1、 Standard Practice for Determining Aggregate Source Shape Values from Digital Image Analysis Shape Properties AASHTO Designation: R 91-181 Technical Section: 1c, Aggregates Release: Group 3 (August) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Sui
2、te 249 Washington, D.C. 20001 TS-1c R 91-1 AASHTO Standard Practice for Determining Aggregate Source Shape Values from Digital Image Analysis Shape Properties AASHTO Designation: R 91-181Technical Section: 1c, Aggregates Release: Group 3 (August) 1. SCOPE 1.1. This standard covers the determination
3、of aggregate source and source blend shape characteristics using gradation analysis and shape properties determined by means of digital image analysis. 1.2. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems
4、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 to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: T 11, Materials Finer Than 75-m (No. 200) Sieve i
5、n 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 T 381, Determining Aggregate Shape Properties by Means of Digital Image Analysis 2.2. Other Document: N
6、ational Cooperative Highway Research Program Report 555, Test Methods for Characterizing Aggregate Shape, Texture, and Angularity 3. TERMINOLOGY 3.1. aggregate sizematerial retained on a given sieve size after passing the next larger sieve. 3.1.1. fine aggregateaggregate material passing 4.75-mm (No
7、. 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). 3.1.2. coarse aggregateaggregate material retained on 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 (3/8i
8、n.), and 4.75 mm (No. 4). 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 91-2 AASHTO 3.2. Shape Properties for Each Retained Sieve (x): 3.2.1. gradient angularity (GA)applies to both fine and c
9、oarse aggregate 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 range of zero to
10、 10,000, with a perfect circle having a value of zero. Gradient angularity: 331113ni iiGAn+= (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. 3.2.2. texture (or microtexture) (TX)applies to coarse aggreg
11、ate sizes only and describes the 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 zero to 1000 with a smooth polished surface approaching a value of zero. ( )( )23,111,3Nn ijijT
12、X D x yN= =(2) where: D = decomposition 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. 3.2.3. sphericity (SP)applies to coarse aggregate sizes only
13、and describes the overall three-dimensional shape of a particle. Sphericity has a relative scale of zero to one. A sphericity value of one indicates a particle has equal dimensions (cubical). 32ISLddSPd=(3) where: dS= particle shortest dimension, dI= particle intermediate dimension, and dL= particle
14、 longest dimension. 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 of one because the diagonal is considered to be the longest dimension. A digital image acquisition and analysis system would measure
15、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. 3.2.4. Form 2DApplies to fine aggregate sizes only and is used to quantify the relative form from 2-dimensional images of aggregate particles. For
16、m 2D has a relative scale of 0 to 20. A perfect circle has a Form 2D value of zero. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 91-3 AASHTO 360 0Form 2DRRR= +=(4) where: R= the radius of the
17、 particle at an angle of , and = the incremental difference in the angle. 3.2.5. 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: dS= particle shortest dimension,
18、 dI= particle intermediate, and dL= particle longest dimension. Flatness ratio ( / ):flatnessSIdSLd=(5) Elongation ratio ( / ):elongationILdILd=(6) Flat and elongated value ( therefore, actual mass is not required. 6.5. Calculate total particle surface area for each sieve size per sample unit mass:
19、Particle surface area (each sieve x) (mm2): #x xxSSA PSA P= (13) 6.6. Calculate sample surface area (per unit mass): 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 91-5 AASHTO 25.00.075Total su
20、rface area (mm ):xxTSA SSA=(14) 25.04.75Coarse surface area (mm ):xxCSA SSA=(15) 2.360.075Fine surface area (mm ):xxFSA SSA=(16) 6.7. Calculate sample particles count (per unit mass): 25.00.075Total particles: #xxTP P=(17) 25.04.75# Coarse particles: # #xxCP P=(18) 2.360.075# Fine particles: # #xxFP
21、 P=(19) 6.8. Calculate sample gradient angularity (weighted by surface area): 2.360.0751Fine gradient angularity:xxxFGA SSA GAFSA= (20) 25.04.751Coarse gradient angularity:xxxCGA SSA GACSA= (21) 25.00.0751Overall gradient angularity:xxxGA SSA GATSA= (22) 6.9. Calculate sample fine aggregate Form 2D
22、(weighted by surface area): 2.360.075Form 2D12xxxSSA DFSA= (23) 6.10. Calculate sample coarse aggregate texture (weighted by surface area): 25.04.751xxxTX SSA TXCSA= (24) 6.11. Calculate sample coarse aggregate sphericity (weighted by particle count): 25.04.751#xxxSP P SPCP= (25) 6.12. Calculate sam
23、ple sphericity range distribution (weighted by particle count): Percent of particles with sphericity 0.3: 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 91-6 AASHTO 25.04.751(0.3) # (0.3)#xxxSP
24、 P SPCP= (26) Percent of particles with sphericity 0.3 2:1, 3:1, 4:1, 5:1 % dL/dS 1: 25.04.75% % / ( 1)% / ( 1)100xxxR LSLS=(29) % dL/dS 2: 25.04.75% % / ( 2)% / ( 2)100xxxR LSLS=(30) % dL/dS 3: 25.04.75% % / ( 3)% / ( 3)100xxxR LSLS=(31) % dL/dS 4: 25.04.75% % / ( 4)% / ( 4)100xxxR LSLS=(32) % dL/d
25、S 5: 25.04.75% % / ( 5)% / ( 5)100xxxR LSLS=(33) 6.13.1. Calculate the sample weighted percentages of coarse aggregate flat or elongated values (weighted by mass fraction) at the following ratios: 1:1, 2:1, 3:1, 4:1, 5:1 % dI/dSor dL/dI 1: ( )( )25.04.75% % or ( 1)% or ( 1)100xxxR FEFE=(34) % dI/dSo
26、r dL/dI 2: ( )( )25.04.75% % or ( 2)% or ( 2)100xxxR FEFE=(35) % dI/dSor dL/dI 3: ( )( )25.04.75% % or ( 3)% or ( 3)100xxxR FEFE=(36) % dI/dSor dL/dI 4: ( )( )25.04.75% % or ( 4)% or ( 4)100xxxR FEFE=(37) 2018 by the American Association of State Highway and Transportation Officials. All rights rese
27、rved. Duplication is a violation of applicable law.TS-1c R 91-7 AASHTO % dI/dSor dL/dI 5: ( )( )25.04.75% % or ( 5)% or ( 5)100xxxR FEFE=(38) 7. CALCULATIONSMULTIPLE-SOURCE BLEND 7.1. Use the calculations in this section to estimate the shape characteristics of multiple-material source blends. Each
28、source must be sampled and characterized according to Section 6 calculations. 7.2. Determine blend composition percentages: %ASn= percent aggregate source n (39) 1% 100niiAS=where: n = number of aggregate sources. 7.3. Calculate blend surface area: Blend total surface area (each sieve): 37.5Blend _1
29、 0.075%100ni ixxixAS SSASSA= =(40) where: x = 0.075 to 25.0 mm, and n = number of aggregate sources. Total surface area blend (all sieves x = 0.075 to 25.0 mm) 25.0Blend Blend _0.075xxTSA SSA=(41) Coarse surface area blend (sieve x = 4.75 to 25.0): 25.0Blend Blend _4.75xxCSA SSA=(42) Fine surface ar
30、ea blend (sieve x =0.075 to 2.36): 2.36Blend Blend _0.075xxFSA SSA=(43) 7.4. Calculate number of particles per blend unit mass for each sieve size: 25.0Blend _1 0.075%#100ni ixxixAS PP= =(44) 7.5. Calculate number of particles per blend unit mass: Total particle count blend: 2018 by the American Ass
31、ociation of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 91-8 AASHTO 25.0Blend Blend _0.075#xxTP P=(45) # Coarse particles blend: 25.0Blend Blend _4.75#xxCP P=(46) # Fine particles blend: 2.36Blend Blend _0.075#xxFP P=(47) 7.6.
32、 Calculate blend gradient angularity for each size x = 0.075 to 25.0 mm and combined (weighted by surface area): Blend _Blend _1%1100ii ix ixxxiAS SSA GAGASSA=(48) Blend fine gradient angularity: 2.36Blend Blend _ Blend _Blend0.0751xxxFGA SSA GAFSA= (49) Blend coarse gradient angularity: 25.0Blend B
33、lend _ Blend _Blend4.751xxxCGA SSA GACSA= (50) Blend overall gradient angularity: 25.0Blend Blend _ Blend _Blend0.0751xxxGA SSA GATSA= (51) 7.7. Calculate blend fine aggregate Form 2D for each sieve size x = 0.075 to 2.36 mm and combined (weighted by surface area): Blend _Blend _ 1%21Form 2D100ni ix
34、 ixxx iAS SSA DSSA=(52) Blend Form 2D: 2.36Blend Blend _ Blend _Blend 0.0751Form 2D 2xxxSSA DFSA=(53) 7.8. Calculate blend texture for each sieve size x = 4.75 to 25.0 mm and combined (weighted by coarse aggregate surface area): Blend _Blend _1%1100ni ix ixxxiAS SSA TXTXSSA=(54) Blend texture: 2018
35、by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 91-9 AASHTO 25.0Blend Blend _ Blend _Blend4.751xxxTX SSA TXCSA= (55) 7.9. Calculate average blend sphericity for each sieve size x = 4.75 to 25.0 mm an
36、d blend (weighted by coarse particle count): Blend _Blend _ 1%#1# 100ni ix ixxx iAS P SPSPP=(56) Blend sphericity: 25.0Blend Blend _ Blend _Blend4.751#xxxSP P SPCP= (57) 7.10. Calculate blend sphericity distribution for each sieve size x = 4.75 to 25.0 mm and blend (weighted by coarse particle count
37、): Percent of particles with sphericity 0.3 (Blend): Blend _Blend _1% # (0.3)1(0.3)100#ni ix ixxxiAS P SPSPP=(58) 25.0Blend Blend _ Blend _Blend4.751(0.3) # (0.3)#xxxSP P SPCP= (59) Percent of particles with sphericity 0.3 2 (Blend): Blend _21% % % / ( 2)% / ( 2)100ni ix ixxiAS R L SLS= (66) 25.0Ble
38、nd Blend _4.75% / ( 2) % / ( 2)xxLS LS= (67) % dL/dS 3 (Blend): Blend _21% % % / ( 3)% / ( 3)100ni ix ixxiAS R L SLS= =(68) 25.0Blend Blend _4.75% / ( 3) % / ( 3)xxLS LS= (69) % dL/dS 4 (Blend): Blend _21% % % / ( 4)% / ( 4)100ni ix ixxiAS R L SLS= =(70) 25.0Blend Blend _4.75% / ( 4) % / ( 4)xxLS LS
39、= (71) % dL/dS 5 (Blend): Blend _21% % % / ( 5)% / ( 5)100ni ix ixxiAS R L SLS= =(72) 37.5Blend Blend _4.75% / ( 5) % / ( 5)xxLS LS= (73) 7.12. Calculate flat or elongated values for each sieve size x = 4.75 to 25.0 mm and blend (weighted by mass fraction): % dI/dSor dL/dI 1 (Blend): ( )( )Blend _ 2
40、1% % % or ( 1)% or ( 1)100ni ix ixxiAS R F EFE= =(74) ( ) ( )25.0Blend Blend _4.75% or ( 1) % or ( 1)xxFE FE= (75)% dI/dSor dL/dI 2 (Blend): ( )( )Blend _ 21% % or ( 2)% or ( 2)100ni ix ixxiAS R F EFE= =(76) 2018 by the American Association of State Highway and Transportation Officials. All rights r
41、eserved. Duplication is a violation of applicable law.TS-1c R 91-11 AASHTO ( ) ( )25.0Blend Blend _4.75% or ( 2) % or ( 2)xxFE FE= (77)% dI/dSor dL/dI 3 (Blend): ( )( )Blend _21% % % or ( 3)% or ( 3)100ni ix ixxiAS R F EFE= =(78) ( ) ( )25.0Blend Blend _4.75% or ( 3) % or ( 3)xxFE FE= (79)% dI/dSor
42、dL/dI 4 (Blend): ( )( )Blend _21% % % or ( 4)% or ( 4)100ii ix ixxiAS R F EFE= =(80) ( ) ( )25.0Blend Blend _4.75% or ( 4) % or ( 4)xxFE FE= (81)% dI/dSor dL/dI 5 (Blend): ( )( )Blend _21% % % or ( 5)% or ( 5)100ni ix ixxiAS R F EFE= =(82) ( ) ( )25.0Blend Blend _4.75% or ( 5) % or ( 5)xxFE FE= (83)
43、 8. REPORT 8.1. Report the following information: 8.1.1. Project name; 8.1.2. Date of the analysis; 8.1.3. Material sample identifications: type, source, size, gradation; 8.1.4. Number of particles analyzed for each size; and 8.1.5. Material shape property mean and standard deviation. Graphical repr
44、esentations of the property distributions may be included. 8.2. A sample report format is presented in Appendix X1. 9. PRECISION AND BIAS 9.1. PrecisionThis practice uses data generated from other testing methods to generate cumulative information; therefore, the precision of the values generated in
45、 this practice are established by the precision of the standards used to collect the raw data. 9.2. BiasThe research required to determine the bias of this procedure has not been conducted. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplicati
46、on is a violation of applicable law.TS-1c R 91-12 AASHTO 10. KEYWORDS 10.1. Aggregate; angularity; consensus property; elongation; form; shape; texture. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.T
47、S-1c R 91-13 AASHTO APPENDIX (Nonmandatory Information) X1. SAMPLE REPORT 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 91-14 AASHTO AIMS Stockpile Summary Project Name: 41_Granite_1 Date: 2/5/09 Workbook: 41_Granite_AIMS_Stockpile_v3.6.xlsm Technician: mjg Description: Combined Properties (weighted) Flat and Elongated Ratio (Coarse) Flat and Elongated Ratio (Coarse) 2D Form (Fine) 7.95 Sphericity (Coarse) % % Cum % Angularity (Coarse & Fine) 3457.5 Low (0.3) 0.0% L/S 1:1 65.0%
