1、Standard Practice for Selection and Use of Emulsified Asphalts AASHTO Designation: R 5-17 Technical Section: 2a, Emulsified Asphalts Release: Group 3 (August 2017) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2a
2、 R 5-1 AASHTO Standard Practice for Selection and Use of Emulsified Asphalts AASHTO Designation: R 5-17 Technical Section: 2a, Emulsified Asphalts Release: Group 3 (August 2017) 1. SCOPE 1.1. This standard provides recommendations on selecting the proper grade and type of emulsified asphalt for vari
3、ous transportation uses. Emulsified asphalt must be selected for the proper application. 1.2. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practi
4、ces and determine the applicability of regulatory limitations prior to use. 2. REFERENCED STANDARDS 2.1. AASHTO Standards: M 140, Emulsified Asphalt M 208, Cationic Emulsified Asphalt M 316, Polymer-Modified Emulsified Asphalt 2.2. FHWA Document: FHWA-IF-00-027, Selecting a Preventive Maintenance Tr
5、eatment for Flexible Pavements (2000) 3. TERMINOLOGY 3.1. Definitions: 3.1.1. prime coata uniform, sprayed application of asphalt material to an untreated subgrade or a granular base to seal the base before paving, and to promote bonding to the upper layers. 3.1.2. tack coata uniform, sprayed applic
6、ation of asphalt material placed between asphalt mix layers to promote bonding. 3.2. Definitions for Preventative Maintenance Treatments Found in FHWA-IF-00-027: 3.2.1. cape seala surface treatment that involves the application of a slurry seal to a newly constructed surface treatment or chip seal.
7、Cape seals are used to provide a dense, waterproof surface with improved skid resistance. 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2a R 5-2 AASHTO 3.2.2. chip seala surface treatment in which
8、a pavement surface is sprayed with asphalt (generally emulsified) and then immediately covered with aggregate and rolled. Chip seals are used primarily to seal the surface of a pavement with non-load-associated cracks and to improve surface friction, although they also are commonly used as a wearing
9、 course on low-volume roads. 3.2.3. crack fillingthe placement of materials into non-working cracks to substantially reduce infiltration of water. Non-working cracks are defined as those that experience minor horizontal movements, generally less than 2 mm (0.1 in.). Crack filling should be distingui
10、shed from crack sealing. 3.2.4. crack sealinga maintenance procedure that involves placement of specialized materials into working cracks using unique configurations to reduce the intrusion of incompressible materials into the crack and to prevent intrusion of water into the underlying pavement laye
11、rs. Working cracks are defined as those that experience significant horizontal movements, generally greater than about 2 mm (0.1 in.). 3.2.5. dense-graded asphalt overlayan overlay course consisting of a mix of asphalt binder and a well-graded (also called dense-graded) aggregate. A well-graded aggr
12、egate is uniformly distributed throughout the full range of sieve sizes. 3.2.6. fog seala light application of slow-setting emulsified asphalt diluted with water is commonly used, although other types of emulsified asphalt may be used. It is used to renew old asphalt surfaces and to seal small crack
13、s and surface voids. 3.2.7. micro surfacinga mixture of polymer-modified emulsified asphalt, mineral aggregate, mineral filler, water, and other additives; properly proportioned, mixed, and spread on a roadway surface. 3.2.8. sand sealan application of asphalt material covered with fine aggregate. I
14、t may be used to improve the skid resistance of slippery pavements and to seal against air and water intrusion. 3.2.9. sandwich seala surface treatment that consists of an application of a large aggregate, followed by an application of emulsified asphalt that is in turn covered with an application o
15、f smaller aggregate. Sandwich seals are used to seal the surface and improve skid resistance. 3.2.10. scrub sealapplication of a emulsified asphalt to the pavement surface followed by the broom scrubbing of the asphalt into cracks and voids, then the application of an even coat of sand or small aggr
16、egate, and finally a second brooming of the aggregate and asphalt mixture. This seal is then rolled with a pneumatic tire roller. 3.2.11. slurry seala mixture of slow-setting emulsified asphalt, well-graded fine aggregate, mineral filler, and water. It is used to fill cracks and seal areas of old pa
17、vements, to restore a uniform surface texture, to seal the surface to prevent moisture and air intrusion into the pavement, and to provide skid resistance. 4. SIGNIFICANCE AND USE 4.1. Emulsified asphalts are mixtures of asphalt binders, water, and emulsifying agents. They may contain other additive
18、s to meet certain grades. Emulsified asphalt grades and types have different uses. 4.2. Emulsified asphalts are named using a prefix and a suffix. The prefix identifies the type and class of emulsified asphalt and the suffix identifies the grade. 2017 by the American Association of State Highway and
19、 Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2a R 5-3 AASHTO 4.2.1. TypeThere are four types of emulsified asphalts that are distinguished by how fast the emulsified asphalt will set or coalesce. The four types are designated with the prefix: 4.2.1.
20、1. SS-slow set, 4.2.1.2. MS-medium set, 4.2.1.3. RS-rapid set, and 4.2.1.4. QS-quick set. 4.2.2. Class: 4.2.2.1. Emulsified asphalt is classified based on particle charge of the asphalt droplets within the water phase of the suspension. Anionic emulsified asphalt has a negative charge and cationic e
21、mulsified asphalt has a positive charge. 4.2.2.2. There are also a limited number of emulsified asphalts with no appreciable charge and they are classified as nonionic. 4.2.2.3. Cationic emulsified asphalts are designated by including the letter “C” before the prefix (i.e., CRS-2). Anionic emulsifie
22、d asphalts are designated without including an additional letter or number in the prefix (i.e. RS-2). 4.2.2.4. High-float emulsified asphalt is a class of emulsified asphalt that can be either anionic or cationic. High-float emulsified asphalt is formulated with a gel structure to produce a thicker
23、asphalt coating on aggregates. They are designated with the letters “HF” before the prefix (i.e., HFRS-2). 4.2.3. Grade: 4.2.3.1. Emulsified asphalts are produced in two viscosity grades. The suffix “1” indicates low-viscosity emulsified asphalts and suffix “2” indicates high-viscosity emulsified as
24、phalts. 4.2.3.2. Emulsified asphalts are designated in three stiffness categories: 4.2.3.2.1. Hard asphalt residue (lower penetration) is designated with an “h” (i.e., CRS-1h). 4.2.3.2.2. Soft asphalt residue (higher penetration) is designated with an “s” (i.e., CRS 1s). 4.2.3.2.3. The intermediate
25、stiffness category, between hard and soft, is designated without an additional letter or number (i.e., CRS-1). 4.2.3.3. “P” is used to designate polymer-modified emulsified asphalts (i.e., CRS-2P). The modifier may be either a solid or latex polymer. The modifier may be added either to the asphalt b
26、inder or emulsifier solution prior to the emulsification process. 4.3. Typical uses of different grades of emulsified asphalts are shown in Tables 1 and 2. Note that other factors that need to be considered include: 4.3.1. Ambient temperature at time of use, 4.3.2. Aggregate type and gradation, 4.3.
27、3. Available application equipment, 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2a R 5-4 AASHTO 4.3.4. Traffic, and 4.3.5. Potential environmental considerations. 4.4. It is recommended to evalua
28、te aggregate and emulsified asphalt compatibility in the laboratory before placing on the roadway. Table 1Typical Uses, Rapid-Set and Slow-Set Emulsified Asphalt M 140 M 208 RS-1 RS-2 HFRS-2 SS-1, SS-1h CRS-1 CRS-2 CSS-1 CSS-1h Plant Mix (Cold) or Mixed in Place Dense-Graded X X X Emulsified Asphalt
29、Aggregate Combinations Chip Seal X X X X X Sand Seal X X X X X Slurry Seal X X X Sandwich Seal X X X Scrub Seal X X Straight Emulsified Asphalt Fog Seal X X XaX XaXaPrime Coat XbXbXbTack Coat X X XaX X XaXaCrack Filler X X X aDiluted with water at point of manufacture. bMixed-in prime only. Table 2T
30、ypical Uses, Medium- and Quick-Set Emulsified Asphalt and Polymer Modified Emulsified Asphalt M 140 M 208 M 316 MS-1, HFMS-1 MS-2, HMS-2 HFMS-2s CQS-1 CQS-1h CMS-2 CRS and CHFRS (2hP, 2P, 2sP) CQS-1hP, CQS-1P CRS-1P, SS-1hP, CSS-1hP Plant Mix (Cold) or Mixed in Place Dense-Graded X Emulsified Asphal
31、tAggregate Combinations Chip Seal X Sand Seal X Slurry Seal X X Micro Surfacing X Sandwich Seal X Straight Emulsified Asphalt Fog Seal XaX X X Prime Coat XbTack Coat XaX X X Crack Filler X aDiluted with water at point of manufacture. bMixed-in prime only. 5. KEYWORDS 5.1. Anionic; asphalt grade; asphalt type; cationic; coat; emulsified asphalt; high float; polymer modified; seal; stiffness; viscosity. 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
