Details:

Creators:
Orlova, Nadejda V. ; Westall, John C. ; Rehani, Manu ; Koretsky, Milo D.
Orlova, Nadejda V. ; Westall, John C. ; Rehani, Manu ; Koretsky, Milo D. Less -
Corporate Creators:
Oregon. Dept. of Transportation
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Cathodes Cathodic Protection Ion Exchange Ion Migration Reinforced Concrete Zinc Anode
Publication/ Report Number:
FHWA-OR-RD-00-03
Resource Type:
Tech Report
Geographical Coverage:
United States ; Oregon
United States ; Oregon Less -
TRIS Online Accession Number:
00778844
OCLC Number:
42470325
Corporate Publisher:
United States. Federal Highway Administration
Abstract:
The migration of chloride ions in concrete with steel reinforcement was investigated. Mortar blocks (15 cm x 15 cm x 17 cm) of various composition (water to cement ratio, chloride ion content) were cast with an iron mesh cathode imbedded along one face and a thermally sprayed zinc anode applied to the opposite face. Current densities of 0.033 and 0.066 A / m2 were applied to the blocks over a period of one year at constant temperature and humidity. The zinc face was covered with a pond of saturated calcium hydroxide to prevent polarization of the zinc concrete interface. Over the course of polarization, potential vs. time curves were recorded and samples of mortar were extracted for determination of chloride concentration. An ion chromatography method was developed for the analysis of small samples of mortar for chloride. The method allowed for the measurement of chloride concentration in mortar samples with a long term overall relative standard deviation of 3.2% in the concentration range 1-15 mg/L in the water extract of the mortar. Under the conditions of the study, no significant migration of chloride ions could be detected over the one-year test. This result was consistent with that which would be expected with a simple transport model of the system. Random fluctuations that were

observed in the chloride concentration profiles were attributed to the inhomogeneous pore structure of the mortar on the scale of the sample size and the associated inhomogeneity in the chloride distribution. Future studies of these phenomena should be designed with larger blocks and larger samples of mortar for chloride analyses; (ii) an automatic misting device to obviate the need for the calcium hydroxide solution; and (iii) higher current densities, longer periods of polarization, or both.


Format:
PDF
Funding:
SPR 357
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:fe9ffcc4ce1b177c8bb46bbfebffe56f29de750fbd523ab88023e7805dd48712
Download URL:
https://rosap.ntl.bts.gov/view/dot/14417/dot_14417_DS1.pdf
File Type:

Supporting Files

• No Additional Files

More +