Fix it with PHOSCRETE.

Weather Conditions: clear, sunny, no precipitation.
Ambient temperature: Begin at 9:00 AM: 67°F End at 11:00 AM: 71°F

Product Used: Phoscrete^® 601-L 
15 units used to cover 6 total spall repairs
Working time: 20 minutes
Set time: 45 minutes (includes working time)

Installation Notes:
16 units of Phoscrete 601-L were ordered for this project. The six spall areas were all adjacent and located in Lane #1 (fast lane) on the I-15 SB bridge. This bridge is subject to heavy traffic and experienced moderate fluttering. The concrete on the bridge showed cracks and spalls in many places and previous repairs on the bridge were failing.

The bridge crew sawcut the edges and used jackhammers to remove the deteriorated concrete in the spalls. The rebar was very close to the surface (less than two inches in most spots) and apparantly had floated during the original construction, likely resulting in the early failure of the concrete and the difficulty in performing past repairs.

Because this was NDOT's first experience with Phoscrete, they were curious how well the material would bond to the surface. Spall area #1 (pictured above) the largest repair area, and spall area #6 received minimal preparation, and the rebar was exposed at the surface only. At the request of the Stellar team, spall areas #2 and #3  were prepared so the rebar was more fully exposed. Spall areas #4 and #5 were very shallow and no rebar was exposed (this was not a recommended preparation, but NDOT wanted to see how well Phoscrete would stick). Loose concrete was removed using an air compressor and the NDOT crew was careful to minimize dust and clean up all debris. No sandblasting is required with Phoscrete.

Mixing was easy and accurate. Pour in one jug of Phoscrete Liquid Activator and then add one bag of Phoscrete dry mix into a bucket for each unit of material. Stellar's UHMW mixing auger wetted out each unit of Phoscrete in less than 60 seconds. Spall Area #1 required just under eight [8] units to fill the spall. We began at the bottom corner of the slope and worked our way from the north edge across to the left. By the time we made it to the end of the repair, the Phoscrete was already setting up at the beginning. Because Phoscrete bonds to itself, there is no concern about cold joints.

Fifteen [15] total units completed the repair in less than one hour. The Interstate lane was open to traffic at 11:00 am.

Follow-up Inspections:
On June 2. 2011 NDOT inspected the repair site and took photos. All repairs were solid in the ground, even the shallow ones in repair areas #4 and #5.

On July 21, 2011 Stellar revisited the installation site with NDOT personnel and took more photos. Again, all repairs were solid in the ground. but the temperature was pushing 100 degrees and the cracking on the rest of the bridge deck appeared even more pronounced.

Conclusion:

Phoscrete chemically bonded to the concrete substrate, creating a permanent repair that will not crack. Installation was fast and easy, and the bridge crew knows how to properly mix and place Phoscrete for future repairs.