EDC-6: Targeted Overlay Pavement Solutions (TOPS)
FHWA has recently published four case studies as part of Every Day Counts – Six (EDC-6) Targeted Overlay Pavement Solutions (TOPS). The case studies are described below:
Crack Attenuating Mixture, Texas DOT
Crack attenuating mixture (CAM) interlayers may reduce the number of reflective cracks and slow the rate of reflective cracking by up to 50 percent. The concept of CAM interlayers was initially developed as a reflective cracking mitigation strategy for Jointed Reinforced Concrete Pavement rehabilitation and have used these mixes successfully on Continuously Reinforced Concrete Pavement (CRCP) and asphalt surfaces where crack mitigation is desired. The document can be accessed directly at: https://www.fhwa.dot.gov/pavement/tops/pubs/TOPS_CAM_Case_Study_2-pager.pdf
Highly Modified Asphalt, Florida DOT
Highly Modified Asphalt (HiMA) used in thin overlays has potential benefits of reduced rutting, delayed fatigue cracking, mitigated crack reflection and improved durability of open-graded mixtures. The document can be accessed directly at: https://www.fhwa.dot.gov/pavement/tops/pubs/TOPS_HiMA_Case_Study_2-pager.pdf
High-Performance Thin Overlays, New Jersey DOT
High-performance thin overlays (HPTO) can be applied to high-traffic volumes with minimal impacts to traffic with short road closures. Benefits include an improved ride quality depending on existing pavement conditions and extended pavement service life without raising profile grade by more than 1 inch. The document can be accessed directly at: https://www.fhwa.dot.gov/pavement/tops/pubs/HPTO_Case_Study_2-pager.pdf
Stone Matrix Asphalt, Georgia DOT
Stone matrix asphalt (SMA) potential benefits include greater rutting resistance, longer fatigue life, longer service life and lower annualized costs. The document can be accessed directly at: https://www.fhwa.dot.gov/pavement/tops/pubs/TOPS_SMA_Case_Study_2-pager.pdf
These documents can also be accessed through the FHWA pavement website at: https://www.fhwa.dot.gov/pavement/tops/ or directly at the links above.