Better Roads

April 2014

Better Roads Digital Magazine

Issue link:

Contents of this Issue


Page 5 of 31

RoadScience by Tom Kuennen, Contributing Editor 4 April 2014 Better Roads I n the long run, does it pay for an agency to seal sawed concrete expansion joints and maintain the seals throughout time? Counterintuitively – given the initial expenditure and the cost to maintain the seals – not all engineers believe it's cost effective to seal concrete expansion joints in all ap- plications, in all places and climates. As it cures, standard concrete pavement cracks. The pave- ment always will crack as it cures. The purpose of the "con- trol" joint sawed into curing or "green" slabs is to control where the concrete cracks as it cures, that is, along the path of least resistance, the sawed joint. Below the joint, though, base erosion can take place and slabs can fault, leading to spalled joint edges and massive slab cracking. Because the sawed crack control joints offer a point of ingress for water and incompressibles into the pavement structure and base, it's perceived by most road agencies that they should be sealed to keep water and debris out of the structure. However, in 1990, the Wisconsin Department of Transpor- tation (WisDOT) instituted a policy that eliminated all sealing of portland cement concrete (PCC) joints in new construction and maintenance. The Wisconsin position on the negative cost effectiveness of sealing joints was summarized in a 2002 technical paper by WisDOT's Stephen E. Shober, P.E., titled, The Great Unsealing: A Perspective on PCC Joint Sealing (Google the title to view). The paper followed a presentation at the 1996 meeting of the American Concrete Institute (ACI) – Effect of PCC Joint Sealing on Total Pavement Performance by Shober and Terry Rutkowski – The debates continues, but here are some tips to determine the most effective strategy for your agency, whether it's seal or no seal, for pavement performance and life-cycle cost. Seal or No Seal? That is the Question In advance of hot-pour sealing, longitudinal joint is blown free of debris and fi nes. Photo courtesy of Seal/No Seal Group

Articles in this issue

Archives of this issue

view archives of Better Roads - April 2014