A subcontractor hired to install the sidewalks on Public Square is scheduled to be back at work Monday after the state Department of Transportation stepped in Wednesday to halt work on the reconstruction project.

Looking for a more workable mixture, crews on Tuesday tinkered with the mixing formula for the concrete being used for the sidewalks from the Henry Keep Apartments to Subway, said Kurt W. Hauk, city engineer.

The change had to be approved by DOT because Public Square is on the state's "national highway system," he said.

The state maintains criteria for contractors doing work along major roadways and approvals must be received before work can begin. That includes even the mixture of concrete being used for the sidewalks.

State and federal grants are funding $4.5 million of the $7.1 million reconstruction project.

Because of a scheduling conflict with the subcontractor and the state's interference, concrete for the sidewalks has not been poured on Public Square since Wednesday morning.

"We're going to have a good, full week this coming week," Mr. Hauk said.

He said the subcontractor hired by Villager Construction was not happy with the concrete being poured and on Tuesday, the company tested a mixture that contained less water reducer, a change that yielded a wetter mixture.

"It worked really well and they were happy with it," Mr. Hauk said.

The city received the go-ahead from the state Friday afternoon to continue with the work. The contractor will not have to remove any of the sidewalk blocks because of the change.

Forms used to shape the freshly poured concrete already have been placed along businesses from Franklin Street to the north side of the YMCA building.

"Everything's under control and they'll be back at it again on Monday," said Kenneth A. Lanning, project engineer.

Mr. Lanning is an engineer for Clough, Harbour & Associates, Syracuse.

Villager, Fairport, did lay the base coat for the speed tables last week.

"We have all the paving done until we're ready for the top course," Mr. Lanning said.

The contractor will focus on pouring the sidewalks and installing brick pavers in the upcoming week.

"We wanted to get a little work done on the sidewalks between when sub(contract) for the concrete and the sub(contract) for the pavers begins," Mr. Hauk said.

The pavers and sidewalks should take as long as six weeks to complete. Once those are done, another subcontractor will install synthetic asphalt for the crosswalks.

"We're still on schedule and we'll continue to make it through," Mr. Lanning said.

A vault in front of Cam's New York Pizzeria, 25 Public Square, has been almost completely secured. Mr. Lanning said workers built foundation walls inside the vault before filling it to the brim with concrete.

The contractor now has to pour a "roof slab" over the vault before the sidewalk can be poured, Mr. Lanning said.

"It was in a bad state," he said.

The City Council could hear a presentation from Mr. Hauk on Monday concerning the Public Square project.

The city engineer said he likely will present a recommendation to the council for an additional entrance to Mr. Sub. Its owner, Carl E. Farone, complained to city lawmakers earlier this month that the design of Public Square has taken away an exit that is essential for delivery trucks to leave his parking lot.

The Public Square exit will become a sidewalk cut used by pedestrians to access a crosswalk.

An entrance to the shop could be constructed from the Black River Parkway or J.B. Wise parking lot, Mr. Hauk has said.