1、Standard Specification for Silica Fume Used in Cementitious Mixtures AASHTO Designation: M 307-13 ASTM Designation: C1240-11 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3b M 307-1 AASHTO Standard Specification
2、for Silica Fume Used in Cementitious Mixtures AASHTO Designation: M 307-13 ASTM Designation: C1240-11 1. SCOPE 1.1. This specification covers silica fume for use in concrete and other systems containing hydraulic cement. 1.2. In the cases of slurried or densified silica fume, perform the tests on th
3、e raw silica fume from which these products have been made. 1.3. The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4. The following safety hazards caveat pertains only to the test methods portions, Section 10, of this specif
4、ication: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. Read t
5、he material safety data sheets for materials used. 1.5. The text of this standard references notes and footnotes that provide explanatory information. These notes and footnotes (excluding those in tables) shall not be considered as requirements of this standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO S
6、tandards: M 194M/M 194, Chemical Admixtures for Concrete R 71, Sampling and Amount of Testing of Hydraulic Cement T 105, Chemical Analysis of Hydraulic Cement T 106M/T 106, Compressive Strength of Hydraulic Cement Mortar (Using 50-mm or 2-in. Cube Specimens) T 137, Air Content of Hydraulic Cement Mo
7、rtar T 192, Fineness of Hydraulic Cement by the 45-m (No. 325) Sieve 2.2. ASTM Standards: C125, Standard Terminology Relating to Concrete and Concrete Aggregates C135, Standard Test Method for True Specific Gravity of Refractory Materials by Water Immersion C219, Standard Terminology Relating to Hyd
8、raulic Cement C311/C311M, Standard Test Methods for Sampling and Testing Fly Ash or Natural Pozzolans for Use in Portland-Cement Concrete 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b M 307-2 AAS
9、HTO C441/C 441M, Standard Test Method for Effectiveness of Pozzolans or Ground Blast-Furnace Slag in Preventing Excessive Expansion of Concrete Due to the Alkali-Silica Reaction C604, Standard Test Method for True Specific Gravity of Refractory Materials by Gas-Comparison Pycnometer C670, Standard P
10、ractice for Preparing Precision and Bias Statements for Test Methods for Construction Materials C1005, Standard Specification for Reference Masses and Devices for Determining Mass and Volume for Use in the Physical Testing of Hydraulic Cements C1012/C1012M, Standard Test Method for Length Change of
11、Hydraulic-Cement Mortars Exposed to a Sulfate Solution C1069, Standard Test Method for Specific Surface Area of Alumina or Quartz by Nitrogen Adsorption C1157/C1157M, Standard Performance Specification for Hydraulic Cement C1437, Standard Test Method for Flow of Hydraulic Cement Mortar 3. TERMINOLOG
12、Y 3.1. Definitions: 3.1.1. silica fumea very fine pozzolanic material, composed mostly of amorphous silica produced by electric arc furnaces as a by-product of the production of elemental silicon or ferro-silicon alloys (also known as condensed silica fume and microsilica). 3.1.2. silica fume, densi
13、fiedsilica fume processed to increase bulk density to facilitate handling and shipping. 3.1.3. silica fume, undensifiedsilica fume in its raw, as produced or as collected, unprocessed form. 3.1.4. Other terms in this specification are defined in ASTM C125 and C219. 4. ORDERING INFORMATION 4.1. The p
14、urchaser shall specify any optional chemical or physical requirements. 5. CHEMICAL REQUIREMENTS 5.1. Silica fume shall conform to the requirements for chemical composition prescribed in Table 1. Table 1Chemical Requirements Silicon dioxide (SiO2), min percent 85.0 Moisture content, max percent 3.0 L
15、oss on ignition, max percent 6.0 6. PHYSICAL REQUIREMENTS 6.1. Silica fume shall conform to the physical requirements prescribed in Table 2. Optional physical requirements are shown in Table 3. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplic
16、ation is a violation of applicable law.TS-3b M 307-3 AASHTO Table 2Physical Requirements Oversize Percent retained on 45-m (No. 325) sieve, max percenta10 Percent retained on 45-m (No. 325) sieve, max variation from average, percentage pointsb5 Accelerated pozzolanic strength activity index:cWith po
17、rtland cement at 7 days, min percent of control 105 Specific surface, min, m2/g 15 aExercise care to avoid retaining agglomerations of extremely fine material. bThe average shall consist of the ten preceding tests or all of the preceding tests if the number is less than 10. cAccelerated pozzolanic s
18、trength activity index is not to be considered a measure of the compressive strength of concrete containing the silica fume. This is a measure of the reactivity of a given silica fume with a given cement and may vary with the source of both the silica fume and the cement. Table 3Optional Physical Re
19、quirementsaUniformity requirements When air-entraining concrete is specified, the quantity of air-entraining agent required to produce an air content volume of 18 percent of the mortar shall not vary from the average established by the 10 preceding tests, or by all preceding tests if less than 10, p
20、ercent 20 Reactivity with cement alkalies:bReduction of mortar expansion at 14 days, min, percenta80 Sulfate resistance expansion:c(moderate resistance) 6 months, max, percent 0.10 (high resistance) 6 months, max, percent 0.05 (very high resistance) one year, max, percent 0.05 aOptional physical req
21、uirements will be made only at the request of the purchaser. bThe indicated tests for reactivity with cement alkalies should not be requested unless the material is to be used with an aggregate that is regarded as deleteriously reactive with alkalies in hydraulic cement. The test for reduction of mo
22、rtar expansion may be made using any high-alkali cement in accordance with ASTM C311/C311M if the cement to be used in the work is not known or is not available at the time of the test. The test for mortar expansion should be performed by each of the high-alkali cements to be used in the work. cOnly
23、 one limit shall be specified. 7. SAMPLING 7.1. When the purchaser desires that the silica fume be sampled and tested to verify compliance with this specification, perform the sampling and testing in accordance with R 71, modified as described in Section 7.3. Note 1Exercise caution in the interpreta
24、tion of R 71 because there is a difference between the continuous manufacture of hydraulic cement and the generation and collection of silica fume. To a great extent, storage is dictated by the design of the silica fume collection system. The design of silica fume collection systems may not have pro
25、vided for sampling points and practices. 7.2. R 71, as modified, is not designed for manufacturing quality control and is not required for manufacturers certification. 7.3. The following modification of R 71 is necessary to render it applicable to silica fume: 7.3.1. Replace the words “hydraulic cem
26、ent” and “cement” with the words “silica fume” every time they appear in the text. 7.3.2. All samples, whether grab or composite, shall have a mass of at least 1 kg (2 lb). 7.3.3. When compliance verification tests of silica fume are required to be made at a laboratory other than that of the silica
27、fume manufacturer or marketer, coordinate the silica fume sampling schedule, sample transportation time, and sample testing schedule among the purchaser, 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.T
28、S-3b M 307-4 AASHTO manufacturer, and testing laboratory so the test results will be available when the decision to accept or reject the silica fume must be made. 7.3.4. The section entitled “Sampling” is modified as follows: 7.3.4.1. Take two grab samples or two composite samples for the first 100
29、Mg (110 tons) of silica fume. Take a grab sample or a composite sample for each subsequent 100 Mg (110 tons) of silica fume, but not less than two samples shall be taken in any sampling program. 7.3.4.2. From Bulk Storage at Points of DischargeWithdraw silica fume from the discharge openings in a st
30、eady stream until sampling is completed. In sampling bulk storage at points of discharge, while the silica fume is flowing through the openings, take samples at such intervals so that, at a minimum, the sampling requirements of Section 7.3.4.1 are met. 7.3.5. The section entitled “Amount of Testing”
31、 is modified by deleting the first paragraph, “General.” 8. FREQUENCY OF TESTS 8.1. Except for the tests listed in Section 8.2, make all chemical determinations and physical tests on composite samples representing no more than 400 Mg (440 tons) each. Prepare each composite sample by combining portio
32、ns from the samples representing each 100 Mg (110 tons) so that each 100 Mg (110 tons) is represented equally. 8.2. Test for specific surface, density, and accelerated pozzolanic strength activity index using composite samples that represent 3200 Mg (3520 tons) or 3 months of production, whichever g
33、ives the highest frequency. Prepare each composite sample by combining portions from the samples representing each 400 Mg (440 tons) or 1 month, whichever gives the highest frequency, so that each sample is represented equally. 9. PREPARATION OF SAMPLE 9.1. Prepare composite samples for tests, as re
34、quired in Section 8, by arranging all test samples in groups, with each group representing the number of megagrams required by the test or tests for which the composite sample is intended. From each of the samples in a group, take equal portions, sufficient in amount to form a composite sample large
35、 enough to permit making the required physical or chemical determinations. 9.2. Prior to testing, mix grab samples and composite samples thoroughly. A clean and dry laboratory concrete drum mixer provides adequate mixing for this purpose. Take care to limit the volume of silica fume in the drum mixe
36、r to the range of 10 to 50 percent of the drums total capacity. If necessary, secure a sheet of polyethylene film on the drum with an elastic tiedown to keep the material in the drum. Limit the mixing action to 5 1 min. 9.2.1. When a small sample size precludes the use of a concrete mixer, use a hea
37、vy plastic bag, of a capacity at least five times larger than the sample volume, to mix the sample thoroughly. After placing the sample in the bag, close the bag by tying the bag opening tightly, and mix the material by rolling the bag around for 5 1 min. 9.3. Take material for specific tests from a
38、 thoroughly mixed sample by using a sampling device (sampling tube, scoop, etc.) of appropriate size to make a test specimen. Make this test specimen from at least six random subsamples. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication i
39、s a violation of applicable law.TS-3b M 307-5 AASHTO TEST METHODSCHEMICAL ANALYSIS 10. SILICON DIOXIDE AND TOTAL ALKALIES 10.1. Reference MethodUse the reference method in T 105 for cements with insoluble residue greater than 1 percent. Analysts performing sodium oxide and potassium oxide determinat
40、ions shall observe the precautions outlined in the applicable section of ASTM C1157/C1157M (refer to the section on Test Methods). Most pozzolans dissolve completely in lithium borate fluxes. 11. MOISTURE CONTENT AND LOSS ON IGNITION 11.1. Follow the applicable provisions of Test Methods ASTM C311/C
41、311M. TEST METHODSPHYSICAL TESTS 12. DENSITY 12.1. Determine density using either ASTM C604 or ASTM C135 modified as follows: 12.1.1. Equipment: 12.1.1.1. Two 500-mL volumetric flasks, Class A; 12.1.1.2. Balance, with an accuracy of at least 0.01 g; 12.1.1.3. Constant temperature bath, capable of be
42、ing regulated within 0.5C (1.0F). 12.1.2. Deionized water: 12.1.3. Procedure: 12.1.3.1. Determine the density of the material as received, unless otherwise specified, as follows. If density determination on an ignited sample is required, first ignite the sample as described in the test for loss on i
43、gnition in the applicable section given in T 105. 12.1.3.2. Determine the mass (Wf) of a 500-mL volumetric flask to an accuracy of 0.01 g. Add 30 g of silica fume. Determine the mass of the flask and the contents (Wa) to the nearest 0.01 g. Add water to the flask to fill it one-half full and shake i
44、t to ensure thorough wetting of the material. Fill to the mark with water. Remove air bubbles by shaking the flask at 15-min intervals until the liquid is free of air or by applying a vacuum to the flask. After all of the air bubbles are removed, place the flask in a constant temperature bath at 23
45、0.5C until the flask and its contents reach a constant temperature. Remove the flask from the water bath; immediately add or remove water, at the same temperature, to the flask to get the meniscus on the mark. Wipe dry the exterior of the flask and determine the mass of the flask and its contents (W
46、s). 12.1.3.3. Empty, clean, and determine the mass of the 500-mL volumetric flask, used above, filled to the mark with water (Wt) stabilized at 23 0.5C. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS
47、-3b M 307-6 AASHTO 12.1.4. Calculation: ( ) 500 mL ( )/afsfs awWWDW WD=(1) where: Dsf= density of silica fume, Mg/m3; Wf= mass of 500-mL volumetric flask, g; Wa= mass of 500-mL volumetric flask plus approximately 30 g of silica fume, g; Ws= mass of 500-mL volumetric flask plus silica fume plus water
48、 to the mark, g; Wt= mass of 500-mL volumetric flask plus water to the mark, g; and Dw= (Wt Wf)/500-mL, Mg/m3. 12.1.5. Report the average of two density determinations and the test method used in determining the density. 13. OVERSIZE, AMOUNT RETAINED WHEN WET-SIEVED ON A 45-M (NO. 325) SIEVE 13.1. U
49、se T 192. Calibrate the sieves in accordance with T 192. Note 2Oversize is used to determine the amount of contaminating material retained on the 45-m (No. 325) sieve. See Appendix X2. 14. SPECIFIC SURFACE 14.1. Determine the specific surface by the Brunauer/Emmett/Teller (BET) nitrogen adsorption method, in accordance with ASTM C1069. Note 3Manufacturers and examples of nitrogen adsorption instrumentation include Horiba Instruments, Inc., Irvine, CA, 5A-9600; Micromeritics Instrument Corporation, Norcross
