A review of the development of asphalt foaming technology

To comprehensively assess the current state-of-art in asphalt foaming technology, the following four key aspectshave been reviewed systematically: foaming principles, test methods, evaluation indicators, and influencing factors.Key findings reveal that asphalt foaming was primarily driven by the vaporization of water, with deteriorationprocesses including bubble collapse and liquid film drainage. However, the current understanding of asphaltfoaming principles remains limited, primarily due to difficulties in capturing and precisely measuring its microscopic behaviors during asphalt foaming process. Volume changes provided an intuitive means to evaluate theexpansion capacity of asphalt and its foaming stability. Bubble evolution characteristics of foamed asphalt offeredpromising insights into its foaming performance. Traditional ruler and stopwatch-based assessments were beingsuperseded by automated techniques like laser and ultrasonic ranging. Nevertheless, the current measuringequipment still lacks the capability to comprehensively evaluate the foaming effect of asphalt across various dimensions. Asphalt temperature and foaming water consumption significantly affected asphalt foaming performance, and the inclusion of foaming agents typically led to a notable increase in the half life of foamed asphalt.However, the interaction between foaming agents and asphalt, as well as the underlying mechanisms affecting thefoaming effect, are still unclear and require further exploration. Future research should primarily focus on thecorrelation between asphalt foaming effect and mixture performance, aiming to guide the practical engineeringapplication of foamed asphalt mixtures and enlarge the advantages of such low-emission and sustainable mixtures.

The Influence of Material Related Parameters on the Mechanical Properties of Foamed Asphalt Mix

By indirect tensile strength （ITS） test and unconfined compressive strength （UCS） test, the influence of various material related parameters, including asphalt foamability, aggregate temperature, mixing moisture content （MMC） and foamed asphalt （FA） content, on the mechanical properties of FA mixes was studied. The results indicated that both asphalt foamability and aggregate temperature greatly affected ITS of FA mixes. Too low aggregate temperature was unfavorable for mechanical properties of FA mixes. Foamed index alone was unfit for the evaluation of asphalt foamability. Compared with half-life, expansion ratio had more prominent influence on ITS of FA mixes. MMC had significant impact on the mechanical properties of FA mixes and should be optimized by trial and test in FA mix design. The mechanical properties of FA mix were sensitive to the change of FA content. Compared with the ITS determined with standard Marshall specimens, both the ITS and UCS determined with static compressed specimens by 15 cm diameter were more effective in terms of choosing the optimal asphalt content for FA mixes.

Evaluation of rutting and low-temperature cracking resistancesof warm-mix recycled asphalt bindersunder the secondary aging condition

The rutting and low-temperature resistances of warm-mix recycled asphalt binders under the secondary aging condition were measured by the dynamic shear rheometer test and bending beam rheometer test.Effects of different types of warm-mix asphalt(WMA)technologies and additives were evaluated.Aging and improvement mechanisms were investigated by the Fourier transform infrared spectroscopy test.It is found that recycled binders after the secondary aging are more resistant to rutting and less resistant to low-temperature cracking.The two warm-mix asphalt technologies have opposite effects.Using the Sasobit WMA significantly improves the rutting resistance and reduces the low temperature resistance for the recycled binders due to its morphological change at different temperatures.The rutting factor values of recycled asphalt binders with the Sasobit additive increase by 4.6 to 5.6 times.However,using the Evotherm WMA causes the deterioration of the rutting resistance due to the structural lubrication effect.The rutting factor values of recycled asphalt binders with the Evotherm additive show the reduction of 52%to 62%.It is recommended to add the styrene butadiene rubber latex or crumb rubber powder into the warm-mix recycled asphalt binders to simultaneously improve the rutting and low-temperature cracking resistances.

Warm-Mix Asphalt and Pavement Sustainability: A Review

Within the past two decades or so, the asphalt paving industry has responded positively to increasing global concerns over shrinking natural resource reserves and worsening environmental conditions through the development and deployment of warm-mix asphalt technologies. Such technologies make it possible to produce and place asphalt concrete at reduced temperatures compared to conventional hot-mix methods. Several studies have reported on the potential of warm-mix asphalt with regard to improved pavement performance, efficiency and environmental stewardship. This paper reviews several of those studies in the context of pavement sustainability. Overall, warm-mix asphalt provides substantial sustainability benefits similar to or, in some cases, better than conventional hot-mix asphalt. Sustainability benefits include lower energy use, reduced emissions, and potential for increased reclaimed asphalt pavement usage. Growth in utilization of warm-mix asphalt worldwide may, in the not-too-distant future, make the material the standard for asphalt paving. Regardless, there are concerns over some aspects of warm-mix asphalt such as lower resistance to fatigue cracking, rutting and potential water-susceptibility problems, particularly with mixes prepared with water-based technologies, which require further research to address.

Status and development trend of asphalt foaming process

The structural design of asphalt foaming device, the determination of foam chamber process and condition parameters are the key technologies to foaming effect of foam asphalt. In this paper, we analyze the research status of foaming mechanism, foaming device design and determination of the various parameters. The paper puts forward opinions for asphalt foaming technology. And development trend of the asphalt foaming technology is analyzed.

富油煤热解重质焦油基泡沫炭性能研究

【目的】富油煤热解重质焦油制备石墨化泡沫材料是富油煤资源高值化利用的方式之一。【方法】为探究不同反应条件与泡沫炭性能的联系从而制备高性能泡沫炭材料,以重质焦油制备中间相沥青为前驱体,采用高温自发泡法制备泡沫炭。考察不同反应温度、升温速率和反应压力对煤焦油基泡沫炭性能的影响,最后进行Box-Behnken响应面设计实验建立二次多项回归方程,揭示泡沫炭孔隙率、导热系数与反应条件的关系。【结果和结论】结果表明:反应温度、升温速率和反应压力对煤焦油基泡沫炭性能有显著影响。泡沫炭孔隙率的最优值为72.8%,对应的条件为温度559℃、压力0.48 MPa、升温速率9℃/min,影响因素温度>压力>升温速率;泡沫炭导热系数最优值为0.219 W/(m·K),对应的条件为温度549℃、压力2 MPa、升温速率3.9℃/min,影响因素升温速率>压力>温度。经过响应面模型优化后的工艺参数可制备具有良好孔隙率及导热性的泡沫炭材料,为提升富油煤热解效率提供新方案。

EC130温拌剂对SBS改性沥青高温性能及抗疲劳性能的影响

作为制备沸石发泡沥青的发泡剂,EC130温拌剂释放的发泡水和残留的沸石矿物对沥青的性能有着不同的影响.为研究EC130温拌剂对SBS改性沥青高温性能和抗疲劳性能的影响,采用石灰岩矿粉、EC130沸石矿物和EC130温拌剂等3种添加物,设计了以添加物掺量为变量的单因素试验.以石灰岩矿粉为参照对象,通过温度扫描试验、多重应力蠕变恢复试验和线性振幅扫描试验,分析了EC130沸石矿物和EC130温拌剂释放的发泡水对SBS改性沥青高温性能和抗疲劳性能的影响.结果表明:同石灰岩矿粉一样,沸石发泡沥青中的EC130沸石矿物使沥青弹性增大、黏性减小,有利于抗车辙性能的提升,但不利于抗疲劳性能;沸石发泡沥青中的发泡水使其黏性增大、弹性减小,有利于抗疲劳性能的提升,但不利于抗车辙性能.

废旧橡胶沥青发泡特性与最佳发泡条件研究

【目的】弥补传统泡沫沥青冷再生混合料力学性能的不足,将橡胶沥青与发泡技术结合,开发一种新型橡胶泡沫沥青。【方法】借助废植物油预润工艺制备了胶粉掺量为15.0%的两种不同活化程度的橡胶沥青,通过发泡特性优化试验,确定最佳发泡条件与工艺技术。【结果】采用活化橡胶沥青制备泡沫沥青具有可行性,发泡气压、发泡温度和发泡用水量对橡胶沥青发泡效果具有重要影响。橡胶沥青的膨胀率随发泡气压的升高而降低,本研究推荐300 kPa为最佳发泡气压。联合废植物油活化工艺和发泡剂,可实现膨胀率高达20.2倍、半衰期超过30 s的发泡效果。【结论】本研究有望解决橡胶沥青发泡效果差的难题,为橡胶泡沫沥青的推广应用提供技术参考。

表面活性泡沫沥青发泡工艺及流变特性研究

温拌沥青技术可降低沥青混合料生产和施工温度,在节能减碳方面极具应用潜力。泡沫温拌沥青技术成本较低,虽存在改性沥青发泡效果不理想、温拌效果不显著等问题,但具有潜在的推广应用前景。表面活性剂兼具“沥青润滑剂”和“泡沫稳定剂”的作用效能,为改善泡沫温拌沥青发泡特性和温拌效果提供了可能。基于此,本研究采用不同质量分数的表面活性剂水溶液,在不同发泡温度下制备了表面活性泡沫沥青(SAFB6,SAFB8,SAFB10),利用发泡试验、动态剪切流变试验以及弯曲梁流变试验测试了沥青的发泡特性、高温性能、抗疲劳性能和低温性能,并借助傅里叶红外光谱试验分析了作用机理,揭示了表面活性剂与发泡过程对泡沫温拌沥青性能的协同提升作用。试验结果表明:表面活性剂对SBS改性沥青的发泡特性有明显的协同作用,特别是半衰期,最大可达69 s;SAFB沥青最佳发泡条件为发泡温度170℃,表面活性剂含量8%;SAFB沥青制备过程中没有发生复杂的化学反应,但是发泡过程导致SBS改性沥青发生了一定程度的氧化作用;表面活性剂和发泡工艺的协同效应提高了SBS改性沥青的高温性能和抗疲劳性能,而低温抗裂性能与SBS改性沥青相当。总体而言,表面活性剂与发泡技术相结合是可行的,提高了SBS改性沥青的发泡效果和路用性能。

泡沫沥青冷再生混合料最佳沥青用量设计

结合泡沫沥青冷再生混合料的室内试验,探讨确定泡沫沥青再生混合料最佳沥青用量的方法和最佳油石比。采用干劈裂强度、湿劈裂强度、干湿劈裂强度比、冻融劈裂强度比、马歇尔稳定度和浸水马歇尔残留稳定度进行综合性能分析,获得最佳沥青用量。

沥青废料基泡沫陶瓷的制备及性能

为了拓展沥青废料的高附加值再利用,采用有机泡沫浸渍法制备沥青废料基泡沫陶瓷,利用X射线衍射分析、傅立叶变换红外光谱、热重-差式扫描量热分析、扫描电子显微分析等手段研究原料组成、性质、烧成工艺参数和样品性能。结果表明:沥青废料主要由二氧化硅,钠、钙、铝、硅元素组成的复杂氧化物,碳酸钙以及沥青残留有机物组成,在温度区间200~800℃存在有机物的两步分解;烧结温度1100℃保温90 min烧成泡沫陶瓷的孔隙率为65%,且表面存在Na_(0.45)Ca_(0.55)Al_(1.55)Si_(2.45)O_(8)复杂氧化物和大量球形二氧化硅,抗压强度为1.01 MPa。

发泡水对泡沫沥青粘聚/粘附性的多尺度影响研究

综合采用分子动力学模拟、水煮法实验、表面自由能实验和拉拔实验等宏微观方法,研究发泡水对沥青粘聚和粘附性的影响机制。结果表明,分子尺度上水分子排斥沥青分子,从而削弱沥青间界面能量;宏观尺度发现泡沫沥青与集料的抗水煮剥落性有所降低,发泡水对沥青的粘聚及粘附性不利,且发泡水越多对沥青的粘聚和粘附性损害越明显。泡沫沥青界面能与其粘聚和粘附性能具有高度相关性,可从宏观尺度和微观分子尺度解释发泡水对泡沫沥青粘聚/粘附性的多尺度影响。

Effects of diluted methanol and water as foaming agents on the performance of latex foamed warm asphalt mixtures

Latex as an asphalt modifier has gained popularity in the asphalt industry as it improves the durability of asphalt pavement.However,the elastomeric properties of latex stiffen the asphalt binders,resulting in additional energy consumption during the production of asphalt mixtures,which may cause a higher emission of greenhouse gases.This is undesirable for sustainable development and the environment.In this study,the applicability of diluted methanol and water was comparatively evaluated as foaming agents in the production of warm mix asphalt(WMA)mixtures incorporating latex.Diluted methanol was used because it has a lower boiling point and latent heat than water,allowing the asphalt mixture to be produced at a lower temperature and thus consuming less energy.The performance of the foamed asphalt mixture was investigated through service characteristics,mechanical performance,and moisture susceptibility of mixtures.The service characteristics,on the other hand,were measured in a laboratory while preparing and compacting the asphalt mixture,which refers to the amount of energy required during the production and construction stages in the asphalt plant and on the construction site,respectively.The degree of energy required was assessed based on the workability index,coatability index,and the compaction energy index.The mechanical performance of asphalt mixtures was characterized by indirect tensile strength,resilient modulus,and dynamic creep tests.The resistance to moisture damage was evaluated based on the common parameter,indirect tensile strength ratio.The findings revealed that the use of diluted methanol foaming agent helped improve the workability of latex modified asphalt mixtures.The foamed latex-modified WMA demonstrated better performance compared to asphalt mixtures prepared using water as the foaming agent.

泡沫沥青复合式冷再生混合料组成设计与性能评价

文中通过发泡试验确定了泡沫沥青的最佳发泡条件,采用马歇尔试验确定了RAP和RAI不同掺配比例下泡沫沥青的最佳掺量,测试分析了泡沫沥青复合式冷再生混合料的抗压强度、抗拉强度、水稳定性和动态模量等性能.结果表明:在发泡温度为160℃,发泡用水量为2.9%的条件下,沥青发泡效果最优;在最佳发泡条件下,RAP掺量为0%、20%、40%的三种方案对应的泡沫沥青最佳掺量分别为3.4%、3.1%、2.9%,此时,三种方案均有较好的抗压、抗拉、水稳定性,并且随着泡沫沥青冷再生混合料中RAP掺量的增加,柔化程度与抗拉性能均逐渐增大,但抗压性能与水稳定性能均有所降低.

基于数字图像技术的泡沫沥青效果评价方法研究

针对目前泡沫沥青仅凭借经验粗略确定最佳发泡参数条件的不足,该文采用数字图像处理技术,通过对不同发泡条件下泡沫沥青与铣刨料RAI拌和后的混合料进行图像采集,然后进行灰度图像转化、形态学处理、二值图像转化及网格划分等处理过程,计算不同区域内沥青裹覆率,以沥青在混合料中的均匀分散性为指标,对泡沫沥青的发泡效果进行评价并优选发泡参数。结果表明:采用数字图像处理技术能够快速有效地对泡沫沥青均匀分散效果进行评价,可计算出精确的数值作为判断依据优选发泡参数,具有简单快捷、易于实施的优点。

泡沫沥青冷再生技术在沅陵县G319路面大修工程中的应用

探讨沅陵县国道G319公路路面大修工程中泡沫沥青冷再生技术的应用效果。通过系统试验,确定了混合料的最佳含水量和最大干密度,为混合料的制备提供了关键参数。同时,确定了泡沫沥青的最佳用量,保障混合料性能的同时,实现了材料的经济和环保利用。工后测试显示,泡沫沥青冷再生混合料在干燥和浸水状态下的劈裂强度均满足设计要求,干湿劈裂强度比均超过77.4%,证明泡沫沥青冷再生混合料具有良好的水稳定性。此外,该技术在全过程中实现了84.4%的CO_(2)减排效率,特别是在拌和和铺筑环节,减排效率超过90%。研究结果表明,泡沫沥青冷再生技术在提高路面性能和耐久性的同时,显著降低了碳排放。

柔性基层泡沫沥青冷再生配合比及其应用

为解决泡沫沥青冷再生混合料的配合比设计难题,应用修正马歇尔法对泡沫沥青冷再生混合料进行配合比设计,确定级配为RAP料∶石屑∶水泥=80∶17.5∶2.5,通过重型击实法确定最佳含水率为7.5%,通过劈裂强度试验法确定水泥含量为2%~2.5%,通过间接抗拉强度ITS试验法确定泡沫沥青最佳用量为2.5%,通过浸水马歇尔试验、冻融劈裂试验及静压法进一步验证了泡沫沥青的水稳定性及无侧限抗压强度,结合实际项目研究了泡沫沥青冷再生柔性基层的应用效果。结果显示,泡沫沥青冷再生柔性基层能够提高施工效率,降低施工成本,具有良好的应用效果。

泡沫沥青再生混合料与水稳碎石试验对比分析

针对公路路面工程领域,提出泡沫沥青再生混合料与水稳碎石试验对比方案。详细阐述水泥稳定碎石基层试验分析与泡沫沥青再生混合料基层试验分析,对沥青发泡试验分析进行详细分析,从而达到节约工程支出的目的,研究表明:按合成级配中铣刨料、水泥的掺加比例,将各部分混合拌匀,再根据重型击实试验确定的最佳含水量对应的水量,加入到混合集料中进行拌和,然后分别加入4种泡沫沥青用量:1.9%、2.2%、2.5%、2.8%,与混合集料进行拌和。在不同沥青用量下制作试件,并测其干湿劈裂强度。通过干、湿劈裂强度及残留劈裂强度比3个指标综合比较,可得到2.2%泡沫沥青用量下再生效果,可满足施工需求与技术要求。

泡沫沥青就地冷再生作为路面基层的工程应用分析

沥青路面在日常养护和改扩建施工时,会产生大量的废旧材料。由于旧料中含有沥青成分,当作垃圾处理会污染环境。因此将这些旧料再生,既减轻了环境污染,又减少了材料消耗。再生技术的应用是实现公路可持续发展的重要手段。现行规范将沥青路面再生方式分为厂拌热再生、就地热再生、厂拌冷再生、就地冷再生和全深式冷再生5种。本文对泡沫沥青就地冷再生技术在工程实际中的应用进行具体说明及分析。

泡沫沥青冷再生技术在高速公路养护中的应用

为进一步提高高速公路使用效率,有必要对病害路段进行新的养护。文章介绍了泡沫沥青冷再生技术的发展现状、施工步骤及特点,结合G6京藏高速公路兰海段路面养护,重点分析了使用泡沫沥青冷再生技术的施工过程,从具体细节探讨混合料配合比设计、施工要点。实践证明,泡沫沥青冷再生技术值得在高速公路的养护中加以应用。