Experimental Study on Chloride Diffusion, Strength and Fresh Properties of Ion-Exchange Resin Mixed Grout

Abstract:

In Japan, a number of existing prestressed concrete bridges are suffering chloride attack. Especially in the cases that bridges were constructed decades ago, grouts tending to bleed or swell were often used, and the grouting was not well done. As a result, ducts were not completely filled and voids remained. For the incompletely grouted zones, tendons were vulnerable and more severely corroded. To repair those bridges, effective and economic regrouting materials and method are requisite. Recently, a new repair grout has been developed in the authors’ group by mixing ion-exchange resin, a widely used polymer in water purification, into cement paste. Since IER can absorb chloride ions, IER mixed grout is promising to remove free chloride ions in the unfilled duct. In this study, the chloride ion diffusion properties of IER mixed grout was investigated experimentally. Tendons, which were preliminarily spread at the surface with chloride, were grouted using the IER mixed grout. After curing, the chloride amount in the grout was analyzed using potentiometric titration against silver nitrate. It was confirmed that IER effectively absorbed chloride ions from the surface of tendon, and thus is promising to alleviate the corrosion. Furthermore, to promote the practical use, other properties of the grout, such as strength, flowability and bleeding ratio, were test. It is found that as IER ratio increased strength and flowability tended to decrease but bleeding did not occur. When mix proportion and addition ratio of IER were adopted properly, those properties satisfied the acceptance criterias in design code.

• Periodical: Key Engineering Materials (Volume 711)
• Pages: 436-443
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.711.436
• Online since: September 2016
• Authors: Osamu Sanada*, Hiroshi Mutsuyoshi, Luan Yao, Atsushi Sumida
• Keywords: Bleeding, Chloride, Diffusion, Grout, Ion Exchange Resin, Rheology, Strength

References

[1] JPCI. Design and Construction Guidelines of PC grout -Revised Edition-, Japan Prestressed Concrete Institute, Ⅱ-63-67, 5 pages.

[2] Osamu, S., Hiroshi, M., and Yao, L. (2014). Experimental study on Chloride Diffusion of Grout Mixed Ion-Exchange Resin , 23th symposium on Development of Prestressed Concrete, 71-76.

[3] Osamu, S., Hiroshi, M., and Atsushi, S. (2014). Effect of Chloride Ion Diffusion in Mortar Mixed with Ion-Exchange Resin, 2nd International Congress on Durability of Concrete, 22, Paper Number 6.

[4] Yao, L., Hiroshi, M., and Osamu, S. (2015). A Study on The Performance with A Grout that were Mixed Ion-Exchange Resin, , 70th JSCE Annual Scientific Lectuer Abstract Collection, 909-910.