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E: Test Procedure for Resilient Modulus of Unstabilized Aggregate Base and Subgrade Materials
Pages 343-386

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From page 344...
... disturbed samples of unbound base, subbase and subgrade soils prepared for testing by compaction in the laboratory. I.3 In this test procedure, stress states used for resilient modulus testing are based upon whether the specimen is located in the base/ subbase or He subgrade.
From page 345...
... These materials may be classified as either Type ~ or Type 2 as subsequently defined in 3.3 and 3.4. 3.3 Material Type I: For the purposes of resilient modulus testing, Material_Type ~ includes all unbound granular base and subbase material and all untreated subgrade soils which meet Me criteria of less than 70% passing Me 2.00 mm (No.
From page 346...
... Load Pulse (Pi ) , ~ ~ \ Maximu nil App' ed \ Load (Pmac )
From page 347...
... stress and a constant confining stress provided by means of cell air pressure. For cohesive subgrade soils a similar repeated cyclic stress is applied to an unconfirmed cylindrical specimen.
From page 348...
... \ \ \ \ \ ~ BASE OF LOAD FRAME (b) Unconfined compression test Figure E-2.
From page 349...
... However, a pair of EVDTs extending between He top and bottom platens can be used to measure axial deformation of these weak soils. 6.3 Loading Device - The loading device shall be a top loading, closed loop electrohydraulic testing machine with a function generator which is capable of applying repeated cycles of a haversine-shaped load pulse.
From page 350...
... Slippage of clamps may be a problem for soft and very soft subgrade soils which undergo large deformations. Specimen damage due to clamps and clamp slippage should not be a problem for reasonable quality base and subbase specimens.
From page 351...
... Typical cIamps used to measure axial deformation E-9
From page 352...
... Specimen preparation is given in Annex Al, specimen compaction equipment and compaction procedures for Type ~ materials in Annex A2 and for Type 2 materials in Annex A3. 6.6 Equipment for trimming test specimens from undisturbed thin-wal1 tube samples of subgrade soils shall be as described in AASHTO T234.
From page 353...
... The following guidelines, based on the sieve analysis test results, shall be used to determine the test specimen size: 7.~.1 Use 71 mm (2.S in.) diameter undisturbed specimens from ~ walled tube samples for cohesive subgrade soils (Material Type 2~.
From page 354...
... 7.3.2.1 Me dry density of a laboratory compacted specimen should not vary more than ~ 2 % from Me target dry density for that layer. 7.3.3 If either the in-situ moisture content or the in-place dry density is not available, then use the optimum moisture content and 95 % of the maximum dry density by using TI8O for the base/subbase and 95 % of T99 for the subgrade.
From page 355...
... An unconfined resilient modulus test is used for cohesive subgrade soils. S.3 Granular and Low Cohesion Subgrade Soils - This procedure is used for laboratory compact specimens of subgrade soils.
From page 356...
... and verify it is working properly. 8.3.2 Conduct We Resilient Modulus Test The following steps are required to conduct the resilient modulus test on a subgrade specimen which has been insured in the Biaxial chamber and placed under Me loading frame.
From page 357...
... g.3.2.S After completion of the resilient modulus test procedure, check the total vertical permanent strain that the specimen was subjected to during the resilient modulus portion of Me test procedure. If the total vertical permanent swain did not exceed 59G, continue with the quick shear test procedure (Section 8.3.2.9~.
From page 358...
... 8.4.2 Soft Specimens - The axial deformation of soft subgrade soils (Su ~ 37.9 kPa; 750 psf) should not be measured using clamps placed on the specimen.
From page 359...
... Then insure He displacement instrumentation is working properly by displacing each device and observing the resulting voltage output as shown by the data acquisition system. 8.4.6 Conduct Resilient Modulus Test - The following steps are required to conduct the unconfined resilient modulus test on a cohesive subgrade specimen placed in a loading frame as described in 8.4.4 and 8.4.5.
From page 360...
... Axial Cyclic Stress Contact Stress Pressure, S3 Stress, Smax ScyCnc Sco~act kPa psi kPa psi kPa psi kPa psi 41.3 6 63.4 9.2 55.1 8 8.3 1.2 13.8 2 16.6 2.4 13.8 2 2.8 0.4 13.8 1 2 1 23.5 1 3.4 20.7 1 3 1 2.8 1 0.4 13.8 2 30.4 4.4 27.6 4 2.8 0.4 20.7 3 24.8 3.6 20.7 3 4.1 0.6 20.7 1 3 1 31.7 1 4.6 27.6 1 4 1 4.1 1 0.6 l 20.7 3 45.4 6.6 41.3 6 4.1 0.6 27.6 ~4 ~ 33.1 ~4.8 27.6 ~4 ~5.5 ~0.8 27.6 1 4 146.8 T6.S 41.3 T 6 T5.5TO.8 27.6 ~ 4 ~ 60.6 ~ 8.S 55.1 ~ 8 ~ 5.5 ~ 0.8 41.3 ~ 6 ~ 35.9 ~ 5.2 27.6 ~ 4 ~ 8.3 ~ 1.2 41.3 | 6 1 49 6 T 7 2 41.3 | 6 T 8.3 | 1.2 41.3 6 63.4 9.2 55.1 8 8.3 1.2 No. of Load Applications lo 500-1000 1 50 2 SO 3 50 1 4 50 5 50 6 SO 7 50 8 50 9 50 1 0 50 1 1 50 12 SO E-18
From page 361...
... 8.5.2.4 Specimen Testing - The resilient modulus test is performed following the loading sequences in Table E-3 using a haversine shaped load pulse as described above. Decrease the cyclic axial stress to 20.7 kPa (3 psi)
From page 362...
... Table E-3. Testing sequence for base/subbase materials ~ Confinin 3 | Max.Axial | Cyclic Str' as| Contac~Suess ~ No.
From page 363...
... If the axial permanent strain exceeds 5 %, the test is complete. 8.5.2.9 Permanent Deformation Test The permanent deformadon test is performed by continuing to apply cyclic load to the specimen after Me completion of the resilient modulus test.
From page 364...
... 8.5.3 Remove the membrane from the specimen and use the entire specimen to determine moisture content in accordance with T265. 8.6 Modeling Environmental Moisture Cycle- An environmental moisture cycle test can, if desired, be performed before the permanent deformation or rapid shear test.
From page 365...
... If these values are not available, record the optimum moisture content, maximum dry density and 95 % maximum dry density values used as the basis for compaction of the specimen as per section 7.3.3. 10.3.~.5 Item ~ - Record the moisture E-23
From page 366...
... prior to resilient modulus testing. Record the moisture content at the completion of resilient modulus testing as per section 8.1.2.12.
From page 367...
... . For cohesionIess and low cohesion subgrade soils calculate and report the resilient modulus using equation (E-la)
From page 369...
... DRY DENSITY, Dime 9SX ~X.
From page 371...
... A1.~.2.2 Determine the mass of oven-dry soil solids (Ws) required to obtain the desired dry density (yg and moisture content (w)
From page 372...
... the mass of the wet soil and container to the nearest gram and record this value on Report Form XI.2.
From page 373...
... required to obtain the desired dry density cyst and moisture content (w) as follows: ws=453.59y,dV where: Ws = mass of oven-dry solids, g, E-31 Y,d - desired dry density, Ib/0c3, V = total volume of compacted specimen, id.
From page 374...
... This method covers the compaction of Type ~ soils for use in resilient modulus testing.
From page 375...
... Typical apparatus for vibratory compaction of Type 1 unbound materials A2.3.7 Measure, to the nearest 0.2S mm (0.01 inch) , the inside diameter of the membrane lined E-33 mold and the distance between the top ofthe lower porous stone and the top of the mold.
From page 376...
... The moisture content of this sample shall be conducted using AASHTO T265.
From page 377...
... ~ . ~ This method covers the compaction of cohesive Type 2 soils for use in resilient modulus testing.
From page 378...
... By having both spacer plugs reach the zero volume change simultaneously, more uniform layer densities are obtained. A4.3.5 Slowly increase the load untilthe plugs rest firmly against the mold ends.
From page 379...
... Moisture Content Methods <80 less than the moisture content at impact time of construction static >80 greater than or equal to the impact moisture content at time of construction <80 | greater then the moisture at time of construction E-37
From page 380...
... A4.3. 12 After compaction is completed, determine the moisture content of the remaining soil using AASHTO T265.
From page 381...
... I Typical apparatus for static compaction of type 2 materials E-39
From page 382...
... steppes Lifts: COIT pardon ~tO be solid c~lodere of speckled heath' and 70.' mm (2.7~ dear.
From page 383...
... Step 3.7 ~ UR 2: · Measure ~ wet maw of HI to use for ~ layer. · Place In mom, ~e.
From page 385...
... Step 3.11 - ~ 4. · Measure sorry wet welds of 801 to use for ~ lay - .
From page 386...
... lot 4 left 2 Uft1 1~3 Uft6 I Step 3.13 - Lm 5: Measure Wet weight of ~ ~ use for ~ layer.


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