1、Designation: C 88 05Standard Test Method forSoundness of Aggregates by Use of Sodium Sulfate orMagnesium Sulfate1This standard is issued under the fixed designation C 88; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of
2、last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the testing
3、of aggregates toestimate their soundness when subjected to weathering actionin concrete or other applications. This is accomplished byrepeated immersion in saturated solutions of sodium or mag-nesium sulfate followed by oven drying to partially or com-pletely dehydrate the salt precipitated in perme
4、able porespaces. The internal expansive force, derived from the rehy-dration of the salt upon re-immersion, simulates the expansionof water on freezing. This test method furnishes informationhelpful in judging the soundness of aggregates when adequateinformation is not available from service records
5、 of thematerial exposed to actual weathering conditions.1.2 The values given in parentheses are provided for infor-mation purposes only.1.3 This standard does not purport to address the safetyproblems associated with its use. It is the responsibility of theuser of this standard to establish appropri
6、ate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:2C33 Specification for Concrete AggregatesC 136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC 670 Practice for Preparing Precision and Bias
7、Statementsfor Test Methods for Construction MaterialsC 702 Practice for Reducing Samples of Aggregate toTesting SizeD75 Practice for Sampling AggregatesE11 Specification for Wire Cloth Sieves for Testing Pur-posesE 100 Specification for ASTM HydrometersE 323 Specification for Perforated-Plate Sieves
8、 for TestingPurposes3. Significance and Use3.1 This test method provides a procedure for making apreliminary estimate of the soundness of aggregates for use inconcrete and other purposes. The values obtained may becompared with specifications, for example Specification C33,that are designed to indic
9、ate the suitability of aggregateproposed for use. Since the precision of this test method is poor(Section 12), it may not be suitable for outright rejection ofaggregates without confirmation from other tests more closelyrelated to the specific service intended.3.2 Values for the permitted-loss perce
10、ntage by this testmethod are usually different for fine and coarse aggregates, andattention is called to the fact that test results by use of the twosalts differ considerably and care must be exercised in fixingproper limits in any specifications that include requirements forthese tests. The test is
11、 usually more severe when magnesiumsulfate is used; accordingly, limits for percent loss allowedwhen magnesium sulfate is used are normally higher thanlimits when sodium sulfate is used.NOTE 1Refer to the appropriate sections in Specification C33estab-lishing conditions for acceptance of coarse and
12、fine aggregates which failto meet requirements based on this test.4. Apparatus4.1 SievesWith square openings of the following sizesconforming to Specifications E11orE323, for sieving thesamples in accordance with Sections 6, 7, and 9:1This test method is under the jurisdiction of ASTM Committee C09
13、onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.20 on Normal Weight Aggregates.Current edition approved July 15, 2005. Published August 2005. Originallyapproved in 1931. Last previous edition approved in 1999 as C 88 99a.2For referenced ASTM standards, visit th
14、e ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
15、United States.150 m (No. 100) 8.0 mm (516 in.)9.5mm(38 in.)300 m (No. 50) 12.5 mm (12 in.)16.0mm(58 in.)600 m (No. 30) 19.0 mm (34 in.)25.0mm(1in.)1.18 mm (No. 16) 31.5 mm (114 in.)2.36 mm (No. 8) 37.5 mm (112 in.)50 mm (2 in.)4.00 mm (No. 5) 63 mm (212 in.)larger sizes by4.75 mm (No. 4) 12.5-mm (12
16、-in.)spread4.2 ContainersContainers for immersing the samples ofaggregate in the solution, in accordance with the proceduredescribed in this test method, shall be perforated in such amanner as to permit free access of the solution to the sampleand drainage of the solution from the sample without los
17、s ofaggregate.NOTE 2Baskets made of suitable wire mesh or sieves with suitableopenings are satisfactory containers for the samples.4.3 Temperature RegulationSuitable means for regulatingthe temperature of the samples during immersion in the sodiumsulfate or magnesium sulfate solution shall be provid
18、ed.4.4 BalancesFor fine aggregate, a balance or scale accu-rate within 0.1 g over the range required for this test; for coarseaggregate, a balance or scale accurate within 0.1 % or 1 g,whichever is greater, over the range required for this test.4.5 Drying OvenThe oven shall be capable of beingheated
19、 continuously at 230 6 9F(1106 5 C) and the rateof evaporation, at this range of temperature, shall be at least 25g/h for 4 h, during which period the doors of the oven shall bekept closed. This rate shall be determined by the loss of waterfrom 1-L Griffin low-form beakers, each initially containing
20、500 g of water at a temperature of 70 6 3F(216 2 C),placed at each corner and the center of each shelf of the oven.The evaporation requirement is to apply to all test locationswhen the oven is empty except for the beakers of water.4.6 Specific Gravity MeasurementHydrometers conform-ing to the requir
21、ements of Specification E 100, or a suitablecombination of graduated glassware and balance, capable ofmeasuring the solution specific gravity within 60.001.5. Special Solutions Required5.1 Prepare the solution for immersion of test samples fromeither sodium or magnesium sulfate in accordance with 5.
22、1.1 or5.1.2 (Note 3). The volume of the solution shall be at least fivetimes the solid volume of all samples immersed at any onetime.NOTE 3Some aggregates containing carbonates of calcium or mag-nesium are attacked chemically by fresh sulfate solution, resulting inerroneously high measured losses. I
23、f this condition is encountered or issuspected, repeat the test using a filtered solution that has been usedpreviously to test the same type of carbonate rock, provided that thesolution meets the requirements of 5.1.1 and 5.1.2 for specific gravity.5.1.1 Sodium Sulfate SolutionPrepare a saturated so
24、lutionof sodium sulfate by dissolving a USP or equal grade of the saltin water at a temperature of 77 to 86 F (25 to 30 C). Addsufficient salt (Note 4), of either the anhydrous (Na2SO4)orthecrystalline (Na2SO410H2O) form,3to ensure not only satura-tion but also the presence of excess crystals when t
25、he solutionis ready for use in the tests. Thoroughly stir the mixture duringthe addition of the salt and stir the solution at frequent intervalsuntil used. To reduce evaporation and prevent contamination,keep the solution covered at all times when access is notneeded. Allow the solution to cool to 7
26、0 6 2F(216 1 C).Again stir, and allow the solution to remain at the designatedtemperature for at least 48 h before use. Prior to each use, breakup the salt cake, if any, in the container, stir the solutionthoroughly, and determine the specific gravity of the solution.When used, the solution shall ha
27、ve a specific gravity not lessthan 1.151 nor more than 1.174. Discard a discolored solution,or filter it and check for specific gravity.NOTE 4For the solution, 215 g of anhydrous salt or 700 g of thedecahydrate per litre of water are sufficient for saturation at 71.6 F (22C). However, since these sa
28、lts are not completely stable and since it isdesirable that an excess of crystals be present, the use of not less than 350g of the anhydrous salt or 750 g of the decahydrate salt per litre of wateris recommended.5.1.2 Magnesium Sulfate SolutionPrepare a saturated so-lution of magnesium sulfate by di
29、ssolving a USP or equalgrade of the salt in water at a temperature of 77 to 86 F (25 to30 C). Add sufficient salt (Note 5), of either the anhydrous(MgSO4) or the crystalline (MgSO47H2O) (Epsom salt) form,to ensure saturation and the presence of excess crystals whenthe solution is ready for use in th
30、e tests. Thoroughly stir themixture during the addition of the salt and stir the solution atfrequent intervals until used. To reduce evaporation andprevent contamination, keep the solution covered at all timeswhen access is not needed. Allow the solution to cool to 70 62F(216 1 C). Again stir, and a
31、llow the solution to remainat the designated temperature for at least 48 h before use. Priorto each use, break up the salt cake, if any, in the container, stirthe solution thoroughly, and determine the specific gravity ofthe solution. When used, the solution shall have a specificgravity not less tha
32、n 1.295 nor more than 1.308. Discard adiscolored solution, or filter it and check for specific gravity.NOTE 5For the solution, 350 g of anhydrous salt or 1230 g of theheptahydrate per litre of water are sufficient for saturation at 73.4 F (23C). However, since these salts are not completely stable,
33、with the hydroussalt being the more stable of the two, and since it is desirable that anexcess of crystals be present, it is recommended that the heptahydrate saltbe used and in an amount of not less than 1400 g/litre of water.5.1.3 Barium Chloride SolutionPrepare 100 mL of 5 %barium chloride soluti
34、on by dissolving5gofBaCl2in 100 mLof distilled water.6. Samples6.1 The sample shall be obtained in general accordance withPractice D75and reduced to test portion size in accordancewith Practice C 702.3Experience with the test method indicates that a grade of sodium sulfate desig-nated by the trade a
35、s dried powder, which may be considered as approximatelyanhydrous, is the most practical for use. That grade is more economically availablethan the anhydrous form. The decahydrate sodium sulfate presents difficulties incompounding the required solution on account of its cooling effect on the solutio
36、n.C880526.2 Fine AggregateFine aggregate for the test shall bepassed through a 9.5-mm (38-in.) sieve. The sample shall be ofsuch size that it will yield not less than 100 g of each of thefollowing sizes, which shall be available in amounts of 5 % ormore, expressed in terms of the following sieves:Pa
37、ssing Sieve Retained on Sieve600 m (No. 30) 300 m (No. 50)1.18 mm (No. 16) 600 m (No. 30)2.36 mm (No. 8) 1.18 mm (No. 16)4.75 mm (No. 4) 2.36 mm (No. 8)9.5mm(38 in.) 4.75 mm (No. 4)6.3 Coarse AggregateCoarse aggregate for the test shallconsist of material from which the sizes finer than the No. 4sie
38、ve have been removed. The sample shall be of such a sizethat it will yield the following amounts of the indicated sizesthat are available in amounts of 5 % or more:Size (Square-Opening Sieves) Mass, g9.5mm(38 in.) to 4.75 mm (No. 4) 300 6 519.0mm(34 in.) to 9.5 mm (38 in.) 1000 6 10Consisting of:12.
39、5-mm (12-in.) to 9.5-mm (38-in.) material 330 6 519.0-mm (34-in.) to 12.5-mm (12-in.) material 670 6 1037.5-mm (112-in.) to 19.0-mm (34 in.) 1500 6 50Consisting of:25.0-mm (1-in.) to 19.0-mm (34-in.) material 500 6 3037.5-mm (112-in.) to 25.0-mm (1-in.) material 1000 6 5063-mm (212 in.) to 37.5-mm (
40、112 in.) 5000 6 300Consisting of:50-mm (2 in.) to 37.5-mm (112-in.) material 2000 6 20063-mm (212-in.) to 50-mm (2-in.) material 3000 6 300Larger sizes by nominal 12.5-mm (12-in.) spread in sievesize, each fractionConsisting of:75-mm (3-in.) to 63-mm (212-in.) material 7000 6 100090-mm (312-in.) to
41、75-mm (3-in.) material 7000 6 1000100-mm (4-in.) to 90-mm (312-in.) material 7000 6 10006.4 When an aggregate to be tested contains appreciableamounts of both fine and coarse material, having a gradingwith more than 10 weight % coarser than the 9.5-mm (38-in.)sieve and, also, more than 10 weight % f
42、iner than the 4.75-mm(No. 4) sieve, test separate samples of the minus No. 4 fractionand the plus No. 4 fraction in accordance with the proceduresfor fine aggregate and coarse aggregate, respectively. Reportthe results separately for the fine-aggregate fraction and thecoarse-aggregate fraction, givi
43、ng the percentages of the coarse-and fine-size fractions in the initial grading.7. Preparation of Test Sample7.1 Fine AggregateThoroughly wash the sample of fineaggregate on a 300-m (No. 50) sieve, dry to constant weightat 230 6 9F(1106 5 C), and separate into the different sizesby sieving, as follo
44、ws: Make a rough separation of the gradedsample by means of a nest of the standard sieves specified in6.2. From the fractions obtained in this manner, select samplesof sufficient size to yield 100 g after sieving to refusal. (Ingeneral, a 110-g sample will be sufficient.) Do not use fineaggregate st
45、icking in the meshes of the sieves in preparing thesamples. Weigh samples consisting of 100 6 0.1 g out of eachof the separated fractions after final sieving and place inseparate containers for the test.7.2 Coarse AggregateThoroughly wash and dry thesample of coarse aggregate to constant weight at 2
46、30 6 9F(110 6 5 C) and separate it into the different sizes shown in6.3 by sieving to refusal. Weigh out quantities of the differentsizes within the tolerances of 6.3 and, where the test portionconsists of two sizes, combine them to the designated totalweight. Record the weights of the test samples
47、and theirfractional components. In the case of sizes larger than 19.0 mm(34 in.), record the number of particles in the test samples.8. Procedure8.1 Storage of Samples in SolutionImmerse the samplesin the prepared solution of sodium sulfate or magnesiumsulfate for not less than 16 h nor more than 18
48、 h in such amanner that the solution covers them to a depth of at least12in. (Note 6). Cover the containers to reduce evaporation andprevent the accidental addition of extraneous substances.Maintain the samples immersed in the solution at a temperatureof 70 6 2F(216 1 C) for the immersion period.NOT
49、E 6Suitably weighted wire grids placed over the sample in thecontainers will permit this coverage to be achieved with very lightweightaggregates.8.2 Drying Samples After ImmersionAfter the immersionperiod, remove the aggregate sample from the solution, permitit to drain for 15 6 5 min, and place in the drying oven. Thetemperature of the oven shall have been brought previously to230 6 9F(1106 5 C). Dry the samples at the specifiedtemperature until constant weight has been achieved. Establishthe time
