subject: Repairing Delaminated Overlays With Epoxy Injection [print this page] During the renovation of an outdoor patio area at the Boeing Headquarters in Chicago various areas of the concrete patio, where an over-layment was recently placed, were observed to be experiencing delamination. Lincoln Company, LLC was contracted to re-bond approximately 2,137 square feet of over-layment which has delaminated from the exterior patio area on the east side of the Boeing Headquarters located at 100 North Riverside Plaza, Chicago, IL. The estimated repair quantity was provided by Klein and Hoffman, Inc. It is the intent of the epoxy injection procedure to bond the delaminated portions of the over-layment to the underlying structural slab.
Holes, 1/2 in diameter were drilled to varying depths sufficient to intersect the underlying delamination interface between the structural slab and the over-layment. Drilling was performed using small rotary percussion hammer drills fitted with hollow bits. Constant air was supplied to the bits while drilling to remove the cuttings that otherwise might plug the circumference of the drilled hole, inhibiting the resin flow into the lateral voids. The injection ports were initially be installed on 30 centers and subsequently adjusted to achieve the desired results of the injection process. These adjustments were made based on the lateral flow of the resin.
Lily Corporation injection ports, in diameter and notched on the base, were inserted into the drilled holes. In the areas where vertical cracking was observed in the delaminated material, the cracks were filled by utilizing a surface mounting procedure for the additional ports. Following the injection procedure, the ports and the surface seal were removed by grinding.
Sikadur 35 Hi-Mod LV was dispensed at sufficient pressure to penetrate the underlying voids while minimizing the potential for over-layment heave. Dispensing was performed using a Lily Corporation CD-15 epoxy injection dispenser. Injection was halted at any location where movement of 1/64th of an inch was observed.
Following the completion of the primary injection, a secondary injection procedure was performed to bond any remaining un-bonded areas. In a number of areas the bonding agent initially used to bond the topping to the structural slab interfered with the epoxy bonding. In areas where inadequate bonding was observed the area was re-injected and another core obtained.
Upon completion of the injection, a total of three 2-inch diameter cores were taken at locations indicated by the site quality assurance personnel to verify the adhesion between the slab and the over-layment. The core holes were primed with an epoxy bonding agent and then filled flush with the adjacent surface using a polymer repair mortar.
In order to minimize congestion and disruption of pedestrian and vehicular traffic the work was performed over a weekend and successfully completed within budget.
