OAKLAND COUNTY, Mich. – Contractor paving crews will have to remove and replace some of the new I-75 concrete in Oakland County because an inspection revealed the incorrect concrete mix was used on portions of the new pavement.

The Michigan Department of Transportation announced Tuesday that inspection teams working on Segment 2 of the I-75 modernization project in Oakland County found the incorrect concrete mix was used recently on portions of the project, including the left two lanes of northbound I-75 from 13 1/2 Mile to 14 Mile roads, and the shoulders on the exit ramps to Big Beaver and Rochester roads.

MDOT and the project contractor determined the incorrect mix was used on small portions of Segment 2 of the I-75 modernization project.

The areas to be replaced include the left two lanes on northbound I-75 from 13 1/2 Mile to 14 Mile roads, and the shoulders on the exit ramps to Big Beaver and Rochester roads.

Some shoulder replacement has taken place; freeway replacement will occur next year.

MDOT said that due to this discovery, contractor paving crews will remove and replace those affected portions before all paving is completed in late 2020. Currently, both directions of I-75 are sharing the southbound side of the freeway, separated by a temporary concrete barrier between 13 Mile Road and Coolidge Highway. Two lanes are open in each direction.

“This is inspectors doing their jobs,” said MDOT Metro Region Engineer Kimberly Avery. “The pavement designated for replacement is safe for drivers to use, but the long-term durability is compromised and the reason for our actions.”

MDOT also said contractor crews began removing the shoulder on a portion of the Rochester Road ramp this past weekend and have already replaced the pavement. Replacement of the left lanes from 13 1/2 Mile to 14 Mile roads and the remainder of the shoulder pavement on the ramps will be delayed until next year during the final year of the overall project.

The transporation department said that in 2020 both directions of I-75 will be sharing the new northbound pavement in order to allow crews to rebuild the southbound lanes between Coolidge Highway and 13 Mile Road. Engineers have determined that this section is safe for drivers to use over the winter months.

"This direction is the equivalent to enforcing a warranty,” Avery said. “This action does not add additional costs to the contract and protects the taxpayer investment in the future.”

This $224 million project involves reconstructing more than 8 miles of pavement in each direction, improving 18 structures, upgrading drainage, constructing community-developed aesthetics and federally approved noise walls, and continuing construction of an additional travel lane between Coolidge Highway and 13 Mile Road.

Last week it was announced that due to weather delays and additional work added to the original contract, switching northbound I-75 traffic to its pre-construction configuration has been delayed until late December.

Both directions of I-75 are sharing the southbound side of the freeway, separated by a temporary concrete barrier between 13 Mile Road and Coolidge Highway. Two lanes are open in each direction. Originally, the traffic switch to place northbound traffic on the newly constructed northbound lanes was to occur by Thanksgiving, MDOT said.

“The delay is primarily due to lost production caused by an abnormally wet spring, heavy rain events during the summer, extreme temperatures, and a record snowfall in November,” reads a statement from MDOT. “The process to move northbound traffic onto the northbound lanes and opening additional lanes will be completed in stages starting this month.”

MDOT said that since March 1 crews have lost roughly 60 days of production due to adverse weather. Before northbound traffic can be switched over, crews need to complete ramp work and some mainline paving.

Work behind schedule on I-75 project in Oakland County -- watch report:

In June 2018, inspectors with MDOT found a problem in the I-696 construction zone, forcing an expensive do-over. The very first bit of new pavement that was laid down had to be replaced. MDOT inspectors noticed a problem with that pavement after it cured.

In that case, it wasn’t up to their standards and needed to be replaced. The contractor agreed, absorbing the cost, which was around $300,000. A half-mile of road just west of Gratiot Avenue had to be redone.