City Releases Report On Longevity of Fly Ash Enhanced Concrete

(Lawrence Journal 7-25-2011) A new audit out of Lawrence City Hall has found that changes to design standards made by the city in 2003 have improved the quality of city streets.
 
“They are lasting longer,” said City Auditor Michael Eglinski, who conducts performance audits of topics selected by the City Commission. “The changes should produce better streets, but it is going to take awhile.”
 
Commissioners ordered Eglinski to study whether the city’s current design standards for streets are providing the city with a better product. Eglinski said they are, and to understand why, you need to understand fly ash.
 
Fly ash is a by-product of burnt coal from power plants, and when you mix it with water it becomes hard like concrete. The city of Lawrence now requires that fly-ash be mixed with dirt to create a solid base for new streets. But it wasn’t until 2003 — about the time that Public Works Director Chuck Soules joined the city — that the city began requiring the base-stabilizing product. The result has been that older streets have bases that are prone to settlement and movement, and are difficult to keep in smooth driving condition.
 
In addition, Eglinski also found that the public works department is doing a good job of monitoring the best-practices of road design to ensure that the city doesn’t fall behind the curve again.
 
The audit, however, does not attempt to answer the question of why the city fell behind in the first place. The audit simply notes that the city changed its standards in 2003 but that “some other area communities had raised their standards years before Lawrence.”
 
As for what the audit did find:
 
The audit compared streets built in 2002 without the fly-ash and streets built in 2003 with it. The report found that 76 percent of nonresidential streets built without the fly-ash treatment had potholes. That compares to 41 percent of the streets that were built using the treatment.
 
Based on current pavement data — collected by public works employees who inspect and rate the condition of each street in the city — nonresidential streets built with the fly ash treatment are expected to last 25 percent to 40 percent longer before they need crack sealing, microsurfacing or mill and overlay.
 
Only 10 percent of the 205 miles of streets built in the 1980s and 1990s had a fly-ash treated subgrade. In the last decade, 70 percent of newly built streets have treated subgrades.
 
Public Works officials are monitoring street conditions and construction standards more closely and are implementing more frequent changes in construction standards. For example, last year the city changed its construction standards related to the use of recycled asphalt after officials began noticing the material seemed to be wearing at a much faster rate than standard asphalt. Since 2009, the city has been hosting an annual meeting with area contractors during which the city communicates changes to design standards.
 
Eglinski’s only recommendation for the city was to create a formal policy on how to maintain brick streets. The city for years has struggled with whether they should rebuild brick streets as brick or whether they should be replaced with traditional asphalt or concrete. It is definitely a money issue. Brick streets cost about three times as much to build as a conventional street.
 
City Manager David Corliss, in his response to the audit, said he agreed that a policy should developed. He said that one option could be that numbered streets that run east/west could be rebuilt with concrete or asphalt, while brick streets that run north/south could be rebuilt with brick. Those north/south streets tend to be more residential in nature, Corliss noted. Plus, he said the bricks from the east/west streets could be salvaged and used in rebuilding the north/south streets. Expect that idea, or something like it, to be presented to the City Commission in the future.
 
City commissioners tentatively are scheduled to review the findings of the audit at their Aug. 2 meeting.
 
To view the original article go to: http://www2.ljworld.com/news/2011/jul/25/city-audit-finds-lawrence-streets-lasting-longer-l/