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Polyvinyl alcohol fiber cement-stabilized macadam: A review and performance evaluation

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Journal of Traffic and transportation engineering(English Edition) 2024年第3期11卷 406-423页

作者： Chaohui Wang Jikang Liu Shaochang Chen Feng Chen Zhiwei Gao school of Highway Chang'an University Shaanxi transportation Technology Consulting Co. Ltd. school of Information engineering Xizang Minzu University

This review evaluated research results on polyvinyl alcohol fiber cement-stabilized macadam (PVA-FCSM) to further improve the long-term durability of road structures and promote its in-depth study and high-quality application.The suitable PVA fiber technical indexes for ordinary cement-stabilized macadam (CSM) were recommended.The difference in the mechanical properties between CSM and PVA-FCSM was described.The extent to which PVA fibers enhance the durability of CSM were clarified.Additionally,the mechanism of enhancement of CSM by PVA fibers was revealed.Finally,the performance of each type of fiber cement-stabilized macadam (FCSM) was compared and evaluated.The results indicated that the suggested PVA fiber length and content for CSM were 12-30 mm and 0.6-1.2 kg/m3,respectively.At different ages,the mean degree of improvement in the unconfined compressive strength was 14%,20%,and 14%,that in the compressive resilience modulus was 8%,11%,and 6%,and that in the splitting strength was 29%,15%,and 22%,respectively.At different ages,the mean degree of decreased in the dry shrinkage coefficient was 21%,16%,and 15%and that in the temperature shrinkage coefficient (20°C-30°C) was 23%,23%,and 18%,respectively.The coefficients increased with extended curing age.Moreover,at the same stress level,PVA-FCSM has a higher fatigue life compared to CSM.The bridging effect,high strength,and high modulus of PVA fiber enhance the strength and anti-cracking of CSM.The recommended fiber type for CSM is PVA fiber.

关键词： Highway and railway engineering PVA fiber cement-stabilized macadam Mechanical performance Durability Enhancement mechanism Performance valuation

Experimental study on the size effect on the equation of state of concretes under shock loading

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Defence Technology（防务技术） 2024年第3期33卷 160-167页

作者： Mei Li Jian Cui Yanchao Shi Baijian Tang Xin Chen Key Laboratory of Coast civil Structural Safety of the Ministry of Education Tianjin UniversityTianjin 300072China school of civil engineering Suzhou University of Science and Technology1701 Binhe RoadSuzhou 215011JiangsuChina school of civil engineering Tianjin UniversityTianjin 300072China

Adopting the classical theory of hydrocodes,the constitutive relations of concretes are separated into an equation of state(EoS)which describes the volumetric behavior of concrete material and a strength model which depicts the shear properties of concrete.The experiments on the EoS of concrete is always challenging due to the technical difficulties and equipment limitations,especially for the specimen size effect on the EoS.Although some researchers investigate the shock properties of concretes by fly-plate impact tests,the specimens used in their tests are usually in one size.In this paper,the fly-plate impact tests on concrete specimens with different sizes are performed to investigate the size effect on the shock properties of concrete materials.The mechanical background of the size effect on the shock properties are revealed,which is related to the lateral rarefaction effect and the deviatoric stress produced in the specimen.According to the tests results,the modified EoS considering the size effect on the shock properties of concrete are proposed,which the bulk modulus of concrete is unpredicted by up to 20% if size effects are not accounted for.

关键词： Concrete Equation of state Size effect Shock wave Fly-plate impact test

Influence of Recycled Concrete Fine Powder on Durability of Cement Mortar

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Fluid Dynamics & Materials Processing 2024年第1期20卷 45-58页

作者： Yadong Bian Xuan Qiu Jihui Zhao Zhong Li Jiana Ouyang school of Architectural and civil engineering Zhongyuan University of TechnologyZhengzhou450007China school of civil engineering Sun Yat-Sen University&Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai519082China

In this paper,the durability of cement mortar prepared with a recycled-concrete fine powder(RFP)was examined;including the analysis of a variety of aspects,such as the carbonization,sulfate attack and chloride ion erosion resistance.The results indicate that the influence of RFP on these three aspects is different.The carbonization depth after 30 days and the chloride diffusion coefficient of mortar containing 10%RFP decreased by 13.3%and 28.19%.With a further increase in the RFP content,interconnected pores formed between the RFP particles,leading to an acceleration of the penetration rate of CO_(2)and Cl^(−).When the RFP content was less than 50%,the corrosion resistance coefficient of the compressive strength of the mortar was 0.84-1.05 after 90 days of sulfate attack.But the expansion and cracking of the mortar was effectively alleviated due to decrease of the gypsum production.Scanning electron microscope(SEM)analysis has confirmed that 10%RFP contributes to the formation of a dense microstructure in the cement mortar.

关键词： Recycled concrete fine powder cement mortar carbonization sulfate chloride ion durability

Predicting the International Roughness Index of JPCP and CRCP Rigid Pavement:A Random Forest(RF)Model Hybridized with Modified Beetle Antennae Search(MBAS)for Higher Accuracy

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Computer Modeling in engineering & Sciences 2024年第5期139卷 1557-1582页

作者： Zhou Ji Mengmeng Zhou Qiang Wang Jiandong Huang College of civil and Environmental engineering Hunan University of Science and EngineeringYongzhou425006China school of Mines China University of Mining and TechnologyXuzhou221116China school of civil engineering Guangzhou UniversityGuangzhou510006China

To improve the prediction accuracy of the International Roughness Index(IRI)of Jointed PlainConcrete Pavements(JPCP)and Continuously Reinforced Concrete Pavements(CRCP),a machine learning approach is developed in this study for the modelling,combining an improved Beetle Antennae Search(MBAS)algorithm and Random Forest(RF)model.The 10-fold cross-validation was applied to verify the reliability and accuracy of the model proposed in this study.The importance scores of all input variables on the IRI of JPCP and CRCP were analysed as well.The results by the comparative analysis showed the prediction accuracy of the IRI of the newly developed MBAS and RF hybrid machine learning model(RF-MBAS)in this study is higher,indicated by the RMSE and R values of 0.2732 and 0.9476 for the JPCP as well as the RMSE and R values of 0.1863 and 0.9182 for the CRCP.The accuracy of this obtained result far exceeds that of the IRI prediction model used in the traditional Mechanistic-Empirical Pavement Design Guide(MEPDG),indicating the great potential of this developed model.The importance analysis showed that the IRI of JPCP and CRCP was proportional to the corresponding input variables in this study,including the total joint faulting cumulated per KM(TFAULT),percent subgrade material passing the 0.075-mm Sieve(P_(200))and pavement surface area with flexible and rigid patching(all Severities)(PATCH)which scored higher.

关键词： Cement pavement JPCP CRCP RF-MBAS IRI

Effect of NaCl Concentration on the Cumulative Strain and Pore Distribution of Clay under Cyclic Loading

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Fluid Dynamics & Materials Processing 2024年第2期20卷 447-461页

作者： Xinshan Zhuang Shunlei Xia Ruijie Pan school of civil engineering and Architecture Hubei University of TechnologyWuhan430068China

Clay,as the most common soil used for foundationﬁll,is widely used in various infrastructure projects.The phy-sical and mechanical properties of clay are inﬂuenced by the pore solution environment.This study uses a GDS static/dynamic triaxial apparatus and nuclear magnetic resonance experiments to investigate the effects of cyclic loading on clay foundations.Moreover,the development of cumulative strain in clay is analyzed,and aﬁtting model for cumulative plastic strain is introduced by considering factors such as NaCl solution concentration,con-solidation stress ratio,and cycle number.In particular,the effects of the NaCl solution concentration and con-solidation stress ratio on the pore distribution of the test samples before and after cyclic loading are examined,and the relationship between microscopic pore size and macroscopic cumulative strain is obtained accordingly.Our results show that as the consolidation stress ratio grows,an increasing number of large pores in the soil samples are transformed into small pores.As the NaCl solution concentration becomes higher,the number of small pores gradually decreases,while the number of large pores remains unchanged.Cyclic loading causes the disappearance of the large pores in the samples,and the average pore size before cyclic loading is posi-tively correlated with the axial cumulative strain after cyclic loading.The cumulative strain produced by the soil under cyclic loading is inversely proportional to the NaCl solution concentration and consolidation stress ratio.

关键词： Geotechnical engineering clay cyclic loading nuclear magnetic resonance NaCl solution consolidation ratio accumulative strain

J/ψ pair hadroproduction at next-to-leading order in nonrelativistic-QCD at ATLAS

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Chinese Physics C 2024年第3期48卷 15-19页

作者：孙立平 school of Science Beijing University of Civil Engineering and ArchitectureBeijingChina

We present a complete study on the J/ψpair hadroproduction at next-to-leading order(NLO)in the nonrelativstic-QCD(NRQCD)framework with the pair of cc¯in either ^(3)S^([1])_(1) or ^(1)S^([8])_(0) fock state.We found that the contribution of the ^(1)S^([8])_(0) channel at NLO is essential,and for ATLAS,the NRQCD results can describe the experimental data to a certain extent.

关键词： NRQCD next-to-leading order ATLAS fock state

Removal of atmospheric methane by soil ecosystems and its controlling variables from microbial to global scales

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Pedosphere 2024年第1期34卷 15-18页

作者： Hojeong KANG Jaehyun LEE school of civil and Environmental engineering Yonsei UniversitySeoul 03722Korea

Methane (CH_(4)), a potent greenhouse gas, plays a pivotal role in the dynamics of climate change. While CH_(4) emissions have been widely investigated,biological removal of CH_(4) by upland soils has been less explored. Understanding the mechanisms and factors affecting CH_(4) oxidation in soils is of paramount importance for devising successful mitigation strategies. This perspective paper discusses different types of aerobic methanotrophs and their activities under varying environmental conditions, highlighting the significant contribution of soil ecosystems to global CH_(4) sinks. We emphasize the need for in-depth research on variables controlling CH_(4) sinks on different spatiotemporal scales and the exploration of previously unidentified CH_(4) sinks, such as deserts and areas of glacier retreat.

关键词： soil ecosystems controlling

Numerical Exploration of Asymmetrical Impact Dynamics: Unveiling Nonlinearities in Collision Problems and Resilience of Reinforced Concrete Structures

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Structural Durability & Health Monitoring 2024年第3期18卷 223-254页

作者： AL-Bukhaiti Khalil Yanhui Liu Shichun Zhao Daguang Han school of civil engineering Southwest Jiaotong UniversityChengdu610031China Faculty of civil engineering Southeast UniversityNanjingChina

This study provides a comprehensive analysis of collision and impact problems’ numerical solutions, focusing ongeometric, contact, and material nonlinearities, all essential in solving large deformation problems during a collision.The initial discussion revolves around the stress and strain of large deformation during a collision, followedby explanations of the fundamental finite element solution method for addressing such issues. The hourglassmode’s control methods, such as single-point reduced integration and contact-collision algorithms are detailedand implemented within the finite element framework. The paper further investigates the dynamic responseand failure modes of Reinforced Concrete (RC) members under asymmetrical impact using a 3D discrete modelin ABAQUS that treats steel bars and concrete connections as bond slips. The model’s validity was confirmedthrough comparisons with the node-sharing algorithm and system energy relations. Experimental parameterswere varied, including the rigid hammer’s mass and initial velocity, concrete strength, and longitudinal and stirrupreinforcement ratios. Findings indicated that increased hammer mass and velocity escalated RC member damage,while increased reinforcement ratios improved impact resistance. Contrarily, increased concrete strength did notsignificantly reduce lateral displacement when considering strain rate effects. The study also explores materialnonlinearity, examining different materials’ responses to collision-induced forces and stresses, demonstratedthrough an elastic rod impact case study. The paper proposes a damage criterion based on the residual axialload-bearing capacity for assessing damage under the asymmetrical impact, showing a correlation betweendamage degree hammer mass and initial velocity. The results, validated through comparison with theoreticaland analytical solutions, verify the ABAQUS program’s accuracy and reliability in analyzing impact problems,offering valuable insights into collision and impact problems’ nonlinearities and practic

关键词： Geometric nonlinearity contact nonlinearity material nonlinearity collision problems finite element method stress and strain damage criterion RC members asymmetrical impact

Mechanical properties and fracture surface roughness of thermally damaged granite under dynamic splitting

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Deep Underground Science and engineering 2024年第1期3卷 103-116页

作者： Yijin Qian Peng Jia Songze Mao Jialiang Lu school of Resources and civil engineering Northeastern UniversityShenyangChina

In order to understand the mechanical properties and the fracture surface roughness characteristics of thermally damaged granite under dynamic splitting,dynamic Brazilian splitting tests were conducted on granite samples after thermal treatment at 25,200,400,and 600℃.Results show that the dynamic peak splitting strength of thermally damaged granite samples increases with increasing strain rate,showing obvious strain‐rate sensitivity.With increasing temperature,thermally induced cracks in granite transform from intergranular cracks to intragranular cracks,and to a transgranular crack network.Thermally induced damages reduce the dynamic peak splitting strength and the maximum absorbed energy while increasing the peak radial strain.The fracture mode of the thermally damaged granite under dynamic loads is mode Ⅱ splitting failure.By using the axial roughness index Z2 a,the distribution ranges of the wedge‐shaped failure zones and the tensile failure zones in the fracture surfaces under dynamic Brazilian splitting can be effectively identified.The radial roughness index Z_(2)^(r)is sensitive to the strain rate and temperature.It shows a linear correlation with the peak splitting strength and the maximum absorbed energy and a linear negative correlation with the peak radial strain.Z_(2)^(r)can be used to quantitatively estimate the dynamic parameters based on the models proposed.

关键词： dynamic splitting fracture surface roughness granite strain rate thermal treatment