In the summer of 1958, a special formulation of epoxy resin was used to seal hairline cracks in the safety walks of the Levisa-Fork bridge at Paintsville, Kentucky. This bridge, a reinforced concrete box girder-type, Fig. 1, developed fine cracks soon after the falsework was removed. The cracks which were typically like those in Figs. 2 and 3, occurred in two areas, each extending about 30 ft. on either side of the center piers. They were through the full depth of the slab and ranged from about .005 in. to .031 in. in width. In all, there were 55 cracks averaging 3 ft. in length, making a total of 165 lineal ft. of cracks to be sealed.

After conducting laboratory investigations to test the flexural and bonding strengths and penetrating ability of the epoxy formulation, "Reliance Relcote 60", Figs. 4 and 5, it was concluded that this material would be suitable for sealing cracks in structural concrete. The resin's strength and resistance to water, weather, and corrosion were considered sufficient to protect the concrete and steel exposed by the cracks.

Report Date


Report Number

No. 143

Digital Object Identifier