MIXTURES USING SATURATED SURFACE-DRY SPECIMENS 1
This Standard is issued under the fixed designation D 2726: the number immediately following the desienation indicates the year of original adoption or. in the case of revision, the year of last revision. A number in parent-heses indicates the year of last reapproval.
Scope
1.1 This method covers the determination of bulk specific gravity of specimens of com-pacted bituminous mixtures, and directly the bulk specific gravity in accordance with ASTM Definitions E 12, Terms Relating, to Density and Specific Gravity of Solids, Liq-uids, and Gases.2
1.2 This method should be used onty with dense-graded or practically nonabsorptive compacted mixtures.
1.3 The bulk specific gravity of the corn-pacted bituminous mixtures may be used in calculating the unit weight of the mixture.
Apparatus
2.1 Balance, with ample capacity, and with sufficient sensitivity to- enable bulk specific gravities of the speci mens to be calculated to at least four significant figures, that is, to at least three decimal places. It .shah l be equipped with
suitable suspension apparatus and holder to permit weighing the specimen while suspended from the center of the scale pan.of the balance.
NOTE 1—Since there are no more significant, figures in the quotient (bulk specific gravity) than appear in either the dividend (the weight of the specimen in air) or in the divisor (the volume of the specimen, obtained from the difference in weight of the saturated surface dry specimen in air and in water), this means that the balance must have a sensitivity capable of providin2 both weight and volume values to at least four figures. For example, a sensitivity of 0.1 g would provide four significant figures for weights in the range from 130.0 g to 999.9
2 when, the specific gtravity is 2.300.
2.2 Water Bath for immersing .the speci.-
men in water while suspended under the bal-ance, equipped with an overflow outlet for maintaining a constant water level.
Test Specimens
3.1 Test specimens ma y be either labora-tory-molded bituminous mixtures or from bitu-minous pavements.
3.2 Size of Specintens—lt is recommended..
(I) that the diameter of cylindrically Molded or cored specimens, or the length of the sides of sawed specimens, be at least equal to .four times the maximum size of the-aggregate; and (2) that the thickness of specimens be at least one and one hall' times the maximum size of the aggregate.
3.3 Pavement specimens shall be taken [rom pavements with core drill, diamond or car-borundum saw, or by other suitable mearts.
3.4 Care shall be taken to avoid distortion, .bending or cracking of specimens durin2 and. after removal [rom pavements or mold. Speci-mens shah l be stored in a safe, cool place.
3.5 Specimens shah l be free of foreign ma-terials such as seal coat, tack coat, foundation material, soil, imper, or foil.
3.6 If desired, specimens may be separated from other pavement layers by sawing or other
'This method is under the jurisdiction of .ASTM Com-mittee D-4 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.21 on Specific Gravity and Densitv of Bituminous Mixtures.
Carrent« edition approved May 31. 1973. Published July 1973. Originally published as D -2726 68T. Last previous edition D 2726 7IT.
A nnual Book of ASTM Standards, Parts 14 and 41.
116
satisfactory means.
4. Procedure
4.1 For Specimens Thaï Contain Moisture:
4.1.1 Weight of Specimen in Water—Im-merse the specimen in a water bath at 25 C (77 F) for 3 to 5 min and then weigh in water.
Designate this weight as C.
4.1.2 Weight of Saturated Surface-Dry Specimen in Air—Surface dry the specimen by blotting quickly with a damp towel and then weigh in air. Designate this weieht as B.
4.1.3 Weight of Oven Dry Specimen—Oven dry the specimen to constant weieht at approx-imately 110 C (230 F) (15 to 24 h is usually sufficient). Allow the specimen to cool and weigh in air. Designate this weight as A.
4.2 For Specimens Thaï Contain Moisture and Solvent:
4.2.1 Weight of Specimen in Water—Im-merse the specimen in a water bath at 25 C (77 F) for 3 to 5 min and then weigh in water.
Designate this weight as C.
4.2.2 Weight of Saturated Surface Dry Specimen in Air—Surface dry the specimen by blotting quickly with a damp towel and then weigh in air. Designate this weight as B.
4.2.3 Weight of Thoroughly Dry Specimen in Air—Immediately subject the saturated surface dry specimen to ASTM Method D
1461, Test for Moisture or Volatile Distillates in Bituminous Paving Mixtures,' for determi-nation of water usine a representative portion
D 2726
if the entire specimen is too large for the still.
Designate as weight A the weight B minus the weight of the moisture determined.
4.3 For Thoroughly Dry Specimens:
4.3.1 Weight of Dry Specimen in Air
—Weigh the specimen after it has been stand-ing in air at room temperature for at least 1 h.
Designate this weight as A.
4.3.2 Weight of Specimen in Water—Im-merse the specimen in a water bath at 25 C (77 F) for 3 to 5 min and then weigh in water.
Designate this weight as C.
4.3.3 Weight of Saturated Surface-Dry Specimen in Air—Surface dry the specimen by blotting quickly with a damp towel and then weigh in air. Designate this weight as B.
5. Calculation
5.1 Calculate the bulk specific gravity of the specimen as follows:
Bulk sp gr = A1(8 – C) where:
A = weight of the dry specimen in air, g, B = weight of the saturated surface-dry
spec-imen in air, g, and
C = weight of the specimen in water, g.
6. Precision
6.1 Duplicate specific gravity results by the same operator should flot be considered sus-pect unless they differ by more than 0.02.
' A nnual Book of ASTM Standards, Part 15.
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19103, which will schedule a further hearing regarding your comments. Failing satisfaction there, you may appeal to the A STM Board of Directors.
D
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Designation: D 3203 – 75