آزمایش رسانایی الکتریکی اصلاح‌شده برای سنجش مقاومت بتن درمقابل نفوذ یون‌های کلرید

نوع مقاله : پژوهشی

نویسندگان

• امیررضا پیلوار ¹
• علی اکبر رمضانیانپور ²
• حسین رجایی ²

¹ موسسه آموزش عالی توس.

² دانشگاه صنعتی امیرکبیر

10.22067/civil.v29i2.48944

چکیده

در این مقاله روشی جدید برای سنجش مقاومت بتن در مقابل نفوذ یون‌های کلرید ارائه شده است که شامل اشباع‌سازی نمونه‌ها توسط محلول NaCl 5 مول، قبل از اندازه‌گیری رسانایی آنها می‌باشد. با اشباع کردن نمونه‌ها توسط محلول با رسانایی بالا، رسانایی‌های نمونه‌های مختلف بتنی متناسب با ساختار منافذ آنها می‌شود. برای بررسی عملکرد این روش، طرح‌های اختلاط مختلف بتن ساخته شد. مشاهده گردید که نتایج روش ارائه‌شده حساسیت کمتری نسبت به رسانایی مایع منفذی درمقایسه با روش‌های آزمایش نفوذ تسریع‌یافتۀ یون‌های کلرید (RCPT) و رسانایی حجمی (BC) دارد. همچنین ارتباط خوبی بین نتایج این روش با نتایج آزمایش انتشار حجمی (BD) به‌دست آمد.

کلیدواژه‌ها

• بتن، نفوذپذیری کلریدی
• رسانایی الکتریکی
• مایع منفذی

---

عنوان مقاله [English]

Modified Electrical Conductivity Test Method for Evaluation Concrete Chloride Ion Permeability

نویسندگان [English]

• Amirreza Pilvar ¹
• Ali Akbar Ramezanianpour ²
• Hosein rajaie ²

¹

² Amirkabir University of Technology

چکیده [English]

Standard test method for bulk electrical conductivity (ASTM C1760) provides a rapid indication of the concrete’s resistance to the penetration of chloride ions by diffusion. In this paper a new approach for assessing the bulk electrical conductivity of saturated specimens of hardened concrete is presented. The test involves saturating concrete specimens with a 5 M NaCl solution before measuring the conductivity of the samples. By saturating specimens with a highly conductive solution, they showed virtually the same pore solution conductivity. Different concrete samples yield different conductivity primarily due to differences in their pore structure. The feasibility of the method has been demonstrated by testing different concrete mixtures consisting ordinary and blended cement of silica fume (SF) and calcined perlite powder (CPP). Two standard test methods of RCPT (ASTM C1202) and Bulk Conductivity (ASTM C1760) were also applied to all of the samples. The results show that for concretes containing SF and CPP, the proposed method is less sensitive towards the variations in the pore solution conductivity in comparison with RCPT and Bulk Conductivity tests. It seems that this method is suitable for the assessment of the performance and durability of different concretes containing supplementary cementitious materials.

کلیدواژه‌ها [English]

• concrete
• Chloride Permeability
• Conductivity
• Pore Solution

مراجع

1. C. Andrade, R. d’Andrea, and N. Rebolledo, "Chloride Ion Penetration in Concrete: The Reaction Factor in the Electrical Resistivity Model", Cement and Concrete Composites, Vol. 47, PP. 41-46, (2014).

2. A. Atkinson and A. K. Nickerson, "The Diffusion of Ions through Water-saturated Cement", Journal of Materials Science, Vol. 19, PP. 3068-3078, (1984).

3. K. Audenaert, Q. Yuan, and G. De Schutter, "On the Time Dependency of the Chloride Migration Coefficient in Concrete", Construction and building materials, Vol. 24, PP. 396-402, (2010).

4. R. D. Hooton and E. Karkar, "Specifying Fluid Penetration Resistance of Concrete", presented at the international congress on durability of concrete, (2012).

5. H. Sorensen and J. M. Fredriksen, "Testing and Modelling of Chloride Penetration into Concrete", Nordic Concrete Research, Research Projects 1990, Oslo, PP. 354-356, (1990).

6. Z. T. and O. E. Gjorv, "A Fundamental Study of Chloride Diffusion into Cementitious Materials" Journal of Physical Chemistry, (1995).

7. A. Pilvar, A. A. Ramezanianpour, and H. Rajaie, "New Method Development for Evaluation Concrete Chloride Ion Permeability", Construction and Building Materials, (2015).

8. D. Whiting, "Rapid Determination of the Chloride Permeability of Concrete", Final Report Portland Cement Association, Skokie, IL. Construction Technology Labs., Vol. 1, (1981).

9. A. A. Ramezanianpour, A. Pilvar, M. Mahdikhani, and F. Moodi, "Practical Evaluation of Relationship between Concrete Resistivity, Water Penetration, Rapid Chloride Penetration and Compressive Strength", Construction and Building Materials, Vol. 25, PP. 2472-2479, (2011).

10. P. E. Streicher and M. G. Alexander, "A Chloride Conduction Test for Concrete", Cement and Concrete Research, Vol. 25, PP. 1284-1294, (1995).

11. Nordtest, "NT Build 355: Concrete, Mortar and Cement Based Repair Mmaterials: Chloride Diffusion Coefficient from Migration Cell Experiments. Nordtest Standards Institution", ed, (1995).

12. T. Luping and L.O. Nilsson, "Rapid Determination of the Chloride Diffusivity in Concrete by Applying an Electric Field", ACI Materials Journal, Vol. 89, (1993).

13. Y. Shimizu, "An Electrical Method for Measuring the Setting Time of Portland Cement", Mill Section of Concrete, Vol. 32, PP. 111-113, (1928).

14. J. Calleja, "Effect of Current Frequency on Measurement of Electrical Resistance of Cement Pastes", in ACI Journal Proceedings, (1952).

15. H. Whittington, J. McCarter, and M. Forde, "The Conduction of Electricity through Concrete", Magazine of Concrete Research, Vol. 33, PP. 48-60, (1981).

16. "Resistivity Measurements in Cementitious Systems: Observations of Factors that Influence the Measurements," Journal of the Transportation Research Board, Vol. 2342, PP. 90 - 98, (2013).

17. A. A. Ramezanianpour, A. R. Pilvar, M. Mahdikhani, F. Moodi, and R. Pilvar, "Developing a Modified Rapid Chloride Permeability Test for Mortar Concrete", in Concrete Repair, Rehabilitation and Retrofitting III, ed: CRC Press, PP. 279-286, (2012).

18. J. O. M. Bockris and A. K. N. Reddy, Modern Electrochemistry, 2nd Edition ed.: Macdonald Ltd. London, (2000).

19. R. K. Dhir, M. R. Jones, H. E. H. Ahmed, and A. M. G. Seneviratne, "Rapid Estimation of Chloride Diffusion Coefficient in Concrete", Magazine of Concrete Research, Vol. 42, PP. 177-185, (1990).

20. K. Snyder, "The Relationship between the Formation Factor and the Diffusion Coefficient of Porous Materials Saturated with Concentrated Electrolytes: Theoretical and Experimental Considerations", Concrete Science and Engineering, Vol. 3, PP. 216-224, (2001).

21. L. Tang, "Electrically Accelerated Methods for Determining Chloride Diffusivity in Concrete—Current Development," Magazine of concrete research, Vol. 48, PP. 173-179, (1996).

22. C. L. Page and Ø. Vennesland, "Pore Solution Composition and Chloride Binding Capacity of Silica-Fume Cement Pastes", Materials and Structures, Vol. 16, PP. 19-25, (1983).

23. M. Pigeon, F. Garnier, R. Pleau, and P.-C. Aitcin, "Influence of Drying on the Chloride Ion Permeability of HPC", Concrete International, Vol. 15, (1993).

24. ASTM, "C 1202: Standard Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration", ed. ASTM International: West Conshohocken Pennsylvania, (2012).

25. ASTM, "C 1760: Standard Test Method for Bulk Electrical Conductivity of Hardened Concrete", ed, (2012).

26. ASTM, "C 1556: Standard Test Method for Determining the Apparent Chloride Diffusion Coefficient of Cementitious Mixtures by Bulk Diffusion", ed, (2011).

27. C. Shi, J. A. Stegemann, and R. J. Caldwell, "Effect of Supplementary Cementing Materials on the Specific Conductivity of Pore Solution and its Implications on the Rapid Chloride Permeability Test (AASHTO T277 and ASTM C1202) Results", ACI Materials Journal, Vol. 95, (1998).

28. A. Ramezanianpour, S. M. Motahari Karein, P. Vosoughi, A. Pilvar, S. Isapour, and F. Moodi, "Effects of Calcined Perlite Powder as a SCM on the Strength and Permeability of Concrete", Construction and Building Materials, Vol. 66, PP. 222-228, (2014).