DOT digs into decay under I-40

Posted October 30, 2013
Updated October 31, 2013

— The Department of Transportation's three-year, 11.5 mile, $130 million Fortify project won't result in more travel lanes on Interstate 40 south of downtown Raleigh. Instead of an expansion, it's a replacement, a reinforcement of pavement – some of it more than 20 years old – that is cracking and crumbling due to a chemical reaction happening underneath the road.

"It is crumbling, and as road pressure goes on the top portion, it is crumbling in," said DOT spokesman Steve Abbott. 

Before the upgrade began, workers drilled into the roadbed, extracting cores that show the extent of the problem. "It is not solid in some places. It is crumbling in some places," Abbott said.

The core samples showed a dark top layer – the road surface – and, underneath, the result of a chemical reaction where water had seeped into the mixture of cement and other materials.

Core samples from Interstate 40 Core samples show I-40's age

Years after the road was built, DOT officials learned that chemicals in some of those ingredients reacted poorly with one another. 

"They now know: Don't pair this with this because it is going to go bad," Abbott said.

It's not a phenomenon unique to Raleigh. "Airports and roads all over the place, it was the same thing," he said.

The Fortify project will require that all the crumbling old mixture be dug up, stripped away and replaced. Workers continued taking core samples through the week of Oct. 28 to determine how deep the road is and predict how hard their project will ultimately be.

In addition to replacing the highway, crews will extend two miles of auxiliary lanes to help manage additional traffic and fix 14 bridges in the construction zone.

The contractor, Granite Construction Company, will begin daytime work in early December along the 2.5-mile section of Interstate 440 between I-40 and the U.S. Highway 64/264 interchange.


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  • GoHeelsGo Oct 31, 2013

    What happens to all of the old material?

  • dirtydozen431 Oct 31, 2013

    This happened under Democrat control and their DOT. But no investigation will ensue.

  • goncampn2 Oct 31, 2013

    @ Obamacare for one and all - "Weclome to the south, where DOT workers never have to worry about job security thanks to our diposable roads. Just toss the old one out every five years and replace.....rinse and repeat."
    You should return to the northern liberal stae you cam from if you don't like the way things are done here!!....jst sayin!! (also learn how to spell and use word check)

  • goncampn2 Oct 31, 2013

    Granite was the contractor on the I-85 project through Durham! Went well over schedule and they are a New Jersey company that has the mind set of unions. Why couldn't the DOT find a local North Carolina contractor to do the job? They go on the cheapest bid!! And we know what that means.

  • DontVote4LiarsCheatsOrThieves Oct 31, 2013

    Is this normal or was the original contractor at fault somehow?

  • HadEnough Oct 31, 2013

    From the N&O this morning, the woman touting this "Fortify" project was hired at DOT this year at $125,000 per year.

  • rasengineers Oct 31, 2013

    LocalYokel wrote, "And for accountability, which NCDOT employees were fired for this $130 million dollar and years of crawleigh "mistake"? I don't want the same people messing up new roads."

    Like all other forms of technology, concrete technology has advanced light years in the last 30 years. We now know much more about the chemical interactions of the various ingredients in concrete, and the material supplied 30 years ago likely met the standard of engineering practice at the time the road was built. One possible cause, which we knew little about 30 years ago, is alkali-silica reaction (ASR). ASR occurs when alkali in the cement reacts with silica in stone used in the concrete. The by-product of the reaction occupies more volume than the original material and blows the concrete apart internally. This is a very slow reaction that can take years to deterirorate the concrete to the point where repairs are required. Today we have additives that help prevent this reaction.

  • itlsss Oct 31, 2013

    "ken d" I am similiarly dismayed about what people don't know about their own jobs.

  • Obamacare for one and all Oct 31, 2013

    Weclome to the south, where DOT workers never have to worry about job security thanks to our diposable roads. Just toss the old one out every five years and replace.....rinse and repeat.

  • Obamacare for one and all Oct 31, 2013

    Was the old road material made in China?