1、Designation: C88 13Standard Test Method forSoundness of Aggregates by Use of Sodium Sulfate orMagnesium Sulfate1This standard is issued under the fixed designation C88; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () 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 of
3、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 permeabl
4、e 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 of
5、 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 appropriate
6、 safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:2C33 Specification for Concrete AggregatesC136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC670 Practice for Preparing Precision and Bias State
7、mentsfor Test Methods for Construction MaterialsC702 Practice for Reducing Samples ofAggregate to TestingSizeD75 Practice for Sampling AggregatesE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE100 Specification for ASTM HydrometersE323 Specification for Perforated-Plate Sieves for T
8、estingPurposes3. 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 indicate th
9、e 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 percentage
10、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 usual
11、ly 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 C33 estab-lishing conditions for acceptance of coarse and fine
12、aggregates which failto meet requirements based on this test.1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregatesand is the direct responsibility of SubcommitteeC09.20 on Normal Weight Aggregates.Current edition approved Aug. 1, 2013. Published August
13、2013. Originallyapproved in 1931. Last previous edition approved in 2005 as C88 05. DOI:10.1520/C0088-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standar
14、ds Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Apparatus4.1 SievesWith square openings of the following sizesconforming to Specifications E11 or E323, for sieving thesamples in accordanc
15、e with Sections 6, 7, and 9:150 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.
16、4) 12.5-mm (12-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 samp
17、le without loss 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 s
18、hall be provided.4.4 Temperature RecorderWith an accuracy of at least 1F (0.5 C) and capable of recording the temperature of thesolution at least once every 15 minutes for the duration of thetest.4.5 BalancesFor fine aggregate, a balance or scale accu-rate within 0.1 g over the range required for th
19、is test; for coarseaggregate, a balance or scale accurate within 0.1 % or 1 g,whichever is greater, over the range required for this test.4.6 Drying OvenThe oven shall be capable of beingheated continuously at 230 6 9F(1106 5 C) and the rateof evaporation, at this range of temperature, shall be at l
20、east 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 containing500 g of water at a temperature of 70 6 3F(216 2 C),placed at each corner and the center of each shelf of t
21、he oven.The evaporation requirement is to apply to all test locationswhen the oven is empty except for the beakers of water.4.7 Specific Gravity MeasurementHydrometers conform-ing to the requirements of Specification E100, or a suitablecombination of graduated glassware and balance, capable ofmeasur
22、ing 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 5.1.1 or5.1.2 (Note 3). The volume of the solution shall be at least fivetimes the solid volume of all samples
23、 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. If this condition is encountered or issuspected, repeat the test using a filtered solution that has been used
24、previously 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 solutionof sodium sulfate by dissolving a USP or equal grade of the saltin water at a temperature of 77 to 86
25、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 the solutionis ready for use in the tests. Thoroughly stir the mixture duringthe addition of the salt and sti
26、r 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 70 6 2F(216 1 C).Again stir, and allow the solution to remain at the designatedtemperature for at least 48 h
27、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 have a specific gravity not lessthan 1.151 nor more than 1.174. Discard a discolored solution,or filter it and
28、 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 salts are not completely stable and since it isdesirable that an excess of crystals be present, the use of not
29、 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 dissolving a USP or equalgrade of the salt in water at a temperature of 77 to 86 F (25 to30 C). Add sufficient
30、 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 the tests. Thoroughly stir themixture during the addition of the salt and stir the solution atfrequent interva
31、ls 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 allow the solution to remainat the designated temperature for at least 48 h before use. Priorto each use, bre
32、ak 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 than 1.295 nor more than 1.308. Discard adiscolored solution, or filter it and check for specific gravity.NOTE
33、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, with the hydroussalt being the more stable of the two, and since it is desirable that anexcess of crystals b
34、e present, it is recommended that the heptahydrate saltbe used and in an amount of not less than 1400 g/litre of water.3Experience with the test method indicates that a grade of sodium sulfate desig-nated by the trade as dried powder, which may be considered as approximatelyanhydrous, is the most pr
35、actical 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 solution.C881325.1.3 Barium Chloride SolutionPrepare 100 mL of 5 %barium chloride soluti
36、on by dissolving5gofBaCl2in 100 mLof distilled water.6. Samples6.1 The sample shall be obtained in general accordance withPractice D75 and reduced to test portion size in accordancewith Practice C702.6.2 Fine AggregateFine aggregate for the test shall bepassed through a 9.5-mm (38-in.) sieve. The sa
37、mple 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:Passing 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) 1.1
38、8 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. 4sieve have been removed. The sample shall be of such a sizethat it will yield the following amounts of the indi
39、cated sizesthat are available in amounts of 5 % or more:Size (Square-Opening Sieves) Mass, g9.5mm(38 in.) to 4.75 mm (No. 4) 300 519.0mm(34 in.) to 9.5 mm (38 in.) 1000 10Consisting of:12.5-mm (12-in.) to 9.5-mm (38-in.) material 330 519.0-mm (34-in.) to 12.5-mm (12-in.) material 670 1037.5-mm (112-
40、in.) to 19.0-mm (34 in.) 1500 50Consisting of:25.0-mm (1-in.) to 19.0-mm (34-in.) material 500 3037.5-mm (112-in.) to 25.0-mm (1-in.) material 1000 5063-mm (212 in.) to 37.5-mm (112 in.) 5000 300Consisting of:50-mm (2 in.) to 37.5-mm (112-in.) material 2000 20063-mm (212-in.) to 50-mm (2-in.) materi
41、al 3000 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 100090-mm (312-in.) to 75-mm (3-in.) material 7000 1000100-mm (4-in.) to 90-mm (312-in.) material 7000 10006.4 When an aggregate to be tested contains ap
42、preciableamounts 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 % finer 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 th
43、e proceduresfor fine aggregate and coarse aggregate, respectively. Reportthe results separately for the fine-aggregate fraction and thecoarse-aggregate fraction, giving the percentages of the coarse-and fine-size fractions in the initial grading.7. Preparation of Test Sample7.1 Fine AggregateThoroug
44、hly 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 follows: Make a rough separation of the gradedsample by means of a nest of the standard sieves specified in6.2. From the fractions obtained
45、 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 sticking in the meshes of the sieves in preparing thesamples. Weigh samples consisting of 100 6 0.1 g out of eachof the separated fracti
46、ons 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 230 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 differentsi
47、zes 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 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
48、. Procedure8.1 Storage of Samples in SolutionImmerse the samples inthe prepared solution of sodium sulfate or magnesium sulfatefor not less than 16 h nor more than 18 h in such a manner thatthe solution covers them to a depth of at least12 in. (Note 6).Cover the containers to reduce evaporation and
49、prevent theaccidental addition of extraneous substances. Maintain thesamples immersed in the solution at a temperature of 70 6 2F(21 6 1 C) for the immersion period.NOTE 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 dryi
