NC State University has a civil engineering lab that’s been around for more than 50 years, packed with all kinds of testing equipment.

The hosts of The Hot Mix Podcast took a trip to the campus to pay a visit to their Civil Engineering Lab and see it with their own eyes. We learned a lot from their trip and had the chance to speak with two experts who shared about the testing conducted in the lab.

Inside the NC State Civil Engineering Lab

The NC State Civil Engineering Lab boasts more than 50 years of testing all in one place. They've pioneered some of the greatest research on small specimen testing using the actual mixer performance tester.

Inside the lab, we checked out one of their main rooms, commonly called a “hot room,” and the name fits. The room was packed with ovens, like Despatch, and thermal. We also saw one of the best products out there, the Pine Gyratory, perfect for creating cores in the lab.

The Dirty Room

We moved on to another main room called “the Dirty Room” (don’t get any funny ideas). This room is where the NC State Lab does most of the sieve shaking, which often lets off a lot of dust, hence the name Dirty Room. But for a lab room, it looked awfully clean and well-taken care of for having such a dirty name.

Inside the room, we saw InstroTek’s very own CoreDry, one of our flagship products. We saw not only one, but two Core Rice systems as well, as well as one of InstroTek’s very first products–the CoreLok. The NC State Lab is still using the product to this day for its testing.

An Oldie but Goodie

There’s a lot of history inside the NC State Lab, and that includes the lab equipment itself. Inside one of the rooms, we discovered the Marshall Stability Machine. This is where compression strength tests all began, with this machine (which goes way back). There’s been a long history of testing inside the NC State Lab, and the existence of the Marshall machine is proof.

Our Talks with a Few Experts

While we were at the Civil Engineering Lab, we met with Dr. Shane Underwood, a professor at NC State University's Department of Civil, Construction, and Environmental Engineering. He showed us around the lab, pointed out some important pieces of equipment, and more.

One such piece of equipment is called the AMPT. It’s something that the lab uses a lot for testing asphalt and concrete.

“We're looking at the cyclic fatigue characteristics material,” Shane explained to us. “We really want to use that information and some models, advanced models, that our group’s developed here over the years.”

The end goal of their testing is to make sure roads will last another year–or even two to three years. And one way to do that is to look at how the asphalt mixture fails, how it fatigues. After all, the longer the road lasts, the less crews have to be out there paving it, and it’ll save money for the state (and taxpayers!) in the long run.

We also met with NC State Civil Engineering Professor Dr. Cassie Castorena, who showed us the DSR (Dynamic Shear Rheometer), and Cassie informed us of the testing they do with this piece of equipment. 

“We use it to conduct standard performance graded tests and to screen asphalt binder performance for pavements,” she told us.  “We also conduct advanced testing to evaluate the durability of both asphalt binders and mastick, which is the combination of binder and mineral filler.”

Asphalt mixtures used today are a combination of asphalt binder and aggregates. And the asphalt binder is really the weak link, Cassie told us.

“To prevent premature failure of our pavements, we need to first screen the asphalt binder to ensure it has adequate performance.” 

We had a great time visiting NC State and seeing their Civil Engineering Lab up close. Special thanks to Shane and Cassie for sharing their knowledge with us! The Hot Mix will be visiting more labs in the future, so stay tuned to their YouTube Channel for future updates.

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