1、Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete AASHTO Designation: M 295-11 (2015) ASTM Designation: C618-12a American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3b M 2
2、95-1 AASHTO Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete AASHTO Designation: M 295-11 (2015) ASTM Designation: C618-12a 1. SCOPE 1.1. This specification covers coal fly ash and raw or calcined natural pozzolan for use in concrete where cementitious
3、 or pozzolanic action, or both, is desired or where other properties normally attributed to finely divided coal fly ash and raw or calcined natural pozzolans may be desired or where both objectives are to be achieved. Note 1Finely divided materials may tend to reduce the entrained air content of con
4、crete. Hence, if a fly ash or natural pozzolan is added to any concrete for which entrainment of air is specified, provision should be made to ensure that the specified air content is maintained by air content tests and by use of additional air-entraining admixture or use of an air-entraining admixt
5、ure in combination with air-entraining hydraulic cement. 1.2. The values stated in SI units are to be regarded as the standard. 2. REFERENCED DOCUMENTS 2.1. ASTM Standards: C125, Standard Terminology Relating to Concrete and Concrete Aggregates C311/C311M, Standard Test Methods for Sampling and Test
6、ing Fly Ash or Natural Pozzolans for Use in Portland-Cement Concrete 3. TERMINOLOGY 3.1. Definitions: 3.1.1. The terms used in this specification are defined in ASTM C125. 3.1.2. fly ashfinely divided residue that results from the combustion of ground or powdered coal and that is transported by flue
7、 gasses. Note 2This definition of fly ash does not include, among other things, the residue resulting from: (1) the burning of municipal garbage or any other refuse with coal; (2) the injection of lime directly into the boiler for sulfur removal; or (3) the burning of industrial or municipal garbage
8、 in incinerators commonly known as “incinerator ash.” 4. CLASSIFICATION 4.1. Class NRaw or calcined natural pozzolans that comply with the applicable requirements for the class as given herein, such as some diatomaceous earths; opaline cherts and shales; tuffs and 2016 by the American Association of
9、 State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b M 295-2 AASHTO volcanic ashes or pumicites, calcined or uncalcined; and various materials requiring calcination to induce satisfactory properties, such as some clays and shales. 4.2. C
10、lass FFly ash that meets the applicable requirements for this class as given herein. This class fly ash has pozzolanic properties. 4.3. Class CFly ash that meets the applicable requirements for this class as given herein. This class of fly ash, in addition to having pozzolanic properties, also has s
11、ome cementitious properties. Note 3Class F fly ash is typically produced from burning anthracite or bituminous coal but may also be produced from sub-bituminous coal and from lignite. Class C fly ash is typically produced from burning lignite or sub-bituminous coal and may also be produced by anthra
12、cite or bituminous coal. Class C fly ashes contain total calcium contents, expressed as calcium oxide (CaO), higher than 10 percent. 5. ORDERING INFORMATION 5.1. The purchaser shall specify any supplementary optional chemical and physical requirements. 5.2. The purchaser shall indicate which procedu
13、re, A or B, shall be used when specifying requirements for effectiveness in contribution to sulfate resistance under Table 4. 6. CHEMICAL COMPOSITION 6.1. Fly ash and natural pozzolans shall conform to the requirements as to chemical composition prescribed in Table 1. Table 1Chemical Requirements Co
14、al Fly Ash and Raw or Calcined Natural Pozzolan Class N F C Silicon dioxide (SiO2) plus aluminum oxide (A12O3) plus iron oxide (Fe2O3), min percent 70.0 70.0 50.0 Sulfur trioxide (SO3), max percent 4.0 5.0 5.0 Moisture content, max percent 3.0 3.0 3.0 Loss on ignition, max percent 5.0 5.0 5.0 Table
15、2Supplementary Optional Chemical Requirement Coal Fly Ash and Raw or Calcined Natural Pozzolan Class N F C Available alkalies, or equivalent, as Na2O, max percenta1.5 1.5 1.5 aApplicable only when specifically required by the purchaser for mineral admixture to be used in concrete containing reactive
16、 aggregate and cement to meet a limitation on content of alkalies. Note 4The chemical component determinations and the limits placed on each do not predict the performance of the fly ash or natural pozzolan with hydraulic cement in concrete but collectively help describe composition and uniformity o
17、f the material. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b M 295-3 AASHTO 7. PHYSICAL PROPERTIES 7.1. Fly ash and natural pozzolans shall conform to the physical requirements prescribed in Tab
18、le 3. Supplementary optional physical requirements are shown in Table 4. Table 3Physical Requirements Coal Fly Ash and Raw or Calcined Natural Pozzolan Class N F C Fineness: Amount retained when wet-sieved on 45-m (No. 325) sieve, max percenta34 34 34 Strength activity index:bWith portland cement, a
19、t 7 days, min percent of control 75c75c75cWith portland cement, at 28 or 56ddays, min percent of control 75c75c75cWater requirement, max percent of control 115 105 105 Soundness:eAutoclave expansion or contraction, max percent 0.8 0.8 0.8 Uniformity requirements: The density and fineness of individu
20、al samples shall not vary from the average established by the 10 preceding tests, or by all preceding tests if the number is less than 10, by more than: Density, max variation from average, percent 5 5 5 Percent retained on 45-m (No. 325) sieve, max variation, percentage points from average 5 5 5 aC
21、are should be taken to avoid the retaining of agglomerations of extremely fine material. bThe strength activity index with portland cement is not to be considered a measure of the compressive strength of concrete containing the coal fly ash and raw or calcined natural pozzolan. The strength activity
22、 index with portland cement is determined by an accelerated test and is intended to evaluate the contribution to be expected from the coal fly ash and raw or calcined natural pozzolan to the longer strength development of concrete. The mass of coal fly ash and raw or calcined natural pozzolan specif
23、ied for the test to determine the strength activity index with portland cement is not considered to be the proportion recommended for the concrete to be used in the work. The optimum amount of coal fly ash and raw or calcined natural pozzolan for any specific project is determined by the required pr
24、operties of the concrete and other constituents of the concrete and should be established by testing. Strength activity index with portland cement is a measure of reactivity with a given cement and is subject to variation depending on the source of both the coal fly ash and raw or calcined natural p
25、ozzolan and the cement. cMeeting the 7-day, 28-day, or 56-day (if specified) strength activity index will indicate specification compliance. dOnly applicable when testing at 56 days is specified. eIf the coal fly ash and raw or calcined natural pozzolan will constitute more than 20 percent by mass o
26、f the cementitious material in the project mix design, the test specimens for autoclave expansion shall contain that anticipated percentage. Excessive autoclave expansion is highly significant in cases where water to coal fly ash and raw or calcined natural pozzolan and cement ratios are low, for ex
27、ample, in block or shotcrete mixes. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b M 295-4 AASHTO Table 4Supplementary Optional Physical Requirements Coal Fly Ash and Raw or Calcined Natural Pozzo
28、lan Class N F C Increase of drying shrinkage of mortar bars at 28 days, max difference in percent over controla0.03 0.03 0.03 Uniformity requirements: In addition, when air-entrained concrete is specified, the quantity of air-entraining agent required to produce an air content of 18.0 vol percent of
29、 mortar shall not vary from the average established by the 10 preceding tests or by all preceding tests if less than 10, by more than, percent 20 20 20 Effectiveness in controlling alkali-silica reaction:bExpansion of test mixture as percentage of low-alkali cement control, at 14 days, max percent 1
30、00 100 100 Effectiveness in contributing to sulfate resistance:cProcedure A: Expansion of test mixture: For moderate sulfate exposure after 6 months of exposure, max percent 0.10 0.10 0.10 For high sulfate exposure after 6 months of exposure, max percent 0.05 0.05 0.05 Procedure B: Expansion of test
31、 mixture as a percentage of sulfate resistance cement control after at least 6 months of exposure, max percent 100 100 100 aDetermination of compliance or noncompliance with the requirement relating to increase in drying shrinkage will be made only at the request of the owner. bCoal fly ash and raw
32、or calcined natural pozzolans meeting this requirement are considered as effective in controlling alkali aggregate reactions as the use of the low-alkali control cement used in the evaluation. However, the coal fly ash and raw or calcined natural pozzolan shall be considered effective only when the
33、coal fly ash and raw or calcined natural pozzolan are used at percentages by mass of the total cementitious material equal to or exceeding that used in the tests and when the alkali content of the cement to be used with the coal fly ash and raw or calcined natural pozzolan does not exceed that used
34、in the tests by more than 0.05 percent. See Appendix X1, ASTM C311/C311M. cFly ash or natural pozzolan shall be considered effective only when the fly ash or natural pozzolan is used at percentages, by mass, of the total cementitious material within 2 percent of those that are successful in the test
35、 mixtures or between 2 percentages that are successful, and when the C3A content of the project cement is less than or equal to that which was used in the test mixtures. See Appendix X2 of ASTM C311/C311M. Note: These optional requirements apply only when specifically requested. 8. METHODS OF SAMPLI
36、NG AND TESTING 8.1. Sample and test the coal fly ash and raw or calcined natural pozzolan in accordance with the requirements of ASTM C311/C311M. 8.2. Use cement of the type proposed for use in the work and, if available, from the mill proposed as the source of the cement, in all tests requiring the
37、 use of hydraulic cement. 9. STORAGE AND INSPECTION 9.1. The coal fly ash and raw or calcined natural pozzolan shall be stored in such a manner as to permit easy access for proper inspection and identification of each shipment. 9.2. Inspection of the material shall be made as agreed upon by the purc
38、haser and the seller as part of the purchaser contract. 10. REJECTION 10.1. Material that fails to conform to the requirements of this specification may be rejected. Rejection should be reported to the producer or supplier promptly and in writing. 2016 by the American Association of State Highway an
39、d Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b M 295-5 AASHTO 10.2. Packages varying more than 5 percent from the stated mass may be rejected. If the average mass of the packages in any shipment, as shown by determining the mass of 50 packages take
40、n at random, is less than that specified, the entire shipment may be rejected. 10.3. Any coal fly ash and raw or calcined natural pozzolan in storage prior to shipment for a period longer than 180 days after testing may be retested and may be rejected if it fails to meet the fineness requirements. 1
41、1. PACKAGING AND PACKAGE MARKING 11.1. When the fly ash or natural pozzolan is delivered in packages, the class, name, and brand of the producer and the mass of the material contained therein shall be plainly marked on each package. Similar information shall be provided in the shipping invoices accompanying the shipment of packaged or bulk material. 12. KEYWORDS 12.1. Coal fly ash; raw or calcined natural pozzolan; pozzolans. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
