1、 CRD-C 662-10 C662Determining the Potential Alkali-Silica Reactivity of Combinations of Cementitious Materials, Lithium Nitrate Admixture and Aggregate (Accelerated Mortar-Bar Method) 1. Scope 1.1 This test method permits detection within 30 days of the potential for deleterious alkali-silica reacti
2、on of combinations of cementitious materials, lithium nitrate admixture and aggregate in mortar bars. The cementitious materials are composed of various proportions of hydraulic cement, pozzolans and ground granulated blastfurnace slag. 1.2 The test results are only valid for the specific combinatio
3、ns of pozzolan, slag, lithium nitrate admixture and reactive aggregates tested. 1.3 This test is not suitable for evaluating the potential for deleterious reaction of combinations of hydraulic cement and aggregate (that is, in the absence of pozzolans, ground granulated blast-furnace slag or lithium
4、 nitrate admixture). 1.4 The values stated in SI units are to be regarded as standard. 1.5 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
5、 and determine the applicability of regulatory limitations prior to use. A specific precautionary statement is given in the section on Reagents. 2. Referenced Documents 2.1 ASTM Standards: C 109/C 109M Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube Specim
6、ens) C 125 Terminology Relating to Concrete and Concreting Aggregates C 150 Specification for Portland Cement C 151 Test Method for Autoclave Expansion of Portland Cement C 305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency C 490 Practice for Use of Appa
7、ratus for the Determination of Length Change of Hardened Cement Paste, Mortar, and Concrete C 494/C 494M Specification for Chemical Admixtures for Concrete C 511 Specification for Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of Hydraulic Cements and Concretes C 618 Specif
8、ication for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Concrete C 670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials C 989 Specification for Ground Granulated Blast-Furnace Slag for Use in Concrete and Mortars
9、 C 1240 Specification for Silica Fume for Use as a Mineral Admixture in Hydraulic-Cement Concrete, Mortar or Grout C 1260 Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method) C 1293 Test Method for Concrete Aggregates by Determination of Length Change of Concrete Due to Alka
10、li-Silica Reaction C 1437 Test Method for Determining Flow of Hydraulic Cement Mortar D 1193 Specification for Reagent Water E 11 Specification for Wire-Cloth and Sieves for Testing Purposes 3. Definitions 3.1 For definitions of terms used in this test method, refer to Terminology ASTM C 125. 4. Sig
11、nificance and Use 4.1 This test method provides a means for evaluating the ability of pozzolans, ground granulated blast-furnace slag, lithium nitrate admixture, and combinations of these, to control deleterious internal expansion due to alkali-silica reaction when used with an aggregate intended fo
12、r use in concrete. It is based on the Accelerated Test Method developed at the National Building Research Institute (NBRI) in the Republic of South Africa (1-4). 4.2 Results obtained using this test method may overestimate the reactivity of some types of aggregates if used in service with the same p
13、ozzolans, slag, lithium admixture and hydraulic cement of low alkali content. First issued Jan 2009 Current revision Jan 2010 1Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CRD-C 662-10 C6624.3 Different levels of pozzolan, ground granulated blast-
14、furnace slag and lithium nitrate admixture may require testing to determine the amount required to reduce expansion to an acceptable level. Pozzolans, ground granulated blast-furnace slag and lithium nitrate admixture may be tested separately or in combination. 4.4 It is recommended to test the same
15、 aggregate and hydraulic cement (without pozzolan, slag or lithium nitrate admixture) using Test Method C 1260. 4.5 This test method may underestimate the expansion of cementitious systems containing pozzolans with an alkali content 4.0 % sodium oxide equivalent (5-8). It is recommended that such ma
16、terials be tested using Test Method C 1293. 4.6 In the case of testing lithium nitrate admixture, this test method is only applicable for testing the admixture in the range from 50% to 150% dose. 5. Apparatus 5.1 The apparatus shall conform to Practice C 490, except as follows: 5.2 SievesSquare hole
17、, woven-wire cloth sieves, shall conform to Specification E 11. 5.3 Mixer, Paddle, and Mixing BowlMixer, paddle, and mixing bowl shall conform to the requirements of Practice C 305, except that the clearance between the lower end of the paddle and the bottom of the bowl shall be 5.1 0.3 mm. 5.4 Tamp
18、er and TrowelThe tamper and trowel shall conform to Test Method C 109/C 109M. 5.5 ContainersThe containers shall be of such a nature that the bars can be totally immersed in either the water or 1N sodium hydroxide (NaOH) solution. The containers shall be made of material that can withstand prolonged
19、 exposure to 80C and must be resistant to a 1N NaOH solution (see Note 1). The containers must be so constructed that when used for storing specimens, the loss or gain of moisture is prevented by tight-fitting covers, by sealing, or both (see Note 2). The bars in the solution must be placed and supp
20、orted so that the solution has access to the entire surface of each bar; therefore, ensure that the specimens do not touch the sides of the container or each other. The specimens, if stood upright in the solution, shall not be supported by the metal gage stud. NOTE 1The NaOH solution corrodes glass
21、or metal containers. NOTE 2Some microwave-proof food storage containers made of polypropylene or high-density polyethylene have been found to be acceptable. 5.6 Oven, or Water BathA convection oven or water bath with temperature control maintaining 80.0 2.0C. 6. Reagents 6.1 Sodium Hydroxide (NaOH)U
22、SP or technical grade may be used, provided the Na+ and OH- concentrations are shown by chemical analysis to lie between 0.99N and 1.01N. 6.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming to Type IV of Specification D 1193. 6.3 Al
23、kaline Soaking SolutionEach liter of alkaline soaking solution shall contain 40.0 g of NaOH dissolved in 800 ml of water. If lithium nitrate admixture is used in the test, add 71 ml of the commercially available admixture multiplied by the decimal equivalent of the lithium nitrate admixture dose. (F
24、or example, to test a 75% lithium admixture dosage, each liter of alkaline soaking solution will contain 0.75 times 71 ml of commercially available lithium nitrate admixture.) This mixture shall be diluted with additional distilled or deionized water to obtain 1.0 liter of solution. The volume propo
25、rtion of soaking solution to mortar bars in a storage container shall be 4 0.5 volumes of solution to 1 volume of mortar bars. The volume of a mortar bar may be taken as 184 ml. Include sufficient test solution to ensure complete immersion of the mortar bars. 6.3.1 WarningBefore using NaOH, review:
26、(1) the safety precautions for using NaOH; (2) first aid for burns; and (3) the emergency response to spills, as described in the manufacturers Material Safety Data Sheet or other reliable safety literature. NaOH can cause very severe burns and injury to unprotected skin and eyes. Suitable personal
27、protective equipment must always be used. These include full-face shields, rubber aprons, and gloves impervious to NaOH. Gloves must be checked periodically for pinholes. 7. Conditioning First issued Jan 2009 Current revision Jan 2010 2Provided by IHSNot for ResaleNo reproduction or networking permi
28、tted without license from IHS-,-,-CRD-C 662-10 C6627.1 Maintain the temperature of the molding room and dry materials at not less than 20C and not more than 27.5C. The temperature of the mixing water, and of the moist closet or moist room, shall not vary from 23C by more than 2C. 7.2 Maintain the re
29、lative humidity of the molding room at not less than 50 %. The moist closet or room shall conform to Specification C 511. 7.3 Maintain the storage oven or water bath in which the specimens are stored at a temperature of 80.0 2.0C. 8. Sampling and Preparation of Test Specimens 8.1 Selection of Aggreg
30、ateProcess materials proposed for use as fine aggregate in concrete as described in 8.2 with a minimum of crushing. Process materials proposed for use as coarse aggregate in concrete by crushing to produce as nearly as practical a graded product from which a sample can be obtained. Grade the sample
31、as prescribed in Table 1. The sample shall represent the composition of the coarse aggregate as proposed for use. 8.1.1 When a given quarried material is proposed for use both as coarse and as fine aggregate, test only a selection of the fine aggregate, unless there is reason to expect that the coar
32、se aggregate has a different composition than the fine aggregate. If such a difference is expected and if the differences might significantly affect expansion due to reaction with the alkalies in cement or from the environment of service, test the coarse aggregate in a manner similar to that employe
33、d in testing the fine aggregate. Table 1 Grading Requirements Sieve Size Mass, % Passing Retained on 4.75 mm (No. 4) 2.36 mm (No. 8) 10 2.36 mm (No. 8) 1.18 mm (No. 16) 25 1.18 mm (No. 16) 600 m (No. 30) 25 600 m (No. 30) 300 m (No. 50) 25 300 m (No. 50) 150 m (No. 100) 15 8.2 Preparation of Aggrega
34、teGrade aggregates to provide a sample meeting the requirements given in Table 1. Crush aggregates in which sufficient quantities of the sizes specified in Table 1 do not exist until the required material has been produced. In the case of aggregates containing insufficient amounts of one or more of
35、the larger sizes listed in Table 1, and if no larger material is available for crushing, the first size in which sufficient material is available shall contain the cumulative percentage of material down to that size as determined from the grading specified in Table 1. When such procedures are requir
36、ed, make a special note thereof in the test report. After the aggregate has been separated into the various sieve sizes, wash each size with a water spray over the sieve to remove adhering dust and fine particles from the aggregate. Dry the portions retained on the various sieves and, unless used im
37、mediately, store each such portion individually in a clean container provided with a tight-fitting cover. 8.3 Selection and Preparation of Cement: 8.3.1 Hydraulic CementUse a hydraulic cement meeting the requirements of Specification C 150 (Note 3). In addition, the autoclave expansion in Test Metho
38、d C 151 shall be less than 0.20 %. NOTE 3The alkali content of the cement has been found to have negligible (3) or minor (6) effects on expansion in this test. 8.3.2 Preparation of CementPass cement for use in this test through an 850-m (No. 20) sieve to remove lumps before use. 8.4 Selection of poz
39、zolan, ground granulated blastfurnace Slag or lithium nitrate admixtureUse one, or a combination, of the following: 8.4.1 Fly ash or natural pozzolan meeting the requirements of Specification C 618. 8.4.2 Silica fume meeting the requirements of Specification C 1240. 8.4.3 Ground granulated blast fur
40、nace slag meeting the requirements of Specification C 989. 8.4.4 Commercially available lithium nitrate admixture which nominally contains 30 0.5 wt% lithium nitrate admixture in water. 8.5 Preparation of Test Specimens: 8.5.1 Number of SpecimensMake at least three test specimens for each cementitio
41、us materials-aggregate combination. 8.5.2 Preparation of MoldsPrepare the specimen molds in accordance with the requirements of Practice C 490 except, the interior surfaces of the molds shall be covered with a release agent (see Note 4). A release agent is acceptable if it serves as a First issued J
42、an 2009 Current revision Jan 2010 3Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CRD-C 662-10 C662parting agent without affecting the time of setting of the cement and without leaving any residue that will inhibit the penetration of water into the
43、specimen. NOTE 4TFE-fluorocarbon (Teflon) tape complies with the requirements for a mold release agent. (Teflon is a registered trademark.) 8.5.3 Proportioning of MortarProportion the dry materials for the test mortar using 1 part of cementitious materials (hydraulic cement plus pozzolan or ground g
44、ranulated blastfurnace slag) to 2.25 parts of graded aggregate by mass. The quantities of dry materials to be mixed at one time in the batch of mortar for making three specimens shall be 440 g of cementitious material and 990 g of aggregate made up by recombining the portions retained on the various
45、 sieves (see the section on Preparation of Aggregate) in the grading prescribed in Table 1. Use a water-cementitious material ratio equal to 0.47 by mass (see Note 5). NOTE 5Ruggedness tests indicated that mortar bar expansions were less variable at a fixed water-cement ratio than when gauged to a c
46、onstant flow (3). If silica fume or metakaolin are used, a high range water reducer (HRWR), meeting the requirements of Specification C 494/C 494M Type F, shall be used (if necessary) to provide adequate dispersion and workability of the mixture. The water-cementitious material ratio shall remain 0.
47、47 by mass and the amount of HRWR shall be that to obtain a flow of 7.5 percentage points of a control mortar without silica fume or metakaolin as determined in accordance with Test Method C 1437 using 25 drops of the flow table. If liquid HRWR is used, the water present in the liquid must be includ
48、ed in the calculation of the water-cementitious material ratio. If lithium nitrate admixture is used, a 100% dose equals 0.0493 times the grams of portland cement in the mortar batch, on a mass basis. To maintain the 0.47 w/c, subtract 0.7 times the grams of lithium nitrate admixture used in the bat
49、ch from the mixing water. For dosages higher or lower than 100%, simply multiply the 100% dose by the decimal equivalent of the percent of the 100% dose. (For example, for a 75% dose, multiply 0.75 times 0.0493 times the grams of portland cement in the mortar batch.) Or, for a volumetric basis, a 100% dose equals 0.0411 ml/g times the grams of portland cement in the mortar batch. If the lithium nitrate admixture dose is being calculated on a volumetric bas
