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Numerical analysis of the effects of subgrade settlement on top-down cracking in epoxy asphalt pavement

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Science China(Technological Sciences) 2024年第10期67卷 3308-3320页

作者： JIANG XiuJie HUANG Wei luo sang WEI Ya KONG WeiYi DU KaiJun School of Transportation Southeast UniversityNanjing 211189China Intelligent Transportation System Research Center Southeast UniversityNanjing 211189China Department of Civil Engineering Tsinghua UniversityBeijing 100084China Nanjing Modern Multimodal Transportation Laboratory Nanjing 211135China

Epoxy asphalt pavement cracking caused by subgrade settlement is detrimental to the long-term safe service of roads.A threedimensional finite element model of epoxy asphalt pavement is established to investigate the effects of subgrade settlement on the propagation of top-down cracking(TDC).The contour integral method is utilized to calculate the stress intensity factor(SIF)at the crack tip,and then the extended finite element method(XFEM)is used to analyze the propagation behavior of TDC under combined subgrade settlement and traffic *** results of these analyses indicate that increased subgrade settlement,stiffer surface layers,and softer bases will increase the SIF,resulting in a faster crack propagation *** is suggested that the use of epoxy asphalt materials in pavement structures can allow more subgrade settlement than conventional asphalt ***,when the base layer modulus is higher than 12500 MPa,the increase in surface modulus can decrease crack propagation *** analysis results demonstrate that subgrade settlement has the most significant impact on TDC *** conclusions of this study are expected to provide a theoretical basis for crack prevention in the design and maintenance of pavement structures.

关键词： epoxy asphalt pavement subgrade settlement XFEM stress intensity factor crack propagation

Prevalence and risk factors for eye diseases, blindness, and low vision in Lhasa, Tibet

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International Journal of Ophthalmology(English edition) 2013年第2期6卷 237-241页

作者： Gui-Qin Wang Zong-Xi Bai Jing Shi sang luo Hong-Fa Chang Xiao-Yong Sai Department of Ophthalmology Naval General Hospital Department of Ophthalmology General Hospital of Tibet Military Command Institute of Geriatrics General Hospital of Chinese PLA

AIM: To determine the prevalence and risk factors for eye diseases, blindness, and low vision in Tibet, and to assist the development of eye disease prevention and treatment ***: We carried out a survey of eye diseases among a population living at high altitude. A total of 1 115 Tibetan permanent residents aged 40 years or older from the towns and villages of Qushui County, Lhasa Prefecture, Tibet Autonomous Region, participated in this study. All participants completed a detailed questio-nnaire, and underwent presenting and pinhole visual acuity tests,and a comprehensive ophthalmic ***: There were 187 blind eyes (8.43%), 231 eyes with low vision (10.41% ). The leading cause of visual impairment was cataract of 55.0% (101/187) blindness and of 50.2% (116/231) low vision, followed by fundus lesions of 22.9% blindness and 23.8% low vision, while only a low prevalence of glaucoma of 9.6% blindness and 1.7% low vision was observed. The analysis of 2 219 eyes showed that the most common external eye disease was pterygium (27.2%) in ***: The high prevalence of blindness and low vision in the Tibetan population at high altitude is a serious public health issue. There is a need to establish and maintain an appropriate effective eye care program in Tibet.

关键词： Tibet eye diseases blindness low vision risk factors

Performance evaluation of open-graded epoxy asphalt concrete with two nominal maximum aggregate sizes

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Journal of Central South University 2015年第11期22卷 4483-4489页

作者：罗桑钱振东薛永超 Intelligent Transport System Research Center Southeast University

Open-graded friction course(OGFC) is applied to pavement surfaces to increase driving safety under wet conditions, and recently, to reduce tire/pavement noise. The durability of OGFC, however, has been a concern since conventional OGFC mixes last typically less than ten years before major maintenance or rehabilitation is needed. This work investigates a new open-graded asphalt mixture that uses epoxy asphalt as binder to improve mix durability. One type of epoxy asphalt that has been successfully applied to dense-graded asphalt concrete for bridge deck paving was selected. A procedure of compacting the mix into slab specimens was developed and a series of laboratory tests were conducted to evaluate the performance of the new mix, including Cantabro loss, permeability, friction, shear strength, and wheel rutting tests. Results show superior overall performance of the open-graded epoxy asphalt mix compared to conventional open-graded asphalt mix. There are also preliminary indications that the OGFC mix with 4.75-mm NMAS gradation can improve the resistance performance to raveling, while the OGFC mix with 9.5-mm NMAS gradation can improve the performance of surface friction at a high slip speed.

关键词： open-graded concrete epoxy asphalt concrete nomina

Research on rheological model and construction time range of epoxy asphalt

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Research on rheological model and construction time range of...

Evaluation of rutting and low-temperature cracking resistancesof warm-mix recycled asphalt bindersunder the secondary aging condition

中国力学大会——2013

作者： luo sang Qian Zhendong Zhang Xiaochun Dun Haotian Intelligent Transportation System Research Center Southeast University

To obtain the allowable time range for construction of epoxy asphalt mixes and quality assurance of pavement,the model and calculation formula of viscosity-time-temperature was studied with double-Arrhenius formula based on chemorheology *** then,the allowable time range for construction of epoxy asphalt mixes at different temperatures were obtained with 1.00 Pa·s taken as paving and compaction control *** indicate that the viscosity-time-temperature

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Journal of Southeast University(English Edition) 2020年第1期36卷 81-87页

作者： Li Qiang Sun Guangxu luo sang Zhou Zhou Meng Yuanpeng College of Civil Engineering Nanjing Forestry University Nanjing 210037 China National-Provincial Joint Engineering Research Center of Electromechanical Product Packaging Nanjing Forestry University Nanjing 210037 China School of Transportation Southeast University Nanjing 211189 China

The rutting and low-temperature resistances of warm-mix recycled asphalt binders under the secondary aging condition were measured by the dynamic shear rheometer test and bending beam rheometer *** of different types of warm-mix asphalt(WMA)technologies and additives were *** and improvement mechanisms were investigated by the Fourier transform infrared spectroscopy *** is found that recycled binders after the secondary aging are more resistant to rutting and less resistant to low-temperature *** two warm-mix asphalt technologies have opposite *** the Sasobit WMA significantly improves the rutting resistance and reduces the low temperature resistance for the recycled binders due to its morphological change at different *** rutting factor values of recycled asphalt binders with the Sasobit additive increase by 4.6 to 5.6 ***,using the Evotherm WMA causes the deterioration of the rutting resistance due to the structural lubrication *** rutting factor values of recycled asphalt binders with the Evotherm additive show the reduction of 52%to 62%.It is recommended to add the styrene butadiene rubber latex or crumb rubber powder into the warm-mix recycled asphalt binders to simultaneously improve the rutting and low-temperature cracking resistances.

关键词： pavement engineering warm-mix recycled asphalt binder low-temperature cracking rutting secondary aging Fourier transform infrared spectroscopy

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小粒径大空隙排水沥青混合料性能试验

公路交通科技 2013年第6期30卷 1-5页

作者：钟科罗桑交通运输部公路科学研究院北京100088 东南大学智能运输系统研究中心江苏南京210096

为实现超薄排水沥青路面的设计与应用,采用渗透性试验、摆式摩擦系数试验、动态摩擦系数试验、声波吸收系数试验、肯塔堡飞散试验、车辙试验、低温弯曲试验和冻融劈裂试验,对最大公称粒径4.75 mm和13.2 mm的2种开级配型式与2种不同沥青... 详细信息

为实现超薄排水沥青路面的设计与应用,采用渗透性试验、摆式摩擦系数试验、动态摩擦系数试验、声波吸收系数试验、肯塔堡飞散试验、车辙试验、低温弯曲试验和冻融劈裂试验,对最大公称粒径4.75 mm和13.2 mm的2种开级配型式与2种不同沥青混合料类型组合而成的4种大空隙排水沥青混合料的综合性能进行试验评价。试验结果显示,最大公称粒径4.75 mm级配形式的开级配沥青混合料的透水性能、摩擦性能及抗松散能力比最大公称粒径13 mm级配的沥青混合料略优,具有很好的排水降噪功能。环氧沥青混合料的使用,有利于提高小粒径大空隙排水沥青混合料的整体路用性能。

关键词：道路工程沥青混合料试验排水降噪表面特性

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钢桥面复合铺装结构永久变形预估

同济大学学报（自然科学版） 2013年第3期41卷 397-401页

作者：罗桑钟科钱振东东南大学智能运输系统研究中心江苏南京210096 交通部公路科学研究院北京100088

针对浇注式与环氧沥青混凝土两种铺装材料组成的5类铺装结构,采用恒高度剪切疲劳试验对铺装材料的流变特性进行试验研究,根据试验结果,利用多元非线性回归方法获得基于Bailey Norton模型的铺装材料高温蠕变参数;而后,建立正交异性钢桥... 详细信息

针对浇注式与环氧沥青混凝土两种铺装材料组成的5类铺装结构,采用恒高度剪切疲劳试验对铺装材料的流变特性进行试验研究,根据试验结果,利用多元非线性回归方法获得基于Bailey Norton模型的铺装材料高温蠕变参数;而后,建立正交异性钢桥面铺装复合结构有限元模型,仿真模拟60℃下铺装的永久变形;最后,利用等厚度修正的车辙试验对5类铺装结构的永久变形仿真结果进行了试验验证.研究表明:浇注与环氧组成的异性铺装结构中,铺装永久变形贡献率大部分是浇注式沥青混凝土,而环氧沥青混凝土的贡献率很小;浇注或环氧组成的双层同质铺装结构中,铺装车辙变形主要发生在上面层.研究内容为钢桥面铺装结构与材料的高温变形设计提供理论支撑.

关键词：钢桥面铺装贡献率恒高度剪切疲劳试验蠕变流变

Exploring practical methods for detecting k-nonseparability in multipartite quantum states

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 255-256页

作者： Shunlong luo Academy of Mathematics and Systems Science Chinese Academy of Sciences

Quantum entanglement, referred to as “spooky action at a distance” by Einstein, is not only an intriguing and fascinating feature of quantum theory challenging our classical intuitions about locality and correlations, but also has practical and profound implications for quantum technologies. Initially described by Einstein, Podolsky and Rosen, as well as by Schro¨dinger, entanglement now has become a basic and crucial ingredient for both foundational and experimental investigations of the quantum world.

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Atorvastatin Attenuates TNF-alpha Production via Heme Oxygenase-1 Pathway in LPS-stimulated RAW264.7 Macrophages

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Biomedical and Environmental Sciences 2014年第10期27卷 786-793页

作者： WANG Xiao Qiao luo Nian sang CHEN Zhong Qing LIN Yong Qing GU Miao Ning CHEN Yang Xin Department of Anesthesiology Nanfang Hospital of Southern Medical University Department of Anesthesiology the Second Affiliated Hospital of Guangzhou Medical University Department of Cardiology Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University Guangdong Provincial Key Laboratory of Arrhythmia and Electrophysiology Department of Surgery Intensive Care Unit Nanfang Hospital of Southern Medical University

Objective To assess the effect of atorvastatin on lipopolysaccharide （LPS）-induced TNF-a production in RAW264.7 macrophages. Methods RAW264.7 macrophages were treated in different LPS concentrations or at different time points with or without atorvastatin. TNF-a level in supernatant was measured. Expressions of TNF-a mRNA and protein and heme oxygenase-1 （HO-1） were detected by ELISA, PCR, and Western blot, respectively. HO activity was assayed. Results LPS significantly increased the TNF-a expression and secretion in a dose- and time-dependent manner. The HO-1 activity and HO-1 expression level were significantly higher after atorvastatin treatment than before atorvastatin treatment and attenuated by SB203580 and PD98059 but not by SP600125, suggesting that the ERK and p38 mitogen-activated protein kinase （MAPK） pathways participate in regulating the above-mentioned effects of atorvastatin. Moreover, the HO-1 activity suppressed by SnPP or the HO-1 expression inhibited by siRNA significantly attenuated the effect of atorvastatin on TNF-c~ expression and production in LPS-stimulated macrophages. Conclusion Atorvastatin can attenuate LPS-induced TNF-e expression and production by activating HO-1 via the ERK and p38 MAPK pathways, suggesting that atorvastatin can be used in treatment of inflammatory diseases such as sepsis, especially in those with atherosclerotic diseases.

关键词： Lipopolysaccharide Tumor necrosis factor-a Heme oxygenase-1 Atorvastatin