For years, the stretch of Interstate 26, beginning near Exit 17, was infamous for the audible “thump, thump thump” caused by the tires of vehicles bouncing from one uneven concrete slab to the next.
Now, that seven-mile stretch of interstate, from Boones Creek to University Parkway — including all the exit ramps in between — has been repaved with a fresh layer of asphalt.
State Sen. Rusty Crowe, R-Johnson City, met with TDOT officials Friday at Bob Evans, just off Exit 17, to thank them for their work on the paving project.
“I probably got more calls about this stretch of road, from right about here (at Bob Evans) up to University Parkway, than any project or any stretch of road that we’ve got,” Crowe said. “I was just really appreciative of TDOT and Summers-Taylor for getting this done.”
Summers-Taylor Inc. was awarded a $6.96 million contract to complete the Interstate 26 resurfacing project through Johnson City.
TDOT District Operations Manager Randy Busler said the project started in late May and was completed roughly four months later. The contract required all the resurfacing work be done overnight, between 7 p.m. and 6 a.m.
“Our volumes have grown to the point now that being able to close lanes is very difficult,” TDOT Region 1 Director Steve Borden said.
Concrete had previously been used on roadways across the state, especially in urban areas, Borden said.
“The view of concrete is you typically get a 30 or 40 years out of it with minimal maintenance,” Busler said. “But once it does start deteriorating and breaking down, the maintenance and repair becomes very, very expensive. You can’t just go throw asphalt in a hole.”
Busler said concrete can be “unforgiving,” which is why Interstate 26 through Johnson City consisted of multiple sections or slabs of concrete.
“Each one of those concrete sections out there operates as an independent slab. Over time, they move around with the weight of the traffic. (Semi) truck traffic is typically what does the most damage,” Busler said. “If you lock (the concrete slabs) up and make it too rigid, it’s going to start breaking apart, so you have to allow for some movement.”
Busler said the numerous “joints” connecting each concrete slab were cut and resealed before a 1.75-inch layer of asphalt was poured to level it all out.
This time around, TDOT paved Interstate 26 with a porous asphalt called “open-graded friction course.” The make-up of the material allows water to drain easier, reducing hydroplaning and splashing while improving surface reflectivity.
Borden said in other areas where open-graded friction course has been used, TDOT has actually noticed a reduction in vehicle accidents.
Exit 17 Project
And now that the “rough” has been smoothed out, it’s nearly time for TDOT to begin work on a “diverging diamond” — an innovative interchange solution in the works for Exit 17.
While Busler said TDOT still has some guardrail upgrades and striping to complete, the next big project for Interstate 26 is transforming the Exit 17 interchange into that “diverging diamond,” which Borden expects to break ground in February or early spring.
The concept — similar to the Interstate 40 Exit 407 interchange in Sevier County—will temporarily shift traffic moving along Boones Creek Road to the left side of the road while crossing underneath Interstate 26. The project is expected to cost around $12.3 million.
Calling it an innovative approach, Borden said the diverging diamond can actually be built more quickly because it has a small footprint, meaning not as much right-of-way is required. The diverging diamond has also been proven safer than traditional designs, as one study in Springfield, Missouri, showed a 60 percent reduction in collisions.
“It will be a great opportunity to improve this interchange, and the improvement of the interchange is something that is going to affect safety, our No. 1 priority, but it will also improve economic development,” Borden said.
In 2010, TDOT built the second-ever diverging diamond in the country in Blount County at the U.S. 129 bypass and Bessemer Street interchange.