Speedy Manhole Repair Using EPP Grade Adjustment System

In early 2010, a manhole had been identified as needing repair by Narragansett Bay Commission (NBC) in Providence, R.I. The issue was that the manhole location on Putnam Pike (State Route 44) was directly in the wheel path of all traffic moving northwest on the highway.

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In early 2010, a manhole had been identified as needing repair by Narragansett Bay Commission (NBC) in Providence, R.I. The issue was that the manhole location on Putnam Pike (State Route 44) was directly in the wheel path of all traffic moving northwest on the highway. Due to the significant amount of traffic moving in both directions, a quick and easy but long-term repair was needed to minimize the impact on traffic during reconstruction and in the future. To complete the repair, the utility would be required to pay for police detail for traffic control in both directions since only one lane would be accessible during the repair.

NBC had recently been contacted by a representative of Cretex Specialty Products because the company was looking for field test sites to demonstrate a new product, the PRO-RING™ Manhole and Catch Basin Grade Adjustment System. The system would be a good fit for this repair.

PRO-RING is the world’s first and only grade adjustment system made from expanded polypropylene (EPP), a high-strength, lightweight plastic ideal for replacing traditional construction methods using concrete grade rings, mortar or other masonry materials.

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Installing the PRO-RING™ Grade Adjustment System.

The manhole adjustment system was of significant interest to NBC. This system was said to be faster, safer and more cost effective, with one person being able to complete an entire adjustment in just minutes. Using the PRO-RING system, a manhole repair site can be opened, reconstructed and closed in one day or less, reducing overall costs by as much as 20 to 30 percent. Since these grade rings weigh 95 percent less than concrete rings, they are much safer to use, minimizing the risk of worker injury.

On the day of the repair, crews and traffic control arrived and were set up by 7:30 a.m. The pavement was saw cut, and the manhole was excavated and ready to be reconstructed by about 8:50 a.m. The installation of the manhole adjustment system started at approximately 9 a.m., with some repair of the brick manhole using a high-early-strength repair mortar and then installing the adjustment rings and manhole frame casting.

The installation was completed by 9:20 a.m., and the excavation was backfilled, compacted and prepared for the asphalt patch. Unfortunately, the asphalt did not arrive to the site until approximately noon, but once on site it was placed and compacted with the entire repair being completed by 12:30 p.m.

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Completed installation, prior to backfill and paving.

A short time later, the road was reopened to traffic in both directions making the entire repair time from start to finish approximately 5 hours. If not for the delay in getting the asphalt to the site, it would have been repaired in less than 4 hours.

Since the installation over 7 years ago, this site has been subjected to an estimated 150 million traffic impacts and annual inspections show no negative effect on the PRO-RING system or surrounding pavement repair.


Cretex Seals is exhibiting at WEFTEC.17, Booth 641. For more information, visit cretexseals.com.

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