渣会降低老化沥青的容许应变(CTOD)和常规弯曲梁流变仪的低温极限分级,经过长期低温恒温处置后,废机油底渣掺量为10%的再生沥青低温极限分级增加明显;老化沥青中添加废机油底渣并不能恢复原样沥青胶结料的表面微观形态,而且形成了更多的相界.     

Effects of aging on the properties of modified asphalt binder with flame retardants

Effects of aging on the properties of asphalt binders modified by incorporating Styrene–Butadiene–Styrene (SBS) and flame retardants (FR) were studied. Asphalt binders were artificially aged in the rolling thin film oven (RTFOT) and Pressure Aging Vessel (PAV). The flame retardancy of modified asphalt binders were characterized using limited oxygen index (LOI), and the effects of aging on the properties of asphalt binders were studied using Brookfield viscometer test and dynamic shear rheometer test. Experimental results indicated that the flame retardancy of asphalt binder was increased after aging. But the increasing amount of LOI is low when the modified asphalt binder containing more flame retardants. The variation of the LOI, softening point, penetration, ductility and viscosity of asphalt binder decreased with flame retardant content increasing, meaning the flame retardants can improve the thermo-oxidative aging resistance of asphalt binder. Furthermore, the G^*/sin δ, stiffness and m-value of flame retardant modified asphalt binders display smaller changes after two different aging.     

Preparation and rheological characterization of asphalt binders reinforced with layered silicate nanoparticles

Bentonite clay (BT) and organically modified bentonite (OBT) were used to reinforce and modify a bituminous paving asphalt binder. The modified asphalt binders were produced by melt processing under sonication and shearing stresses. The interlayer spacing of silicate layers in bentonite, organically modified bentonite and the modified asphalt binders were analyzed by wide angle X-ray diffraction (WAXD). The softening point, viscosity and ductility of the modified asphalts were tested as a function of clay content and clay type. The dynamic shear rheological tests showed that the modified asphalts have higher rutting resistance. Bending beam rheometer (BBR) test results for aged specimens (through rolling thin film oven (RTFO) and pressure aging vessel (PAV)) indicated that adding BT and OBT can significantly improve low temperature rheological properties and cracking of asphalt.