William G. Buttlar
Published: 1999
Total Pages: 192
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The Illinois Department of Transportation (IDOT) spends two million dollars annually on reflective crack control treatments; however, their cost-effectiveness has never before been reliably determined. The study evaluated the cost-effectiveness of IDOT reflective crack control system "A", which consists of a non-woven, polypropylene paving fabric, placed either in strips longitudinally over lane-widening joints or over the entire pavement ("area" treatment). Performance of 52 projects across Illinois was assessed through crack mapping and from distress and serviceability data in IDOT's Condition Rating Survey (CRS) database. Comparisons of measured reflective cracking in treated and control sections revealed that system "A" retards longitudinal reflective widening crack development, but does not significantly retard transverse reflective cracking. However, both strip and area applications of these fabric treatments appeared to improve overall pavement serviceability, and were estimated to increase rehabilitation life spans by 1.1 and 3.6 years, respectively. Life-cycle cost analyses (LCCA) found strip and area reflective crack control treatments to be marginally cost effective, where a 4.5% reduction in life-cycle costs was estimated, for medium-sized projects [between 1 and 6 mi (1.6 and 9.7 km) of two-lane road]. Small projects [under 1 mi (1.6 km) of two-lane road] showed a breakeven level of cost-effectiveness, while large projects [over 6 mi (9.7 km) of two-lane road] showed a 6.2% savings in life-cycle costs. Permeability testing of field cores taken over transverse joints showed that waterproofing benefits can exist after reflective crack appearance, which explains why serviceability was improved with area treatment even though crack development was not retarded. Guidelines for establishing and monitoring future experimental sections were also developed.