Epoxy Jointing of Concrete Bridge Segments

Epoxy is used between precast bridge segments to fill voids on the faces, keep water and contaminants from seeping into joints, prevent grout from bleeding into joints from posttensioning ducts, and act as a lubricant between the segments during assembly. To create a good seal at the joint faces, two experimental epoxy applications were tested: a top strip recess at the joint formed in the concrete during precasting, and a recessed annulus groove around the duct that provides a distinct guide for epoxy application. Eight beams were fabricated with various combinations of epoxy face applications, top strip, and annulus. Six segments were cast by using match casting. After curing, the beams were posttensioned with the minimum required prestress force. Tanks above the joints were used to measure the seepage of water and joint permeability comparisons. Pressurized water was used to test the cross grouting between ducts. The top strip provided slightly more resistance than did the current one face epoxy application technique and improved alignment problems, segment defects, and epoxy application procedures. The annulus created a watertight seal around the ducts and assisted in aligning the segments and coupling the ducts. The existing practice of one face application performed well in both tests, but problems occurred in epoxy thickness and clearances. The top strip and annulus features eliminated the approximation of edge and duct clearances. Both performed well together and helped the epoxy application process produce a more reliable joint without additional work in casting or erection of the segments.