1、Standard Method of Test for Determining Degree of Particle Coating of Asphalt Mixtures AASHTO Designation: T 195-11 (2015) ASTM Designation: D2489/D2489M-08 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2c T 195-
2、1 AASHTO Standard Method of Test for Determining Degree of Particle Coating of Asphalt Mixtures AASHTO Designation: T 195-11 (2015) ASTM Designation: D2489/D2489M-08 1. SCOPE 1.1. This method covers the determination of the degree of particle coating in an asphalt mix on the basis of the percentage
3、of coarse aggregate particles that are completely coated. Determination of the percentage of coated particles for varying mixing times may be used to establish the least mixing time required to produce satisfactory coating of the aggregate for a given set of conditions. This test method applies to m
4、ixtures containing aggregate of a nominal maximum aggregate size less than 38 mm (11/2in.). 1.2. The values stated in SI units are to be regarded as the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 92, Wire-Cloth Sieves for Testing Purposes T 168, Sampling Bituminous Paving Mixtures 3.
5、 APPARATUS 3.1. Sieves9.5-mm (3/8-in.) and 4.75-mm (No. 4) sieves conforming to M 92. 3.2. StopwatchFor checking the actual mixing time. 3.3. ThermometerWith a range from 10 to 204.4C (50 to 400F). 3.4. Sample Shovel. 3.5. Sample Trays. 4. SAMPLING 4.1. Batch PlantPermit the plant to operate at an e
6、stablished mixing time per batch (timed by a stopwatch). 4.2. Continuous PlantEstablish a mixing time by use of the following formula: ( )( )pug mill contents, kg lbpug mill output, kg s lb s(1) 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Dupli
7、cation is a violation of applicable law.TS-2c T 195-2 AASHTO 4.3. Samples should be taken at the asphalt mixing plant, immediately after discharge from the pug mill, from three alternate truckloads of mixture (see T 168). 4.4. The amount of material required to perform the test is approximately 2.3
8、to 3.6 kg (5 to 8 lb). 5. PROCEDURE 5.1. Sieve each material immediately, while it is still hot, on a 9.5-mm (3/8-in.) sieve for materials with a maximum size larger than 9.5 mm (3/8in.). For materials with a maximum size of 9.5 mm (3/8in.) or less, use a 4.75-mm (No. 4) sieve. Take a sample large e
9、nough to yield between 200 and 500 coarse particles retained on the 9.5-mm (3/8-in.) or 4.75-mm (No. 4) sieve. Do not overload the sieves. If necessary, sieve the sample in two or three operations. Shaking should be reduced to a minimum to prevent recoating of uncoated particles. 5.2. Place the part
10、icles on a clean surface in a one-particle layer, and start counting them immediately. 5.3. Very carefully examine each particle under direct sunlight, fluorescent light, or similar light conditions. If even a tiny speck of uncoated stone is noted, classify the particle as “partially uncoated.” If c
11、ompletely coated, classify the particle as “completely coated.” 6. CALCULATION 6.1. The required computation is as follows: no. of completely coated particles 100percent of coated particlestotal no. of particles= (2) 7. REPORT 7.1. Report the following information: 7.1.1. Type of plantbatch or conti
12、nuous; 7.1.2. Type of mix; 7.1.3. Mixing time to the nearest 0.5 min; 7.1.4. Mixing temperature to the nearest 5C (9F); and 7.1.5. Percent of coated particles to the nearest 0.1 percent. 8. PRECISION AND BIAS 8.1. PrecisionNo precision data are available at this time. 8.2. BiasBecause there are no a
13、ccepted reference materials suitable for determining the bias of this test method, no statement of bias is presented. 9. KEYWORDS 9.1. Asphalt; asphalt mixing plant; coating; mixing time; pug mill. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
