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Effect of ground granulated blast-furnace slag(GGBFS) and silica fume(SF) on chloride migration through concrete subjected to repeated loading

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Science China(Technological Sciences) 2012年第12期55卷 3102-3108页

作者： ZHANG WuMan BA HengJing School of Transportation Science and Engineering Beihang UniversityBeijin g 100191China School of Civil and Engineering Harbin Institute of Technology Harbin 150006China

The effect of ground granulated blast-furnace slag(GGBFS) and silica fume(SF) on the chloride migration through concrete subjected to repeated loading was *** cement was replaced by 20%,30%,40% GGBFS and 5%,10% SF,*** times repeated loadings were applied to specimens,the maximum loadings were 40% and 80% of the axial cylinder compressive strength(f′c),*** migration through concretes was evaluated using the rapid chloride migration test and the chloride concentration in the anode chamber was *** results indicate that the transport number of chloride through concrete containing 20% and 30% GGBFS replacements and 5% and 10% SF replacements is lower than that of the control concrete,but 40% GGBFS replacement increases the transport number of *** loadings at 40% f′cor 80% f′c increase the transport number of chloride for all mixes investigated in this study.5% SF replacement has a very close effect on the chloride permeability of concrete with 20% GGBFS when concrete is subjected to 40% f′cor 80% f′c.

关键词： concrete ground granulated blast-furnace slag (GGBFS) silica fume (SF) chloride migration repeated loading

Load-bearing characteristics of square footing on geogrid-reinforced sand subjected to repeated loading

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Journal of Central South University 2020年第3期27卷 920-936页

作者： ZHANG Liang-liang WANG Jia-quan Victor N.KALIAKIN TANG Yi College of Civil and Architectural Engineering Guangxi University of Science and TechnologyLiuzhou 545006China Department of Civil and Environmental Engineering Harbin Institute of TechnologyUniversity Town of ShenzhenShenzhen 518055China Department of Civil and Environmental Engineering University of DelawareNewarkDE 19716USA

A series of dynamic model tests that were performed on a geogrid-reinforced square footing are *** dynamic(sinusoidal)loading was applied using a mechanical testing and simulation(MTS)electro-hydraulic servo loading *** all the tests,the amplitude of loading was±160 kPa;the frequency of loading was 2 *** better ascertain the effect of reinforcement,an unreinforced square footing was first *** was followed by a series of tests,each with a single layer of *** reinforcement was placed at depths of 0.3B,0.6B and 0.9B,where B is the width of *** optimal depth of reinforcement was found to be *** effect of adopting this value versus the other two depths was *** single layer of geogrid had an effective reinforcement depth of 1.7B below the footing *** increase of the depth between the topmost geogrid layer and the bottom of the footing(within the range of 0.9B)did not change the failure mode of the foundation.

关键词： repeated loading geogrid square footing depth of reinforcement bearing capacity

Permanent Deformation of Highway Subgrade Soils

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Journal of Modern Transportation 1999年第1期16卷 32-43页

作者：邱延峻 School of Civil Engineering Southwest Jiaotong University Chengdu 610031 China Department of Civil Engineering University of Arkansas Fayetteville AR 72701 U.S.A.

Based on a comprehensive review of the literature and preliminary testing performed on a subgrade soil, a testing methodology for repeated load testing was established. This testing protocol was verified using data from subgrade soil. The successful application of this testing protocol on the two subgrade soils proves that it can provide consistent, reliable results. A power model was used to fit the accumulated axial strain over load repetitions with the first hundred cycles excluded from the data set. A number of factors influencing the accumulation of permanent deformation were investigated. The results indicate that confining pressure, load frequency and density are relatively minor contributors to deformation accumulation. Moisture content, deviator stress and first cycle freeze thaw are major factors governing permanent deformation. The effects of stress history resulting from staged loading are dependent upon the level of applied deviator stress. The interpretation of the rich and consistent deformation data derived from this testing protocol provide valuable insights for transportation engineers relative to the design, construction, operation and maintenance strategy of highway subgrades as well as railway roadbeds.

关键词： deformation pavements and roads repeated loading