Title: Interfacial Effects of Cathodic Protection on Alkali-Silica Reaction in Reinforced Concrete Beams
Author(s): K. Torii, K. Ishii, and M. Kawamura
Publication: Symposium Paper
Appears on pages(s): 859-872
Keywords: alkail-silica reactions; beams; cathodic protection; flexural tests; gels
Reinforced Concrete (RC) beams with two different water-cement (w/c) ratios of .35 and .53, whose dimensions are .2 by .3 by 2 m. were made with the non-reactive river sand and the reactive andesitic crushed stone. After 28 days of the steam during RC beams were exposed outdoors, and then the cathodic protection current of 50mA/m2 was applied to the steel reinforcement in the beams. The expansion and cracking of the beams were monitored for 3 years in order to investigate whether or not the cathodic protection current may actually accelerate the alkali-silica reaction (ASR) around the steel cathode in RC beam. After 3 years of the exposure time in a natural environment, the flexural loading tes was carried out for ASR damaged RC beams with and without the cathodic protection. From the experimental results, it was found that the application of cathodic protection in RC beams increased significantly the risk of damaging expansion and cracking in the concrete containing alkali-reactive aggregates, which resulted in the reduction of load-bearing capacity of RC beam in the bending test. This indicates the importance f the survey relating to the alkali-reactivity of the aggregates used in concrete structures and the alkali content of concrete before the cathodic protection is applied.