1、Standard Method of Test for Resistance R-Value and Expansion Pressure of Compacted Soils AASHTO Designation: T 190-14 ASTM Designation: D2844-07 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1a T 190-1 AASHTO Sta
2、ndard Method of Test for Resistance R-Value and Expansion Pressure of Compacted Soils AASHTO Designation: T 190-14 ASTM Designation: D2844-07 1. SCOPE 1.1. This method covers the procedure for testing both treated and untreated laboratory compacted soils or aggregates with the stabilometer and expan
3、sion pressure devices to obtain results indicative of performance when placed in the base, subbase, or subgrade of a road subjected to traffic. 1.2. The values stated in SI units are to be regarded as the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 92, Wire-Cloth Sieves for Testing Pu
4、rposes M 231, Weighing Devices Used in the Testing of Materials 2.2. ASTM Standard: E4, Standard Practices for Force Verification of Testing Machines 3. APPARATUS 3.1. Kneading Compactor capable of applying an average contact pressure of 2413 110 kPa (350 16 psi) to the tamper foot shown in Figure 1
5、 and with provisions for maintaining this pressure during changes in sample height. The load-time trace shall be free of “chatter” or evidence of impact-associated changes in slope. The rise time for application of foot pressure, in the range from 241 to 2068 kPa (35 to 300 psi), shall not be less t
6、han 0.07 nor more than 0.20 s. The dwell time, measured at 2068 kPa (300 psi) foot pressure, shall not be less than 0.15 nor more than 0.45 s. The pressure-release or removal time shall not be greater than 0.60 s. 3.1.1. The compactor shall include a counter or timer for measuring the number of tamp
7、s applied to a specimen and a mold holder, for use in compacting specimens, that rotates equally between tamps to give five to seven tamps per revolution of the mold. The holder shall firmly restrain the mold during compaction. The base of the mold holder shall have a metal plate 100.8 mm (331/32in.
8、) in diameter and 12.7 mm (1/2in.) high to which is cemented a rubber disk having a diameter of 100.0 mm (315/16in.) and a height of 3.2 mm (1/8in.). The plate shall be an integral part of the base of the mold holder. The compactor shall also include a trough for feeding the sample into the mold in
9、20 increments (Figure 2). Troughs with a semicircular cross section of 3871 mm2(6 in.2) in area and 508 mm (20 in.) long have proven satisfactory. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T
10、190-2 AASHTO 3.2. Compression Testing Machine, with a minimum capacity of 45 kN (10,000 lbf) and satisfying the requirements of ASTM E4. 3.3. Mold, 101.6 0.05 mm (4 0.002 in.) inside diameter by 127.00 0.20 mm (5 0.008 in.) high. (See Figure 3 for surface roughness.) mm in. 50.80 0.05 2.00 0.002 6.3
11、5 0.51 1/4 0.020 6.35 1/450.80 2 22.22 7/8Figure 1Tamper Foot for Kneading Compactor 120 Typ2.778cm(13/32in.)RTyp2.302cm(129/32in.)RTyp0.635cm(11/4in.)RTyp5.080cm(2in.)RTypDimensional Limits, cm (in.)Min MaxDistance across Foot3 Measurements 5.189 5.289120 Apart (2.042) (2.082) 2015 by the American
12、Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 190-3 AASHTO Figure 2Compactor with Sample Feed Trough Note: Inside roughness is obtained by smooth machining inside to required diameter of 101.60 0.05 mm (4.000 0.002
13、 in.), followed on final operation with a boring tool ground to a 90 degree point with sharp point ground flat measuring 0.02 to 0.08 mm (0.001 to 0.003 in.) across. Depth of cut is 0.05 mm (0.002 in.) with 0.25-mm (0.010-in.) feed using sulfur-based oil coolant. Figure 3Mold 6.35 mDia 114.05 0.13 m
14、m127.00 0.20mm0.40 mm x 45 Chamfer onOutside OnlyBoth EndsBurr SlightlyBoth EndsDia 101.60 0.05 mm 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 190-4 AASHTO 3.4. Rubber Disks, 100 mm (315/16in
15、.) in diameter by 3.2 mm (1/8in.) thick and having a durometer hardness of 60 15. 3.5. Metal Follower, solid-walled, metal specimen follower 100.33 0.13 mm (3.95 0.005 in.) in outside diameter with a minimum height of 127 mm (5 in.). 3.6. Exudation-Indicator Device, as shown in Figures 4 and 5, or e
16、quivalent with linear light display. 3.7. Phosphor Bronze Disk, as shown in Figure 6. Figure 4Exudation-Indicator Device 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 190-5 AASHTO Figure 5Exuda
17、tion-Indicator Device (Alternate Method) Figure 6Phosphor-Bronze Disk Perforated DiskPhosphor Bronze 28 Gauge331/32in.13/4in.Forty-two5/32-in. Holes 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a
18、T 190-6 AASHTO 3.8. Filter Paper, 100 mm in diameter and 0.15 mm (0.006 in.) thick, smooth surface, medium filtering speed, medium retention. 3.9. Filter Paper, 110 mm in diameter and 0.15 mm (0.006 in.) thick, creped surface, medium-fast filtering speed, medium retention. 3.10. Expansion-Pressure D
19、evice, with accessories as shown in Figure 7. There should be at least three of these devices for each sample to be tested within a days time. 3.11. Deflection Gauge, with divisions of 0.002 mm (0.0001 in.) and an Allen wrench as shown in Figure 7. Figure 7Expansion-Pressure Device and Accessories 3
20、.12. Stabilometer, with accessories, as shown in Figures 8 and 9. 3.13. Standard Metal Specimen, 101.60 mm (4 in.) in outside diameter by 152.4 mm (6 in.) high as shown in Figure 9. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a v
21、iolation of applicable law.TS-1a T 190-7 AASHTO Figure 8Hveem Stabilometer Figure 9Stabilometer and Accessories MoldTest SpecimenStage BaseStabilometerStandardMetalSpecimenSpecimenFollower 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication
22、 is a violation of applicable law.TS-1a T 190-8 AASHTO 3.14. Balance, of sufficient capacity, conforming to the requirements of M 231, Class G 5. 3.15. Sieves, 25.0 mm (1 in.), 19.0 mm (3/4in.), and 4.75 mm (No. 4), conforming to the requirements of M 92 for Wire-Cloth Sieves for Testing Purposes. 3
23、.16. Miscellaneous equipment, including mixing pans, spoons, spatulas, and gallon cans with close-fitting lids. 3.17. Tamping Rod, a metal rod, 38 to 51 mm (1.5 in. to 2.0 in.) in diameter. 3.18. Expansion pressure calibration equipment, a suitable hanger and weights, and a calibrated proving ring.
24、4. SOIL PREPARATION 4.1. Remove any coatings from coarse aggregate and break clay lumps to pass the 4.75-mm (No. 4) sieve. 4.2. Adjust the soil gradation when some of the material is retained on the 19.0-mm (3/4-in.) sieve. When 75 percent or more passes the 19.0-mm sieve, use that part of the sampl
25、e passing the 19.0-mm sieve. If less than 75 percent of the sample passes the 19.0-mm sieve, use that part of the sample passing the 25.0-mm (1-in.) sieve. 5. PREPARATION OF SOIL SPECIMENS 5.1. Thoroughly mix four 1200-g samples of soil with the amount of water estimated to equal one half to two thi
26、rds of the water required to produce saturation as defined in Sections 5.3 and 5.4. Place the samples in covered containers and allow them to stand overnight. Just prior to compaction, mix the samples with the final amount of water required to produce saturation. The first sample is used as a pilot
27、specimen to assist in determining the final amount of water required. 5.2. Weigh out enough material to fabricate a compacted sample 101.6 mm (4 in.) in diameter by 63.5 mm (2.5 in.) high. Compacted specimens having heights from 58.4 to 68.6 mm (2.3 to 2.7 in.) are acceptable. Compact the soil into
28、the mold by means of the kneading compactor as follows: Place the mold in the mold holder that has a rubber disk, 100 mm (315/16in.) in diameter and 3 mm (1/8in.) thick cemented to the plate. Adjust the mold for approximately 3-mm (1/8-in.) clearance between the lower edge of the mold and base of th
29、e mold holder by placing a shim under the edge of the mold or by tightening the set screw (if available) on the mold holder. With the compactor foot pressure set at 1724 172 kPa (250 25 psi), feed 76.2 mm (3 in.) of the soil in the trough into the mold. Feed the balance of the soil into the mold in
30、20 equal increments with one application of the ram after each increment. Allow 10 additional tamps to level the soil, then place a rubber disk on top of the specimen, loosen the set screw (if available), and remove the shim from under the mold. Apply 100 additional tamps with a foot pressure of 241
31、3 kPa (350 psi). Stop compacting the soil at any time before 100 tamps if water appears around the bottom of the mold. Note 1Use lower compaction pressures when necessary to limit penetration of the ram into the soil to not greater than 6.35 mm (1/4in.). 5.3. Remove the mold containing the compacted
32、 specimen from the compactor. Level the surface by hand tamping with the tamping rod. Place a phosphor-bronze disk on the tamped surface of the soil and place a filter paper on top of the bronze disk. Invert the mold and place it on the exudation-indicator device so the filter paper is on the bottom
33、. Using the compression testing machine, apply a uniformly increasing pressure to the soil at the rate of 8896 N/min 5 percent 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 190-9 AASHTO (2000 l
34、bf/min 5 percent). Water should be exuded from the soil at 2068 kPa (300 psi) as evidence that enough moisture is present to produce saturation. On an exudation device with a circular light display, stop the loading and record the exudation pressure to the nearest 10 kPa (1 psi) when either five of
35、the six outer lights on the exudation pressure device are lighted or three outer lights are lighted and free water is visible around the bottom of the mold. On an exudation device with a linear light display, stop the loading and record the exudation pressure to the nearest 10 kPa (1 psi) when eithe
36、r five lights on the indicator are lighted or three lights are lighted and free water is visible around the bottom of the mold. Do not exceed a loading of 5516 kPa (800 psi). 5.4. Mold at least two more specimens with different amounts of moisture so that a range of exudation pressures from 689 to 5
37、516 kPa (100 to 800 psi) (Note 2) is obtained that brackets the 2068 kPa (300 psi) value. For some high volume-change soils, additional specimens having exudation pressures lower than 689 kPa (100 psi) may be necessary to obtain expansion pressures that are low enough to provide a suitable range of
38、data for a complete expansion pressure analysis of the soil. Note 2Occasionally, material from very plastic, clay-test specimens will extrude from under the mold and around the follower ram during the loading operation. If this occurs when the 5516-kPa (800-psi) point is reached and fewer than five
39、lights are lighted, or, for the alternate method, 5/6of the circumference of the filter paper is wet, the soil should be reported as an R-value of less than five. Coarse granular materials and clean sands may require the use of paper baskets to permit testing. 6. CALIBRATION OF EXPANSION-PRESSURE AP
40、PARATUS 6.1. Calibrate the spring steel bar of the expansion-pressure device (Figure 7) by applying upward measured loads at the center of the bar and measuring the respective deflections of the bar with the deflection gauge. 6.2. The spring steel bar is considered in calibration when the deflection
41、s are within the following tolerances: Applied Load, N (lbf) Dial Reading (mm) (in.) 36 (8) 0.053 0.005 (0.0021 0.0002) 71 (16) 0.107 0.005 (0.0042 0.0002) 107 (24) 0.160 0.005 (0.0063 0.0002) 142 (32) 0.213 0.005 (0.0084 0.0002) 6.3. If the deflection gauge does not check the above readings, loosen
42、 the top frame bar and adjust the position of the shims, between the frame and the spring steel bar, until the required readings are obtained. Note 3Some models of the expansion-pressure apparatus have set screw adjustments in lieu of shims. 7. EXPANSION-PRESSURE TESTING 7.1. After determination of
43、the exudation pressure, allow the test specimen to rebound in a covered mold for at least 30 min, and then measure the compacted specimen height to the nearest 2.5 mm (0.1 in.). 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a viola
44、tion of applicable law.TS-1a T 190-10 AASHTO 7.2. Place the deflection gauge in position on the expansion-pressure device with the single-bearing end of the gauge base resting on the adjustment ring. 7.3. Using an Allen wrench, raise or lower the adjustment plug until the deflection gauge is on 0.02
45、5 mm (0.0010 in.). The deflection gauge will read 0.229 mm (0.0090 in.). 7.4. Place the perforated disk with stem firmly on the face of the compacted specimen in the mold and place the mold in the expansion-pressure device after placing creped surface filter paper on the turntable. 7.5. Seat the per
46、forated disk firmly on the specimen with pressure applied by the fingers. Raise the turntable on the expansion device until the deflection gauge reads zero. If the device was properly adjusted, according to Section 7.3, this will apply the preset surcharge deflection of 0.025 mm (0.0010 in.). 7.6. P
47、ut approximately 200 mL of water into the mold and allow pressure from expansion of the specimen to develop for 16 to 24 h. Note 4Do not leave a test specimen unconfined by the expansion-pressure device while there is free water on top of the specimen in the mold. 7.7. Read the deflection of the cal
48、ibrated spring steel bar to 0.002 mm (0.0001 in.). When the deflection is greater than 0.254 mm (0.0100 in.), the expansion-pressure device should be recalibrated before using again. 7.8. Determine the expansion pressure, P, as follows: P = kd (1) where: k = spring constant of steel bar calculated f
49、rom calibration of the expansion-pressure apparatus and expressed in kPa/0.025 mm (psi/0.0010 in.), and, d = deflection shown by deflection gauge, mm (in.). 8. ADJUSTMENT OF STABILOMETER 8.1. Adjust the bronze nut on the stabilometer stage base so that the top of the stage is 89 mm (31/2in.) below the bottom of the upper tapered ring of the stabilometer. Perform all tests at this setting. 8.2. Place the standard metal specimen in the stabilometer chamber. Adjust the amount of air in the stabilomet
