Kansas City, Mo. Cities across the Kansas City metro area are facing millions of dollars in repairs to concrete structures that were installed years ago.
The problem of concrete that’s falling apart and appears to affect several area streets and curbs is called D-cracking and can be traced back to bad limestone that was used in the late 1980s, The Kansas City Star reported. The key ingredients of concrete are rock, or what’s called large aggregate, mixed with sand, cement and water.
“Kansas City is a big metropolitan area with a lot of streets built at a lot of different times in the past,” said Michael Ross, manager of technical and administrative services for the public works department in neighboring Overland Park, Kan. “There’s a block of infrastructure that is old enough that has this problem and that will be very expensive to go back in and replace.”
Joe Johnson, director of public works for Leawood, Kan., said some of the limestone was susceptible to water getting in it. In winter the low temperatures made that water expand. When it warmed back up it thawed and the aggregate would contract.
“As it would go through the cycle, the rocks would disintegrate,” Johnson said.
Overland Park will spend about $2 million next year replacing curbs and gutters, largely because of D-cracking, Ross said. Leawood will spend about $12 million to $16 million over the next four years to replace curbs.
And in Lee’s Summit, the city asked voters in 2010 to approve bonds for a large-scale curb replacement program to get ahead of the problem. The city was able to fund about $9 million through that program to replace about 400,000 feet of curb and gutter. The city has enough left to do about $50,000 in repairs next year to address the worst areas.