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A state-of-the-art review on interfacial behavior between asphalt binder and mineral aggregate

Meng GUO, Yiqiu TAN, Linbing WANG, Yue HOU

《结构与土木工程前沿（英文）》 2018年 第12卷 第2期   页码 248-259 doi: 10.1007/s11709-017-0422-x

摘要： The interface between asphalt binder and mineral aggregate directly affects the service life of pavement because the defects and stress concentration occur more easily there. The interaction between asphalt binder and mineral aggregate is the main cause of forming the interface. This paper presents an extensive review on the test technologies and analysis methods of interfacial interaction, including molecular dynamics simulation, phase field approach, absorption tests, rheological methods and macro mechanical tests. All of the studies conducted on this topic clearly indicated that the interfacial interaction between asphalt binder and mineral aggregate is a physical-chemical process, and can be qualitatively characterized by microscopical technique (such as SEM and AFM), and also can be quantitatively evaluated by rheological methods and interfacial mechanical tests. Molecular dynamics simulation and phase field approach were also demonstrated to be effective methods to study the interfacial behavior and its mechanism.

关键词： Asphalt binder     Mineral aggregate     Interfacial behavior     Multiscale    

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Experimental study on behavior of mortar-aggregate interface after elevated temperatures

Wan WANG, Jianzhuang XIAO, Shiying XU, Chunhui WANG

《结构与土木工程前沿（英文）》 2017年 第11卷 第2期   页码 158-168 doi: 10.1007/s11709-016-0374-6

摘要： A push-out test program was designed and conducted to study the meso-scale behavior of mortar-aggregate interface for concrete after elevated temperatures ranging from 20°C to 600°C with the concept of modeled concrete (MC) and modeled recycled aggregate concrete (MRAC). The MCs and MRACs were designed with different strength grade of mortar and were exposed to different elevated temperatures. Following that the specimens were cooled to room temperature and push-out tests were conducted. Failure process and mechanical behaviors were analyzed based on failure modes, residual load-displacement curves, residual peak loads and peak displacements. It is found that failure modes significantly depended on specimen type, the elevated temperature and the strength grade of mortar. For MC, major cracks started to propagate along the initial cracks caused by elevated temperatures at about 80% of residual peak load. For MRAC, the cracks appeared at a lower level of load with the increasing elevated temperatures. The cracks connected with each other, formed a failure face and the specimens were split into several parts suddenly when reaching the residual peak load. Residual load-displacement curves of different specimens had similarities in shape. Besides, effect of temperatures and strength grade of mortar on residual peak load and peak displacement were analyzed. For MC and MRAC with higher strength of new hardened mortar, the residual peak load kept constant when the temperature is lower than 400°C and dropped by 43.5% on average at 600°C. For MRAC with lower strength of new hardened mortar, the residual peak load began to reduce when the temperatures exceeded 200°C and reduced by 27.4% and 60.8% respectively at 400°C and 600°C. The properties of recycled aggregate concrete (RAC) may be more sensitive to elevated temperatures than those of natural aggregate concrete (NAC) due to the fact that the interfacial properties of RAC are lower than those of NAC, and are deteriorated at lower temperatures.

关键词： mortar-aggregate interface     push-out test     elevated temperatures     modeled concrete (MC)     modeled recycled aggregate concrete (MRAC)    

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Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1415-1425 doi: 10.1007/s11709-021-0786-9

摘要： To study the behavior of coral aggregate concrete (CAC) column under axial and eccentric compression, the compression behavior of CAC column with different types of steel and initial eccentricity (ei) were tested, and the deformation behavior and ultimate bearing capacity (Nu) were studied. The results showed that as the ei increases, the Nu of CAC column decreases nonlinearly. Besides, the steel corrosion in CAC column is severe, which reduces the steel section and steel strength, and decreases the Nu of CAC column. The durability of CAC structures can be improved by using new organic coated steel. Considering the influence of steel corrosion and interfacial bond deterioration, the calculation models of Nu under axial and eccentric compression were presented.

关键词： coral aggregate concrete column     axial compression     eccentric compression     steel corrosion     calculation model    

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Chloride ingress and macro-cell corrosion of steel in concrete made with recycled brick aggregate

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1358-1371 doi: 10.1007/s11709-021-0769-x

摘要： An investigation on chloride ingress and macro-cell corrosion of steel bars in concrete made with recycled brick aggregate (RBA) was carried out. As control cases, virgin brick aggregate (BA) and stone aggregate (SA) were also investigated. Both cylindrical and cracked prism specimens were studied for 16 different cases. The prism specimens were made with a segmented steel bar providing electrical connection from outside of the specimens to measure macro-cell corrosion current continuously under seawater splash exposure for a period of 30 d using a data logger. Cylindrical specimens were submerged in 3% NaCl solution at a temperature of 40°C to investigate chloride ingress in concrete made with RBA, BA, and SA after 120 and 180 d. Half-cell potential, corrosion area, and depths of corrosion were also investigated. The chloride ingress as well as corrosion of steel bars in concrete made with the different types of aggregate is ordered as RBA > BA > SA.

关键词： brick aggregate     chloride ingress     macro-cell corrosion     recycled brick aggregate    

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Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1400-1414 doi: 10.1007/s11709-021-0779-8

摘要： Aggregates are the biggest contributor to concrete volume and are a crucial parameter in dictating its mechanical properties. As such, a detailed experimental investigation was carried out to evaluate the effect of sand-to-aggregate volume ratio (s/a) on the mechanical properties of concrete utilizing both destructive and non-destructive testing (employing UPV (ultrasonic pulse velocity) measurements). For investigation, standard cylindrical concrete samples were made with different s/a (0.36, 0.40, 0.44, 0.48, 0.52, and 0.56), cement content (340 and 450 kg/m3), water-to-cement ratio (0.45 and 0.50), and maximum aggregate size (12 and 19 mm). The effect of these design parameters on the 7, 14, and 28 d compressive strength, tensile strength, elastic modulus, and UPV of concrete were assessed. The careful analysis demonstrates that aggregate proportions and size need to be optimized for formulating mix designs; optimum ratios of s/a were found to be 0.40 and 0.44 for the maximum aggregate size of 12 and 19 mm, respectively, irrespective of the W/C (water-to-cement) and cement content.

关键词： aggregates     non-destructive testing     sand-to-aggregate volume ratio (s/a)     maximum aggregate size (MAS)    

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Effects of exercise therapy on bone mineral density in early postmenopausal women: a controlled trial

Shilin DENG MD ,

《医学前沿（英文）》 2009年 第3卷 第3期   页码 323-329 doi: 10.1007/s11684-009-0061-2

摘要： The purpose of this article is to determine the effect of a well-designed combined aerobic, resistance, and extension exercise program on bone mineral density (BMD) in postmenopausal women. The population comprised 45 postmenopausal women, who exercised over 12months (exercise group), and 36 women who served as a non-training control group. BMD of the hip, and lumbar spine was measured at the baseline and 12th month. Repeated measurement analysis of variance and nonparametric test were utilized to compare differences between the exercise group and controls. Thirty-six out of 45 persons in the exercise group and 36 controls completed the study. Average compliance was 82.2% for the whole exercise group at the 12th month. All the subjects had decreased BMD, but the rate of bone loss was lower in the exercise group than in the control group at the L4 and hip. Although the exercise program in this study may probably reduce the rate of bone loss in weight-bearing skeletal sites, we do not suggest the exercise by itself be viewed as prevention or treatment for osteoporosis. Further, the exact dose-response relationship of exercise and bone mass in early postmenopause is not clear.

关键词： early postmenopausal women     bone mineral density     exercise     effects    

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矿物浮选吸附平衡模型构建与应用：精准解析矿物 表面离子 / 药剂特征吸附

高雅,付心壮,韩海生,王丽,岳彤,孙伟

《中国工程科学》 2023年 第25卷 第6期   页码 248-258 doi: 10.15302/J-SSCAE-2023.07.020

摘要：

矿物浮选吸附平衡模型是准确描述矿物浮选过程中所涉及的矿物表面离子 / 药剂吸附平衡的数学模型，首次实现了矿物表面位点与浮选药剂吸附作用亲和性的量化解析。传统浮选理论对矿物表面作用位点缺乏科学描述，难以阐明浮选药剂的吸附作用能力及平衡状态，新浮选药剂体系开发多以“试错法”“复配法”等经验性方法为主。药剂选择性吸附作为浮选作业的核心机制，若不能准确预测其在各矿物表面的吸附行为，将严重限制浮选工艺智能化控制的发展。本文详细论述了矿物浮选吸附平衡模型的构建原理，以赤铁矿 ‒ 石英和一水硬铝石 ‒ 高岭石两个浮选体系为例，通过对少量实验数据的拟合计算，解析出矿物表面活性位点密度Ns、加 / 去质子反应常数Kt1/Kt2、药剂吸附常数Kf等矿物浮选特征常数。将解析的矿物浮选特征常数代入到平衡模型中，预测出各条件下矿物表面电性、离子及浮选药剂的吸附量，通过零电点、实验及测试等方法验证了可靠性，形成了矿物浮选过程预测系统的内核算法。该算法对各条件下每种矿物药剂吸附的初步准确预测，可在一定程度上反映其可浮性趋势，有助于缩短浮选工艺开发周期，对矿物表面药剂吸附机理研究、浮选药剂分子设计、浮选工艺流程优化及智能控制等具有重要意义。

关键词： 矿物加工；浮选机理；矿物浮选吸附平衡模型；可浮性预测；矿物浮选特征常数    

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Relationship between the development of energy and mineral resources and ecological conservation redline

Dawei ZHANG

《工程管理前沿（英文）》 2019年 第6卷 第4期   页码 557-563 doi: 10.1007/s42524-019-0077-5

摘要： From a philosophical point of view, this study discusses the dialectical relationship between the development of energy and mineral resources and the ecological conservation redline. We propose that the ecological conservation redline and the development of energy and mineral resources should be guided by ecological civilization construction, that is, the energy and mineral resources should be rationally developed under the condition that the ecological environment is protected. This study analyzes the influence of the development of energy and mineral resources on the ecological environment. The handling of mining rights within the ecological conservation redline based on the law and the reduction of the influence of the development of energy mineral resources on the ecological environment by science and technology are presented. The environmental assessment system and technical standards for energy and mineral development are suggested to implement policies and measures for the disposal of mining rights within the redline and facilitate technological innovations of ecological conservation for energy and mineral development. Hence, a coordinated development between the ecological conservation redline and the development of energy and mineral resources can be promoted.

关键词： ecological conservation redline     development of energy and mineral resources     coordinated development    

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Punching shear behavior of recycled aggregate concrete slabs with and without steel fibres

Jianzhuang XIAO, Wan WANG, Zhengjiu ZHOU, Mathews M. TAWANA

《结构与土木工程前沿（英文）》 2019年 第13卷 第3期   页码 725-740 doi: 10.1007/s11709-018-0510-6

摘要： A study on the punching shear behavior of 8 slabs with recycled aggregate concrete (RAC) was carried out. The two main factors considered were the recycled coarse aggregate (RCA) replacement percentage and the steel fibre volumetric ratio. The failure pattern, load-displacement curves, energy consumption and the punching shear capacity of the slabs were intensively investigated. It was concluded that the punching shear capacity, ductility and energy consumption decreased with the increase of RCA replacement percentage. Research findings indicated that the incorporation of steel fibres could not only improve the energy dissipation capacity and the punching shear capacity of the slab, but also effectively improve the integrity of the slab tension surface and thereby changing the trend from typical punching failure pattern to bending-punching failure pattern. On the basis of the test, the punching shear capacity formula of RAC slabs with and without steel fibres was proposed and discussed.

关键词： recycled aggregate concrete     steel fibres     slab     punching shear     recycled coarse aggregates replacement percentage    

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Quantification of coarse aggregate shape in concrete

Xianglin GU,Yvonne TRAN,Li HONG

《结构与土木工程前沿（英文）》 2014年 第8卷 第3期   页码 308-321 doi: 10.1007/s11709-014-0266-6

摘要： The objective of this study is to choose indices for the characterization of aggregate form and angularity for large scale application. For this purpose, several parameters for aggregate form and angularity featured in previous research are presented. Then, based on these established parameters, 200 coarse quartzite aggregates are analyzed herein by using image processing technology. This paper also analyzes the statistical distributions of parameters for aggregate form and angularity as well as the correlation between form and angularity parameters. It was determined that the parameters for form or angularity of coarse aggregates could be fitted by either normal distribution or log-normal distribution at a 95% confidence level. Some of the form parameters were influenced by changes in angularity characteristics, while aspect ratio and angularity using outline slope, area ratio and radius angularity index, and aspect ratio and angularity index were independent of each other, respectively; and consequently, the independent parameters could be used to quantify the aggregate form and angularity for the purpose to study the influence of aggregate shape on the mechanical behavior of concrete. Furthermore, results from this study’s in-depth investigations showed that the aspect ratio and the angularity index can further understanding of the effects of coarse aggregates form and angularity on concrete mechanical properties, respectively. Finally, coarse aggregates with the same content, type and surfaces texture, but different aspect ratios and angularity indices were used to study the influence of coarse aggregate form and angularity on the behavior of concrete. It was revealed that the splitting tensile strength of concrete increased with increases in the aspect ratio or angularity index of coarse aggregates.

关键词： coarse aggregate     form     angularity     digital image analysis     statistical distribution     splitting tensile strength    

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Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 754-772 doi: 10.1007/s11709-021-0711-2

摘要： Typical effects of coarse and fine aggregates on the long-term properties of sea sand recycled aggregate concrete (SSRAC) are analyzed by a series of axial compression tests. Two different types of fine (coarse) aggregates are considered: sea sand and river sand (natural and recycled coarse aggregates). Variations in SSRAC properties at different ages are investigated. A novel test system is developed via axial compression experiments and the digital image correlation method to obtain the deformation field and crack development of concrete. Supportive results show that the compressive strength of SSRAC increase with decreasing recycled coarse aggregate replacement percentage and increasing sea sand chloride ion content. The elastic modulus of SSRAC increases with age. However, the Poisson’s ratio reduces after 2 years. Typical axial stress–strain curves of SSRAC vary with age. Generally, the effect of coarse aggregates on the axial deformation of SSRAC is clear; however, the deformation differences between coarse aggregate and cement mortar reduce by adopting sea sand. The aggregate type changes the crack characteristics and propagation of SSRAC. Finally, an analytical expression is suggested to construct the long-term stress–strain curve of SSRAC.

关键词： sea sand recycled aggregate concrete     recycled coarse aggregate replacement percentage     sea sand chloride ion content     long-term mechanical properties     stress–strain curve    

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Understanding the behavior of recycled aggregate concrete by using thermogravimetric analysis

Subhasis PRADHAN, Shailendra KUMAR, Sudhirkumar V. BARAI

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1561-1572 doi: 10.1007/s11709-020-0640-5

摘要： The physio-chemical changes in concrete mixes due to different coarse aggregate (natural coarse aggregate and recycled coarse aggregate (RCA)) and mix design methods (conventional method and Particle Packing Method (PPM)) are studied using thermogravimetric analysis of the hydrated cement paste. A method is proposed to estimate the degree of hydration ( ) from chemically bound water ( ). The PPM mix designed concrete mixes exhibit lower . Recycled aggregate concrete (RAC) mixes exhibit higher and after 7 d of curing, contrary to that after 28 and 90 d. The chemically bound water at infinite time ( ) of RAC mixes are lower than the respective conventional concrete mixes. The lower , Ca(OH) bound water, free Ca(OH) content and FT-IR analysis substantiate the use of pozzolanic cement in the parent concrete of RCA. The compressive strength of concrete and cannot be correlated for concrete mixes with different aggregate type and mix design method as the present study confirms that the degree of hydration is not the only parameter which governs the macro-mechanical properties of concrete. In this regard, further study on the influence of interfacial transition zone, voids content and aggregate quality on macro-mechanical properties of concrete is needed.

关键词： recycled aggregate concrete     Particle Packing Method     thermogravimetric analysis     chemically bound water     degree of hydration     Fourier transform infrared spectroscopy    

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Comments on “Prediction on CO uptake of recycled aggregate concrete”, Frontiers of Structural and Civil

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1504-1506 doi: 10.1007/s11709-021-0782-0

摘要： A methodology to compute the CO2 uptake of recycled aggregate concrete is proposed in the commented paper. Besides some typos in several formulas, it is found that the approach to estimate the specific surface area of the recycled aggregates is not correct. This issue has some impact in the conclusions of the commented paper. Therefore, aiming to improve the understanding, accuracy and findings of the commented paper, an alternative approach to estimate the specific surface area of the recycled aggregates, as well as an erratum of the formulas and revised conclusions are suggested.
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Long term performance of recycled concrete beams with different water–cement ratio and recycled aggregate

Jingwei YING; Feiming SU; Shuangren CHEN

《结构与土木工程前沿（英文）》 2022年 第16卷 第3期   页码 302-315 doi: 10.1007/s11709-022-0803-7

摘要： The purpose of this study is to reveal the service performance of recycled aggregate concrete (RAC) components for different values of water−cement ratio and replacement rate of recycled coarse aggregate (RCA). Generally, the concrete strength decreases with the increase of the replacement rate of RCA, in order to meet the strength requirements when changing the replacement rate of RCA, it is necessary to change the water−cement ratio at the same time. Therefore, the axial compressive strengths of prism with 25 mix proportions, the short-term mechanical properties and long-term deformation properties of reinforced concrete beams were tested respectively by changing water−cement ratio and RCA replacement rate. The bearing capacity and the strain nephogram of samples under different loads were obtained using the Digital Image Correlation (DIC) method, and a self-made gravity loading experimental device was used for long-term deformation investigation. Results showed that the damage pattern of RAC was the same as that of natural aggregate concrete (NAC), but the brittleness was more pronounced. The brittleness of concrete before failure can be reduced more effectively by adjusting the replacement rate of RCA than by adjusting the water−cement ratio. The water−cement ratio has an evident influence on the axial compressive strength and early creep of concrete, while the replacement rate of RCA has a remarkable effect on the long-term deformation of the concrete beams.

关键词： recycled concrete     beam     the replacement rate of recycled coarse aggregate     water–cement ratio     digital image correlation    

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Fracture resistance on aggregate bridging crack in concrete

ZHANG Xiufang, XU Shilang

《结构与土木工程前沿（英文）》 2007年 第1卷 第1期   页码 63-70 doi: 10.1007/s11709-007-0006-2

摘要： Fracture toughening exhibited in quasi-brittle materials such as concrete is often mainly related to the action of aggregate bridging, which leads to the presence of a fracture process zone ahead of stress-free cracks in such materials. In this investigation, the fracture resistance induced by aggregate bridging, denoted by GI-bridging, is the primary focus. In order to quantitatively determine it, a general analytical formula is firstly developed, based on the definition of fracture energy by Hillerborg. After this, we further present the calculated procedures of determining this fracture resistance from the recorded load vs. crack opening displacement curve. Then, both numerical simulations and fracture experiments are performed on concrete three-point bending beams. Utilizing the obtained load against crack opening displacement curve, the value of G at any crack extension as well as the change of G with the crack extension is examined. It is found that G will firstly increase with the development of crack and then stay constant once the initial crack tip opening displacement reaches the characteristic crack opening displacement w0. The effects of material strength and specimen depth on this fracture resistance are also investigated. The results reveal that the values of G of different specimens at any crack propagation are strongly associated with the values of fracture energy of specimens. If the values of fracture energy between different specimens are comparable, the differences between G are ignored. Instead, if values of fracture energy are different, the G will be different. This shows that for specimens with different strengths, G will change greatly whereas for specimens that are different in depth, whether GI-bridging exhibits size effect depends on whether the fracture energy of specimens considered in the calculation of G is assumed to be a size-dependent material parameter.
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标题 作者 时间 类型 操作

A state-of-the-art review on interfacial behavior between asphalt binder and mineral aggregate

Meng GUO, Yiqiu TAN, Linbing WANG, Yue HOU

期刊论文

Experimental study on behavior of mortar-aggregate interface after elevated temperatures

Wan WANG, Jianzhuang XIAO, Shiying XU, Chunhui WANG

期刊论文

Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete

期刊论文

Chloride ingress and macro-cell corrosion of steel in concrete made with recycled brick aggregate

期刊论文

Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

期刊论文

Effects of exercise therapy on bone mineral density in early postmenopausal women: a controlled trial

Shilin DENG MD ,

期刊论文

矿物浮选吸附平衡模型构建与应用：精准解析矿物 表面离子 / 药剂特征吸附

高雅,付心壮,韩海生,王丽,岳彤,孙伟

期刊论文

Relationship between the development of energy and mineral resources and ecological conservation redline

Dawei ZHANG

期刊论文

Punching shear behavior of recycled aggregate concrete slabs with and without steel fibres

Jianzhuang XIAO, Wan WANG, Zhengjiu ZHOU, Mathews M. TAWANA

期刊论文

Quantification of coarse aggregate shape in concrete

Xianglin GU,Yvonne TRAN,Li HONG

期刊论文

Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate

期刊论文

Understanding the behavior of recycled aggregate concrete by using thermogravimetric analysis

Subhasis PRADHAN, Shailendra KUMAR, Sudhirkumar V. BARAI

期刊论文

Comments on “Prediction on CO uptake of recycled aggregate concrete”, Frontiers of Structural and Civil

期刊论文

Long term performance of recycled concrete beams with different water–cement ratio and recycled aggregate

Jingwei YING; Feiming SU; Shuangren CHEN

期刊论文

Fracture resistance on aggregate bridging crack in concrete

ZHANG Xiufang, XU Shilang

期刊论文