1、Standard Method of Test for Particle Size Analysis of Hydraulic Cement and Related Materials by Light Scattering AASHTO Designation: T 353-141American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3a T 353-1 AASHTO Standa
2、rd Method of Test for Particle Size Analysis of Hydraulic Cement and Related Materials by Light Scattering AASHTO Designation: T 353-1411. SCOPE 1.1. This test method covers the determination of the particle size distribution (PSD) of hydraulic cement and related compounds by means of the laser diff
3、raction technique, reported as volume percent of particulate materials.2This test method applies to analyses with both nonaqueous and gaseous dispersions. This test method is applicable to the measurement of particulate materials in the size range of 0.4 to 2000 m. 1.2. The values stated in SI units
4、 are to be regarded as the standard. 1.3. 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 standard to consult and establish appropriate
5、 safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. ASTM Standards: B822, Standard Test Method for Particle Size Distribution of Metal Powders and Related Compounds by Light Scattering C115/C115M, Standard Test Method for
6、Fineness of Portland Cement by the Turbidimeter C204, Standard Test Methods for Fineness of Hydraulic Cement by Air-Permeability Apparatus C219, Standard Terminology Relating to Hydraulic Cement C430, Standard Test Method for Fineness of Hydraulic Cement by the 45-m (No. 325) Sieve E1458, Standard T
7、est Method for Calibration Verification of Laser Diffraction Particle Sizing Instruments Using Photomask Reticles E1617, Standard Practice for Reporting Particle Size Characterization Data 2.2. ISO Standards: ISO 13320:2009, Particle Size AnalysisLaser Diffraction MethodsPart 1: General Principles I
8、SO 14887:2000, Sample PreparationDispersing Procedures for Powders in Liquids 2.3. Other Documents: Ferraris, C. F., V. A. Hackley, A. I. Avils, and C. E. Buchanan, Jr. Analysis of the ASTM Round-Robin Test on Particle Size Distribution of Portland Cement: Phase I. NISTIR 6883. National Institute of
9、 Standards and Technology, Gaithersburg, MD, May 2002. (http:/fire.nist.gov/bfrlpubs/build02/PDF/b02015.pdf). 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 353-2 AASHTO Ferraris, C. F., V. A. H
10、ackley, A. I. Avils, and C. E. Buchanan, Jr. Analysis of the ASTM Round-Robin Test on Particle Size Distribution of Portland Cement: Phase II. NISTIR 6931. National Institute of Standards and Technology, Gaithersburg, MD, December 2002. (http:/fire.nist.gov/bfrlpubs/build02/PDF/b02084.pdf) Ferraris,
11、 C. F., V. A. Hackley, and A. I. Avils. “Measurement of Particle Size Distribution in Portland Cement Powder: Analysis of ASTM Round Robin Studies,” Cement, Concrete and Aggregates Journal, Vol. 26, No. 2. ASTM International, West Conshohocken, PA, 2004, pp. 7181. (http:/www.astm.org/DIGITAL_LIBRARY
12、/JOURNALS/CEMENT/PAGES/CCA11920.htm) Ferraris, C. F., W. Guthrie, A. I. Avils, M. Peltz, R. Haupt, and B. S. MacDonald. Certification of SRM 114q: Phase II (Particle Size Distribution). NIST SP 260-166. National Institute of Standards and Technology, Gaithersburg, MD, November 2006. (http:/www.nist.
13、gov/srm/upload/SP260-166.pdf) 3. TERMINOLOGY 3.1. For general terms or for definitions related to cement, refer to ASTM C219. 3.2. Definitions for Terms Specific to This Standard: 3.2.1. laser diffractiona method for determining the particle size distribution based on the detection and analysis of t
14、he angular distribution of scattered light, produced by a laser, passing through a dilute dispersion of particles. 3.2.2. backgroundextraneous scattering of light by elements other than the particles to be measured; includes scattering by contamination in the measurement path. 3.2.3. Fraunhofer diff
15、ractionthe optical theory that describes the low-angle scattering of light by particles that are large compared with the wavelength of the incident light. 3.2.4. Mie theorythe electromagnetic theory that describes the scattering of light by spherical particles. 3.2.5. multiple scatteringthe rescatte
16、ring of light by a particle in the path of light scattered by another particle; typically occurs in dispersions with high particle concentrations. 3.2.6. wet methodthe particles are dispersed in isopropyl alcohol, then recirculated through the path of the light beam. 3.2.7. dry methodthe particles a
17、re dispersed in air, and then passed through the path of the light beam. 3.2.8. d10, d50, and d90particle size values corresponding to a cumulative distribution at 10, 50, and 90 percent, respectively. 3.2.9. spanthe width of the differential particle size distribution, calculated using the followin
18、g formula: ( )90 1050spanddd= (1) 4. SUMMARY OF METHOD 4.1. The method consists in dispersing the cement particles in a medium (wet or dry) and passing through a laser beam. The wet method involves a sample of cement powder dispersed in isopropyl 2016 by the American Association of State Highway and
19、 Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 353-3 AASHTO alcohol (IPA) and recirculated through the path of the light beam. A dry sample can be pushed under air pressure or pulled under vacuum so that it flows through the light beam. Photodetec
20、tor arrays collect the light scattered by the particles, which is then converted to electrical signals and analyzed by a computer to calculate the particle size distribution (PSD) using an optical model based on Fraunhofer diffraction or Mie scattering. Calculated particle sizes are therefore presen
21、ted as equivalent spherical diameters. Additional information pertaining to the general principles of PSD analysis by light scattering can be found in ISO Standard 13320 or in the publications by Ferraris et al. (See Section 2.3.) 5. SIGNIFICANCE AND USE 5.1. Accurate measurement of the PSD of cemen
22、t powder is a beneficial tool for process monitoring in the cement industry. In addition, the PSD is a key factor in ongoing computational efforts to simulate microstructure development and predict the performance of cement-based materials. 5.2. The laser diffraction method is capable of measuring p
23、owders with a size distribution ranging from 0.4 to 2000 m, covering the full size range in hydraulic cement. The limitation of this test method is that it is not a direct measurement of particle size. To calculate the PSD, some assumptions must be made: (1) the particles are spherical, and (2) the
24、refractive indices of the particles and of the medium are known (needed for the Mie model only). Also, to correctly measure the particles, the powder must be dispersed so that individual particles, and not agglomerates of particles, will scatter light independently. 5.2.1. It is important to recogni
25、ze that the results obtained by this test method may disagree with the results obtained from other methods for particle size determination using different physical principles. The results are influenced strongly by the physical principles employed by each method of particle size analysis. The result
26、s of any indirect particle sizing method should not be regarded as absolute when comparing with results obtained by other methods. 5.2.2. A key aspect of the procedure is to ensure dispersion of the cement particles. To verify the adequacy of the procedure that is used, the PSD of a sample of Standa
27、rd Reference Material (SRM) 114 is measured, and the resulting PSD is compared with the reference PSD. Lack of agreement means that the procedure for dispersing the cement sample needs to be modified or the instrument is not functioning properly. 6. INTERFERENCES 6.1. Air bubbles entrained in the ci
28、rculating fluid will scatter light and be reported as particles. Circulating fluids shall be bubble-free upon visual inspection. Elimination of the bubbles may require degassing or could also be achieved by allowing time (20 min could be sufficient) for any formed bubble to dissipate and by reducing
29、 the intensity of the circulating method used (ultrasound or stirrer). The presence of air bubbles can be detected by the presence of two peaks in the PSD, with the second peak being at about 1500 m or higher. 6.2. In most devices using a fluid, there is the option of dispersing the particles by app
30、lying an ultrasound vibration to the suspension. This method is highly effective in dispersing the particles, but it could also increase the temperature of the medium. Therefore, after satisfactory dispersion is achieved, the suspension should be allowed to regain an equilibrium temperature. Typical
31、ly a wait of about 10 to 15 min is enough. 6.3. Contaminants, such as particles or foreign substances dispersed in IPA, scatter light and thus are reported as part of the PSD. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violati
32、on of applicable law.TS-3a T 353-4 AASHTO 6.4. The presence of oil, water, or foreign substances in air will cause clogging or agglomeration in dry dispersal that will bias the particle size results. The air supplied shall be free of such substances. 6.5. Agglomeration or settling of particles durin
33、g analysis will cause erroneous results. Dispersions shall be prepared in accordance with the instrument manufacturers instructions, and a stable dispersion shall be maintained throughout the analysis. A sufficient flow rate for wet dispersions shall be maintained during the analysis to prevent sett
34、ling of large particles. 6.6. A low concentration of particles in the dispersion may result in poor data repeatability. A high concentration of particles in the dispersion may cause excessive light attenuation and multiple scattering, resulting in an erroneous PSD. Follow the instrument manufacturer
35、s instructions in determining the correct light attenuation level. 7. APPARATUS 7.1. Particle Size AnalyzerBased on Fraunhofer diffraction or Mie scattering, or a combination of both models. Use care to ensure the analyzer system or its subsystems are appropriate for the size range of hydraulic ceme
36、nt or related compounds. 7.2. Liquid or Air Sample Handling SystemTo transport the dispersed test specimen across the light beam. 7.3. IPAIsopropyl alcohol, reagent grade, to be used with the wet method. 7.4. Fine SandAs recommended by the manufacturer to clean the instrument after a measurement usi
37、ng the dry method. 7.5. SRM 114Current reference cement is available from the National Institute of Standards and Technology (NIST).3A letter indicating the lot numbers follows the number 114. This material is provided with a certificate including a reference PSD. This reference PSD is obtained by s
38、tatistical analysis of test results from an ASTM-sponsored round robin (see Section 2.3) for SRM 114P and from NIST-sponsored round robins for subsequent reference materials (see Section 2.3). 8. SAMPLING 8.1. Obtain a representative specimen of hydraulic cement (see Note 1). The amount needed for t
39、he wet method is less than 1 g and for the dry method is about 3 to 4 g. The exact amount depends on the loading method adopted. Note 1The operator needs to ensure fines are not lost. It is suggested that samples should be homogenized in closed vessels, and settled layers should be gently recombined
40、 before extracting the final samples. 8.2. For the wet method, disperse the specimen either in the device or external to the device. Follow the manufacturers recommendations to determine the most appropriate method. 8.3. For the dry method, load the specimen directly on the device feeder. 9. CALIBRA
41、TION AND STANDARDIZATION 9.1. Verify proper operation of the instrument using ASTM E1458 or the manufacturers calibration procedure. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 353-5 AASHTO 9
42、.2. Hydraulic cement SRM 114 is intended to be used as a reference material. The use of SRM 114 will not permit direct calibration of the instrument (i.e., an instrument correction factor should not be calculated). The scope of the SRM 114 is to provide the means to the operator to develop an approp
43、riate procedure for measuring PSD by optimizing the parameters of the instrument. To use SRM 114, conduct a test using a method as described in Section 10. To use these uncertainties to assess agreement with other laboratories, the user should compute the absolute difference in cumulative volume fra
44、ction between his or her results and the certified values for SRM 114q for each particle size. These differences should then be compared to the appropriate expanded uncertainties in columns 3 or 4 of Table 5 in Appendix A of the SRM 114q certificate to determine conformance. If the observed absolute
45、 difference between the users results and the certified values for SRM 114q is always less than the corresponding expanded uncertainty, the user can conclude that his or her results are in agreement with other laboratories with a confidence level of approximately 95 percent. If one or more of the ob
46、served absolute differences is larger than the corresponding expanded uncertainty, this is evidence that the users results are not in agreement with the results of other laboratories and changes to the measurement procedures are needed. (See Note 2.) Note 2For more details on this methodology, see t
47、he reference Certification of SRM 114q: Phase II (Particle Size Distribution) Ferraris et al. (2006) listed in Section 2.3. 10. PROCEDURE 10.1. Install the desired sample delivery system and select the applicable instrument range, as indicated by the manufacturers instructions. 10.2. Allow the instr
48、ument to warm up for at least 20 min. 10.3. If necessary, establish the correct optical alignment according to the requirements of the manufacturer (see Note 3). Note 3It is advisable that optical alignment be checked upon startup, whenever the sample delivery system is changed, and frequently there
49、after. 10.4. Measure the background in the mode in which the analysis will be conducted. Ensure the carrier (air or IPA) is flowing through the light path while measuring background. Background values shall not exceed the specifications of the manufacturer. If the background values exceed the manufacturers specifications, perform the necessary procedures as specified by the manufacturer to bring the background values within acceptable limits. 10.5. Extract a test portion from the cement sample. Refer to the manufactu
