Damage model of fresh concrete in sulphate environment

Abstract

A model of damage to fresh concrete in a corrosive sulphate environment was formulated to investigate how and why the strength of corroded concrete changes over time. First, a corroded concrete block was divided into three regions: an expanded and dense region; a crack-development region; and a noncorroded region. Second, based on the thickness of the surface corrosion layer and the rate of loss of compressive strength of the corroding region, a computational model of the concrete blocks’ corrosion-resistance coefficient of compressive strength in a sulphate environment was generated. Third, experimental tests of the corrosion of concrete were conducted by immersing specimens in a corrosive medium for 270 d. A comparison of the experimental results with the computational formulae shows that the calculation results and test results are in good agreement. A parameter analysis reveals that the corrosion reaction plays a major role in the corrosion of fresh concrete containing ordinary Portland cement, but the diffusion of the corrosion medium plays a major role in the corrosion of concrete mixtures containing fly ash and sulphate-resistant cement. Fresh concrete with a high water-to-cement ratio shows high performance during the whole experiment process whereas fresh concrete with a low water-to-cement ratio shows poor performance during the late experiment period.

Keywords

fresh concrete / sulphate corrosion / corrosion coefficient / computational model

References

[1] TixierR, MobasherB. Modeling of damage in cement-based materials subjected to external sulfate attack. II: Comparison with experiments [J]. Journal of Materials in Civil Engineering, 2003, 15(4): 314-322

[2] JamesR C, JamesMPonnersheim. Sulfate attack of cementitious materials: Volumetric relations and expansions [R], 1994, Gaithersburg, Building and Fire Research Laboratory, National Institute of Standards and Technology

[3] KumarS, RaoC V S. Sulfate attack on concrete in simulated cast-in-situ and precast situations [J]. Cement and Concrete Research, 1995, 25(1): 1-8

[4] KumarS. Influence of water quality on the strength of plain and blended cement concretes in marine environments [J]. Cement and Concrete Research, 2000, 30(3): 345-350

[5] CastroP, VelevaL, BalancanM. Corrosion of reinforced concrete in a tropical marine environment and in accelerated tests [J]. Construction and Building Materials, 1997, 11(2): 75-81

[6] CrammondN J, CollettG W, LongworthT I. Thaumasite field trial at Shipston on Stour: Three-year preliminary assessment of buried concretes [J]. Cement & Concrete Composites, 2003, 25(8): 1035-1043

[7] WangC-chengAdaptability experimental research of the filling pile in strong sulphate corrosive environment [D], 2011, Lanzhou, Lanzhou University

[8] LongG-c, XieY-j, DengD-h, LiX-kun. Deterioration of concrete in railway tunnel suffering from sulfate attack [J]. Journal of Central South University of Technology, 2011, 18(3): 881-888

[9] LongG-c, XieY-j, TangX-guang. Evaluating deterioration of concrete by sulfate attack [J]. Journal of Central South University of Technology, 2007, 22(3): 572-576

[10] YuanX-l, LiB-x, CuiG, ZhaoS-c, ZhouM-kai. Grey clustering theory to assess the effect of mineral admixtures on the cyclic sulfate resistance of concrete [J]. Journal of Wuhan University of Technology: Materials Science, 2010, 25(2): 316-318

[11] DongQ-y, ZhangY-h, FengL-p, JinD-b, ZhangJ-s, WangC-cheng. Experimental research of sulfate corrosion resistance of fresh concrete with fly ash [J]. Advanced Materials Research (International), 2013, 772: 109-116

[12] ZhangJ-s, ZhangY-h, FengL-p, DongQ-y, WangC-cheng. Corrosion resistant coefficient of concrete compressive strength under sulphate environment [J]. Journal of Building Materials, 2014, 17(3): 371-379

[13] TixierR, MobasherB. Modeling of damage in cement-based materials subjected to external sulfate attack. I: Formulation [J]. Journal of Materials in Civil Engineering, 2003, 15(4): 305-313

[14] IdiartA E, LópezC M, CarolI. Chemo-mechanical analysis of concrete cracking and degradation due to external sulfate attack: A meso-scale model [J]. Cement and Concrete Composites, 2011, 33(3): 411-423

[15] LeemannA, LoserR. Analysis of concrete in a vertical ventilation shaft exposed to sulfate-containing groundwater for 45 years [J]. Cement and Concrete Composites, 2011, 33(1): 74-83

[16] GB/T50082-2009.Standard for test methods of long-term performance and durability of ordinary concrete [S], 2009, Beijing, China Architecture & Building Press

[17] LiS-w, WangY-f, WangS-nian. Research on the prediction model of the concrete damage in the sulfate aggressive environment [J]. Journal of Wuhan University of Technology, 2010, 32(14): 35-39

[18] CaoS-yin. Mechanical properties of corroded concrete [J]. Journal of Southeast University, 1991, 21(4): 89-95

[19] ChenY-s, LiX, FanY-fang. Test research on the salt corrosion concrete compressive strength [C]. Proceedings of the 15th Nationwide Academic Conference on Structural Engineering (II), 2006, Beijing, The Engineering Mechanics Editorial Department of CSTAM: 5-10

[20] WangZ-q, ZhuS-q, YuR-peiChina saline soil [M], 1993, Beijing, Science Press

[21] LevenspielOChemical reaction engineering [M], 1972, New York, Wiley