新老混凝土修补界面过渡区微细观结构改善方法的研究

针对新老混凝土修补界面薄弱过渡区的特点，提出改善方法，既选用适量浓度HCl和时间酸洗老混凝土界面，以显著提高老混凝土界面的微细观糙度，并不过度损务界面；在水泥净浆界面剂中加入粉灰和砂，以大幅度减少过渡区的收缩和粗大晶体含量，对比实验结果表明，以上两项措施，使老混凝土比表面积显著增加，过渡区微细观结构显著改善，粘结强度显著增高。     

PAN纤维增强沥青混合料断裂性能的数值模拟

以聚丙烯腈纤维(PAN纤维)为增强体,沥青混合料为基体,利用ABAQUS软件建立了多种纤维参数下的纤维沥青混合料两相结构有限元模型,并基于扩展有限元方法模拟PAN纤维沥青混合料的劈裂试验过程,由此分析纤维长度、掺量、直径、模量和强度对沥青混合料劈裂强度的影响.结果表明:在纤维掺量为0.1％～0.5％的范围内,有限元模拟...     

阻燃抑烟沥青混合料研究进展

为梳理阻燃抑烟沥青混合料研究现状,阐述了沥青热解与烟气产生的相关过程。其次,对现有的阻燃抑烟性能测试方法进行了总结,并将沥青烟气释放量测试方法分为质量损失法与吸附法。对阻燃沥青、阻燃纤维、多孔型阻燃路面三种沥青路面阻燃技术进行了介绍,并分析了降低拌合温度与添加抑烟组分两种抑烟手段的特点。针对沥青路面阻燃抑烟研究热点,提出了沥青路面阻燃抑烟后续研究要点与方向。     

沥青混合料原位取样结构的优化

沥青混合料是道路工程施工中的常用材料,通过对沥青混合料的测试,可以对沥青混合料的使用性能进行检测,反映出道路工程施工质量以及运行情况。在道路工程施工中,合理应用沥青混合料检测技术,做好现场取样、检测结果分析十分重要。在沥青混合料取样施工过程中,取样的精度、效率提升和降低取样对材料的影响常常是工程控制的重点和难点。对沥青混合料原位取样结构的优化,不仅提高了取样精度,还降低了取样对材料本身的影响,工程应用效果良好。     

沥青混合料高频振动搅拌施工技术浅析

公路养护中存在较多小范围路面破坏,为了精准快速地进行路面修复,将多级高频振动搅拌装置引入到沥青混合料搅拌中。应用结果表明：相较于常规搅拌技术,高频振动沥青混合物搅拌技术可以防止沥青混合料发生结块现象,减少内部孔隙,提高搅拌的均匀性和路面强度,延长路面使用寿命;搅拌装置内部构造设计合理,联动效果好,很好地保证了沥青混合料的搅拌质量,达到了高效、简洁、快速施工的效果。     

氯盐侵蚀条件下沥青混合料性能损伤评价

盐蚀环境使沥青路面性能劣化严重。采用马歇尔试件劈裂强度表征NaCl溶液浸泡与干湿循环作用下沥青混合料宏观力学性能;基于红外光谱(FTIR)、CT扫描图像探究氯盐对沥青性能损伤机理。从细观层次提出采用CT图像灰度变化方差值来定量评价沥青混合料盐蚀损伤程度。结果表明,干湿循环作用是导致沥青混合料性能劣化的显著因素;沥青混合料氯盐侵蚀损伤以物理作用为主;CT图像灰度变化方差值与沥青混合料力学强度呈极强负相关性,为研究盐蚀环境下沥青混合料性能损伤演化及耐久性预估提供新思路。     

沥青混合料的超声波强度检测

根据超声波检测的基本原理对沥青混合料长方体试件进行了强度检测,并对超声波检测的影响因素进行了理论分析.结果表明:超声波的声速与沥青混合料强度之间具有良好的相关性,可以很好地预测沥青混合料的强度.     

LM-S沥青改性剂提高沥青混合料黏附性能的分子模拟计算及路用性能考察

沥青与石料的黏附性大小直接影响沥青混合料的强度、稳定性、耐久性等性质。通过分子模拟计算的方法研究沥青与石料的黏附作用,计算比较沥青改性前后与石料间的黏附功,并与水煮法沥青黏附性实验结果及沥青混合料微观形貌研究结果进行比对;同时考察沥青改性剂LM-S对沥青混合料路用性能的改进效果。结果表明,采用LM-S改性后的沥青-石料体系的界面黏附功比基质沥青-石料体系提高了近26%,因而具有更好的黏附性;沥青混合料实验结果亦表明LM-S改性剂可显著提高基质沥青和SBS改性沥青混合料的高温稳定性能、低温稳定性能及水稳定性性能,其中动稳定度分别提高了162%和43%。     

钢渣沥青混合料微波加热自愈合性能研究

为了研究钢渣沥青混合料微波加热自愈合性能,制备了全石型、粗石细钢型、粗钢细石型、全钢型4种沥青混合料,采用热常数分析仪和矢量网络分析仪测试了沥青混合料的热参数和电磁参数,利用热电偶温度传感器和红外测温仪测试了沥青混合料的温度分布,并对比分析了COMSOL软件数值模拟温度场与试验温度分布;最后,采用三点弯曲破坏试验评价了沥青混合料的自愈合性能。结果表明:4种沥青混合料具有不同的微波吸收性能和传热性能,会对沥青混合料的加热速率产生一定影响;钢渣的掺入大大提高了沥青混合料的微波加热性能,且3种钢渣沥青混合料中粗石细钢型表现出较好的加热均匀性;COMSOL软件能够较好地模拟沥青混合料在微波加热下的温度分布;相比于全石型沥青混合料,粗石细钢型、粗钢细石型、全钢型沥青混合料的自愈合性能分别提高了1.11倍、1.14倍、1.11倍,钢渣的掺入较好地提高了沥青混合料的自愈合性能。     

Quantitative evaluation of asphalt blending characteristics in epoxy-modified hot recycled asphalt mixtures based on 3D confocal fluorescence technology

This study proposes a novel method to quantitatively evaluate the blending effect between aged asphalt and epoxy asphalt in epoxy asphalt-modified hot recycled asphalt mixture, based on three-dimensional confocal fluorescence microscopy technology. Samples of epoxy asphalt-modified hot recycled asphalt mixtures were prepared in a laboratory using new aggregates, epoxy asphalt, and reclaimed asphalt pavement materials that were simulated in the laboratory by subjecting new asphalt mixtures to a short-term and long-term aging process. Cube-shaped stone aggregates were designed to distinguish between new aggregates and reclaimed aggregates. The distribution of epoxy resin in the epoxy asphalt-modified hot recycled mixtures was tracked using a laser scanning confocal microscope. To address the depth attenuation issue caused by light absorption and scattering, as well as the overall intensity differences resulting from field depth differences and attenuation morphology, a depth compensation function and a feature weight allocation method were proposed. Results from the above method indicated that the degree of blending (DoB) ranged from 65% to 75% on the surface of new aggregates but from 45% to 70% on the surface of reclaimed aggregates. Most of the old asphalt still adhered to the surface of reclaimed aggregates after migration. The proportion of epoxy asphalt in the outer layer of asphalt film on new aggregates is higher than that on reclaimed aggregates. The DoB between the asphalt binders significantly decreased as the aging degree increased. Increasing the epoxy content reduced the viscosity of the epoxy asphalt and effectively improved the DoB between the new and old asphalt binders.     

溶剂脱沥青生产道路沥青技术进展

道路沥青是一种重要的筑路材料 ,国内多数原油通过蒸馏不能生产合格道路沥青 ,溶剂脱沥青生产道路沥青对国内道路沥青的生产具有重要的意义。本文综述了国内溶剂脱沥青生产道路沥青的研究进展。     

基于化学链技术制氢的研究进展

利用氢能替代常规化石能源是运输行业应对气候变化和环境污染问题的一个重要突破口。将化学链技术应用于制氢过程不仅可以提高能量转换效率、减少环境污染,还可以在制氢的同时捕捉该过程产生的CO2,具有广阔的发展前景。本文概述了化学链制氢的两种方式的原理及特点,总结了不同过程在载氧体的筛选、反应器的形式以及系统模拟方面的研究现状。指出高效载氧体的筛选和制备是各个过程成功运行的关键。化学链水蒸气重整制氢[CLR(s)]过程需要考虑管束的磨损问题,而自热化学链重整制氢[CLR(a)]过程需要注意过程中的反应热量平衡。廉价载氧体的筛选、固体燃料的化学链制氢及其系统开发是化学链制氢(CLH)过程未来研究方向。     

Influence of composition on temperature induced stresses in asphalt concrete mixtures

In an earlier paper a theoretical approach to calculate temperature induced stresses in viscoelastic plain plates which are cooled from one side is described. In this supplementary contribution the viscoelastic behaviour of samples of asphalt concrete with four different mix proportions has been studied. Corresponding values of an earlier report are included for reasons of comparison. It is shown that the maximum stress created by a temperature change is dependent on the composition of the material, i.e., the amount and type of bitumen added to the concrete. Using the experimentally determined materials properties, thermal stresses to be expected under given climatic conditions can be calculated by means of a computer parameter study. In this way an optimum mix proportion for different climatic environments can be found systematically.     

Crystallization of mullite in the mixtures obtained using the sol-gel technology

Translated from Steklo i Keramika, No. 8, pp. 18–19, August, 1989.     

Investigation on compatibility and microstructure of PCBs‐modified asphalt

Due to the increasing production of waste Printed Circuit Boards (PCBs), there is a strong need to investigate the effective method how to recycle PCBs for protecting the environment. In this study, the PCBs were added to asphalt for preparing the PCBs‐modified asphalt to improve the performance of asphalt. The influences of PCBs on Cole‐Cole plots, segregation index, ratio difference number, and microstructure of modified asphalt were evaluated by storage stability tests, dynamic shear rheometer tests, fluorescence microscopy analysis, and fourier‐transform infrared spectroscopy analysis, respectively. The results show that addition of PCBs can improve rheological properties of asphalt and the PCBs content has significant influence on the compatibility and microstructure of modified asphalt. The optimum content of PCBs is no more than 10 wt % for the better compatibility and storage stability of PCBs‐modified asphalt. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44798.     

超临界流体技术制备微胶囊的研究进展

介绍了国内外使用超临界流体技术制备微胶囊的原理和方法,叙述了微胶囊技术的发展,着重分析了超临界流体快速膨胀(RESS)法、气体抗溶剂结晶(SAS)法和气体饱和(PGSS)法的特点,阐述了各种制备微胶囊方法的应用研究现状和存在的问题.     

渗透汽化汽油脱硫技术研究进展

随着环保法规的日益严格,世界各国对清洁汽油中硫含量做出了严格的规定,汽油的低硫化甚至无硫化已成为一种必然趋势,汽油的深度脱硫技术已成为各石油公司和相关研究者的研究热点。渗透汽化是一种新型高效的膜分离技术,其在汽油深度脱硫技术方面具有独特优势。介绍了渗透汽化汽油脱硫技术的基本原理、工艺特点及国内外有关研究进展情况。     

Study on combustion mechanism of asphalt binder by using TG-FTIR technique

The combustion mechanism of asphalt binder was investigated by using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FTIR) in a mixed gas environment of 21% oxygen and 79% nitrogen. The results show that the combustion process of asphalt binder consists of three main consecutive stages at a low heating rate. The combustion reaction becomes more and more intense from the 1st to 3rd stage. The release of volatiles occurs mainly at 300-570 °C, and the gaseous products in each stage are different. The main products in the 1st stage are CO₂, CO, H₂O, hydrocarbons, formaldehyde, tetrahydrofuran, formic acid, aromatic compounds, etc. In the next stage, the combustion products mentioned above keep on increasing, but some new volatiles such as alcohols, phenols, styrene, etc. are present. In the last stage, the CH and CO bonds continue to fracture and aromatization reaction occurs, and the release amount of CO₂, CO, and H₂O reaches the maximum. But the content of other products decreases or even disappears due to burning. Among the above volatiles, CO₂ is the dominant gaseous product in the whole combustion process. The concentration of CO₂ and CO keeps increasing, and reaches the maximum intensity at about 520 °C. The evolution of H₂O, CH₄, and formic acid exhibits the trend of increase first, and then decrease. Over 570 °C, there are few products released at the end of the combustion process. Asphalt binder combustion process includes two modes of complete and incomplete combustion, and the latter may be main combustion mode of asphalt binder.     

Advances in the stabilization of flexible PVC by using a liquid calcium‐zinc technology

The global market for liquid mixed‐metal stabilizers is migrating toward heavy‐metal‐free products, Historically, these systems have not been performance and cost competitive. High efficiency calcium‐zinc stabilizers have the potential to replace heavy‐metal‐based products. The intrinsic value of non‐phenolic lubricating calcium intermediates and calcium‐zinc stabilizers is discussed.