1、Standard Method of Test for Determining Aggregate Shape Properties by Means of Digital Image Analysis AASHTO Designation: T 381-181 Technical Section: 1c, Aggregates Release: Group 3 (August) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249
2、Washington, D.C. 20001 TS-1c T 381-1 AASHTO Standard Method of Test for Determining Aggregate Shape Properties by Means of Digital Image Analysis AASHTO Designation: T 381-181Technical Section: 1c, Aggregates Release: Group 3 (August) 1. SCOPE 1.1. This standard covers the measurement of aggregate s
3、hape properties using the digital image analysis techniques. 1.2. This standard may involve hazardous materials, 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 procedure to establis
4、h appropriate safety and health practices and to determine the applicability of regulatory limitations prior to its use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 231, Weighing Devices Used in the Testing of Materials R 76, Reducing Samples of Aggregate to Testing Size R 90, Sampling Aggregat
5、e Products T 11, Materials Finer Than 75-m (No. 200) Sieve in Mineral Aggregates by Washing T 27, Sieve Analysis of Fine and Coarse Aggregates T 84, Specific Gravity and Absorption of Fine Aggregate T 85, Specific Gravity and Absorption of Coarse Aggregate 2.2. ASTM Standards: C670, Standard Practic
6、e for Preparing Precision and Bias Statements for Test Methods for Construction Materials C802, Standard Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods for Construction Materials 2.3. Other Document: National Cooperative Highway Research Program Re
7、port 555, Test Methods for Characterizing Aggregate Shape, Texture, and Angularity 3. TERMINOLOGY 3.1. Definitions: 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c T 381-2 AASHTO 3.1.1. aggregate
8、sizesieve size in which material is retained after passing the next larger sieve. 3.1.1.1. fine aggregateaggregate material passing a 4.75-mm (No. 4) sieve. Sieve sizes are 2.36 mm (No. 8), 1.18 mm (No. 16), 0.60 mm (No. 30), 0.30 mm (No. 50), 0.15 mm (No. 100), and 0.075 mm (No. 200). 3.1.1.2. coar
9、se aggregateaggregate material retained on a 4.75-mm (No. 4) sieve. Sieve sizes are 25.0 mm (1 in.), 19.0 mm (3/4in.), 12.5 mm (1/2in.), 9.5 mm (3/8in.), and 4.75 mm (No. 4). 3.1.2. Shape Properties for Each Retained Sieve (x): 3.1.2.1. gradient angularity (GA)applies to both fine and coarse aggrega
10、te sizes and is related to the sharpness of the corners of two-dimensional images of aggregate particles. The gradient angularity quantifies changes along a particle boundary with higher gradient values indicating a more angular shape. Gradient angularity has a relative scale of 0 to 10,000, with a
11、perfect circle having a value of 0. Gradient Angularity: 331113niiiGAn+= (1) where: = angle of orientation of the edge points, n = the total number of points, and i = denoting the ith point on the edge of the particle. 3.1.2.2. texture or microtexture (TX)applies to coarse aggregate sizes only and d
12、escribes relative smoothness or roughness of surface features less than approximately 0.5 mm in size that are too small to affect the overall shape. Texture has a relative scale of 0 to 1000 with a smooth polished surface approaching a value of 0. ( )( )23,111,3Nn ijijTX D x yN= =(2) where: D = deco
13、mposition function, n = decomposition level, N = total number of coefficients in an image, i = 1, 2, or 3 for detailed images, j = wavelet index, and x, y = location of the coefficients in transformed domain. 3.1.2.3. sphericity (SP)applies to coarse aggregate sizes only and describes the overall th
14、ree-dimensional shape of a particle. Sphericity has a relative scale of 0 to 1. A sphericity value of 1 indicates a particle has equal dimensions (cubical). 32SILddSPd= (3) where: dS= particle shortest dimension, dI= particle intermediate dimension, and dL= particle longest dimension. 2018 by the Am
15、erican Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c T 381-3 AASHTO Note 1The term “sphericity” has been used for many years in research to describe this measurement. In principle, a cube does not have a sphericity
16、of one because the diagonal is considered to be the longest dimension. A digital image acquisition and analysis system would measure a value of one for a cube because it would be sitting in front of the camera on one of its faces and the longest dimension will be measured as the width. 3.1.2.4. Form
17、 2DApplies to fine aggregate sizes only and is used to quantify the relative form from two-dimensional images of aggregate particles. Form 2D has a relative scale of 0 to 20. A perfect circle has a Form 2D value of 0. 3600Form 2DRRR= + =(4) where: R= the radius of the particle at an angle of , and =
18、 the incremental difference in the angle. 3.1.2.5. flat and elongatedthose particles having a ratio of longest dimension to shortest dimension greater than a specified value. Aggregate particle dimensions in an x, y, z coordinate system are: dS= particle shortest dimension, dI= particle intermediate
19、 dimension, and dL= particle longest dimension. Flatness ratio (S/L): SIdFlatnessd=(5) Elongation ratio (I/L): ILdElongationd=(6) Flat and elongated value (F 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable
20、law.TS-1c T 381-8 AASHTO 13.1.2. Date of the analysis; 13.1.3. Material Sample Identificationtype, source, and size; 13.1.4. Number of particles analyzed; and 13.1.5. Material shape property mean and standard deviation. Graphical representations of the property distributions may be included. 13.2. A
21、 sample report format is presented in Appendix X1. 14. PRECISION AND BIAS 14.1. PrecisionAn Interlaboratory Study (ILS) was conducted in 2009 in accordance with ASTM C802. The ILS results were used to develop a precision statement for the test method using ASTM C670. The ILS featured eight systems,
22、32 laboratories, and three material sources. Table 1Precision for Sizes 25 mm, 19 mm, 12.5 mm, 9.5 mm, 4.75 mm, 2.36 mm, 1.18 mm, 0.60 mm, 0.30 mm, and 0.15 mm Aggregate Shape Characteristic Within Laboratory Between Laboratories Coefficient of Variation, % of Mean Acceptable Range of Two Test Resul
23、ts, % of Mean Coefficient of Variation, % of Mean Acceptable Range of Two Test Results, % of Mean Angularity 2.9 8.3 4.3 12.2 Texture 4.5 12.7 7.1 20.0 Dimensional ratio 1.2 3.4 2.6 7.4 Flat or elongated 2.1 5.9 3.4 9.7 Form 2D 2.7 7.7 3.5 10.0 Table 2Precision for Size 0.075 mm Aggregate Shape Char
24、acteristic Within Laboratory Between Laboratories Coefficient of Variation, % of Mean Acceptable Range of Two Test Results, % of Mean Coefficient of Variation, % of Mean Acceptable Range of Two Test Results, % of Mean Angularity 10.8 30.6 14.2 40.2 Form 2D 5.0 14.2 6.2 17.6 14.2. BiasBecause there i
25、s no accepted reference device suitable for determining the bias in this method, no statement of bias is made. 15. KEYWORDS 15.1. Aggregate; angularity; consensus property; elongated; form; shape; texture. 2018 by the American Association of State Highway and Transportation Officials. All rights res
26、erved. Duplication is a violation of applicable law.TS-1c T 381-9 AASHTO APPENDIX (Nonmandatory Information) X1. SAMPLE REPORT Material Information Date: 5/20/09 Project: Coarse Aggregate Sample Technician: TEC Workbook Name: AIMS_Shape_3.6.xlsm Description: Include Samples Size Comment 12.5 (0.50)_
27、33_LS_1 12.5 12.5 (0.50)_41_GRT_1 12.5 12.5 (0.50)_41_GRV_1 12.5 12.5 (0.50)_17_GRT_1 12.5 12.5 (0.50)_17_ GRV _1 12.5 12.5 (0.50)_17_LS_1 12.5 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c T 38
28、1-10 AASHTO AIMS Material Summary Project Name: Coarse Aggregate Sample Date: 5/20/09 Workbook: AIMS_Shape_3.6 xlsm Technician: TEC Description: Form2D Sample Size Particles in Range Average Standard Deviation Low (6) (6) Medium (612) (12) High (1220) (20) Out of Range # % Cum % # % Cum % # % Cum %
29、# Angularity Sample Size Particles in Range Average Standard Deviation Low (3300) (3300) Medium (33006600) (6600) High (660010000) (10000) Out of Range # % Cum % # % Cum % # % Cum % # 12.5 (0.50)_33_LS_1 12.5 50 2784.3 669.0 37 74.0% 74.0% 13 26.0% 100.0% 0 0.0% 100.0% 0 12.5 (0.50)_41_GRT_1 12.5 50
30、 3138.7 597.3 28 56.0% 56.0% 22 44.0% 100.0% 0 0.0% 100.0% 0 12.5 (0.50)_41_GRV_1 12.5 50 2791.7 978.7 35 70.0% 70.0% 15 30.0% 100.0% 0 0.0% 100.0% 0 12.5 (0.50)_17_GRT_1 12.5 50 3118.7 655.3 33 66.0% 66.0% 17 34.0% 100.0% 0 0.0% 100.0% 0 12.5 (0.50)_17_GRV_1 12.5 50 2623.1 862.9 40 80.0% 80.0% 10 2
31、0.0% 100.0% 0 0.0% 100.0% 0 12.5 (0.50)_17_LS_1 12.5 50 2670.4 726.4 42 84.0% 84.0% 8 16.0% 100.0% 0 0.0% 100.0% 0 Texture Sample Size Particles in Range Average Standard Deviation Low (260) (260) Medium (260550) (550) High (5501000) (1000) Out of Range # % Cum % # % Cum % # % Cum % # 12.5 (0.50)_33
32、_LS_1 12.5 50 281.8 98.1 22 44.0% 44.0% 28 56.0% 100.0% 0 0.0% 100.0% 0 12.5 (0.50)_41_GRT_1 12.5 50 455.5 119.8 1 2.0% 2.0% 41 82.0% 84.0% 8 16.0% 100.0% 0 12.5 (0.50)_41_GRV_1 12.5 49 211.8 131.9 35 71.4% 71.4% 14 28.6% 100.0% 0 0.0% 100.0% 1 12.5 (0.50)_17_GRT_1 12.5 50 457.4 88.6 0 0.0% 0.0% 43
33、86.0% 86.0% 7 14.0% 100.0% 0 12.5 (0.50)_17_GRV_1 12.5 50 224.4 141.9 35 70.0% 70.0% 14 28.0% 98.0% 1 2.0% 100.0% 0 12.5 (0.50)_17_LS_1 12.5 50 252.3 84.4 32 64.0% 64.0% 17 340% 98.0% 1 2.0% 100.0% 0 AIMS Material Summary Project Name: Coarse Aggregate Sample Date: 5/20/09 Workbook: AIMS_Shape_3.6 x
34、lsm Technician: TEC Description: Sphericity Sample Size Particles in Range Average Standard Deviation Low (0.3) (0.3) Medium (0.30.7) (0.7) High (0.71.0) (1.0) Out of Range # % Cum % # % Cum % # % Cum % # 12.5 (0.50)_33_LS_1 12.5 50 0.69 0.10 0 0.0% 0.0% 28 56.0% 56.0% 22 44.0% 100.0% 0 12.5 (0.50)_
35、41_GRT_1 12.5 49 0.62 0.09 0 0.0% 0.0% 37 75.5% 75.5% 12 24.5% 100.0% 1 12.5 (0.50)_41_GRV_1 12.5 49 0.69 0.08 0 0.0% 0.0% 24 49.0% 49.0% 25 51.0% 100.0% 1 12.5 (0.50)_17_GRT_1 12.5 50 0.63 0.11 0 0.0% 0.0% 37 74.0% 74.0% 13 26.0% 100.0% 0 12.5 (0.50)_17_GRV_1 12.5 50 0.69 0.08 0 0.0% 0.0% 27 54.0%
36、54.0% 23 46.0% 100.0% 0 12.5 (0.50)_17_LS_1 12.5 50 0.69 0.09 0 0.0% 0.0% 27 54.0% 54.0% 23 46.0% 100.0% 0 Flat and Elongated Distribution Sample Size Particles in Range L/S 1:1 L/S 2:1 L/S 3:1 L/S 4:1 L/S 5:1 Out of Range # % # % # % # % # % # 12.5 (0.50)_33_LS_1 12.5 50 50 100.0% 28 56.0% 6 12.0%
37、1 2.0% 0 0.0% 0 12.5 (0.50)_41_GRT_1 12.5 49 49 100.0% 43 87.8% 21 42.9% 6 12.2% 1 2.0% 1 12.5 (0.50)_41_GRV_1 12.5 49 49 100.0% 29 59.2% 5 10.2% 1 2.0% 0 0.0% 1 12.5 (0.50)_17_GRT_1 12.5 50 50 100.0% 40 80.0% 22 44.0% 9 18.0% 1 2.0% 0 12.5 (0.50)_17_GRV_1 12.5 50 50 100.0% 26 52.0% 4 8.0% 2 4.0% 0
38、0.0% 0 12.5 (0.50)_17_LS_1 12.5 50 50 100.0% 33 66.0% 7 14.0% 1 2.0% 0 0.0% 0 Flat or Elongated Distribution Sample Size Particles in Range F or E 1:1 F or E 2:1 F or E 3:1 F or E 4:1 F or E 5:1 Out of Range # % # % # % # % # % # 12.5 (0.50)_33_LS_1 12.5 50 50 100.0% 10 20.0% 0 0.0% 0 0.0% 0 0.0% 0
39、12.5 (0.50)_41_GRT_1 12.5 49 49 100.0% 23 46.9% 4 8.2% 0 0.0% 0 0.0% 1 12.5 (0.50)_41_GRV_1 12.5 49 49 100.0% 8 16.3% 0 0.0% 0 0.0% 0 0.0% 1 12.5 (0.50)_17_GRT_1 12.5 50 50 100.0% 24 48.0% 5 10.0% 0 0.0% 0 0.0% 0 12.5 (0.50)_17_GRV_1 12.5 50 50 100.0% 6 12.0% 1 2.0% 0 0.0% 0 0.0% 0 12.5 (0.50)_17_LS
40、_1 12.5 50 50 100.0% 13 26.0% 1 2.0% 0 0.0% 0 0.0% 0 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c T 381-11 AASHTO AIMS Angularity Project Name: Coarse Aggregate Sample Date: 5/20/09 Workbook: A
41、IMS_Shape_3.6 xlsm Technician: TEC Description: # % Cum. % # % Particles in Range 300 Low (3300) 215 71.7% (3300) 71.7% 3 4 1.3% Mode #N/A 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c T 381-12
42、AASHTO AIMS Texture Project Name: Coarse Aggregate Sample Date: 5/20/09 Workbook: AIMS_Shape_3.6 xlsm Technician: TEC Description: # % Cum. % # % Particles in Range 299 Low (260) 125 41.8% ( 260) 41.8% 3 2 0.7% Mode 175.6 2018 by the American Association of State Highway and Transportation Officials
43、. All rights reserved. Duplication is a violation of applicable law.TS-1c T 381-13 AASHTO AIMS Sphericity Project Name: Coarse Aggregate Sample Date: 5/20/09 Workbook: AIMS_Shape_3.6 xlsm Technician: TEC Description: # % Cum. % # % Particles in Range 298 Low (0.3) 0 0.0% (0.3) 0.0% 3 0 0.0% Mode 0.6
44、94 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c T 381-14 AASHTO AIMS Flat and Elongated Project Name: Coarse Aggregate Sample Date: 5/20/09 Workbook: AIMS_Shape_3.6 xlsm Technician: TEC Descrip
45、tion: F&E Sphericity F&E Sphericity F&E Sphericity Particles in Range 298 298 # % # % # % # % Average 2.481 0.669 L/S 1:1 298 100.0% Low (0.3) 0 0.0% 2:1 199 66.8% Medium (0.30.7) 180 60.4% 2 3:1 65 21.8% High (0.71.0) 118 39.6% 3 4:1 20 6.7% Out of Range 2 n 3 2 0.7% 0 0.0% L/S 5:1 2 0.7% 2018 by t
46、he American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c T 381-15 AASHTO AIMS Flat and Elongated Distribution Project Name: Coarse Aggregate Sample Date: 5/20/09 Workbook: AIMS_Shape_3.6 xlsm Technician: TEC Descri
47、ption: F & E Ratio # Cum.% L/S 1:1 298 100.0% L/S 2:1 199 66.8% L/S 3:1 65 21.8% L/S 4:1 20 6.7% L/S 5:1 2 0.7% 1Formerly AASHTO Provisional Standard TP 81. First published as a full standard in 2018. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
