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Frontiers of Structural and Civil Engineering 2023年第2期17卷 256-270页

作者： Kun FANG Liang CUI School of Mines China University of Mining&TechnologyXuzhou 221116China Department of Civil Engineering Lakehead UniversityOntario P7B 5E1Canada

The curing temperature-dependent cement hydration causes the nonlinear evolution of fracture behavior and properties of fiber-reinforced cemented paste backfill(CPB)and thus influences the stability of mine backfill materials in deep ***,the coupled effect of curing temperature(20,35,and 45℃)and cement hydration at different curing times(3,7,and 28 d)on the mode-I and mode-II fracture behavior and properties of fiber-reinforced CPB is investigated.A comprehensive experimental testing program consisting of semicircular bend tests,direct shear tests,measurement of volumetric water content and matric suction,TG/DTG tests,and SEM observation is carried *** results show that the coupled thermochemical effect results in strongly nonlinear development of pre-and post-peak behavior of fiber-reinforced ***,the results discover a positive linear correlation between fracture toughness and shear strength parameters and also reveal the vital role played by matric suction in the formation of fracture ***,predictive functions are developed to estimate the coupled thermochemical effect on the development of KIc and ***,the findings and the developed mathematical tools have the potential to promote the successful application of fiber-reinforced CPB technology in deep underground mines.

关键词： fiber reinforcement cemented paste backfill fracture behavior underground mine cement hydration

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Time- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill

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Frontiers of Structural and Civil Engineering 2021年第4期15卷 1025-1037页

作者： Iarley Loan Sampaio LIBOS Liang CUI Department of Civil Engineering Lakehead UniversityOntarioP7B 5E1Canada

The understanding of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill(FR-CPB)play crucial roles in the successful implementation of reinforcement technique in underground mine backfilling ***,very limited studies have been performed to gain insight into the evolution of compressive and tensile behaviors and associated mechanical properties of FR-CPB under various curing temperatures from early to advanced ***,this study aims to investigate the time(7,28,and 90 d)-and temperature(20°C,35°C,and 45°C)-dependence of constitutive behavior and mechanical properties of *** obtained results show that pre-and post-failure behaviors of FR-CPB demonstrate strongly curing temperature-dependence from early to advanced ***,the pseudo-hardening behavior is sensitive to curing temperature,especially at early ***,the mechanical properties including elastic modulus,material stiffness,strengths,brittleness,cohesion,and internal friction angle of FR-CPB show increasing trends with curing temperature as curing time ***,a predictive model is developed to capture the strong correlation between compressive and tensile strength of *** findings of this study will contribute to the successful implementation of FR-CPB technology.

关键词： cemented paste backfill fiber reinforcement constitutive behavior temperature tailings

Tensile strength behavior of cement-stabilized dredged sediment reinforced by polypropylene fiber

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Frontiers of Structural and Civil Engineering 2024年第3期18卷 380-392页

作者： Lei LANG Jiangshan LI Xin CHEN Lijun HAN Ping WANG State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicChinese Academy of SciencesWuhan 430071China Hubei Provincial Key Laboratory of Contaminated Sludge and Soil Science and Engineering Wuhan 430071China University of Chinese Academy of Sciences Beijing 100049China

This study evaluated the feasibility of using polypropylene fiber(PF)as reinforcement in improving tensile strength behavior of cement-stabilized dredged sediment(CDS).The effects of cement content,water content,PF content and length on the tensile strength and stress–strain behavioral evolutions were evaluated by conducting splitting tensile strength ***,the micro-mechanisms characterizing the tensile strength behavior inside PF-reinforced CDS(CPFDS)were clarified via analyzing macro failure and microstructure *** results indicate that the highest tensile strengths of 7,28,60,and 90 d CPFDS were reached at PF contents of 0.6%,1.0%,1.0%,and 1.0%,exhibiting values 5.96%,65.16%,34.10%,and 35.83%higher than those of CDS,***,3 mm,PF of showed the best reinforcement *** CPFDS exhibited obvious tensile strain-hardening characteristic,and also had better ductility than *** mix factor(C_(C)^(a)/C_(w)^(b))and time parameter(q_(t0)(t))of CDS,and the reinforcement index(k_(t-PF))of CPFDS were used to establish the tensile strength prediction models of CDS and CPFDS,considering multiple *** PF“bridge effect”and associated cementation-reinforcement coupling actions inside CPFDS were mainly responsible for tensile strength behavior *** key findings contribute to the use of CPFDS as recycled engineering soils.

关键词： dredged sediment chemical stabilization fiber reinforcement splitting tensile strength micro-mechanisms

Multiphysics processes in the interfacial transition zone of fiber-reinforced cementitious composites under induced curing pressure and implications for mine backfill materials: A critical review

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International Journal of Minerals,Metallurgy and Materials 2023年第8期30卷 1474-1489页

作者： Brett Holmberg Liang Cui Department of Civil Engineering Lakehead UniversityThunder BayON P7B 5E1Canada

The mesoscale fiber-matrix interfacial transition zone(FM-ITZ) under induced curing pressure plays a key role in the effectiveness of fiber reinforcement and the engineering application of fiber-reinforced cementitious composites(FRCCs). This critical review establishes the link among induced curing pressure(i.e., external loading condition), multiphysics processes(i.e., internal governing mechanism), and interface behavior(i.e., material behavior) for FRCC materials through analysis of the state-of-the-art research findings on the FM-ITZ of FRCC materials. The following results are obtained. For the mechanical process, the induced curing pressure changes the stress state and enhances multicracking behavior, which can strengthen the FM-ITZ. For the hydraulic process, the strengthened seepage of the FM-ITZ under induced curing pressure weakens the effective stress and exaggerates the deficiency in water retention capacity between the bulk matrix and the FMITZ. For the thermal process, the induced curing pressure causes a steep temperature gradient in the FM-ITZ and thus influences the temperature evolution and thermally-induced microcracks in the FM-ITZ. For the chemical process, the induced curing pressure enhances hydration kinetics and results in the formation of additional hydration products in the FM-ITZ. Moreover, recommendations are proposed on the basis of findings from this review to facilitate the implementation of fiber reinforcement in cemented paste backfill technology.

关键词： cemented paste backfill cementitious composites interfacial transition zone fiber reinforcement multiphysics induced curing pressure

Uniaxial Compressive Properties of Ultra High Toughness Cementitious Composite

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Journal of Wuhan University of Technology(Materials Science) 2011年第4期26卷 762-769页

作者：蔡向荣徐世烺 State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology

Uniaxial compression tests were conducted to characterize the main compressive performance of ultra high toughness cementitious composite （UHTCC） in terms of strength and toughness and to obtain its stress-strain relationships. The compressive strength investigated ranges from 30 MPa to 60 MPa. Complete stress-strain curves were directly obtained, and the strength indexes, including uniaxial compressive strength, compressive strain at peak stress, elastic modulus and Poisson＇s ratio, were calculated. The comparisons between UHTCC and matrix were also carried out to understand the fiber effect on the compressive strength indexes. Three dimensionless toughness indexes were calculated, which either represent its relative improvement in energy absorption capacity because of fiber addition or provide an indication of its behavior relative to a rigid-plastic material. Moreover, two new toughness indexes, which were named as post-crack deformation energy and equivalent compressive strength, were proposed and calculated with the aim at linking up the compressive toughness of UHTCC with the existing design concept of concrete. The failure mode was also given. The study production provides material characteristics for the practical engineering application of UHTCC.

关键词： ultra high toughness cementitious composite compressive strength compressive toughness fiber reinforcement

Effects of fibers on the mechanical properties of UHPC:A review

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Journal of Traffic and Transportation Engineering(English Edition) 2022年第3期9卷 363-387页

作者： Jian Yang Baochun Chen Jiazhan Su Gang Xu Dong Zhang Jialiang Zhou Hubei Key Laboratory of Disaster Prevention and Mitigation Yichang 443002China College of Civil Engineering&Architecture China Three Gorges UniversityYichang 443002China School of Civil Engineering Fujian University of TechnologyFuzhou 350116China College of Civil Engineering Fuzhou UniversityFuzhou 350116China National Center for Joint International Research of Bridges Technology Innovation and Risk Mitigation Fuzhou UniversityFuzhou 350116China

Ultra-high performance concrete(UHPC) developed rapidly in research and commercial use during the recent decade. Significant progress has been achieved in its material science and technology, including why and how to add discontinuous fiber reinforcement in *** paper reviews the researches on understanding the effects of various fibers on the mechanical properties of UHPC, focus on the straight steel fibers but involving also deformed steel fibers, non-steel fibers as well as hybrid fibers. It also discusses the research methodology, prediction of mechanical properties by fiber factors, and the classification of UHPC mechanical properties related to this topic. It shows that(1) the experimental research is the main methodology for investigating the effect of the fibers on the mechanical properties of UHPC;the tensile performance of UHPC should be studied by uniaxial tensile tests and its representative indicators should include tensile strength, initial cracking strength, and peak tensile strain;(2) fiber plays an essential role in the reinforcement of the tensile strength, compressive strength, modulus of elasticity, and other material properties of UHPC, but in weakening the flowability of fresh UHPC. The positive and negative effects of fibers on the mechanical properties of UHPC should be considered,and the technology should be developed to maintain the flowability when high volume fraction of fibers is added in the UHPC;(3) the parameters of steel fibers affecting the mechanical properties of UHPC include volume fraction, size, shape, orientation and distribution, average bonding strength and minimum tensile strength, etc., which are mainly studied independently in the existing research. The studies on the combined effect of these parameters are limited but worthy of further investigation;(4) hybrid fibers could efficiently produce reinforcement effects for UHPC. It has great practical and research significance to conduct in-depth studies though the theoret

关键词： Ultra-high performance concrete(UHPC) fiber reinforcement Effect factor Hybrid fiber Quantitative analysis Mechanical properties

Effects of Polypropylene fibers on the Physical and Mechanical Properties of Recycled Aggregate Concrete

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Journal of Wuhan University of Technology(Materials Science) 2019年第6期34卷 1327-1344页

作者： Pierre Matar Gérard-Philippe Zéhil Lebanese University Faculty of EngineeringBranch 2RoumiehLebanon Notre Dame University-Louaize Faculty of EngineeringZouk MosbehLebanon

The viability of using polypropylene fibers(PPF) in concrete was largely studied. Yet, few of the existing research studies investigated the effects of PPF on the properties of concrete containing recycled concrete aggregate(RCA). Mixes with different RCA replacement ratios and different PPF content were designed and tested. The test results showed that the addition of PPF did not change significantly the compressive strength and the density of the concrete, but slightly decreased its modulus of elasticity and Poisson’s ratio. The drop in the splitting tensile strength and the flexural strength due to RCA inclusions was to a large extent compensated by the PPF addition. The water absorption decreased and the percent voids increased with increased PPF addition. Correlations between the RCA content, the PPF content and the properties of concrete were studied. Useful regression models were proposed to predict the properties of concrete in relevant ranges of RCA and PPF content.

关键词： concrete recycled aggregate fiber reinforcement physical properties mechanical properties

Simulation of fiber Pushing-out Test

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Journal of Wuhan University of Technology(Materials Science) 2009年第6期24卷 965-969页

作者：张亚芳 Faculty of Civil Engineering Guangzhou University

The stress distribution on the failure progress of fiber pushed-out test was studied. A numerical program, developed by meso-damage mechanics, was adopted to simulate the whole failure process of interface debonding and fiber pushing out. From the simulation, it can be concluded that, the interfacial stress on load side and support side is larger than other portions. Simultaneously, the shear stress in both sides becomes larger when thickness of sample reduces. Furthermore, when the diameter of fiber increases, the shear stress on load side is getting larger but in support side it is diminishing. On the other hand, changes of the support hole’s diameter only affect the interfacial shear stress on the support side.

关键词： push out fiber reinforcement interface debonding heterogeneous

Effect of raw materials and proportion on mechanical properties of magnesium phosphate cement

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Journal of Road Engineering 2022年第3期2卷 243-251页

作者： Yangzezhi Zheng Yang Zhou Xiaoming Huang Haoyuan Luo School of Transportation Southeast UniversityNanjing 211189China National Demonstration Center for Experimental Education of Road and Traffic Engineering Southeast UniversityNanjing 211189China School of Materials Science and Engineering Southeast UniversityNanjing 211189China State Key Laboratory of High Performance Civil Engineering Materials Jiangsu Research Institute of Building Science Co.Nanjing 211103China

Magnesium phosphate cement (MPC) cementitious material is a phosphate cement-based material with strengthformed by a serious of acid-base neutralization reactions among magnesium oxide, phosphate retarder and water,which has a high early strength and a broad application prospect in the field of pavement rehabilitation. Thisreview collects and organizes the latest progress in the field of research on the influencing factors of mechanicalproperties of magnesium phosphate cementitious materials worldwide in recent years, and discusses the possibilitiesof application in airport *** type of phosphate has a great influence on the reaction products, and the strength of the reaction productsof ammonium salt is higher. Borax is the most commonly used retarder, and the retarding effect is related to theratio of boron to magnesium. However, borax retarders have an adverse effect on the strength of MPC. In terms ofthe influence of mineral admixtures on the properties of MPC, fly ash, silica fume and metakaolin, as commonmineral admixtures, have a positive influence on the mechanical properties of MPC, but the mechanism anddegree of the influence of the three materials on the strength of MPC are slightly different;Aggregates can alsoimprove the volume stability and mechanical properties of MPC by forming skeleton structure and slowing downthe exothermic reaction. In fiber reinforced MPC matrix, steel fiber is the most widely used and the bondingperformance between special-shaped steel fiber and MPC matrix is higher than that of straight fiber;basalt fiberhas also been proved to be used to improve the mechanical properties of MPC system.

关键词： Magnesium phosphate cement Mechanical properties Proportion of mixture fiber reinforcement

Photocatalytic and Thermal Insulating Performances of fiber Reinforced Hierarchical TiO_2/SiO_2 Xerogel Composites Synthesized by Ambient Drying Route

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Journal of Donghua University(English Edition) 2017年第4期34卷 570-576页

作者：徐海珣赵善宇郑猛贾佳佳朱平华 School of Environmental and Safety Engineering Changzhou UniversityChangzhou 213000China Swiss Federal Institute of Materials Science and Technology Diibendorf CH-8600Switzerland

Silica( SiO_2) based aerogel/xerogel materials have been received ever-growing attentions for versatile applications. However,the widespread applications are narrowed by the inert properties,fragile and brittle natureof silica materials and cumbersome preparation processes. In this paper,titania( TiO_2) was introduced into SiO_2 matrix to form photocatalytic hybrid gels. The TiO_2/SiO_2 composites were then reinforced by the impregnation of various fibrillary reinforcements,such as glass,mullite mineral and ceramic fibers. The properties of the composites were studied systematically in terms of fiberstability,microstructure,chemical interaction and thermal conductivity. The final xerogel composites displayed improved monolithic geometry,satisfied thermal conductivity(0. 09-0. 25 W·m^(-1)·K^(-1)) and optimized photocatalytic performance(85% removal of model pollutant of methyl orange( Mo)),which could be expected to be a feasible route to multi-functional building facades in the future.

关键词： titania-silica(TiO2/SiO2) composite photocatalytic thermal conductivity fiber reinforcement