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Crack sealâProduct used to fill individual pave- ment cracks to prevent entry of water or other non- compressible substances such as sand, dirt, rocks, and weeds. Diamond grindingâThe process of removing a thin layer of existing concrete pavement surface by grinding it with a machine that has a series of closely spaced rotating diamond saw blades. Dowel bar retrofitâA method of reinforcing cracks in highway pavement by inserting steel dowel bars in slots cut across the cracks. Dust palliativeâA highly diluted petroleum emulsion sprayed on an unpaved surface to control direct particulate matter emissions (commonly called âroad dustâ) from unpaved roads and other surfaces with vehicle and machinery traffic. Fog sealâA light application of a diluted, slow- setting asphalt emulsion to the surface of an aged pavement surface. Gravel bladingâThe process of spreading small amounts of gravel on localized areas of unpaved roads to fill holes, restore ride quality, and reestablish the transverse geometry (commonly called the âcrownâ) to facilitate drainage. Hot patchesâPothole and other pavement defect repair made with hot-mix asphalt Joint sealâJoint seals, seal expansion, and con- traction joints in concrete. MicrosurfacingâA polymer-modified cold-mix paving system that can remedy a broad range of prob- lems on todayâs streets, highways, and air fields. This is a mixture of dense-graded aggregate, asphalt emul- sion, water, and mineral filler. Mud jackingâProcess of pumping a water, dirt, and cement mixture under concrete slabs in order to lift it. Otta sealâA low-cost type of road surface, usu- ally a 16â30-mm-thick mixture of bitumen emulsion and well-graded crushed rock. Otta seal (New Zealand)âLow-cost type of road surface, usually a 16â30-mm-thick mixture of recycled motor oil (commonly called âNorwegian road oilâ) and well-graded crushed rock. Pavement preservationâThe sum of all activ- ities undertaken to provide and maintain serviceable roadways. This includes corrective maintenance and preventive maintenance, as well as minor rehabilita- tion projects. Pavement preventive maintenanceâPlanned strategy of cost-effective treatments to an existing roadway system and its appurtenances that preserves the system, retards future deterioration, and main- tains or improves the functional condition of the sys- tem (without increasing the structural capacity). Pavement rehabilitationâWork undertaken to extend the service life of an existing pavement. This includes the restoration, placing an overlay, and/or other work required to return an existing roadway to a condition of structural and functional adequacy. Regrade/regravelâA process similar to âgravel gradingâ defined earlier, but including the entire length of a given road project. Shot blastingâA process that restores the micro- texture and macrotexture of both asphalt and concrete pavement surfaces by abrading it with steel shot. The process includes a magnetic system that collects and recycles the expended shot and a vacuum system that collects the residue for disposal. Slurry sealâMixture of emulsified asphalt, water, well-graded fine aggregate, and mineral filler that has a creamy, fluid-like appearance when applied. Spread millingsâThe use of recycled asphalt pavement millings to maintain gravel roads. The millings are used in place of virgin aggregate. Thin overlayâA layer of new pavement that is laid on the existing surface for purposes of restoring surface characteristics with no intention of enhancing the structural capacity of the under- lying pavement. These are usually less than 1.5 in. (3.75 cm) thick. Thin portland cement concrete overlayâA thin overlay consisting of portland cement concrete (com- monly called âwhite-toppingâ). Thin hot mix asphalt overlayâA thin overlay consisting of hot mix asphaltic concrete (commonly called âblack-toppingâ). APPENDICES A AND B Appendices A and B as submitted by the con- sultant are not published herein. These appendices are available as part of the web version of this document at: http://www.trb.org/Publications/Pubs NCHRPResearchResultsDigests.aspx, see Research Results Digest 365. 26
Transportation Research Board 500 Fifth Street, NW Washington, DC 20001 These digests are issued in order to increase awareness of research results emanating from projects in the Cooperative Research Programs (CRP). Persons wanting to pursue the project subject matter in greater depth should contact the CRP Staff, Transportation Research Board of the National Academies, 500 Fifth Street, NW, Washington, DC 20001. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMCSA, FTA, or Transit Development Corporation endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. Subscriber Categories: Environment ⢠Highways ⢠Maintenance and Preservation ISBN 978-0-309-22349-2 9 780309 223492 9 0 0 0 0