CITY STREETS: Maintaining momentum

Bill Wilson / August 05, 2011

Quality roads are always worth a mention in the morning newspaper in Lakewood, Colo. They also are practically delivered right at the residents’ doorstep.

The Denver suburb has been committed to road maintenance for quite some time, and it has never shied away from bold practices, and the approach is validated on the residential streets. It makes complete sense—Lakewood is dominated by personal addresses (896 lane-miles). Collector and arterial streets combine for less than half at 402 lane-miles.

The city council also has taken ownership in budgetary numbers when it comes to repairing roads since a major sales tax increase passed in 2006. That is when funding doubled to $10 million.

“We had a big resurfacing program then,” Chris Jacobsen, maintenance director for Lakewood’s public works department, told Roads & Bridges. “One of the items [on the agenda] was to catch up on a lot of our maintenance because we had been cutting back years prior because of budget reasons.”

These days it is hard to catch up with Jacobsen and his crew. Funding marked for maintenance has stayed at roughly $6 million annually for the last five years, including $6.2 million for FY 2011, which is good for 104 lane-miles of work. The recession had more fur than sharp teeth, thanks in part to a retail development boom prior to the national crisis. The boom contributed to the sales tax increase.

“We have had to tighten our belt some, but it has not been extreme,” Jacobsen admitted. “Lakewood has a pretty good reserve built up over the years, so they have been using that to get through the dip in the economy. “We know how much it costs to keep our street network on those [maintenance] cycles, so we can put a number to it, and our council has funded it at 100%.”

Lakewood’s pavement maintenance cycle spins like this: Residential streets are overlaid every 16 years, with crack sealant or patching conducted every four, while collector streets and arterials are milled and filled every 12 and 10 years, respectively. Jacobsen works by the motto of keeping good roads good and claims one-half of 1% of the roads could be rated in poor condition. If a road has been devalued, it is usually because there is utility work that is slow to complete or a neighboring town feeling the budget crunch, as is the case with 20th Avenue, which is shared with Edgewater.

“What I have found after being here this long is that those cycles are pretty good at keeping the streets in fair-to-good condition at all times,” said Jacobsen.

Lakewood’s maintenance programs also have included concrete repair, and up to this year, some chip seal work. However, snowplow damage, particularly on busy streets, has Jacobsen pulling chip seals from the program.

Neighborly ways

Still, Lakewood’s forward vision is usually celebrated at the residential level. After following state of Colorado protocol by using 20% reclaimed asphalt pavement (RAP) in its mixes, Lakewood, after extensive laboratory testing, decided to bump it up to 30% in 2006 on a test strip in a residential neighborhood. Crews dropped down 8,000 tons of the high-RAP material. According to Jacobsen, the test section has held up as well as those containing virgin asphalt.

“There were a lot of streets done that year using the 20% mix and we don’t see any difference in performance,” he noted. “Visually you would not know it was different than the 20% mix.”

However, so far Jacobsen has stopped short of applying the 30% RAP version on collector and arterial streets. The mix will most likely hit alleyways and maybe a parking lot before hitting the big time.

“I wouldn’t mind trying 50% RAP in a parking lot some day to just get a good look at it,” Jacobsen said. “I do think [using as much as 50% RAP] is a possibility in the future. You have to know where you are using it, because if you lose some confidence in the material by using more RAP, then maybe it belongs someplace else where it is not as critical that the material be a premium material.”

Increasing the percentage of RAP also helps owners and contractors play with material price increases, which have been constant this year. Lakewood, however, does have an escalator clause in its road contracts that covers contractors if the price of oil increases more than 10% throughout the year. The clause also is activated if the price goes down.

“The city of Lakewood used to be able to lock in a price for the oil it was going to use for the whole year. They can’t do that anymore because the refineries are giving them a price month to month,” said Jacobsen.

Currently, the only area where 30% RAP is receiving citywide coverage is when it comes to pothole patching. Most asphalt plants in the Denver area stay open throughout the year, so even in the winter months Lakewood conducts its road-patching operation with hot-mix material. Crews cut out a square section around the hole before applying the patch, and then run a compactor over it.

“If we get into a condition where we have bad weather conditions, we just might throw a [cold] mix in a hole and hope for the best, but we generally try to avoid that,” said Jacobsen.

Lakewood put its hopes into warm-mix asphalt (WMA) three years ago at the urging of local contractor Asphalt Paving Co., which had just purchased a plant capable of producing the mix. Again, the initiation happened on a residential street. After watching the pavement for a year and noticing no difference in performance compared with hot-mix asphalt, Lakewood expanded its WMA use to 30% of the program, including applications on collector and arterial streets. This year the decision to go WMA has been left up to the contractor, and so far it has been the material of choice on all applications.

Porous pavement also is about to make an appearance in Lakewood at the city’s recycling center, located at 1050 Quail Street. About 10 years ago, the Urban Drainage Flood Control District applied pervious pavement to a section of the recycling center lot, and the feeling has been so positive Lakewood is trying the asphalt version of the drainage pavement this fall.

“There were some porous applications around [Lakewood] that the Colorado Asphalt Pavement Association has promoted pretty heavily, so I attended a couple of their presentations and looked at what was done and decided it was something that might work in some of our situations,” said Jacobsen.

The ideal situations, according to Jacobsen, are alleyways, because most are flat and have drainage issues, which are only magnified in the winter time when freezing temperatures coat the area.

“The biggest problem I have heard [with porous pavement] is the plugging of the pavement with sand or something like that, so you have to be really careful where you put it,” noted Jacobsen. “The recycling center should serve as a good testing ground because we don’t plan on doing any kind of sanding in that area.”

The newest pavement-management hit to cover Lakewood is the Reclamite surface sealant process. According to Jacobsen, the surface sealer penetrates the asphalt and is designed to rejuvenate the top layer and put back some of the oil that is lost in sunlight. The contractor sprays it at a certain rate, usually one-tenth of a gallon per square yard, before applying a light layer of sand, which is removed the following day. The city of Lakewood has been doing some before and after core testing, which involves a penetration test on the top 1?8 in. of the core. Jacobsen is looking to see if the penetration does indeed improve, and if the softening of the top layer of oil translates into less cracking and raveling in the pavement. After doing an initial application in 2010, Lakewood used Reclamite on 8 lane-miles in 2011 and is looking to expand the program moving forward.

“We are seeing promising results,” said Jacobsen. “It kinda swells that asphalt surface so it doesn’t have as many voids, and you can definitely see that. It seems to be slowing down the rate of reflective cracking.”

Jacobsen also said the Reclamite provides a seal, and he is trying to apply it at the four-year mark in the maintenance cycle when the street is still in relatively good shape.

“What you are doing is trying to rejuvenate that top layer that has been oxidized and has gotten brittle from the sunlight. It is a fairly inexpensive and simple process,” added Jacobsen.

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