Technologies for Asphalt Pavement Surface Testing in Road and Bridge Construction

Asphalt pavement is currently one of the main components in the construction of roads and bridges.However,from a practical point of view,various quality problems are prone to occur in the surface layer of asphalt pavement,which will lead to the poor overall quality of road and bridge projects.Therefore,it should be applied reasonably.Advanced testing technologies are used to test the mixture quality,compaction,segregation,thickness,and other aspects of the asphalt pavement surface layer,so as to improve the quality of the asphalt pavement surface layer,and then improve the overall quality of road and bridge construction.Therefore,this paper mainly analyzes the technologies for asphalt pavement surface layer testing in road and bridge engineering construction.

Bamboo Fiber Modified Asphalt Mixture Proportion Design and Road Performances Based on Response Surface Method

In order to comprehensively utilize the remaining bamboo residue of bamboo products,this paper presents a research on recycling the bamboo fibers from bamboo residue for improving the performance of the asphalt mixtures.First of all,the basic performance parameters of sinocalamus affinis fiber,phyllostachys pubescens fiber,green bamboo fiber were tested and analyzed,and the optimal content and length were put forward.Then,the mix ratio design of the bamboo fiber modified asphalt mixture was further designed through the response surface method,and was verified the rationality of the mix ratio.Finally,the mixture specimens were made according to the experimental design mix ratio,and the high temperature,low temperature performance and moisture susceptibility of the bamboo fiber modified mixtures asphalt were tested.The results showed that the high temperature performance,low temperature performance and moisture susceptibility of bamboo fiber modified asphalt mixtures were improved compared with the performance of SBS modified asphalt mixture.When the length of bamboo fiber is 7.25 mm and the content of 0.22%,the road performance of the asphalt mixture was optimal.Consequentially,the decomposition of bamboo residue into bamboo fiber and its application in asphalt pavement can improve the reuse of bamboo waste,with remarkable environmental benefits and great promotion value.

Evaluation of Compatibilizers for Improving Compatibility between Waste Vegetable Oil and Aged Asphalt

Modifying agents 2,2-Bis(4-glycidyloxyphenyl)propane(2BPE)and dibutyl phthalate(DBP)were selected to enhance the compatibility.By using molecular simulation software(Materials Studio,MS),nine systems were constructed,including molecular models of aged asphalt and WVO monomers with 2BPE and/or DBP.The solubility parameters,Flory-Huggins parameters,and interaction energies of these systems were calculated to determine the impact of 2BPE and DBP on the compatibility of WVO and aged asphalt.Results showed that the addition of 2BPE and DBP reduced the difference in the solubility parameters between WVO and aged asphalt,thus improving the compatibility between WVO and aged asphalt.Additionally,using a combination of 2BPE and DBP in both aged asphalt and rejuvenator was found to be more effective than using either 2BPE or DBP alone.Finally,it was determined that evaluating the compatibility of WVO and aged asphalt using Van der Waals potential and non-bonding energy as evaluation indicators was more accurate than using electrostatic potential energy.

Application of Modified Asphalt in Municipal Roads

The article expounds modified asphalt technology by introducing commonly used modifiers and fillers and analyzing the construction technology of modified asphalt.The use of modified asphalt in municipal roads provides new alternatives for asphalt pavement materials,but also solves the existing construction problems and reduces project costs.Therefore,the research and application of modified asphalt using new materials and new processes is a crucial aspect in road construction.

Research Progress of Epoxy Asphalt Material for Roads

Asphalt is a semi-solid or solid mixture formed by hydrocarbons and non-metallic elements.It is widely applied in the fields of building waterproofing and road paving.Asphalt is a low noise,durable,and renewable pavement material.However,asphalt materials have some shortcomings such as liquefying at high temperatures and brittleness at low temperatures,which are less adaptable to different environments.Therefore,people have gradually shifted their focus to asphalt modification.This paper presents an in-depth analysis and research on the composition,structure,and performance of epoxy asphalt materials for roads,so that this material can be widely used.

Preparation and Analysis of Carbon Fiber-Silicon Carbide Thermally Conductive Asphalt Concrete

An experimental investigation into the thermal conductivity of CF-SiC two-phase composite asphalt concrete is presented.The main objective of this study was to verify the possibility of using SiC powder instead of mineral powder as the thermal conductive filler to prepare a new type of asphalt concrete and improve the efficiency of electrothermal snow and ice melting systems accordingly.The thermal conductivity of asphalt concrete prepared with different thermally conductive fillers was tested by a transient plane source method,and the related performances were measured.Then the temperature rise rate and surface temperature were studied through field heating tests.Finally,the actual ice melting efficiency of the thermally conductive asphalt concrete was evaluated using an effective electrothermal system.As shown by the experimental results,the composite made of SiC powder and carbon fiber has a high thermal conductivity.When SiC replaces mineral powder,the thermal conductivity of the asphalt mixture increases first and then decreases with the increase of carbon fiber content.In the present study,in particular,the thermal conductivity attained a peak when the carbon fiber content was 0.2%of the aggregate mass.

基于响应曲面法的TiO_(2)/ZnO/BF改性沥青混合料性能分析

探究玄武岩纤维掺量、纳米TiO_(2)/ZnO掺量和油石比对沥青混合料的路用性能的影响,依据最优解制备复合改性沥青混合料,通过车辙试验、低温弯曲试验、浸水马歇尔试验、冻融劈裂试验和四点弯曲疲劳试验进行路用性能验证。结果表明,复合改性沥青混合料最优配比为:纳米TiO_(2)/ZnO掺量3.99%,玄武岩纤维掺量6.16%,油石比5.44%。此方案下复合改性沥青混合料路用性能显著提升,相比于基质沥青和仅采用玄武岩纤维的改性沥青混合料,其水稳定性和高温性能提升最为明显。在不同应变条件下,复合改性沥青混合料疲劳寿命均为3种混合料中最大值,但其低温性能相较于仅采用玄武岩纤维的改性沥青混合料提升较小。

Intelligent Segmentation and Measurement Model for Asphalt Road Cracks Based on Modified Mask R-CNN Algorithm

Nowadays, asphalt road has dominated highways around the world. Among various defects of asphalt road, crackshave been paid more attention, since cracks often cause major engineering and personnel safety incidents. Currentmanual crack inspection methods are time-consuming and labor-intensive, and most segmentation methods cannot detect cracks at the pixel level. This paper proposes an intelligent segmentation and measurement model basedon the modified Mask R-CNN algorithm to automatically and accurately detect asphalt road cracks. The modelproposed in this paper mainly includes a convolutional neural network (CNN), an optimized region proposalnetwork (RPN), a region of interest (RoI) Align layer, a candidate area classification network and a Mask branch offully convolutional network (FCN). The ratio and size of anchors in the RPN are adjusted to improve the accuracyand efficiency of segmentation. Soft non-maximum suppression (Soft-NMS) algorithm is developed to improvethe segmentation accuracy. A dataset including 8,689 images (512× 512 pixels) of asphalt cracks is established andthe road crack is manually marked. Transfer learning is used to initialize the model parameters in the trainingprocess. To optimize the model training parameters, multiple comparison experiments are performed, and the testresults show that the mean average precision (mAP) value and F1-score of the optimal trained model are 0.952 and0.949. Subsequently, the robustness verification test and comparative test of the trained model are conducted andthe topological features of the crack are extracted. Then, the damage area, length and average width of the crackare measured automatically and accurately at pixel level. More importantly, this paper develops an automatic crackdetection platform for asphalt roads to automatically extract the number, area, length and average width of cracks,which can significantly improve the crack detection efficiency for the road maintenance industry.

Dynamic Mechanical Characterizations and Road Performances of Flame Retardant Asphalt Mortars and Concretes

To research the dynamic mechanical properties and road performances of flame retardant asphalt mortars and mixtures, four different asphalt mortars/mixtures were prepared: a reference group and three asphalt mortars/mixtures containing composite flame retardant materials(M-FRs) of different proportions. Temperature sweep, frequency sweep, repeated creep test, force ductility test and bending beam rheological test were carried out to research the dynamic mechanical properties of asphalt mortars containing M-FRs; wheeltracking test, low-temperature bending test and freeze-thaw split test were used to study the road performances of asphalt mixtures containing M-FRs. The results show that high-temperature performances of the three flame retardant asphalt mortars improve greatly, while low-temperature cracking resistances decline. Both hightemperature performances and water stabilities of asphalt mixtures containing M-FRs are quite good and exceed the specification requirements. However, their low-temperature performances decline in different degrees. In summary, besides their good flame retardancy, the flame retardant asphalt mortars and mixtures also exhibit acceptable road performance.

Normalization method for asphalt mixture fatigue equation under different loading frequencies

In order to analyze the effect of different loading frequencies on the fatigue performance for asphalt mixture,the changing law of asphalt mixture strengths with loading speed was revealed by strength tests under different loading speeds.Fatigue equations of asphalt mixtures based on the nominal stress ratio and real stress ratio were established using fatigue tests under different loading frequencies.It was revealed that the strength of the asphalt mixture is affected by the loading speed greatly.It was also discovered that the fatigue equation based on the nominal stress ratio will change with the change of the fatigue loading speed.There is no uniqueness.But the fatigue equation based on the real stress ratio doesn't change with the loading frequency.It has the uniqueness.The results indicate the fatigue equation based on the real stress ratio can realize the normalization of the asphalt mixture fatigue equation under different loading frequencies.It can greatly benefit the analysis of the fatigue characteristics under different vehicle speeds for asphalt pavement.

Recent developments in asphalt-aggregate separation technology for reclaimed asphalt pavement

Reclaimed asphalt pavement(RAP)has significant recycling value because it contains nonrenewable resources including asphalt and aggregate.However,thus far,only a small part of RAP materials can be used in the con-struction of recycled asphalt pavement,and the usage is regarded as a low-value utilization in the underlying layers.One of the most important reasons for this shortcoming is the problem of false particle size and pseudo gradation of RAP materials.Therefore,identifying suitable asphalt-aggregate separation technology is essential for improving the utilization of RAP materials in recycled asphalt mixture and enhancing the construction quality of recycled asphalt pavement.To address this,the paper performed a systematic review of asphalt-aggregate separation technologies for processing RAP materials and their prospects.Firstly,based on the composition of the asphalt mixture and the characteristics of RAP materials after aging,the key RAP separation technologies were proposed.Then,the concept,principle,and implementation methods of physical,chemical,and biological sep-aration methods of RAP materials were comprehensively analyzed.Moreover,the advantages and disadvantages of various separation technologies were discussed by comparing them with the related technologies in the petrochemical industry.The application prospects of various asphalt-aggregate separation methods for RAP materials can provide a reference for upgrading and expanding solid waste recycling technology for asphalt pavement.

Structural Design of Asphalt Pavement for Low Cost Rural Roads

On the basis of the equivalent axle load action frequency, the traffic classifications of rural roads as well as their corresponding types are classified. The asphalt pavement structure, road surface types and thickness of the rural roads are suggested for the various action frequency of the equivalent axle load. Furthermore, the roadbase thickness graphs are provided according to different equivalent axle load action frequency with different roadbed modulus and road surface modulus taken into account.

基于正交试验的纳米ZnO/SEBS复合改性沥青性能

为使改性沥青混合料具有良好的性能,能够在一些极端环境下正常使用,选择纳米ZnO和苯乙烯-乙烯-丁二烯-苯乙烯(styrene-ethylene-butadiene-styrene,SEBS)两类改性剂复合对70号沥青进行改性。利用正交试验对复合改性沥青的制备方案进行优化,并通过布氏旋转黏度、针入度、延度、软化点和高低温流变等实验,对纳米ZnO、SEBS、纳米ZnO/SEBS改性沥青以及基质沥青的黏滞性、温度敏感性、高低温流变性能以及性能分级(performance grading,PG)进行比较分析,以此确定最优配方。试验结果表明,纳米ZnO/SEBS复合改性沥青最优制备改性剂掺量为3%纳米ZnO+5%SEBS,最优制备方案为先加SEBS后加纳米ZnO;此掺量复合改性沥青的温度敏感性显著降低,低温抗裂性能以及PG连续分级的高低温服务温度范围均有明显改善,对沥青高温性能提升最为显著。

Materials,preparation,performances and mechanism of polyurethane modified asphalt and its mixture:A systematic review

With the rapid development of asphalt pavement technology,it has attracted considerable attention to improving the durability of asphalt pavement.An effective action is to use modified asphalt with high performance and durability.Polyurethane(PU)has been used in asphalt pavement engineering to enhance the durability and service life of asphalt pavement because of its excellent high-temperature performance,toughness,wear resistance,aging resistance and oil resistance.However,PU modified asphalt technology is still in the exploratory stage.The preparation,modification mechanism and working performances of PU modified asphalt need to be further clarified.Therefore,this paper summarized the research progress of PU modified asphalt and its mixture.The composition of PU modified asphalt was introduced.The addition methods of PU materials and preparation process parameters of the PU modified asphalt were determined.The modification mechanism of PU on asphalt was discussed.The effects of polyurethane on asphalt were analyzed and the road performances of its mixture were evaluated.Finally,the development tendency towards PU modified asphalt and its mixture were forecasted.

醋酸钠融雪剂对纳米ZnO改性沥青混合料性能评价分析

为研究醋酸钠融雪剂对于纳米ZnO改性沥青及其混合料性能的影响规律,采用不同质量浓度醋酸钠对应的融冰体积指标评价了融冰化雪能力,从沥青3大指标试验分析了醋酸钠融雪剂对于沥青基本性能的影响,采用车辙试验、低温小梁弯曲试验和浸水马歇尔试验探讨了醋酸钠融雪剂对于纳米ZnO改性沥青混合料路用性能的影响。结果表明,醋酸钠质量浓度在0.2 g/mL时融冰效果最佳,沥青3大指标随融雪剂质量浓度增大而减小,纳米ZnO不仅提高了沥青混合料的高低温性能和水稳定性,而且明显改善了沥青混合料路用性能对于醋酸钠融雪剂的耐侵蚀性。

不同纤维增韧环氧沥青混合料性能

为探究不同种类纤维(玄武岩纤维、玻璃纤维和聚酯纤维)对环氧沥青混合料抗开裂和耐疲劳性能的提升效果,在混合料配比设计的基础上,采用车辙试验、低温小梁试验、浸水马歇尔试验以及冻融劈裂试验等对其进行路用性能测试。通过冲击试验,探究纤维对环氧沥青混合料的三种增韧效果:在环氧沥青混合料中添加纤维可以不同程度提高其路用性能;低温性能再加入纤维后,提升效果较为明显;添加玄武岩纤维路用性能优于玻璃纤维和聚酯纤维。

道路沥青紫外老化及抗老化材料研究综述

道路沥青材料在使用过程中由于长期受到太阳光紫外辐射作用会产生紫外老化现象,并且这种现象在紫外辐射强度高的地区更明显。紫外老化会使沥青的物理特性和化学组成发生改变,从而导致沥青黏塑性上升、低温和疲劳性能下降、使用裂缝增加,进而劣化路面的耐久性、影响沥青路面的运营品质和服役寿命。为了防止和延缓紫外老化的产生和发展,可在道路沥青中添加抗老化材料以增强其抵御紫外老化能力,同时延长沥青路面的使用寿命并降低其性能的衰变速率。本文阐述了基于自由基和胶体理论的紫外老化机理;从处理方式、光源与辐射强度选择等方面介绍了室内模拟老化试验条件;总结了紫外老化对沥青物理和流变性能、组分构成、微观形貌、特征峰和官能团等宏微观特性的影响;归纳了现行抗老化材料的优缺点和使用情况。分析表明后期可在老化机理深度、试验方法标准化、室外老化监测、微观数值模拟、抗紫外老化剂针对性和抑制紫外老化措施等方面开展进一步研究。

不同钢渣掺量AC-16沥青混合料性能研究

研究将钢渣应用于道路建设中的可行性和钢渣沥青混合料性能特点,揭示混合料性能随钢渣掺量不同的变化规律。将钢渣0%、25%、50%、75%掺量代替石灰岩集料制备钢渣沥青混合料,采用高温单轴贯入试验、低温劈裂强度试验、冻融劈裂强度试验、间接拉伸疲劳试验,分别针对不同钢渣掺量下沥青混合料的高温性能、低温性能、水稳定性与疲劳性能展开相应研究。试验结果表明,钢渣各项性能指标均满足规范要求,可以作为集料制备沥青混合料,掺加钢渣后沥青混合料各项性能均有不同程度提高。随着钢渣掺量的提高沥青混合料各项性能变化规律不同,建议钢渣掺量控制在50%左右,以达到沥青混合料综合性能最优。

Analysis of New Materials Application in Municipal Road Construction

In order to promote the development of road traffic in our country,it is necessary to strengthen the research on municipal road construction technology,constantly innovate construction technology and construction technique,and then effectively ensure the rapid development of urban traffic.This paper mainly elaborates on asphalt road surface regeneration technology,modified asphalt concrete,concrete road surface anti-cracking technology,three-dimensional printing technology,composite material road surface,polymer composite materials,etc.,to ensure the development of urban transportation and the quality of municipal road projects.

高模量改性沥青的零剪切黏度研究

零剪切黏度(Zero-shear Viscosity, ZSV)是表征沥青抵抗永久变形能力的高温性能评价指标。为明确不同测试方法及计算模型对高模量改性沥青的ZSV计算值的影响及适用性,以推广高模量改性剂在道路工程的应用,采用动态剪切流变仪对基质沥青(Base Asphalt, BA)和含不同质量分数改性剂的高模量改性沥青(K1-HMB)进行60℃频率扫描试验和60℃稳态流动试验,并采用Cross流变模型及Carreau流变模型分别拟合沥青的ZSV,最后采用灰色关联分析法探讨ZSV与软化点之间的关联程度。结果表明:BA及K1-HMB属于伪塑性流体,在加载频率作用下均呈现剪切变稀的特征;含0.6%改性剂的K1-HMB具有最高的弹性恢复能力,K1-HM改性剂的建议质量分数为0.4%~0.6%;60℃频率扫描试验结合Cross模型计算的ZSV拟合值具有最高的可信度,可作为高模量改性沥青高温性能的评价指标。