共查询到19条相似文献,搜索用时 578 毫秒
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沥青微观相态结构为呈现相分离现象的"蜂状结构",沥青微观相态结构与其裂缝的萌生、扩展及愈合密切相关。相场理论是以动力学微分方程表示扩散、有序化势和热力学驱动等过程的研究方法。基于相场理论,可实现沥青疲劳与愈合过程中微观相态结构变化模拟,进而揭示沥青自愈合机理。论文介绍了扩散界面、相场变量、自由能函数、相场控制方程等相场理论的基本概念,综述了相场理论在沥青疲劳损伤及自愈合中的研究进展,并提出未来研究中可考虑进行相场与温度场、结晶场的多场耦合分析,并建立沥青相场模型与流变模型、化学组分间的联系,以深刻理解沥青自愈合微观进程与机理。 相似文献
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将氢氧化镁、红磷和十溴二苯乙烷分别均匀混入SBS改性沥青中制备阻燃沥青,利用红外光谱分析仪探究阻燃剂与沥青的化学反应情况,然后通过室内试验分析阻燃剂掺量对沥青基本性能和阻燃性能的影响,最后通过基于动态剪切流变仪(DSR)的疲劳-愈合-疲劳试验研究了阻燃剂和愈合温度对沥青疲劳与自愈合性能的影响规律。结果表明:红外光谱分析结果表明阻燃剂与沥青之间没有发生明显的化学反应;阻燃剂虽然提高了沥青材料的阻燃性能,但是降低了沥青的施工和易性和存储稳定性;随阻燃剂掺量增加,沥青的疲劳与自愈合性能先升高后降低,存在最佳阻燃剂掺量;在不同愈合温度下,适量阻燃剂均能提高SBS改性沥青的疲劳与自愈合性能。 相似文献
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沥青混合料疲劳性能研究及寿命预估的新方法 总被引:1,自引:0,他引:1
裂缝是沥青路面破坏的主要形式。裂缝主要分为疲劳裂缝、反射裂缝和温缩裂缝。当沥青路面重复地经受某一荷载应力时就会发生疲劳裂缝。为了减少沥青路面产生疲劳裂缝,必须了解沥青混合料的疲劳产生机理,并对疲劳寿命进行研究。通过概述沥青混合料的疲劳机理,并对最常见AC-20I型沥青混合料进行疲劳试验,回归出基于应变模型疲劳寿命的公式,同时为了提高疲劳寿命方程的实用性,采用SPSS多元回归模型预估疲劳寿命,最后建立室内试验和实际路面的疲劳寿命换算系数。 相似文献
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沥青公路在服役期间,其长时间受环境因素影响容易老化,造成沥青粘弹性变差,脆性增强;路面出现裂纹,路面平整性变差,大大降低了公路的使用寿命,造成沥青路面的养护成本提高与维修任务日趋繁重。针对近年来国际上所倡导的一种先进沥青路面养护理念-构建智能自修复沥青材料,对其自我修复、自我愈合的能力的影响因素及理论基础进行了介绍。由于在荷载间歇期,沥青混凝土中小于某尺度(阈值尺度)的微裂纹会自动加速修复,使其模量和强度得到恢复。通过对沥青自修复机理的分析,以期待根据理论建立相应自修复方法的评估体系,为沥青自修复的系统化提供理论基础。 相似文献
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为研究沥青混凝土的裂缝生成与疲劳寿命,采用级配类型为AC-20的某高速公路的现场钻芯试件,进行室内控制应变疲劳试验;应用劲度变化曲线的裂缝生成机制,与应力-应变回圈面积的消散能理论,推估沥青混凝土疲劳寿命与临界应变。结果表明:应用劲度变化曲线与消散能理论,所得的疲劳寿命都有一致性,故可判断其都可作为疲劳寿命的定义。其中以劲度变化曲线较为便捷,可以作为推估裂缝生成与疲劳寿命的参考方法。 相似文献
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Zhe Liu 《Petroleum Science and Technology》2019,37(9):1025-1032
A kind of microcapsule was prepared, and a new type of self-healing asphalt was manufactured by mixing asphalt, microcapsule and curing agent with proper ratio. The ductility(15?°C and 10?°C), softening point and penetration of asphalt were tested both before and after adding microcapsule and curing agent into the asphalt. The results showed that the three indexes were kept in normal ranges after adding microcapsule and curing agent. However, the ductility(10?°C) was lower than the technical standard when the additive amount of microcapsule was 5.0wt%. Whereafter, the influence of additive amount, self-healing temperature and time on the asphalt self-healing property were all investigated by ductility self-healing tests (10?°C). The outcome indicated that the addition of microcapsule into the asphalt promote its self-healing properties obviously. The self-healing rate of blank asphalt in 20?°C and for 3?h was 20%, and when the microcapsule additive amount was 3.0wt%, the rate was improved to 40.0%. The highest self-healing rate was 52.0%. The elevation of temperature and extension of time were both beneficial for the promotion of the self-healing properties of asphalt. However, when healing temperature and healing time were improved to 30?°C and 7?h, the improvement of self-healing rate was not obvious. 相似文献
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以动力学、断裂力学和有限元理论为基础,应用ABAQUS有限元软件,建立带裂缝沥青路面结构三维有限元模型,分析了不同行车速度、裂缝深度对结构动力响应的影响。研究结果表明:无裂缝路面结构的路面弯沉随着行车速度的增加而减小,面层层底最大拉应变和面层最大剪应力则对行车速度不敏感。当沥青路面面层已开裂,应力强度因子和路面弯沉随着裂缝深度的增加而增大,面层层底最大拉应变和面层最大剪应力则均比元裂缝时小,层底最大拉应变随着行车速度的增加而增大。 相似文献
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针对顺北油气田凝析气藏在生产期间产生的微裂隙和微环隙,研制了适用于顺北油气田的遇气自愈合乳液,该乳液遇天然气体积膨胀率达30%,并配制出了密度范围在1.45~2.20 g/cm3的自愈合水泥浆体系。该水泥浆体系的适用温度在90~180℃,弹性模量小于7 GPa。同时,还设计了合理的水泥石遇气自愈合能力评价方法,通过首次造缝和二次造缝,水泥石的自愈合能力分别达到了100%和95.1%。研制的遇气自愈合水泥浆体系兼具自愈合能力和优异的弹性性能,已现场试验3口井,固井质量优质率为100%,满足了顺北油气田高温高压气井长期密封需要。 相似文献
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H. Ziari 《Petroleum Science and Technology》2013,31(17-18):1627-1632
In this research study, Sasobit as warm additive was used to modify original binder (60/70 penetration grade). The binder fatigue and rutting performance was evaluated through linear amplitude sweep (LAS) and multiple stress creep and recovery test, respectively. Results indicated that 3% Sasobit modified binder has the highest percent recovery value and the lowest Jnr value, but had the highest sensitivity to a sudden increase in the stress level inside the asphalt mixture. The LAS test results demonstrated that the fatigue behavior of asphalt binders modified with 1% Sasobit is the highest one. 相似文献
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AbstractIn order to investigate the enhancing effect of basalt fiber (BF) on toughness of asphalt, BF modified asphalt and mixture were prepared. Strip tensile test was performed to study the anti-cracking ability of BF modified asphalt. The effect of BF on toughness of asphalt mixture was investigated using MTS system. SEM was conducted to explore the enhancing mechanism of BF. The results showed that the ultimate tensile stress of BF modified asphalt peaked when fiber content reached 0.4% by weight of asphalt mixture. Composite materialization and self-healing force of BF led to the enhancing effect on toughness capacity of asphalt. 相似文献
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固井水泥石微裂缝严重影响层间封隔完整性、缩短油气井寿命,水泥石微裂缝自修复技术是解决这一问题的有效途径。然而,目前对于膨胀性自修复剂机理研究较少,缺乏理论支撑。提出利用填充系数评价水泥石微裂缝自修复效果,建立了膨胀性自修复剂封堵水泥石微裂缝的数学模型,明确了影响水泥石微裂缝自修复效果的主要影响因素。此外,根据巴西劈裂试验,设计了一种简单的、能够定量模拟水泥石微裂缝的方法。利用水泥石微裂缝自封堵评价仪,对自选择修复材料进行自修复评价实验,验证了自修复效果与自修复剂吸液倍率、加量、微裂缝宽度的关系。结果显示,自选择修复材料的遇水自修复临界填充系数为0.473,最大可封堵234 μm微裂缝;遇油自修复临界填充系数为0.490,最大可封堵150μm微裂缝。研究结果为膨胀性自修复剂实现固井水泥石微裂缝自修复奠定了理论基础。 相似文献