Gravity-fill polymer crack sealers

Cracking in bridge deck concrete is a serious problem. Cracks allow the direct infiltration of water and chloride ion and the carbonation of the walls of the crack, causing the reinforcing steel to corrode. Gravity-fill polymer crack sealers consist of two or more low-viscosity liquid monomer or polymer components that can be mixed and poured directly over a cracked surface. The monomer or polymer fills the cracks and hardens into polymer. The laboratory evaluation of three two-component epoxies, a three-component high-molecular-weight methacrylate, and a two-component polyurethane is described. Tests included measurements of the flexural strengths and freeze-thaw durabilities of repaired beams and the gel times and penetration abilities of the sealers. The five sealers were evaluated with respect to the effects of temperature and crack width on the quality of the repair, cost, ease of application, safety, appearance, and odor. The gravity-fill polymer crack sealers completely penetrated 0.2-mm-wide cracks, restored >100 percent of the original flexural strengths of the beams, had satisfactory freeze-thaw durabilities, and had gel times that decreased as the temperature increased. The laboratory tests suggest that all five gravity-fill polymer crack sealers can adequately seal cracks in bridge deck concrete.