Reid makes clear it’s not only the lack of a bureaucracy that enables him to test products as he sees fit — it’s the nature of working over a much smaller area and a more homogenous environment than across an entire state. He says TDOT divides the state into four regions, and each sees a slightly different set of factors that affect the expected lifetime of pavement.
”So it’s difficult to implement a new fog seal or rejuvenator on a state-wide basis, for example, because the different regions may not benefit equally from the same types of products or treatments. What works in East Tennessee might not work in West Tennessee, because of differences in climate or types of aggregate, for example,” Reid says. “I don’t have that nearly as many variables here in Nashville as exist across the whole state.”
Currently, more than a dozen producers have placed 500-foot test strips of fog seals, slurry seals, micro surfacing, and more for Reid to evaluate, and more than half of those strips are on the pavement immediately in front of the Nashville Public Works building.
“It’s great having them tested right in front of our facility so our director and chief engineer and everyone involved can drive over these products every day,” he says. “This way, my counterparts can see how it goes down, and they can watch how it performs.”
Reid says he tests material not only to evaluate the effectiveness of the material, but also to help determine which materials can work best on which roads. As paving and right-of-way manager he is responsible for the maintenance of arterials, collector routes, and local roads, and he says traffic volumes and traffic type varies significantly for each type of roadway.
“Some materials worked on local roads, but didn’t work on collector routes, for example,” he says. “What might last on a local road might last only three months on a collector route because of the traffic density.”
The first material he tested was the rejuvenator Reclamite Preservative Seal made by Tricor Refining. “We tested that because we were skeptical of jumping in to heavy black fog seals,” he says.
Reid says the rejuvenator worked well and is still in use throughout the area. “But Reclamite has to be put down on new roads,” Reid says. “You can’t put it down on raveled roads; it has to be put down on roads that are only three to five years old. But we have more nine- or 10-year-old roads than we do three-to-five-year old roads, so that’s what led me to look for other products.”
The pros & cons
Reid says when testing is complete, his department provides the producer with the city’s viewpoint of the new material —the pros and the cons.
Among the materials currently being tested or in use because of successful tests are Western Emulsion’s PASS QB and textured PASS QB, Star Inc.’s Road-Guard road sealant/micro surfacing material, SealMaster’s PMM (Polymer Modified MasterSeal) and Liquid Road. In addition, Reid three years ago tested a warm-mix asphalt overlay (which led to a TDOT spec that could lead to the use of WMA on 10% of paving jobs).
Currently Reid works through various contractors, with projects going to the low bidder. In a perfect world — a world without budget cuts and with enough tax dollars coming in — Reid would like his own in-house crew, which he says he could keep busy doing infrared repairs, cracksealing, and fog sealing.
“I could keep one crew busy all year now because cracksealing is best done in spring and fall, infrared patching can be done all year round, and fog seal is best applied in summer,” he explains.
Reid says he will soon deploy a test area using a new hot-in-place polymer, Kraton Polymers’ HiMA formula, that when added to the hot mix asphalt makes it easier to place and work by hand.
“Typically, the more polymer added to a mix, the more difficult it is to place that mix and work it by hand. According to the developers, this polymer is supposed to make all that easier,” Reid says.
The product will be used in a state aid paving job along one side of an intersection alongside a more standard full-depth concrete construction on another part of the same intersection.