Field and laboratory performance comparison for asphalt mixtures with different moisture conditioning systems

The purpose of this study is to compare laboratory and field performances for dense graded asphalt mixtures. Control road pavement section was constructed in Black Sea Coast Highway. Marshall identical control samples produced in laboratory and core samples taken from wearing courses before the traffic opened were used. Three different moisture conditioning methods were applied to control laboratory and core samples. Mechanical properties of samples were evaluated with indirect tension, indirect tension strength and repeated creep tests. Indirect tensile strength test results for laboratory mixtures were found 1.22 and 1.30 times more in accordance with field samples at 10 °C and 20 °C respectively. Marshall samples gave higher resilient modulus for all control and conditioned mixtures. Repeated creep test results also proved the difference between laboratory and field sample performance. Laboratory samples protected their structural integrity along with the test duration and did not showed tertiary creep. It is concluded from this study that laboratory samples state expressly higher performance according to the core field samples.     

燃烧法在检测沥青混合料中的应用

阐明了利用燃烧法测定沥青混合料的原理,结合沥青混合料的组成成分,从沥青用量修正系数确定与混合料级配修正两方面对燃烧炉的标定进行了分析研究,以供参考借鉴。     

Utilization of steel slag as aggregates for stone mastic asphalt (SMA) mixtures

Steel slag is a byproduct making up a portion of 15–20% of iron output in an integrated steel mill. Most of them are deposited in slag storing yards and thus results in many serious environment problems in China. This paper aims to explore the feasibility of utilizing steel slag as aggregates in stone mastic asphalt (SMA) mixtures, and properties of such asphalt mixtures are evaluated as well. X-ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) were employed to study the compositions, structure and morphology of aggregates. Volume properties and pavement performances of SMA mixture with steel slag were also evaluated as compared to that with basalt as aggregates. Results indicated that volume properties of SMA mixture with steel slag satisfied the related specifications and expansion rate was below 1% after 7 days. When compared with basalt, high temperature property and the resistance to low temperature cracking of SMA mixture were improved by using steel slag as aggregate. In-service SMA pavement with steel slag also presented excellent performance on roughness and British Pendulum Number (BPN) coefficient of surface.     

沥青含量对多孔隙沥青混合料性能的影响

本文通过旋转压实试验分析沥青结合料含量与沥青混合料体积性能的关系。结果表明:多孔隙沥青混合料密度随沥青含量的增加而增加;混合料的空隙率随沥青含量的增加而减小;孔隙率随沥青含量的增加而降低;沥青饱和度随沥青含量的增加呈线性递增关系;沥青含量越低,多孔隙沥青混合料渗透性越高;多孔隙沥青混合料磨损损失随沥青含量的增加而降低。     

浅谈沥青混合料的拌合时间

介绍了沥青混合料拌合时间的物理意义及其重要性,阐述了影响拌合时间的因素,并对如何确定最佳拌合时间进行了论述,以提高沥青路面的使用质量,延长沥青路面的使用寿命。     

沥青及沥青混合料低温流变性质研究

针对低温开裂在沥青路面上普遍存在的现象，对沥青和沥青混合料低温性质进行了研究，提出了改善沥青低温性能的方法，并对沥青和沥青混合料的低温性质进行了比较。     

Framework for developing a static strength test for measuring deformation resistance of asphalt concrete mixtures

This study deals with a strength property which is showing high correlation with rutting resistance of asphalt mixtures. The test procedure was developed by applying a load to the compacted asphalt samples and calculating the strength by using the deformation of the mixture at the failure point. To evaluate the validity of this test, various mixtures were prepared with two aggregates and seven binders using four loading head types at the loading speed of 50.8 mm/min at 60 °C. Maximum load and deformation were recorded for each test and deformation strength, S_D, was calculated using a newly developed equation. For the same mixture, wheel tracking test was performed and two rut parameters, depth of rut and dynamic stability were obtained. The relationship between S_D and rut parameters was evaluated using regression analyses. In most cases, R² values were found to be over 0.9. This test procedure is still under development; however, current results indicate that it might be a simple test to predict the deformation resistance of asphalt mixtures at high temperatures.     

高模量改性沥青与基质沥青混合料路用性能对比实验研究

本文为了寻求满足湿热地区气候特征的改性沥青,通过室内实验研究壳牌70#基质沥青混合料和高模量改性沥青混合料(壳牌70#基质沥青添加高模量改性剂)的高温性能、低温性能以及水稳定性,并对两种沥青混合料路用性能进行对比,实验研究表明添加高模量改性剂后混合料的动稳定度得到明显的提高,且低温性能和水稳定性也有一定程度的提高。这将为解决南方湿热地区车辙病害等问题提供一种新材料。     

增强沥青混合料低温抗裂性能的试验研究

针对我国东北地区冬季低温路面开裂现象,从路面材料角度着手,采用AC-131和AK-131两种沥青混合料级配、SBS改性剂、木质素纤维和钢纤维等加强材料,通过-10℃低温劈裂试验,研究加强前后沥青混合料的低温劈裂强度、劲度模量以及变形能力等力学指标,分析其对沥青混合料低温抗裂性能的改善作用并揭示其作用机理.结果表明,钢纤维掺入到AC-131沥青混合料中低温抗裂作用显著提高,适合于东北寒冷地区路面使用.     

密级配沥青混合料沥青膜厚度优选

通过Bailey,Superpave和马歇尔三种方法设计级配,选用六种沥青含量进行了车辙试验,研究了沥青膜厚与车辙动稳定度之间的关系,提出了基于高温性能的密级配沥青混合料沥青膜厚的建议.     

沥青类型对沥青混凝土路用性能影响的试验研究

通过马歇尔试验,确定了不同沥青含量条件下AC-13Ⅰ的最佳沥青含量,进而对沥青混凝土的各项路用指标进行了车辙试验,水稳性试验及疲劳试验研究,结果表明,采用SBS改性沥青的混合料具有良好的路用性能,经济效益和社会效益。     

冷铺沥青混合料路用性能评价

结合冷拌冷铺沥青混合料在国外的广泛应用,针对国内在冷拌冷铺沥青混合料路用性能检测方面的空白,对其路用性能评价方法与评价指标进行了研究,提出了冷拌冷铺沥青混合料各项技术指标的评价方法及推荐值。     

Investigation into the properties of asphalt mixtures containing magnesium hydroxide flame retardant

In this study, horizontal burning, limiting oxygen index (LOI) and direct burning tests were conducted to evaluate the effects of magnesium hydroxide (MH) on flame retardancy for asphalt. The influence of MH on the mechanical properties of the asphalt mixtures was also evaluated using a Marshall stability test and an indirect tensile strength test. The results indicate that MH improves the thermal stability of asphalt. The presence of MH reduces the horizontal burning classification of asphalt from FH-3 to FH-1, and the LOI is also increased. Reductions in the average burning time and mass loss were observed. The volume of flammable volatiles released from asphalt was reduced. By replacing some of the mineral filler in asphalt with equal quantities of MH, the Marshall stability was increased, its loss decreased. Similarly, the indirect tensile strength (ITS) was increased, but the ITS loss increased slightly. It is concluded that MH can be used as flame retardant for asphalt mixtures without significantly reducing the original pavement performance. This may provide a novel and safer road material, especially for use in tunnel roadways.     

抗车辙剂沥青混合料性能试验研究

本文主要研究抗车辙剂对沥青混合料性能的影响,通过一系列室内试验对掺入的抗车辙剂沥青混合料的高温性能、低温抗裂性能、水稳定性能进行评价。同时又进一步分析了加载频率影响下的动态模量和相位角的变化规律。试验结果表明:抗车辙剂对沥青混合料性能有促进作用,能明显提高沥青混合料高温性能。冻断试验结果证明抗车辙剂对沥青混合料低温性能没有太大影响。根据动态模量及相位角与加载频率的关系,说明随着加载频率的增加动态模量增加有一个限定值,抗车辙剂的加入使沥青混合料在低温高频时弹性体特征表现得更强。     

沥青混合料的老化机理分析

从沥青、沥青与集料之间的相互作用和环境影响因素方面，研究了沥青混合料的老化，从化学方面探讨了沥青混合料的老化机理，指出老化伴随着沥青路面的整个使用过程，也影响着沥青路面路用性能的各个方面。     

光老化对沥青混合料空隙率的影响

通过室内实验方法模拟沥青路面在外界自然条件下的光老化,然后对比不同级配的混合料在老化后的孔隙率的分布情况,得出了开级配和半开级配空隙率在不同光照条件下的变化情况,并分析其原因,对今后沥青路面施工具有一定指导意义。     

影响沥青混合料振动压实的主要因素分析研究

沥青混合料的振动压实对沥青混凝土结构的形成起着至关重要的作用,是保证沥青混凝土防渗性能的重要环节。结合土石坝沥青混凝土心墙工程实例,介绍了沥青混合料的振动压实原理、各项工艺参数,并对影响沥青混合料振动压实的各种因素逐一进行分析。     

抽提法测定沥青混合料沥青含量的误差分析

针对抽提法测定沥青混合料试验操作误差对试验结果的影响问题,从滤纸、矿料、抽提液中矿粉含量的确定等方面对试验误差进行了分析,从而为确保沥青路面的正常使用提供了前提保证。     

沥青混合料损伤蠕变特性及模型研究

沥青混合料蠕变过程中,硬化、损伤两种机制同时存在。当硬化机制占主导地位时,蠕变呈现为衰减状态;当损伤机制占主导地位时,蠕变呈现为加速状态;两者互为接近时,则呈现为等速或者近似等速状态。只考虑损伤或黏滞系数的非线性变化均不能合理地描述和解析蠕变过程的3个阶段。以流变学模型理论为基础,综合考虑损伤和硬化效应,建立了一个统一的沥青混合料损伤蠕变模型。将该模型与试验曲线进行对比,两者吻合较好,说明该模型能够反映沥青混合料三阶段蠕变的全过程。在蠕变的大部分时间内损伤的发展都是平稳的,在接近破坏时损伤则会快速发展。在蠕变的第一、二阶段也存在损伤,只是损伤值较小,而将其忽略是不合理的。定义第三阶段起始的时间为流变时间,可作为研究沥青混合料损伤蠕变特性的指标,其值越大,表示蠕变变形进入破坏阶段所需要的时间越长。     

高速公路排水性沥青混合料配合比设计

对排水性沥青混合料原材料选择鉴定及性能评价怍了阐述，分析了影响排水性沥青混合料功能性及耐久性的因素，并对一种排水性能良好、抗高温变形能力强、水稳定性好的排水性沥青混合料进行了探讨研究。