自诊断沥青混凝土及其应用前景

自诊断沥青混凝土是一种通过掺入导电相材料,改善沥青混合料的导电性能,利用导电性能与路用性能的变化规律,即时、无损地评价路面结构的应变与破损的新型道路材料,其在机场跑道、桥面及高速公路上有广泛的应用前景.因此,介绍自诊断沥青混凝土的导电相材料优选、级配设计、制备方法及其自诊断机理,依据其电学性能的变化规律可及时了解路面的使用状况和健康水平,用以指导沥青路面的养护与维修.     

基于分子尺度的沥青材料设计

基于分子尺度的沥青材料设计是指利用多尺度分子模拟预测沥青材料的性能,指导制备符合高性能要求的沥青材料。分子尺度的设计方法主要有量子力学方法、蒙特卡洛方法和分子动力学方法。总结了沥青质模型、沥青模型、量子力学和分子模拟在沥青材料性能预测和设计中的应用,重点介绍了改性沥青材料常用物理力学性质的模拟计算方法及相关研究成果。     

Rheological properties of asphalt modified by supramolecular UV resistant material-LDHs

Dynamic rheological properties of asphalt modified by Supramolecular UV resistant material-layered double hydroxides(LDHs) was studied by means of the dynamic shear rheometer(DSR) test.Two typical base asphalts were chosen and modified by 2 different LDHs contents.DSR tests were performed on the original samples,samples after exposed to outdoor and samples after the artificial accelerated UV aging tests respectively to analyze the rheological properties.It is found that when the LDHs content is between 3wt% and 5wt% of asphalt weight,the high temperature performance and fatigue resistant property of the modified asphalt become better,the UV aging resistance properties are improved.     

胶凝材料的过去现在和将来

新石器的前陶器时代人们就开始使用天然材料粘土和姜石,并在9000年前开始使用最早的人造胶凝材料——石灰。公元前2500～3000年,人们就开始使用石膏——石灰类胶凝材料。公元初期,石灰——火山灰水硬性材料开始应用。现代波特兰水泥是在18世纪末19世纪初随着水硬性石灰的发展而发展起来的。现代波特兰水泥的最大特点是水化反应速度快,但也反映出较差的耐久性和环境协调性。未来的混凝土应该具有更好的耐久性,更适合于采用低价位的原料,更适合于回收利用,适合清洁生产的要求。发明于1957年的碱硅酸盐水泥及上世纪70年代末的土聚水泥的耐久性和环境协调性能满足上述要求。     

排水沥青路面的材料组成及特性

结合排水性沥青路面的特点,分析了排水性沥青路面的各种组成材料在混合料中的作用,得出排水性沥青混合料的各种组成材料应有的品质。最后总结了良好的排水性沥青混合料的组成特性。     

光氧老化对沥青物理和化学性能的影响

本文介绍了沥青的光氧老化机理,并对沥青的四组分、针入度、延度、软化点、动力粘度和红外光谱试验指标进行分析,发现光氧老化对沥青性能指标的影响不同与热氧老化.试验结果表明,光 氧老化使沥青组分向大分子量方向转化,针入度、延度减小,软化点、粘度增加,并且羰基官能团随着老化时间的延长其吸收峰明显增加.     

沥青氧化过程中“诱导期”的研究

一、前言在一定反应温度下,以一定的吹风速率,向融熔状态的渣油或沥青中吹入空气的过程,通常称为沥青的氧化过和。在氧化过程的初期,软化点随时间上升的很缓慢,经过此阶段,随氧化时间的延长,软化点有明显的上升,而延伸和针入度均剧烈下降,随后趋于平稳。沥青氧化工艺称这阶段为沥青氧化的“诱导期”。缩短氧化沥青生产的时     

Fatigue performance of bridge deck pavement materials

Three beam samples of bridge deck pavement were prepared, with gradation types of AC-13, and AC-16 and combined AC-13+AC-16. Four-point bending test was adopted to investigate the fatigue performance of these beam samples. The experimental results indicate that the initial bending stiffness is related to the type of beam sample and testing temperature. Fatigue life of these samples decreases as the increase of the controlled strain level. The AC-13 beam sample exhibits better fatigue resistance and bigger limiting bending strain at the given strain level and temperature. Compared with single beam sample, the fatigue performance of combining beam sample is relatively poor. Funded by the National Natural Science Foundation of China (No. 50878171)     

Rheological characteristics of aged asphalt binder

Different aging levels(RTFOT,PAV-10h,PAV-20h and PAV-30 h) of asphalt binders with various mass ratios of mineral powder to asphalt(0,0.4,0.8,1.2,1.6,2.0) were used to investigate the rheological properties of aged asphalt binders with respect to their short and long terms aging characteristics.Viscosity test,dynamic shear test and creep test were conducted.The test results indicate that the viscosity of aged asphalt binder increases sharply with the extension of aging period.Complex shear modulus of aged asphalt increases,which indicates that the stiffness of asphalt binders can increase.The phase angle for aged asphalt binders reduces,which indicates that the elastic portion for viscoelastic property of asphalt binders increases.|G*|·sin δ increases after aging procedure which means that the fatigue resistance becomes poor.The creep test results show that creep strain curves varies remarkably for virgin and aged asphalt binders.The total strain during loading period and the permanent strain decreases significantly for aged asphalt binders,which implies that the elastic portion increases and the viscous portion decreases.