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frost resistance and Damage Velocity of Compressively Preloaded Concrete

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Journal of Donghua University(English Edition) 2012年第3期29卷 215-221页

作者：陈思佳宋晓冰刘西拉 School of Naval Architecture Ocean&Civil EngineeringShanghai Jiaotong University

The frost resistance and compressive strength degradation of concrete under the simultaneous action of compressive load and freeze-thaw cycles were experimentally investigated. Air-entrained and non-air-entrained specimens with different water/cement(w/c) ratios were subjected to different compressive stress by specially designed apparatus, while the specimens suffered freeze-thaw cycles. In order to track the strength degradation process, the nondestructive tests were carried out after each freeze-thaw cycle got the residual strength for each specimen. Based on the experimental data, a variable Kss was proposed to describe the damage velocity. Experimental results indicate that the deterioration processes are accelerated by the compressive loads, and the damage velocity increases with the increases of the preloading levels and w/c ratios. The air entrainment decreases the damage velocity and improves the frost resistance of non-air-entrained concrete, although it would reduce the compressive strength of concrete.

关键词： compressive strength degradation frost resistance freeze-thaw cycle damage velocity preloading level

Experiment on the frost resistance of Modified Phospho Gypsum: A case used to Improve Baozhong Railway Subgrade loess

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Journal of Mountain Science 2019年第12期16卷 2920-2930页

作者： ZHAO Meng GUO Wei CHEN Li-yi WANG Shan-yong State Key Laboratory of Geo-Hazard Prevention and Geo-Protection Chengdu University of TechnologyChengdu 610059China Priority Research Centre for Geotechnical Science&Engineering The University of Newcastle CallaghanNSW 2308Australia

It has been widely recognized that loess has a low stability and permeability,and it is susceptible to a sudden decrease in total volume or collapse upon *** the railway subgrade was under the dynamic trainload,the loess subgrade was prone to instability and *** is higher than that of the cement modified loess,but lower than that of the MPG modified ***,the coefficient of permeability for the MPGcement modified loess has an opposite result,and the MPG-cement modified loess specimens have the best frost *** addition,the mechanism of MPG-Bao Zhong railway is a key railway for Guyuan city,in Ningxia province of China,which is an important city of the Belt and *** to the influence of largearea flood irrigation on the farmland,the subgrade had a degree of *** settlement had not been alleviated after three treatments,which seriously affected the safety of the *** this reason,cement,Modified Phospho Gypsum(MPG)and MPGcement were used to reinforce the subgrade loess,and the unconfined compressive strength test,permeability test and freeze-thaw cycle test were carried *** the compressive strength,impermeability and frost resistance of the three were analyzed and *** results indicate that the compressive strength of the MPG-cement modified cement modified loess is *** is found that cement and MPG have two hydration reactions with water in ***,the hydration reaction product,which not only fills the pores,restricts the movement of the soil particles,but also acts as a connecting soil particle in the soil ***,the strength of the modified loess continues to increase,and the physical properties of the modified loess are improved.

关键词： Loess Modified Phospho Gypsum frost resistance Freeze-thaw cycle

frost resistance OF POLYVINYL ALCOHOL FIBER REINFORCED CEMENTITIOUS COMPOSITES

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Acta Mechanica Solida Sinica 2011年第S1期24卷 68-73页

作者： Jianwen Bai 1 Shuguang Liu 1 Rongyue Guo 2 Rong Xu 3 ( 1 Institute of Mining Technology, Inner Mongolia University of Technology, Hohhot 010051, China) ( 2 Testing Center of China Railway Group Six Hohhot Railway Bureau Construction CO. LTD, Hohhot 010050, China) ( 3 Civil Engineering and Architectural, Inner Mongolia Institute of Architectural Technology, Hohhot 010070, China)

This article studies the frost resistance of polyvinyl alcohol (PVA) fiber reinforced cementitious composites. The test samples contain different PVA fiber volume fractions such as 0, 0.5%, 1% and 2%. The freeze-thaw test is carried on in TDR type apparatus. The outward appearance, the weight loss factor and the relative dynamic elastic modulus are analyzed, and conclusions are drawn that PVA fibers can significantly improve the frost resistance of cementitious composites and frost resistance of PVA fiber reinforced cementitious composites with fiber volumetric fraction of 1% is better.

关键词： PVA fiber cementitious composites frost resistance scanning electron microscope

STUDY ON frost resistance OF ROLLER COMPACTED CONCRETE PAVEMENT

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STUDY ON FROST RESISTANCE OF ROLLER COMPACTED CONCRETE PAVEM...

Influence and Mechanisms of Crumb Rubber on the frost resistance of Concrete

第四届北京国际水泥与混凝土会议

作者： Li Shiqi, Niu Kaimin, Xia Lingling Research Institute of Highway, Ministry of Communications, Xi Tucheng Road, Beijing, 100088, P.R.China

This paper presents the findings of the study on frost resistance of roller compacted concrete pavement. Effective measures to improve frost resistance of roller compacted concrete pavement by air entrapment are put forward based on test and study and successful solution of air entrapment and air content measurement technology. The mechanism of improvement of flexural strength and frost resistance by air entrapment is expounded in terms of microstructure of the pavement.

关键词： Roller compacted concrete pavement frost resistance Air content Microstructure

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Influence and Mechanisms of Crumb Rubber on the Frost Resist...

Investigation on Thermal Insulation and Mechanical Strength of Lightweight Aggregate Concrete and Porous Mortar in Cold Regions

2011中国材料研讨会

作者： ZHU Xiao-bin1,2 MIAO Chang-wen1,2 LIU Jia-ping1,2 HONG Jin-xiang1,2 (1State Key Laboratory of High Performance Civil Engineering Materials,Jiangsu Academy of Building Science Co.,Ltd,Nanjing 210008,China) (2Jiangsu Bote New Material Co.,Ltd,Nanjing 210008,China)

To provide the relationship between the frost resistance of concrete and crumb rubber,the effection of particles size,volume of crumb rubber on the frost resistance of concrete is experimentally *** results show that the effect of particles size and the volume of crumb rubber on the frost resistance of concrete are very obvious,except for the air content of *** thick or excessively fine crumb rubber is not conducive to the frost resistance of *** addition,the excessive dosage of crumb rubber is also bad for the frost resistance of *** swelling is one of the reasons of freezing and thawing damage of crumb rubber concrete in comparison to normal concrete.

关键词： crumb rubber concrete frost resistance water swelling durability

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Journal of Renewable Materials 2022年第12期10卷 3167-3183页

作者： Jianan Wu Ke Xue Zhaowei Ding Lei Lang Kang Gu Xiaolin Li Mingli Zhang Desheng Li Ningbo City College of Vocational Technology NingboChina College of Water Conservancy and Hydropower Engineering Sichuan Agricultural UniversityYa’anChina State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghaiChina College of Civil Engineering and Architecture Jiaxing UniversityJiaxingChina Department of Civil Engineering Lanzhou University of TechnologyLanzhouChina Department of Civil Engineering College of ScienceNanjing University of Science and TechnologyNanjingChina

Thermal insulation is an important indicator to evaluate the construction material in cold region *** we know,adding the industrial waste as lightweight aggregate or creating the pore inside the cement-based composite could make the texture loose,and the thermal insulating capacity of the material would be improved with this *** these methods,the industrial by-product and engineering waste could be cycled in an efficient ***,after service the fragmented cement composites paste could be used as aggregate in the thermal insulating concrete *** the porous texture is not favorable for the mechanical strength and long-term durability in a cold *** balance the above three requirements from two opposite directions,different processing methods were applied to create the thermal insulation concrete/***,the organic/inorganic lightweight aggregate,including the Expanded Polystyrene(EPS),Expanded Perlite(EP),and Ceramsite(CRMST)particles,were applied to create the Lightweight Aggregate Concrete(LWAC).As the comparative tests,the expanded Superabsorbent Polymer(SAP)hydrogel and Air-Entraining Agent(AEA)were also introduced to create the porous *** above concrete/mortar was tested in the normal state and under the Freeze-Thaw cycle to explore the engineering performance in cold *** the experimenting process,the thermal insulation,mechanical strength,and frost resistance of these cement-based composites were investigated,and an optimal thermal insulation concrete/mortar was determined.

关键词： Thermal insulation mechanical strength cement-based composite freeze-thaw cycle frost resistance

Effect of Functional Chemical Admixtures on the Performance of Cement Asphalt Mortar Used in Ballastless Track

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Journal of Wuhan University of Technology(Materials Science) 2015年第5期30卷 995-1000页

作者：蒋金洋 SHE Wei LI Wei PAN Li Jiangsu Key Laboratory for Construction Materials Southeast University Jiangsu Institute of Building Science Co.LTD

Chemical admixtures are of paramount importance to the performance of modern cement based composites. In this paper, we performed a series of tests to investigate the effects of chemical admixtures on the cement asphalt mortar(CA mortar), i e, compressive strength, frost resistance, permeability, fatigue resistance, pore structure and microstructure. In particular, two types of chemical admixtures were tested, i e, defoamer(tributyl phosphate(TBP)) and polycarboxylate superplasticizer(PS). The results indicate that the addition of TBP and PS eliminates big bubbles and promotes small non-connected pores forming in matrix. Besides, an optimum dosage of TBP and PS may be determined with respect to the frost resistance, permeability and fatigue resistance of CA mortar. Further elaborative discussions are presented as well as experimental evidences from mercury intrusion porosimetry, scanning electron microscopy and energy dispersive spectroscopy.

关键词： cement asphalt mortar chemical admixture frost resistance fatigue resistance pore structure microstructure

Effect of Ceramsite Structure on Microstructure of Interfacial Zone and Durability of Combined Aggregate Concrete

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Journal of Wuhan University of Technology(Materials Science) 2009年第1期24卷 145-149页

作者：孔丽娟 School of Materials Science and Engineering Harbin Institute of Technology

Structure characteristics of three kinds of ceramsite with different water absorption and the influence on microstructure of interfacial zone as well as performance of chloride permeabil-ity and frost resistance of combined aggregate concrete were investigated. The results show that, dense shell and closed internal pore have sharp effects on lowering water absorption of ceramsite. However, the ceramsite with high water absorption has obvious effect on the densification of interfa-cial paste which would develop a structure with lower porosity, finer aperture and higher microhard-ness. Furthermore, the impermeability and frost-resistance of concrete can be improved due to the ef-fect of water absorption and releasing by ceramsite with higher water absorption.

关键词： ceramsite combined aggregate concrete chloride permeability frost resistance pore structure microhardness