AASHTO R 78-2016 Standard Practice for Recovering Residue from Emulsified Asphalt Using Low- Temperature Evaporative Techniques.pdf

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1、Standard Practice for Recovering Residue from Emulsified Asphalt Using Low-Temperature Evaporative Techniques AASHTO Designation: R 78-161Release: Group 3 (August 2016) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001

2、TS-2a R 78-1 AASHTO Standard Practice for Recovering Residue from Emulsified Asphalt Using Low-Temperature Evaporative Techniques AASHTO Designation: R 78-161Release: Group 3 (August 2016) 1. SCOPE 1.1. This practice covers two methods for recovering the residue from emulsified asphalts such as thos

3、e specified in M 140 and M 208, using low-temperature evaporative techniques that are similar to pavement conditions. The recovered residue can be used for further testing as required. 1.2. The values stated in SI units are to be regarded as the standard. 1.3. This standard may involve hazardous mat

4、erials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior

5、to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 140, Emulsified Asphalt M 208, Cationic Emulsified Asphalt T 59, Emulsified Asphalts 2.2. ASTM Standard: E145, Standard Specification for Gravity-Convection and Forced-Ventilation Ovens 2.3. French Standard Institute: NF EN 13074, Recovery of

6、Binder from Bitumen Emulsions by Evaporation Note 1The EN 13074 Standard is published and distributed through AFNOR (French Standard Institute) and is available online at www.afnor.fr. 3. SIGNIFICANCE AND USE 3.1. Use the procedures described in this practice to obtain a residue from emulsified asph

7、alt for further testing in devices such as a dynamic shear rheometer. The lower evaporative temperatures of these procedures provide conditions that are very close to that of application techniques for these materials. Use this practice in place of recovery techniques such as those in T 59; the temp

8、eratures used in that standard may negatively affect the residue. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2a R 78-2 AASHTO 4. APPARATUS 4.1. Silicone MatThe mat used can be similar to that sp

9、ecified in NF EN 13074 or any mat that will allow an emulsified asphalt spread rate of 1.5 to 2.0 kg/m2(0.31 to 0.41 lb/ft2) for Procedure A or a 0.381-mm (0.015-in.) wet film thickness for Procedure B. The mat may have a lip to contain the emulsified asphalt in the appropriate area. Note 2A silicon

10、e mat can be purchased at restaurant supply stores. The size of the mat should be larger than the wet film applicator or other suitable sample-spreading tool. The mat size should be sufficient to produce a sample of the desired volume for subsequent testing. A good size for this application is a hal

11、f-sheet pan size, which will fit in most laboratory ovens. 4.2. Flat Oven TrayA flat oven tray or other flat heat-resistant tray or pan to support the silicone mat and allow easy transfer to the oven. Note 3A metal cookie sheet, slightly larger than the silicone mat, works well. The tray and silicon

12、e mat must fit on a rack in the forced-draft oven. 4.3. Spatula A spatula or palette knife for spreading the emulsified asphalt. 4.4. RodsRounded-end glass or metal rods of sufficient diameter and length to roll up the residue sample. 4.5. Forced-Draft OvenHorizontal air flow, mechanical convection

13、oven meeting the requirements of ASTM E145, Type IIA, at 25C (77F) and 60C (140F). Racks shall be spaced a minimum of 10 cm (4 in.) from the top and bottom of the oven and with a minimum spacing of 4 cm (1.6 in.) between racks with samples. Use a bubble level of 25-cm (10-in.) minimum length to ensu

14、re the racks are level from side to side and front to back in the oven in its operating location. Note 4Ambient laboratory conditions (22 to 28C) (72 to 82F) may be used for the 25C (77F) temperature curing for Procedure A if the sample is placed in a dust- or contaminant-free environment with some

15、air flow. A laboratory hood with an operating fan is a suitable alternative. 4.6. Wet Film ApplicatorA wet film applicator designated to produce a wet film thickness of 0.381 mm (0.015 in.) a gap depth of 0.762 mm (0.030 in.) and a width of less than the application direction of the silicone mat. No

16、te 5Examples of applicators that work are Bird-type film applicators and 8-sided applicators. 5. PROCEDURE A 5.1. Pour the required amount of emulsified asphalt onto a silicone mat supported by a flat oven tray, and spread it evenly with a spatula to produce a spread rate of 1.5 to 2.0 kg/m2(0.31 to

17、 0.41 lb/ft2) of emulsified asphalt. Use Table 1 as a guide for the quantities of emulsified asphalt necessary to produce the appropriate spread rate for a given area. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of a

18、pplicable law.TS-2a R 78-3 AASHTO Table 1Emulsion Spread Rate Guidance Emulsified Asphalt Spread Rate Emulsified Asphalt Quantity in Grams for Each Area, m2(ft2) 0.01 m2(0.11 ft2) 0.0225 m2(0.24 ft2) 0.04 m2(0.43 ft2) 0.0625 m2(0.67 ft2) 1.5 kg/m2(0.31 lb/ft2) 15.0 g 33.75 g 60.0 g 93.75 g 2.0 kg/m2

19、(0.41 lb/ft2) 20.0 g 45.0 g 80.0 g 125.0 g Note: The area dimensions correspond to the following square and circle sizes in millimeters. Area Square Circle 0.01 m2(0.11 ft2) 100 100 mm (3.9 3.9 in.) 56.4-mm (2.22-in.) radius 0.0225 m2(0.24 ft2) 150 150 mm (5.9 5.9 in.) 84.6-mm (3.33-in.) radius 0.04

20、 m2(0.43 ft2) 200 200 mm (7.8 7.8 in.) 112.8-mm (4.44-in.) radius 0.0625 m2(0.67 ft2) 250 250 mm (9.8 9.8 in.) 141.0-mm (5.55-in.) radius 5.2. Place the sample into a 25C (77F) forced-draft oven for 24 1 h. 5.3. Transfer the sample to a 60C (140F) forced-draft oven for 24 1 h. 5.4. Remove the sample

21、 from the oven, and allow it to cool at room temperature for 1 h prior to removal from the mat. 5.5. Carefully peel the emulsified asphalt residue from the mat using a wooden or plastic utensil, taking care not to damage the silicone mat. The residue can be kneaded into the appropriate sample size f

22、or testing if appropriate gloves are worn to prevent skin contact with the residue. Note 6For softer binders, it may be necessary to cool the mat and residue in a refrigerator prior to removal. Note 7Examples of a wooden or plastic utensil may be a tongue depressor, silicone spatula, or plastic knif

23、e. Note 8The recovered binder may be stored in a sealed container at ambient laboratory conditions for up to 1 week prior to testing. Note 9The recovered binder properties may change if the sample is heated to a liquid state for further testing. 6. PROCEDURE B 6.1. Pour the emulsified asphalt onto t

24、he silicone mat and, in one continuous motion, spread it evenly using the wet film applicator. Support the silicone mat with an oven tray or other flat tray or pan to allow easy transfer to the oven. Note 10The amount of emulsion should be appropriate for the size of the silicone mat, applicator, an

25、d applied sample size desired. Approximately 50 g is sufficient for a half-sheet silicone mat and a Bird-type applicator. 6.2. Place the sample into a 60C (140F) forced-draft oven for 6 h 15 min. 6.3. Remove the sample from the oven. While it is still hot, place a glass or metal rod on the surface o

26、f the sample, near an edge, and allow the sample to cool at room temperature for 15 min prior to removal from the mat. 6.4. Carefully peel the emulsified asphalt residue from the mat using a uniform rolling motion of the glass or steel rod to prevent damage to the silicone mat. Without warming the m

27、aterial, obtain a representative sample from the rod and shape it into the appropriate size for testing. Wear appropriate gloves to prevent skin contact with the residue. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation o

28、f applicable law.TS-2a R 78-4 AASHTO 7. KEYWORDS 7.1. Asphalt residue; emulsified asphalt. 1Formerly AASHTO Provisional Standard PP 72. First published as a full standard in 2016. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.