抽提过程中影响回收沥青性能因素的研究

通过对比实验,验证了抽提沥青中残余的三氯乙烯和矿粉对其性能指标测试结果产生的影响,并通过控制抽提沥青中三氯乙烯和矿粉的掺量,分析了不同杂质含量下沥青三大指标的变化规律,提出了相应的解决措施,有效消除了抽提操作对回收沥青性能指标的影响。     

布敦岩天然沥青原材质控与检测评价技术指标研究

为了对布敦岩天然沥青原材的质量进行有效控制,保证其品质稳定,采用三氯乙烯溶解度和燃烧抽提试验、标准筛分试验、含水率试验、加热损失试验、闪点试验、密度试验、抽提后沥青物质的针入度和软化点试验进行了系统试验研究。传统闪点试验方法实测的闪点温度离析偏差60℃,不适用于客观评价布敦岩沥青的施工安全性,对其进行了优化改进。通过研究,提出了有效的布敦岩天然沥青质量检测评价技术指标体系及技术要求。     

超热老化条件下改性沥青的老化机理

对浇筑式沥青混凝土抽提回收沥青、SMA抽提回收沥青以及旋转薄膜烘箱老化沥青进行了常规沥青指标试验、DSR试验、红外光谱分析以及凝胶渗透色谱(GPC)相对分子质量分布分析.结果表明,浇筑式沥青混凝土抽提回收沥青车辙因子和疲劳因子明显提高,羰基红外光谱吸收峰明显增强,SBS分子断链现象明显,浇筑式沥青混凝土存在明显的超热老化现象.     

回收沥青方法研究——蒸馏温度和延迟时间

测试、对比了回收沥青和原沥青的基本性能、热失重和流变性能,分析了回收沥青和原沥青的微观结构.结果表明：采用阿布森标准方法(蒸馏温度165℃、延迟时间5min)回收的沥青针入度增加,软化点下降,15℃延度减小,135℃布什黏度上升,热失重增大,流变特性发生变化,并出现因氧化而生成的O—H,CO,SO和CC基团,因此该回收沥青存在沥青老化和三氯乙烯残留问题;当蒸馏温度为135℃、延迟时间为1,2h时,回收沥青基本性能、热失重和流变性能与原沥青基本一致,没有氧化基团出现;当蒸馏温度为135℃、延迟时间为4,8h时,回收沥青中虽无三氯乙烯残留,但是其发生轻质油挥发和沥青氧化反应,因此建议在回收沥青时,蒸馏温度宜为135℃,延迟时间宜为1~2h.     

基于减压过滤分离旧沥青中矿粉的研究

为了明确矿粉残余量对沥青胶浆性能影响的下限值范围,通过空白对照试验,制备一定矿粉梯度的沥青胶浆,以沥青胶浆延度和旋转黏度为指标进行试验,试验结果表明:当矿粉残余量小于1%时对沥青胶浆性能的影响不明显。为了除去回收沥青抽提液中残余矿粉,提出一种便捷可行减压过滤的方法。通过具体试验予以验证。结果表明,该方法可使回收沥青中矿粉残余量低于1%。     

溶剂法测定再生沥青混合料理论最大密度

进行再生沥青混合料试验时,由于无法检测回收沥青混合料旧料的组成材料密度,计算再生沥青混合料体积指标的理论最大密度必须使用溶剂法或真空法进行检测,本文就溶剂法检测理论最大密度的试验进行讨论。     

城市道路改扩建工程中铣刨料全循环再生应用

依托扬州市江阳路改扩建工程,通过对原沥青路上下面层沥青混凝土的铣刨回收、沥青抽提试验和集料筛分试验,测试抽提沥青的基本性能,并分析确定其老化程度、测试回收集料的物理力学性能及其级配特征,提出铣刨料再生方案;将铣刨料以旧料掺量为20%、30%分别应用于不同级配(AC-13C、AC-20C、AC-25C)的沥青混合料中,进行再生沥青混合料路用性能测试,为铣刨料应用于改扩建工程新建路面结构不同层次提供理论依据。在室内研究的基础上结合实体工程,将旧沥青路面铣刨料应用于扬州城市南部快速通道先导段进行铺筑,验证了旧沥青路面铣刨料全循环再生应用的有效性和科学性。     

常温生产SBS改性沥青防水涂料的研究

介绍常温生产SBS改性沥青防水涂料的配方、生产工艺。讨论沥青、SBS、增粘树脂、溶剂对防水涂料性能的影响。实验结果表明:应用含蜡较少和沥青质较低的沥青、SBS含量在8%～16%、使用混合溶剂、用石油树脂和萜烯树脂作增粘剂、使用云母粉作填料,生产的产品性能较好。     

一种沥青抽提仪转速校准方法及其测量值的不确定度评定

沥青抽提仪是快速抽提沥青混合料中沥青并准确测定和分析沥青混合料沥青含量(油石比)的仪器,其通过控制离心分离器的转速来保证沥青混合料中沥青的抽提效果,其转速的准确度直接影响到沥青混合料的成品率。本文介绍一种沥青抽提仪转速校准方法及其过程中分析其不确定度分量主要来源,并对各不确定度分量、合成不确定度、扩展不确定度进行评定。     

再生沥青混合料性能研究

该文通过再生沥青混合料和再生沥青的复合模量,探讨旧沥青混合料掺量对混合料以及再生沥青的影响。对于PG 64-22级沥青,考虑了15%,25%,40%三个旧料掺量水平;对于PG58-28,考虑了25%和40%两个旧料掺量水平;同时以PG64-22沥青,不添加旧料作为对照组。成型后的混合料试件在三个不同的温度下进行测试以确定其复合动态模量（｜E＊｜）。同时分别在相同的温度下对抽提后的再生沥青,抽提后新沥青以及新沥青进行复合剪切模量测试（｜G＊｜）。对混合料试件进行了低温蠕变和间接拉伸试验,以确定其低温蠕变柔量和间接拉伸强度,以用来预估路面的临界开裂温度。统计分析结果表明,旧料掺量为15%和25%时,其平均强度和动态模量没有显著差别。只有当温度较高时,对照组和旧料掺量为40%的混合料间存在一些差异。     

Source apportionment of trichloroethylene in groundwater of the industrial complex in Wonju,Korea: a 15‐year dispute and perspective

The groundwater of an industrial complex has been contaminated with trichloroethylene (TCE) since 1995. High levels of TCE exceeding the Korean groundwater standard can still be found. However, ongoing controversial debate on the contamination source has hindered the remedial works. Wonju city suggested a single source, while the Gangwon Province considered multiple sources. The TCE plume appeared as two separate plumes rather than a single plume. Carbon tetrachloride (CT), a formerly used solvent, formed a plume but its extent was restricted to the left half of the overall TCE plume. The soil contamination survey revealed the existence of at least two contamination source areas. All the evidences pointed to the asphalt test laboratory as being one of the major sources, but the possibility of other sources cannot be excluded. The maximum extent of the TCE contamination caused by the asphalt laboratory may have been restricted to the left half of the overall TCE plume.     

Two-phase ozonation of hazardous organics in single and multicomponent systems

The destruction of pentachlorophenol (PCP), oxalic acid, chlorendic acid, and a mixture of pentachlorophenol, 1,3-dichlorobenzene (DCB), and trichloroethylene (TCE) were studied using a two-phase ozonation system. A two-phase ozonation system consists of water containing the pollutant and a second solvent phase which houses the ozone. The solvent phase is an inert fluorinated hydrocarbon (FC40) that is nonpolar and reusable. The solvent phase is desirable because it has a high ozone stability (k = 0.0033 min⁻¹) and an ozone solubility of 120 mg/L at 25°C, 10 times that of water. In addition to an enhanced oxidation rate of PCP, less ozone was utilized. At high pH (10.3), a first-order rate constant of 200 min⁻¹ in the two-phase system was found for PCP degradation compared to k_app = 0.154 min⁻¹ in a single aqueous-phase system. Within 15 s, the concentration of PCP (100 mg/L initially) was degraded more than 90%, and 100% dechlorination was obtained with longer reaction times. This system also demonstrated the ability to selectively oxidize PCP while in the presence of free radical scavengers existing in the water phase. PCP was also successfully oxidized using actual wastwater which contained alkalinity, hardness, many inorganics, and trace hazardous organics. Oxalic acid, an intermediate formed during the degradation of PCP, was also degraded by two-phase ozonation. Preliminary work with chlorendic acid showed that two-phase ozonation was faster than single aqueous-phase ozonation at dechlorinating the compound. TCE and DCB degraded slightly faster when PCP was added to the mxture, possibly due to the production of other radicals during the oxidation of PCP.     

Trichloroethylene adsorption by activated carbon preloaded with humic substances: effects of solution chemistry

Trichloroethylene (TCE) adsorption by activated carbon previously loaded ("preloaded") with humic substances was found to decrease with increasing concentrations of monovalent ions (NaCl), calcium (until solubility was exceeded), or dissolved oxygen in the preloading solution. For a given percentage of organic carbon removal during humic acid loading, greater reductions in TCE adsorption occurred with increasing monovalent ion concentration and calcium concentration at constant ionic strength. However, this effect was related primarily to the amount of humic material adsorbed--the reduction in TCE adsorption was independent of the ionic composition of the preloading solution when compared at similar humic acid loading. Experiments were performed which showed that calcium ions can associate with humic material after the humic has been adsorbed, which subsequently reduces TCE uptake, but this effect does not dominate when calcium is present during humic loading. At sufficiently high calcium concentrations (approaching solubility), aggregation or co-precipitation of humic acid mitigated the effects of preloading. In contrast to the effects of ionic composition, the presence of dissolved oxygen did fundamentally change the mechanism by which organic macromolecules compete with TCE. TCE uptake was lower when preloading by poly(maleic acid) (PMA) occurred in the presence of dissolved oxygen, even when the amount loaded was the same. One explanation invokes a coupling mechanism promoted by the carbon surface, which results in either additional blockage of TCE sorption sites, additional site competition, or both. In all experiments, the effects of preloading were consistent with those reported previously, which have been interpreted as a loss of high-energy sites available to TCE, causing a significant reduction in the site-energy heterogeneity, and reduced uptake in the low concentration region.     

Degradation of trichloroethylene in wetland microcosms containing broad-leaved cattail and eastern cottonwood

Remediation of aquifers containing trichloroethylene (TCE) relies primarily on physical extraction of contaminated groundwater and soil. Unfortunately, this is typically expensive and does not always attain the desired treatment goals. In situ bioremediation via natural attenuation is an alternative treatment process in which TCE is transformed by indigenous microorganisms and plants. In this study, TCE was observed in a surficial aquifer that discharges into a wetland. Experiments were undertaken to determine whether natural attenuation of TCE in the wetland was possible. Microcosms were constructed using sandy soil+/-eastern cottonwoods (Populus deltoides) from the wetland's edge and organic soil+broad-leaved cattails (Typha latifolia) from the wetland's interior. [14C] TCE was added to each microcosm (1.27 microCi). Overtime, 14C was recovered from four microcosm compartments: (1) as 14C bound to soil and water, (2) as volatilized [14C] TCE, (3) as [14C] CO2 produced by mineralization of [14C] TCE, and (4) as 14C incorporated into the plants. Total recoveries of the 14C-label ranged from 73.6% to 95.8%. Volatilized [14C] TCE accounted for the majority ( > 50%) of the recovered label. In microcosms without plants, [14C] CO2 represented 3.2% (organic soil) to 15.6% (sandy soil) of the recovered 14C, indicating that TCE was mineralized by indigenous microorganisms. The presence of the broad-leaved cattail resulted in increased production of [14C] CO2 to 5.3% in the organic soil. The data thus suggest that natural attenuation is a potential bioremediative strategy for TCE-contaminated wetlands.     

老化前后沥青与胶粉相容性的分子动力学研究

为了探究热老化对沥青与胶粉之间相容性的影响,采用压力老化法(PAV)制备长期老化沥青.采用四组分分析法对基质沥青与老化沥青进行分析,并在此基础上,以丁苯橡胶(SBR)作为胶粉的代表建立分子模型.结果表明:老化前后沥青的密度没有明显变化,但是老化沥青的能量由于老化后沥青中大分子比例的增加而增加;老化沥青与SBR溶解度系数差值较基质沥青与SBR溶解度系数差值更大,表明老化降低了沥青与SBR之间的相互溶解能力;老化使沥青与SBR之间的相互作用能下降,最终降低了沥青与SBR的相容性.     

新型高效沥青阻燃剂的制备

为了制备低掺量高效沥青阻燃剂,以氢氧化铝、氢氧化镁、聚磷酸铵为元素设计正交组合制备新型阻燃剂中间体,同时用钛酸酯偶联剂处理液对其进行表面活化得到新型高效沥青阻燃剂。在此基础上,研究不同组合的阻燃剂对改性沥青的针入度、软化点、延度、弹性恢复的影响,结合阻燃剂的吸油率,推荐新型沥青阻燃剂的制备配方。结果表明:沥青阻燃剂经钛酸酯表处理后,相容性会增强;沥青阻燃剂的添加对阻燃沥青低温延度的影响比较明显,而对针入度、软化点和弹性恢复的影响较小;推荐新型沥青阻燃剂的制备配方为氢氧化铝Al(OH)3、氢氧化镁(Mg(OH)2、聚磷酸铵(APP)比例为1:1:2.2制备的新型阻燃剂中间体,同时用乙醇作溶剂将钛酸酯偶联剂配制成10.0%的处理液对其进行表面活化。     

GYPJH2000型排水性路面机能恢复车

排水性沥青路面是一种安全、降噪功能显著的新型路面,但维持其排水机能需要相应的养护技术和专门的养护设备.GYPJH2000型排水性路面机能恢复车采用“高压水冲洗+气穴清洗+真空抽吸”的作业方式,能够冲洗清理堵塞在排水性沥青路面内部的灰尘、泥沙等杂物,并可将清理出来的杂物进行集中回收处理,恢复被堵塞路面的排水机能,使其符合使用要求.介绍GYPJH2000型排水性路面机能恢复车的结构组成、工作原理、关键技术、性能特点及施工工艺基本要求.经实际应用显示,通过该设备处理后,排水性沥青路面的排水机能可恢复到新建时期的60％以上,清洗效果显著.     

纳米蒙脱土对沥青愈合性能的影响研究

通过“疲劳-愈合-疲劳”试验评价纳米蒙脱土(NMMT)对沥青自愈合性能的影响,并且将愈合指标与物理性能指标进行拟合。结果表明NMMT改性沥青的自愈能力有所增强,且掺量对其自愈能力有较大的影响,随着掺量的增加其初始模量恢复能力逐渐减弱,但自愈后所恢复的模量其抵抗荷载作用的能力有所增强;当掺量为1%时改性沥青具有较好的自愈性能;改性沥青自愈后初始模量恢复的能力HI与软化点指标存在着较强的线性关系,通过软化点可以较好的评价其初始模量的恢复能力。     

钢桥面铺装浇筑式沥青混凝土维修技术

基于桥面铺装维修的技术要求,研究了浇筑式沥青混凝土的相关性能和界面处治技术,结果表明,岩沥青浇筑式沥青混凝土具有较好的流动性和热稳性;界面刻槽和采用溶剂型粘结剂,可以改善新旧沥青混凝土的界面结合状态。     

Evaluation of the compatibility between rubber and asphalt based on molecular dynamics simulation

Using of rubber asphalt can both promote the recycling of waste tires and improve the performance of asphalt pavement. However, the segregation of rubber asphalt caused by the poor storage stability always appears during its application. Storage stability of asphalt and rubber is related to the compatibility and also influenced by rubber content. In this study, molecular models of different rubbers and chemical fractions of asphalt were built to perform the molecular dynamics simulation. The solubility parameter and binding energy between rubber and asphalt were obtained to evaluate the compatibility between rubber and asphalt as well as the influence of rubber content on compatibility. Results show that all three kinds of rubber are commendably compatible with asphalt, where the compatibility between asphalt and cis-polybutadiene rubber (BR) is the best, followed by styrene-butadiene rubber (SBR), and natural rubber (NR) is the worst. The optimum rubber contents for BR asphalt, SBR asphalt, and NR asphalt were determined as 15%, 15%, and 20%, respectively. In addition, the upper limits of rubber contents were found as between 25% and 30%, between 20% and 25%, and between 25% and 30%, respectively.