LTPP Lessons Learned:Kansas SPS-2 July 17, 2013 Abilene, KS Gabe Cimini Database Manager, LTPP NRSC
Kansas SPS-2 Lessons Learned Overview • How are the Sections Performing? • Construction Related Performance Issues • What Lies Ahead?
Kansas SPS-2 Lessons Learned Overview • SPS-2 experiments examine effects of climatic region, subgrade soil and Traffic rate on doweled jointed plain concrete pavement • Structural factors include drainage, concrete thickness, base type, concrete flexural strength and lane width • Requires that all test sections be constructed with perpendicular joints at 4.9 m spacing and stipulate a traffic load level in the lane in excess of 200,000 ESALs per year • The Climate for this SPS-2 project is considered to be a dry, freeze environment by LTPP definitions • Construction began January 1992 • Construction completed July 1992
How are the Section Performing? • Maintenance and Rehabilitation over time • Longitudinal Cracking over Time • Transverse Cracking over Time • Roughness over Time • Pavement Deflections over Time
How are the Section Performing? Overview of Maintenance/Rehabilitation Treatments
Transverse Cracking 200202
Construction Related Performance Issues • Construction delayed due to an extremely wet and rainy season • Type C flyash was used to help “dry-up” and stabilize the subgrade • Contractor experienced many problems trying to place the PATB. Trimming was often required to obtain the desired thickness • Several sections have PCC thickness that exceed the allowable tolerance of ¼ inch
Construction Related Performance Issues (cont.) • Several underground structures exist within the limits of the test sections • 18 inch median drains located 5 feet or more below • Box culverts – 200204, 200208, 200209, 200211 • Transverse Drain located in Section 200210 • Median drain 4 feet below surface in Section 200211 • Vertical curves exist within the limits of the test sections
Overview of Performance • More maintenance/rehabilitation treatments were required for sections with No Drainage • Sections with Drainage reported less cracking and lower maximum wheel path faulting as well as lower initial deflections with more sections performing better over time. • Maintenance/rehabilitation treatments were effective at reducing cracking and faulting values
What Lies Ahead? • LTPP monitoring to continue • Potential for SPS-2 Pavement Preservation Pooled Fund Study • FactSheets available for Sections • Data available on InfoPave
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