Laboratory evaluation of epoxy resin modified asphalt mixtures

The pavement performance of epoxy resin modified asphalt mixtures was investigated by the Marshall test, the indirect tensile test, the rutting test, the three-pointed bending test and the composite beam fatigue test. In comparison with the performance of epoxy resin modified asphalt mixtures, the performance of stone matrix asphalt mixtures （SMA10） was also investigated. The rutting test and composite beam fatigue test results show that the epoxy resin modified asphalt mixtures can improve permanent deformation and fatigue characteristics. They also show lower temperature susceptibility and greater resistance to moisture damage compared to the SMA10. Findings from the research indicate that the epoxy resin modified asphalt mixture provides an optional material for the pavement of long-span steel bridges in China due to profound performance and economic advantages.

Shear resistance properties of TPS modified bitumen binders and asphalt mixtures

Shear resistance properties of the virgin bitumen and modified bitumen binders with Tafpack Super(TPS) modifier and SBS modified bitumen were discussed.Dynamic shear rheometer(DSR) was used to measure the laboratory creep data for these binders over a wide range of constant shear stresses at 20 ℃ to characterize the shear creep behaviors of all kinds of asphalt binders,and the rutting test system was used to investigate the permanent deformation of porous asphalt mixtures using the above bitumen binders for a fixed compressive stress.The shear strain rate and shear creep modulus were used to characterize the shear creep behavior of the TPS modified bitumen,and the rutting test results were used to show the consistency of porous asphalt mixtures with the bitumen binders.Results indicate that a distinction of shear creep strain can be made among different contents of TPS modified bitumen at the same stress level,where the shear creep strain-time response curve of the SBS modified bitumen binder is between the curves of the 8% TPS and 12% TPS modified bitumen binders.The shear strain rate and the shear creep modulus of the TPS modified bitumen binders are obtained to compare with those of the SBS modified bitumen binder which results in the same trend as the shear creep strain-time response curve.Permanent deformation results of all the porous asphalt mixtures from the rutting test show reasonable agreement with the findings of the shear strain rates and shear creep modulus over the range of shear stress levels.

Performance and mechanism of solid waste coking sulfur paste modified asphalt mixture before and after curing

For the resource utilization of the solid waste coking sulfur paste and the improvement of performance of the asphalt mixture,a method for preparing modified asphalt mixture with coking sulfur paste modifier(CSPM)is herein proposed.Compared with the matrix asphalt mixture,the Marshall stability of the 30%CSPM modified asphalt mixture increased by 38.3%,the dynamic stability increased by nearly one time(reaching 1847.5 times/mm),the splitting strength ratio increased by 39.3%while the splitting tensile strength decreased by 11.7%.After curing,the performance of the CSPM modified asphalt mixture was further improved.The results show that CSPM improved the high temperature stability and water damage resistance of the asphalt mixture,and the low-temperature anti-cracking performance of that was slightly reduced.Chemical analysis of asphalt binders shows that a little sulfur reacted with asphalt to produce polysulfide compounds(R-Sx-R′),and a part of sulfur existed in the form of crystalline sulfur which was further increased after curing.The presence of crystalline sulfur as an inorganic filler is the key point for improving the high temperature stability and water resistance performance of modified asphalt mixture.

Evaluation of modification effect of epoxy resin based on performance of asphalt mixtures

Based on the analysis of the main failures discovered in pavement on steel deck plate and the demanding service condition of the pavement on steel deck, high-temperature rutting test, low-temperature bending test and controlled stress flexural fatigue test are used to study the performance of asphalt mixtures modified by epoxy resin including high-temperature stability, low-temperature cracking-resistance, and fatigue cracking-resistance, which are served to evaluate the modification effect of epoxy resin of different contents. With the addition of epoxy resin, all the three performances are improved greatly. However, when the amount of epoxy resin added is over a certain value, the modification effect will be stable with no extra benefit detected. Finally, in terms of the properties of the three respects, 20%, 30%, 30% are given separately as the proposal adding contents.

DCLR Modifi ed Petroleum Asphalt Optimization and Mixture Road Performance

In recent decades,modified asphalt materials have been used in enhancing the traffic load on the roads.The main objective of this paper is to explore the modifi cation effect of direct coal liquefaction residue(DCLR)on as-phalt binders and investigate the effectiveness of DCLR in improving the performance of asphalt road.This paper prepared modifi ed petroleum as-phalt under diff erent process conditions and tested its penetration,softening point and ductility index.Based on the experimental data,according to gray correlation degree,the performance for the asphalt was compared.The performance for the modified asphalt is simulated and predicted using poly-nomial functions.The modifi ed asphalt was analyzed by FT-IR,TGA,SEM and HPLC.The results show that the optimal process conditions for DCLR modifi ed asphalt are shear mixing time of 45 min,shear mixing tempera-ture of 150℃ and shear mixing rate of 4000 r/min.The predicted fit with the experimental data of 0.993 further demonstrates the effectiveness of the method.The characterization results show no significant chemical change between the DCLR and the asphalt.DCLR can significantly improve the high temperature performance and water stability of the asphalt,but it has little impact on its low temperature performance.

Physical-Rheological Properties and Performances of Rejuvenated(Styrene-Butadiene-Styrene)Asphalt with Polymerized-MDI and Aromatic Oil

Traditional asphalt rejuvenators,like aromatic oil(AO),are known to be effective in improving the low-temperature properties and fatigue performances of aged SBS(styrene-butadiene-styrene)modified asphalt(SBSMA)binders and mixtures.However,these rejuvenators inevitably compromise their high-temperature properties and deformation resistances because they dilute asphalt binder but do not fix the damaged structures of aged SBS.In this study,a highly-active chemical called polymerized 4,4-diphenylmethane diisocyanate(PMDI)was used to assist the traditional AO asphalt rejuvenator.The physical and rheological characteristics of rejuvenated SBSMA binders and the moisture-induced damage and rut deformation performances of corresponding mixtures were comparatively evaluated.The results showed that the increasing proportion of AO compromises the hightemperature property and hardness of aged SBSMA binder,and an appropriate amount of PMDI works to compensate such losses;3%rejuvenator at mass ratio of AO:PMDI=70:30 can have a rejuvenated SBSMA binder with a high-temperature performance similar to that of fresh binder,approximately at 71.4°C;the use of AO can help reduce the viscosity of PMDI rejuvenated SBSMA binder for improving its workability;PMDI can help improve the resistance of AO rejuvenated SBSMA binder to deformation,especially at elevated temperatures,through its chemical reactions with aged SBS;moisture induction can enhance the resistance to damage of rejuvenated mixtures containing AO/PMDI or only PMDI;and the rejuvenator with a mass ratio of AO:PMDI=70:30 can lead the rejuvenated mixture to meet the application requirement,with a rut depth of only 2.973 mm,although more PMDI can result in a higher resistance of rejuvenated mixtures to high-temperature deformation.

Rheological properties of asphalt mixtures containing various fibers

Rheological characteristics of fiber-modified asphalt mixture were investigated.Cellulous fiber,polyester fiber and mineral fiber were used as additives for asphalt mixture,and the dosages were 0.3%,0.3%,0.4%,respectively.Dynamic modulus test using superpave simple performance tester(SPT) was adopted to study the dynamic modulus and phase angle for the control mixture and fiber-modified ones at various temperatures and frequencies.Test results show that the rheological properties can be improved significantly by the addition of various fibers.The dynamic modulus increases with the increase of frequency,and the phase angle decreases with the increase of frequency.When various fibers are used,the dynamic modulus increases and phase angle decreases at each frequency.This indicates that the stiffness and the elastic portion of fiber-modified asphalt mixtures can be enhanced when various fibers are used,which results in the change of viscoelastic properties of mixtures.The creep test results show that the total strain and the permanent strain of asphalt mixtures during load-unload cycle can be significantly reduced,which results in the improvement of resistance to permanent deformation for asphalt mixtures containing various fiber additives.The Burgers model can be employed effectively to illustrate the rheological properties of fiber modified asphalt mixtures.

Finite Element Analysis of Thiopave Modified Asphalt Pavement

With the aim of studying the anti-rutting performance of Thiopave modified asphalt mixture applied to the upper layer of pavement, the strain-hardening creep model in ABAQUS finite element software was used to analyze the rutting under the condition of introducing temperature field. Compared with the calculation results of the rutting of ordinary asphalt pavement, it is found that Thiopave can improve the temperature sensitivity of asphalt mixture. With the increase of temperature, the rutting change of Thiopave modified asphalt pavement is smaller than that of ordinary asphalt. Thiopave also has a certain degree of improvement in the fatigue resistance of asphalt pavements, which can be applied to sections with high traffic volume in high temperature areas.

上面层改性沥青混合料低温性能综合对比评价

【目的】分析足尺路面试验环道所用7种上面层细粒式改性沥青混合料的低温性能。【方法】通过小梁低温弯曲、中梁线收缩系数和法国M2F梯形梁动态模量3种室内试验开展研究及相关性分析,并应用多指标试验结果的无量纲归一化赋权求和法进行综合对比评价。【结果】最大弯拉应变、应变能密度、线收缩系数、复模量和相位角均可作为改性沥青混合料低温性能的合理评价指标;对比改性沥青类型,采用低温延性强的SBS改性沥青制备的混合料低温性能最优,橡胶沥青混合料的次之,掺抗车辙剂能增强SBS改性AC类混合料的低温性能;对比矿料合成级配,SMA类的低温性能最优,SBS改性AC类中粗集料含量越低,其低温性能越好;多孔排水式高黏SBS改性PAC类具有优良的黏弹性和低温收缩性能。【结论】评价结果可为环道沥青路面低温性能长期监测对比提供参考。

基于加速加载试验的青川岩改沥青混合料疲劳性能研究

为评价青川岩改沥青混合料疲劳性能,该文设计了基于比例尺为1∶3的路面加速加载试验系统的动轮载三点弯曲加载疲劳试验装置,对双层沥青混合料复合车辙试件进行轮胎碾压下的三点弯曲重复加载疲劳试验,结合沥青混合料小梁试件MTS弯曲疲劳试验,评价青川岩改沥青及复合改性沥青等对沥青混合料疲劳性能的改善效果。结果表明:青川岩改沥青提高了沥青混合料承受重复弯拉荷载的能力,改善了沥青混合料的抗疲劳性能,其抗疲劳性能优于青川岩沥青与SBS复合改性沥青、SBS改性沥青和基质沥青;基于比例尺为1∶3的路面加速加载试验的动轮载三点弯曲重复加载疲劳试验,能更真实地模拟现场路面轮载作用,减少了小梁试件尺寸效应对疲劳寿命的影响,再现了轮载作用下路面结构的受力状况。

紫外吸收剂/环烷油对高寒区SBS沥青路面的性能影响

为提高沥青混合料在高寒高海拔地区路用性能,选择不同掺量的紫外吸收剂(UV-531)/环烷油(NPO)对SBS沥青进行复合改性,研究复合改性剂对SBS改性沥青及混合料路用性能的影响。结果表明,相比于原样SBS沥青,UV-531/NPO复合改性剂能显著提高SBS沥青的低温变形能力和感温性能,但会降低沥青的高温性能(延度增加117.6%,当量脆点和感温系数分别降低52.0%和11.9%,当量软化点降低2.3℃)。同时,复合改性剂能显著提高混合料的低温抗裂性能(弯曲劲度模量降低9.61%,最大弯拉应变提升11.20%),然而对其高温稳定性与水稳定性会产生一定程度消极影响。高寒高海拔地区主要考虑混合料的低温抗裂性,因此,UV-531/NPO复合改性沥青路面具有很大应用潜力。

复合多聚磷酸改性沥青混合料动态力学性能

为研究多聚磷酸(polyphosphoric acid,PPA)+SBS复合改性沥青混合料的动态力学性能,采用单轴压缩动态模量试验,分析温度和频率对动态模量和相位角的影响,并基于改进Havriliak-Negam(i HN)模型构建动态模量和相位角主曲线,同时与SBS改性沥青混合料相对比。结果表明:2种沥青混合料动态模量和相位角随温度和频率的变化呈现相同的趋势,HN模型可准确拟合2种沥青混合料的动态模量和相位角主曲线。相较于SBS改性沥青混合料,PPA+SBS复合改性沥青混合料的相位角在-10、20、50℃时均降低,而动态模量在-10℃时降低,20℃时变化较小,50℃时增加;较宽频域范围内,PPA+SBS复合改性沥青混合料在高温低频下动态模量变大,相位角变小,在低温高频下动态模量变小,相位角变化不大;PPA+SBS复合改性沥青混合料具有更优的动态力学性能。

改性钢渣-沥青混合料的性能及机理

采用甲基硅酸钠溶液、二氧化硅胶体溶液、聚丙烯酸酯乳液对钢渣进行浸泡改性处理,通过性能测试、扫描电子显微镜(SEM)、声发射等测试方法研究了改性钢渣的物理、力学性能,改性钢渣-沥青混合料的性能,钢渣的改性机理和改性钢渣-沥青混合料的抗裂机理。结果表明,4.75~19 mm钢渣经1%~4%浓度溶剂改性后,物理性能得到明显改善;经3%浓度溶剂改性后的钢渣制备的改性钢渣-沥青混合料的体积稳定性较未改性钢渣-沥青混合料(RSAM)提高了27.92%~39.09%;改性钢渣表面包裹着不同状态的不溶于水的改性保护层,经二氧化硅改性后的钢渣(SMS)表面呈现出致密的层状结构且保持表面粗糙,改性效果最优;二氧化硅改性钢渣-沥青混合料(SMSAM)的裂纹宽度减小,主裂纹出现的时间较晚,SMS对SMSAM的断裂破坏起到了一定的减缓作用,提高了混合料的抗开裂性能。

聚氨酯/纳米ZnO复合改性沥青及其混合料性能研究

为提升沥青路面的路用性能,选用聚氨酯、纳米ZnO和基质沥青制备聚氨酯/纳米ZnO复合改性沥青。以针入度、软化点、延度和135℃运动黏度为评价指标,研究改性剂对沥青性能的影响,采用软化点差值评价储存稳定性,并制备3种复合改性沥青AC-13C混合料进行车辙试验、小梁弯曲试验和浸水马歇尔试验,研究改性沥青混合料的性能。结果表明,聚氨酯和纳米ZnO的掺入能显著改善基质沥青的高低温性能,且储存稳定性符合规范要求。复合改性沥青混合料能够满足沥青路面的路用性能,5%聚氨酯复配3%纳米ZnO掺量的改性沥青混合料改善高温性能和水稳性能效果最好,与基质沥青混合料相比其动稳定度提高了2.32倍,残留稳定度上升了9.0%,最大弯拉应变(-10℃)提升了8.3%。综合考虑路用性能改善效果,推荐选用5%聚氨酯复配3%纳米ZnO为复合改性沥青及其混合料的最佳掺量。

赤泥填料对排水沥青混合料路用性能的影响

为探究赤泥填料对排水沥青混合料路用性能的影响,首先选择两种国产高黏改性剂PT-HVA和AR-HVA制备得到高黏改性沥青,并将成品苯乙烯-丁二烯-苯乙烯(styrene-butadiene-styrene,SBS)改性沥青作为对照组,对三种改性沥青进行各项沥青性能试验。结果表明:两种改性剂的最佳掺量均为15%。接着以三种改性沥青为胶结料配制三种排水性沥青混合料(填料为赤泥和矿粉),并进行各项路用性能试验。结果表明:由赤泥制备的混合料的路用性能良好,其中AR-HVA高黏改性沥青+赤泥制备的混合料性能最优,动稳定度达11053次/mm,残留稳定度为91.46%,冻融劈裂比为89.60%,飞散损失为5.20%,老化系数为24.60%。同时,由赤泥制备而成的混合料的弯拉强度和弯拉应变比由矿粉制备的混合料的小,这表明赤泥虽能有效地提高混合料的高温性能、水稳性能、抗松散性能和抗老化性能,但会降低混合料的低温性能。

废胶粉改性沥青混合料路用性能研究

为保证我国道路工程建设持续高质量绿色发展,文章依托国内大市场优势,采用国产原材料与15%掺量的废胶粉改性沥青分别拌制AC-13(C),SBS(Ⅰ-D)SMA-13混合料,依据现行规范测试混合料的各项路用性能指标。测试结果表明,密级配废胶粉改性沥青混合料的高温稳定性与抗损水性能较基质沥青混合料大幅提高,基本接近SBS(Ⅰ-D)改性沥青混合料。低温抗裂性能方面表现出良好的路用性能,更适用于温差较大的地区。文章研究内容可为废胎胶粉改性沥青混合料的应用提供参考和借鉴。

纤维增韧水性环氧乳化沥青混合料性能研究

为提升水性环氧乳化沥青混合料的韧性,采用3种不同类型的纤维材料,分别为木质素纤维、聚酯纤维和玄武岩纤维,并探究它们在不同掺量(0.2%,0.4%,0.6%)下对水性环氧乳化沥青混合料路用性能的影响规律,对9组纤维改性后的水性环氧乳化沥青混合料进行了马歇尔稳定度试验、单轴压缩蠕变试验、低温劈裂试验、冻融劈裂试验、动态模量试验和间接拉伸疲劳试验,得到了马歇尔稳定度、蠕变变形量、破坏拉伸应变、冻融劈裂抗拉强度比、动态模量和疲劳寿命等评价指标结果,并与空白样的各项性能进行了对比分析。研究结果显示:纤维的掺加增加了混合料的最佳乳液含量,并显著增强了集料间的黏结力,从而有效改善了混合料的抗水损害能力。同时,纤维改性对水性环氧乳化沥青混合料的韧性和扩张力也有显著影响,经过纤维增韧处理的混合料在低温劈裂试验中的破坏拉伸应变最大可提升33.6%。基于纤维在提升水性环氧乳化沥青混合料性能方面的效果进行排序,玄武岩纤维表现最佳,其次为聚酯纤维,而木质素纤维排在第3。综合考虑路用性能和经济性,木质素纤维、聚酯纤维、玄武岩纤维的推荐掺量分别为0.2%,0.2%,0.4%。值得注意的是,高掺量的纤维可能导致其在混合料中分散性差,形成力学薄弱点,因此在选择纤维掺量时应对其予以谨慎考虑。

高掺量SBS改性沥青及其混合料老化行为

为了探究高掺量SBS改性沥青及其混合料的抗老化性能,分别对高掺量SBS改性沥青和70号基质沥青进行老化,并进行沥青流变性能试验,分别评价高掺量SBS改性沥青老化前后的弹性恢复性能、高温抗变形性能、抗疲劳性能,并对其混合料老化前后的高温稳定性、抗车辙性能和抗裂性能进行评价。研究结果表明:随着老化程度的加深,高掺量SBS改性沥青的模量增大,弹性恢复性能、高温抗变形能力、疲劳性能减弱,其混合料的高温稳定性与高温抗变形能力降低,抗裂性能逐渐变差;沥青氧化硬化和SBS氧化降解的博弈对高掺量SBS改性沥青及其混合料各性能均有不同程度的影响;尽管高掺量SBS改性沥青具有良好的抗老化性能,但仍需额外关注其老化所导致的性能下降问题。

废弃热固性复合材料应用于沥青混合料的研究进展

本文综述了废弃热固性复合材料应用于沥青混合料的研究进展,废弃热固性复合材料既可以作为沥青改性剂又可以作为填料,在路用性能方面起到促进作用。废弃玻璃钢作为改性剂能显著提高沥青混合料的高温性能、抗车辙能力、耐湿热性能和低温开裂能力,这是由于沥青混合料中玻璃钢网络形成稳定的三维结构,玻璃钢组分通过溶胀与吸附桥接作用可增加沥青组分结构中的大分子组分。玻璃钢粉末作为沥青混合料填料能提高沥青混合料的中、高温性能、抗车辙性能和抗疲劳性能,这是由于玻璃钢粉末与沥青的粘附性能优异,在沥青混合料内部,玻璃钢可以形成良好的嵌锁骨架结构并可以形成密实充填。同时,总结了废弃热固性复合材料在沥青混合料中的作用机制,最后对废弃热固性复合材料在道路工程中的广泛应用进行了展望。

废旧塑料在沥青道路工程中的应用进展

将废旧塑料应用于沥青道路工程既可以改善路用性能,又可以促进废旧资源的高效利用和环境保护。概述了废旧塑料物理及化学回收产物在沥青道路工程中的应用情况,介绍了废旧塑料对沥青及其混合料的改性机理及影响因素。通过对研究成果进行总结归纳,梳理了废旧塑料对沥青及沥青混合料高温、低温、抗老化和疲劳性能的改善作用,分析了目前存在的问题,并展望了未来沥青道路工程用废旧塑料的研究方向。