ASTM D698 标准击实

Designation: D 698 – 00a Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/ft3(600 kN-m/m3))1 This standard is issued under the fixed designation D 698; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. 1. Scope * 1.1 These test methods covers laboratory compaction meth- ods used to determine the relationship between water content and dry unit weight of soils (compaction curve) compacted in a 4 or 6-in. (101.6 or 152.4-mm) diameter mold with a 5.5-lbf (24.4-N) rammer dropped from a height of 12 in. (305 mm) producing a compactive effort of 12,400 ft-lbf/ft3(600 kN-m/ m3). NOTE 1—The equipment and procedures are similar as those proposed by R. R. Proctor (Engineering News Record—September 7, 1933) with this one major exception: his rammer blows were applied as “12 inch firm strokes” instead of free fall, producing variable compactive effort depend- ing on the operator, but probably in the range 15,000 to 25,000 ft-lbf/ft3 (700 to 1,200 kN-m/m3). The standard effort test (see 3.2.2) is sometimes referred to as the Proctor Test. NOTE 2—Soils and soil-aggregate mixtures should be regarded as natural occurring fine- or coarse-grained soils or composites or mixtures of natural soils, or mixtures of natural and processed soils or aggregates such as silt, gravel, or crushed rock. 1.2 These test methods apply only to soils (materials) that have 30 % or less by mass of particles retained on the 3⁄4-inch (19.0-mm) sieve. NOTE 3—For relationships between unit weights and water contents of soils with 30 % or less by mass of material retained on the 3⁄4-in. (19.0-mm) sieve to unit weights and water contents of the fraction passing 3⁄4-in. (19.0-mm) sieve, see Practice D 4718. 1.3 Three alternative methods are provided. The method used shall be as indicated in the specification for the material being tested. If no method is specified, the choice should be based on the material gradation. 1.3.1 Method A: 1.3.1.1 Mold—4-in. (101.6-mm) diameter. 1.3.1.2 Material—Passing No. 4 (4.75-mm) sieve. 1.3.1.3 Layers—Three. 1.3.1.4 Blows per layer—25. 1.3.1.5 Use—May be used if 20 % or less by mass of the material is retained on the No. 4 (4.75-mm) sieve. 1.3.1.6 Other Use—If this method is not specified, materials that meet these gradation requirements may be tested using Methods B or C. 1.3.2 Method B: 1.3.2.1 Mold—4-in. (101.6-mm) diameter. 1.3.2.2 Material—Passing 3⁄8-in. (9.5-mm) sieve. 1.3.2.3 Layers—Three. 1.3.2.4 Blows per layer—25. 1.3.2.5 Use—Shall be used if more than 20 % by mass of the material is retained on the No. 4 (4.75-mm) sieve and 20 % or less by mass of the material is retained on the 3⁄8-in. (9.5-mm) sieve. 1.3.2.6 Other Use—If this method is not specified, materials that meet these gradation requirements may be tested using Method C. 1.3.3 Method C: 1.3.3.1 Mold—6-in. (152.4-mm) diameter. 1.3.3.2 Material—Passing 3⁄4-inch (19.0-mm) sieve. 1.3.3.3 Layers—Three. 1.3.3.4 Blows per layer—56. 1.3.3.5 Use—Shall be used if more than 20 % by mass of the material is retained on the 3⁄8-in. (9.5-mm) sieve and less than 30 % by mass of the material is retained on the 3⁄4-in. (19.0-mm) sieve. 1.3.4 The 6-in. (152.4-mm) diameter mold shall not be used with Method A or B. NOTE 4—Results have been found to vary slightly when a material is tested at the same compactive effort in different size molds. 1.4 If the test specimen contains more than 5 % by mass of oversize fraction (coarse fraction) and the material will not be included in the test, corrections must be made to the unit mass and water content of the specimen or to the appropriate field in place density test specimen using Practice D 4718. 1.5 This test method will generally produce a well defined maximum dry unit weight for non-free draining soils. If this test method is used for free draining soils the maximum unit weight may not be well defined, and can be less than obtained using Test Methods D 4253. 1.6 The values in inch-pound units are to be regarded as the standard. The values stated in SI units are provided for information only. 1.6.1 In the engineering profession it is customary practice 1 This standard is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.03 on Texture, Plasticity and Density Characteristics of Soils. Current edition approved June 10, 2000. Published September 2000. Originally published as D 698 – 42T. Last previous edition D 698 – 00. 1 *A Summary of Changes section appears at the end of this standard. Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States. to use, interchangeably, units representing both mass and force, unless dynamic calculations (F = Ma) are involved. This implicitly combines two separate systems of units, that is, the absolute system and the gravimetric system. It is scientifically undesirable to combine the use of two separate systems within a single standard. This test method has been written using inch-pound units (gravimetric system) where the pound (lbf) represents a unit of force. The use of mass (lbm) is for convenience of units and is not intended to convey the use is scientifically correct. Conversions are given in the SI system in accordance with IEEE/ASTM SI 10. The use of balances or scales recording pounds of mass (lbm), or the recording of density in lbm/ft3 should not be regarded as nonconformance with this standard. 1.7 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 appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: C 127 Test Method for Specific Gravity and Absorption of Coarse Aggregate2 C 136 Method for Sieve Analysis of Fine and Coarse Aggregate2 D 422 Test Method for Particle Size Analysis of Soils3 D 653 Terminology Relating to Soil, Rock, and Contained Fluids3 D 854 Test Methods for Specific Gravity of Soil Solids by Water Pycnometer3 D 1557 Test Methods for Laboratory Compaction Charac- teristics of Soil Using Modified Efforts (56,000 ft-lbf/ ft3(2,700 kN-m/m3)) Drop3 D 2168 Test Methods for Calibration of Laboratory Mechanical-Rammer Soil Compactors3 D 2216 Test Method for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass3 D 2487 Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)3 D 2488 Practice for Description and Identification of Soils (Visual-Manual Procedure)3 D 3740 Practice for Minimum Requirements for Agencies Engaged in the Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction3 D 4220 Practices for Preserving and Transporting Soil Samples3 D 4253 Test Methods for Maximum Index Density and Unit Weight of Soils Using a Vibratory Table3 D 4718 Practice for Correction of Unit Weight and Water Content for Soils Containing Oversize Particles3 D 4753 Specification for Evaluating, Selecting and Speci- fying Balances and Scales For Use in Soil, Rock, and Construction Materials Testing3 D 4914 Test Methods for Density of Soil and Rock in Place by the Sand Replacement Method in a Test Pit3 D 5030 Test Method for Density of Soil and Rock in Place by the Water Replacement Method in a Test Pit3 D 6026 Practice for Using Significant Digits in Geotechni- cal Data4 E 1 Specification for ASTM Thermometers5 E 11 Specification for Wire-Cloth Sieves for Testing Pur- poses6 E 177 Practice for Use of the Terms Precision and Bias in ASTM Test Metods7 E 319 Practice for the Evaluation of Single-Pan Mechanical Balances6 E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method6 IEEE/ASTM SI 10 Standard for Use of the International System of Units (SI): the Modern Metric System8 3. Terminology 3.1 Definitions: See Terminology D 653 for general defini- tions. 3.2 Description of Terms Specific to This Standard: 3.2.1 oversize fraction (coarse fraction), Pc in %—the portion of total sample not used in performing the compaction test; it may be the portion of total sample retained on the No. 4 (4.75-mm), 3⁄8-in. (9.5-mm), or 3⁄4-in. (19.0-mm) sieve. 3.2.2 standard effort—the term for the 12,400 ft-lbf/ft3(600 kN-m/m3) compactive effort applied by the equipment and methods of this test. 3.2.3 standard maximum dry unit weight, gdmax in lbf/ft3 (kN/m3)—the maximum value defined by the compaction curve for a compaction test using standard effort. 3.2.4 standard optimum water content, w, in %—the water content at which a soil can be compacted to the maximum dry unit weight using standard compactive effort. 3.2.5 test fraction (finer fraction), PF in %—the portion of the total sample used in performing the compaction test; it is the fraction passing the No. 4 (4.75-mm) sieve in Method A, minus 3⁄8-in. (9.5-mm) sieve in Method B, or minus 3⁄4-in. (19.0-mm) sieve in Method C. 4. Summary of Test Method 4.1 A soil at a selected water content is placed in three layers into a mold of given dimensions, with each layer compacted by 25 or 56 blows of a 5.5-lbf (24.4-N) rammer dropped from a distance of 12-in. (305-mm), subjecting the soil to a total compactive effort of about 12,400 ft-lbf/ft3 (600 kN-m/m3). The resulting dry unit weight is determined. The procedure is repeated for a sufficient number of water contents to establish a relationship between the dry unit weight and the water content for the soil. This data, when plotted, represents a curvilinear relationship known as the compaction curve. The values of optimum water content and standard maximum dry unit weight are determined from the compaction curve. 2 Annual Book of ASTM Standards, Vol 04.02. 3 Annual Book of ASTM Standards, Vol 04.08. 4 Annual Book of ASTM Standards, Vol 04.09. 5 Annual Book of ASTM Standards, Vol 14.03. 6 Annual Book of ASTM Standards, Vol 14.02. 7 Annual Book of ASTM Standards, Vol 15.09. 8 Annual Book of ASTM Standards, Vol 14.04. D 698 2 5. Significance and Use 5.1 Soil placed as engineering fill (embankments, founda- tion pads, road bases) is compacted to a dense state to obtain satisfactory engineering properties such as, shear strength, compressibility, or permeability. Also, foundation soils are often compacted to improve their engineering properties. Laboratory compaction tests provide the basis for determining the percent compaction and water content needed to achieve the required engineering properties, and for controlling con- struction to assure that the required compaction and water contents are achieved. 5.2 During design of an engineered fill, shear, consolidation, permeability, or other tests require preparation of test speci- mens by compacting at some water content to some unit weight. It is common practice to first determine the optimum water content (wo) and maximum dry unit weight (gdmax) by means of a compaction test. Test specimens are compacted at a selected water content (w), either wet or dry of optimum (wo) or at optimum (wo), and at a selected dry unit weight related to a percentage of maximum dry unit weight (gdmax). The selection of water content (w), either wet or dry of optimum (wo) or at optimum (wo) and the dry unit weight (gdmax) may be based on past experience, or a range of values may be investigated to determine the necessary percent of compaction. 5.3 Experience indicates that the methods outlined in 5.2 or the construction control aspects discussed in 5.1 are extremely difficult to implement or yield erroneous results when dealing with certain soils. 5.3.1-5.3.3 describe typical problem soils, the problems encountered when dealing with such soils and possible solutions for these problems. 5.3.1 Oversize Fraction—Soils containing more than 30 % oversize fraction (material retained on the 3⁄4-in. (19-mm) sieve) are a problem. For such soils, there is no ASTM test method to control their compaction and very few laboratories are equipped to determine the laboratory maximum unit weight (density) of such soils (USDI Bureau of Reclamation, Denver, CO and U.S. Army Corps of Engineers, Vicksburg, MS). Although Test Methods D 4914 and D 5030 determine the “field” dry unit weight of such soils, they are difficult and expensive to perform. 5.3.1.1 One method to design and control the compaction of such soils is to use a test fill to determine the required degree of compaction and the method to obtain that compaction, followed by use of a method specification to control the compaction. Components of a method specification typically contain the type and size of compaction equipment to be used, the lift thickness, and the number of passes. NOTE 5—Success in executing the compaction control of an earthwork project, especially when a method specification is used, is highly dependent upon the quality and experience of the “contractor” and “inspector.” 5.3.1.2 Another method is to apply the use of density correction factors developed by the USDI Bureau of Reclama- tion (1,2)9 and U.S. Corps of Engineers (3). These correction factors may be applied for soils containing up to about 50 to 70 % oversize fraction. Each agency uses a different term for these density correction factors. The USDI Bureau of Recla- mation uses D ratio (or D – VALUE), while the U.S. Corps of Engineers uses Density Interference Coefficient (Ic). 5.3.1.3 The use of the replacement technique (Test Method D 698–78, Method D), in which the oversize fraction is replaced with a finer fraction, is inappropriate to determine the maximum dry unit weight, gdmax, of soils containing oversize fractions (3). 5.3.2 Degradation—Soils containing particles that degrade during compaction are a problem, especially when more degradation occurs during laboratory compaction than field compaction, as is typical. Degradation typically occurs during the compaction of a granular-residual soil or aggregate. When degradation occurs, the maximum dry-unit weight increases (4) so that the laboratory maximum value is not representative of field conditions. Often, in these cases, the maximum dry unit weight is impossible to achieve in the field. 5.3.2.1 Again, for soils subject to degradation, the use of test fills and method specifications may help. Use of replace- ment techniques is not correct. 5.3.3 Gap Graded—Gap-graded soils (soils containing many large particles with limited small particles) are a problem because the compacted soil will have larger voids than usual. To handle these large voids, standard test methods (laboratory or field) typically have to be modified using engineering judgement. NOTE 6—The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D 3740 are generally considered capable of competent and objective testing/sampling/inspection, and the like. Users of this standard are cautioned that compliance with Practice D 3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D 3740 provides a means of evaluating some of those factors. 6. Apparatus 6.1 Mold Assembly —The molds shall be cylindrical in shape, made of rigid metal and be within the capacity and dimensions indicated in 6.1.1 or 6.1.2 and Fig. 1 and Fig. 2. See also Table 1. The walls of the mold may be solid, split, or tapered. The “split” type may consist of two half-round sections, or a section of pipe split along one element, which can be securely locked together to form a cylinder meeting the requirements of this section. The “tapered” type shall an 9 The boldface numbers in parentheses refer to the list of references at the end of this standard. FIG. 1 4.0-in. Cylindrical Mold D 698 3 internal diameter taper that is uniform and not more than 0.200 in./ft (16.7- mm/m) of mold height. Each mold shall have a base plate and an extension collar assembly, both made of rigid metal and constructed so they can be securely attached and easily detached from the mold. The extension collar assembly shall have a height extending above the top of the mold of at least 2.0 in. (50.8-mm) which may include an upper section that flares out to form a funnel provided there is at least a 0.75 in. (19.0-mm) straight cylindrical section beneath it. The extension collar shall align with the inside of the mold. The bottom of the base plate and bottom of the centrally recessed area that accepts the cylindrical mold shall be planar. 6.1.1 Mold, 4 in.—A mold having a 4.000 6 0.016-in. (101.6 6 0.4-mm) average inside diameter, a height of 4.584 6 0.018 in. (116.4 6 0.5 mm) and a volume of 0.0333 6 0.0005 ft3 (944 6 14 cm3). A mold assembly having the minimum required features is shown in Fig. 1. 6.1.2 Mold, 6 in. —A mold having a 6.000 6 0.026-in. (152.4 6 0.7-mm) average inside diameter, a height of 4.584 6 0.018 in. (116.4 6 0.5 mm), and a volume of 0.075 6 0.0009 ft3 (2124 6 25 cm3). A mold assembly having the minimum required features is shown in Fig. 2. 6.2 Rammer—A rammer, either manually operated as de- scribed further in 6.2.1 or mechanically operated as described in 6.2.2. The rammer shall fall freely through a distance of 12 6 0.05 in. (304.8 6 1.3 mm) from the surface of the specimen. The mass of the rammer shall be 5.5 6 0.02 lbm (2.5 6 0.01 kg), except that the mass of the mechanical rammers may be adjusted as described in Test Methods D 2168; see Note 7. The striking face of the rammer shall be planar and circular, except as noted in 6.2.2.1, with a diameter when new of 2.000 6 0.005 in. (50.80 6 0.13 mm). The rammer shall be replaced if the striking face becomes worn or bellied to the extent that the diameter exceeds 2.000 6 0.01 in. (50.80 6 0.25 mm). NOTE 7—It is a common and acceptable practice in the inch-pound system to assume that the mass of the rammer is equal to its mass determined using either a kilogram or pound balance and 1 lbf is equal to 1 lbm or 0.4536 kg. or 1 N is equal to 0.2248 lbm or 0.1020 kg. 6.2.1 Manual Rammer—The rammer shall be equipped with a guide sleeve that has sufficient clearance that the free fall of the rammer shaft and head is not restricted. The guide sleeve shall have at least four vent holes at each end (eight holes total) located with centers 3⁄4 6 1⁄16-in. (19.0 6 1.6-mm) from each end and spaced 90 degrees apart. The minimum diameter of the vent holes shall be 3⁄8-in. (9.5-mm). Additional holes or slots may be incorporated in the guide sleeve. 6.2.2 Mechanical Rammer-Circular Face —The rammer shall operate mechanically in such a manner as to provide uniform and complete coverage of the specimen surface. There shall be 0.10 6 0.03-in. (2.5 6 0.8-mm) clearance between the rammer and the inside surface of the mold at its smallest diameter. The mechanical rammer shall meet the calibration requirements of Test Methods D 2168. The mechanical rammer shall be equipped with a positive mechanical means to support the rammer when not in operation. 6.2.2.1 Mechanical Rammer-Sector Face—When used with the 6-in. (152.4-mm) mold, a sector face rammer may be used in place of the circular face rammer. The specimen contact face shall have the shape of a sector of a circle of radius equal to 2.90 6 0.02-in. (73.7 6 0.5-mm). The rammer shall operate in such a manner that the vertex of the sector is positioned at the center of the specimen. 6.3 Sample Extruder (optional) —A jack, frame or other device adapted for the purpose o