Annotated Literature Review for NCHRP Report 640 (2009)

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138 Localized repairs can be made to correct small surface defects by patching with a dense- graded mix. 1.30.6 Rehabilitation Practices MHD offers the following rehabilitation techniques: 1. The most desired practice is to mill out the OGFC to a depth of 63.5mm and replace it with 45mm of dense binder and 19mm of OGFC. 2. The second option is to mill the OGFC to the top of the dense binder and replace it with 9.5mm or less of surface treatment. 3. The final option is to micro-mill the OGFC to the top of the dense binder. 1.30.7 Performance MHD paving policy is to place OGFC on all high speed, high volume roadways. 1.30.8 Structural Design MHD did not discuss structural design. 1.30.9 Limitations MHD recognizes the following limitations of OGFC: 1. OGFC can be prone to premature raveling and weathering due to oxidation and hardening of the binder. 2. Application of thermoplastic paint markings can heat up the OGFC surface and cause localized draindown of the binder material from the aggregate. This can lead to delamination of the OGFC and /or raveling of the mix under the thermoplastic line markings. 3. Snow plows can hit off raised markers and bounce along the OGFC surface causing a “chatter” or plow marks in the surface of the OGFC. 4. Primary causes for OGFC failure were raveling and delamination. 1.31 Milne, R. “Open-Graded Comes Clean.” Asphalt Review. Australian Asphalt Pavement Association. Volume 20, Number 3. pp. 11-12. December 2001. 1.31.1 General This article provides a description of equipment used in New Zealand to clean open- graded porous asphalt. 1.31.2 Benefits of Permeable Asphalt Mixtures No specific benefits were given. 1.31.3 Materials and Mix Design No specifics on materials and mix design were given.