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71.
A case history is described where Class C fly ash was used to stabilize recycled pavement material (RPM) during construction of a flexible pavement in Waseca, MN, USA. The project consisted of pulverizing the existing hot-mix asphalt (HMA), base, and subgrade to a depth of 300 mm to form RPM, blending the RPM with fly ash (10% by dry weight) and water, compacting the RPM, and placement of a new HMA surface. California bearing ratio (CBR), resilient modulus (Mr), and unconfined compression (qu) tests were conducted on the RPM alone and the fly ash stabilized RPM (SRPM) prepared in the field and laboratory to evaluate how addition of fly ash improved the strength and stiffness. After 7 days of curing, SRPM prepared in the laboratory had CBR ranging between 70 and 94, Mr between 78 and 119 MPa, and qu between 284 and 454 kPa, whereas the RPM alone had CBR between 3 and 17 and Mr between 46 and 50 MPa. Lower CBR, Mr, and qu were obtained for SRPM mixed in the field relative to the SRPM mixed in the laboratory (64% lower for CBR, 25% lower for Mr, and 50% lower for qu). In situ falling weight deflectometer testing conducted 1 year after construction showed no degradation in the modulus of the SRPM, even though the SRPM underwent a freeze–thaw cycle. Analysis of leachate collected in the lysimeter showed that concentrations of all trace elements were below USEPA maximum contaminant levels.  相似文献   
72.
本文根据余杭泰山地区上震旦统灯影组砂岩、藻叠层石白云岩和下寒武统荷塘组以及中寒武统杨柳岗组产层状、似层状之固体沥青。经对固体沥青的分布范围、物化性质特征分析及古油田构造平衡剖面模拟的研究,确认了余杭泰山古油田的存在。对探索南方海相油气藏的分布,揭示了震旦统油气藏的形成—演化—破坏规律有着独特的意义。  相似文献   
73.
陈强路  范明  郑伦举 《沉积学报》2007,25(3):358-364
志留系储层原油演化成沥青过程中,沥青充填于粒间孔及填隙物中,占据了孔隙空间,残余孔隙率、渗透率很低。通过模拟实验的方法分析了油气充注对沥青砂岩储集性的影响,早期充填沥青少而残余孔隙率、渗透率很低的砂岩,晚期油气仍不能充注,是非储层;早期沥青均匀充填、充填程度高,残余孔隙率、渗透率低的砂岩,晚期低粘度稀油仍能充注,孔隙率、渗透率有大幅度提高,是有效储层;早期沥青充填较均匀,残余孔隙率相对较高,不同粘度的原油充注后,孔渗条件发生明显的改善。常温的实验表明,原油的物理性质是决定沥青砂岩能否再次充注的关键因素之一,稀油充注是志留系沥青砂岩成藏的必要条件。  相似文献   
74.
There is a type of asphalt that originated from differentiation from reservoir bed (named reservoir bed-differentiated asphalt)in the Silurian asphaltic sandstones of the Tarim Basin.These asphalts are the result of second-time charging of hydrocarbons into the Silurian reservoir,which were derived from Lower Paleozoic source rocks.Asphalt was differentiated from the reservoir bed in the hydrocarbon gathering area of secondary migration.The different-tiation is caused by changes in reservoir physical properties when pearl or chain hydrocarbons migrating through and gathering in the reservoir bed,and light components are lost and heavy ones are involved in the formation of asphalt or heavy oil.There are two kinds of occurrence of these asphalts in the Silurian system of the Tarim Basin.One is the poor heavy oil layer with lower oil saturation in trap and the other is scattered hydrocarbon distributed along the trans-port layer and unconformity surface.Reservoir bed-differentiated asphalts have two characteris-tics:total hydrocarbon content is high in extractable organic matter and the ratio of saturated to aromatic hydrocarbon is usually greater than unity.The physically modeling experiment has confirmed these characteristics and the genesis of the reservoir bed-differentiated asphalts.  相似文献   
75.
青藏公路多年冻土段沥青路面热量平衡及路基稳定性研究   总被引:29,自引:18,他引:29  
为彻底了解和治理青藏公路多年冻土段路基病害,选择昆仑山垭口和66道班两种不同并土类型路段,首次在沥青路面上开展路面辐射和热量平衡观测,并同时和路旁天然场地自然下垫面进行同项目的对比观测,通过观测和计算,研究了不同冻土类型路沥青路面下热量收支状况及路基热量年周转,找出了致使路基沉陷及产生融化核的根本原因,并对路基内融化核形成演化及其稳定性进行分析,计算了路基下人为上限达到最大深度及所需时间和融化核的最终稳定厚度,为青藏公路整治提出了可行性措施。  相似文献   
76.
Interaction study of permafrost and highway along Qinghai-Xizang Highway   总被引:14,自引:2,他引:14  
Qinghai-Xizang Highway crosses permafrost areas, sporadic permafrost areas and seasonal frozen soil areas. It is very important to study the engineering geology of frozen soil in construc-tion of cold regions engineering, and the choices of engineering st…  相似文献   
77.
青藏公路铺筑沥青路面后路基下多年冻土的变化   总被引:30,自引:12,他引:18  
王绍令  米海珍 《冰川冻土》1993,15(4):566-573
由于黑色沥青路面强烈吸热,使多年冻土区内约60%路段的路基下人为上限逐年下降,造成冻土在垂向上呈不衔接接状,形成融化核,它加剧了路基不均匀沉陷,最后导致路面破坏,一路段路基下冻土类别发生变化或多年冻土层已完全融化。  相似文献   
78.
The formation of low-maturity asphaltic oils (immature asphalts) from carbonate source rocks was investigated. The Senonian bituminous rocks (SBR) in Israel are organic-rich carbonate rocks that were deposited in a high productivity environment, and they are part of a sedimentary sequence that also contains cherts and phosphorites. The SBR were studied in different basins, and the samples are from outcrops and three deep drillholes. The bitumen contents of the rocks are exceptionally high (up to 700 mg/g Corg), and immature asphalts are found to be associated with them. Geochemical analysis indicates that the bitumens are indigenous to the host SBR, and the associated asphalts are bitumens that have migrated a short distance with negligible chemical fractionation. The high heteroatom content of the kerogens (up to 30%) in the SBR is suggested as a possible cause of the generation of asphaltic oils in an early stage of maturation.  相似文献   
79.
张倩  李泽  温志广  杨永红 《冰川冻土》2017,39(2):358-365
针对寒区道路工程中的沥青路面冻融受荷损伤问题,借助细观损伤力学和宏观统计随机损伤模型,建立了冻融与荷载耦合作用下的沥青混合料损伤本构关系和损伤演化方程;探讨了冻融循环次数、应变和油石比影响下的沥青混合料冻融受荷损伤劣化机理。研究表明:冻融循环疲劳损伤累积和荷载作用于带有微缺陷粗集料界面附近产生的应力集中加剧了沥青混合料总损伤劣化程度。冻融循环20次之后,损伤度变化不大,基本趋于恒定;相同损伤程度时,应变值随冻融次数的增加而减小。油石比对总损伤影响显著,当油石比相对较小时,以冻融破坏为主;当油石比较大时,以受荷破损为主。研究成果可为寒区沥青路面抗冻设计、性能评价及养护维修时机选择提供参考。  相似文献   
80.
长寿沥青路面结构的层厚设计与分析   总被引:1,自引:0,他引:1  
邹维列  王钊  彭远新 《岩土力学》2009,30(3):645-649
介绍和讨论了一种用于重交通长寿沥青路面的层厚设计方法。该方法基于限制沥青层底的拉应变和路基顶面的压应变,采用两个准则来校核所设计的沥青层厚度的适宜性:一是控制设计荷载作用下的最大路表弯沉;二是控制相邻两个无结合料处治的集料层的模量比。采用“等效模量”概念来考虑路基、路面材料的模量随季节的变化;在预测疲劳(与荷载相关的裂缝)和路基变形时,采用了“累计损伤”的概念。给出了广东-梧州高速试验路段长寿沥青路面结构组合设计实例,最后对与疲劳裂缝有关的两个关键问题进行了讨论。  相似文献   
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