Behavior of Epoxy-Injected Diagonally Cracked Full-Scale Reinforced Concrete Girders

Many cast-in place reinforced concrete deck-girder (RCDG) bridges in the national inventory contain diagonal cracks typically associated with shear-moment interaction. Many transportation agencies use epoxy injection as a prophylactic to seal cracks. The shear-dominated performance of girders treated with epoxy injection is not well understood and the existing data regarding performance of members injected with epoxy have been gathered from reduced-scale test specimens. To provide new data on the shear performance of girders with epoxy-injected diagonal cracks, five full-scale RCDG specimens were constructed to reflect 1950s proportions and details. The specimens were loaded to produce diagonal cracks, injected with epoxy under varying degrees of axial tension and service loading, and tested to failure. The test data indicated that epoxy injection resulted in minimal increased shear capacity. However, the epoxy-injected specimens exhibited increased load magnitudes prior to crack re-initiation and reduced stirrup stresses at serviceability levels compared to the cracked condition prior to repair.