North Carolina DOT minimizes traffic disruption during continuous reinforced concrete pavement (CRCP) replacement by specifying cement that reaches 400 psi in four hours.
Since 2014, the North Carolina Department of Transportation (NCDOT) has specified mix designs containing Rapid Set® Cement to repair and replace more than 400 miles of deteriorating jointed plain concrete pavement (JPCP), continuously reinforced concrete pavement (CRCP), unbonded jointed concrete, and bonded portland cement concrete (PCC) overlay with as little disruption as possible to the driving public. The hydraulic cement, which conforms to ASTM C1600, reaches 4,500 psi in 1.5 hours, which facilitates fast return to service. In addition, its low shrinkage and resistance to chemical attack minimizes future cracking-induced maintenance requirements.
One recent project included replacing broken CRCP panels, typically at least 9 inches thick, along a 3-mile stretch of Interstate 40 in Asheville, a historic and growing city of more than 92,000 in the Blue Ridge Mountains For highway panel replacement projects, NCDOT requires concrete to reach 400 psi flexural strength in four hours. Work is done overnight so roads can be reopened to traffic by 6:30 a.m.
On this job, the contractor faced a penalty of $1,000 to $2,000 for every 15-minute reopening delay. Asheville-based NHM Constructors was contracted to perform the work, which included removing the existing concrete from the east- and west-bound lanes as well as the on- and off-ramps. Beginning at 8 p.m. every day, the crew used concrete saws and jackhammers to remove the broken panels, being careful not to cut through needed portions of rebar. They spliced new rebar to existing reinforcement and checked the subgrade to ensure adequate compaction.
IVS Hydro produced the concrete as needed each night in a volumetric mobile mixer. The repaired sections were roller-screeded, floated, hand-troweled, broom-finished and wet-cured before reopening in time for morning rush-hour traffic. Repairs began May 2021 and were completed in November 2021, with approximately 1,300 cubic yards of concrete placed.
As with previous projects, NCDOT was pleased with Rapid Set Cement’s performance and plans to continue using the cement in future projects.
Editor's Note: Scranton Gillette Communications and the SGC Infrastructure Group are not liable for the accuracy, efficacy and validity of the claims made in this piece. The views expressed in this content do not reflect the position of the Roads & Bridges' Editorial Team.