Aashto T 193-93
Aashto T 193-93
Aashto T 193-93
373
METHODS OF SAMPLING AND TESTING T 193
oximately 5l mm (2.0 in.) in height suitable for mainraining the *,ater level with thc compaction method specified,
rd a perforated base plate that can be I in. (2-5 rrrm) above rhe rop o[ the speci- either T 99 or T 180. A previously per-
ted to either end of the rtrold (See merls. fbrmed cbmpaction test on the same rna-
gure I ). lt is desirable to have at least 4.10 Drt'ing Oven-A rhermostari- terial may be substituted for the compac-
ree molds tor each soil to bc tested. cally controlled drying oven capable of tion test just described, provided rhar if
4.2 Spacer Disk-A circular spacer maintaining a ternperarure of I l0 t 5"C the sample contains rnaterial retained on
sk made of metal 150.8 I 0.8 mm (230 i 9"F) for drying moisrure samples. the 19 mm (1/1-in.) sieve, soil prepared
,t:/,n t
'/r, in.) in diame(er and 61.4 t 4.11 Moi.sture Content Contain- as described in Section -5.1 is used
25 mm (2.416 t 0.01 in.) in height ers-As specified in T 265. (NOTE 3).
ee Figure l). 4.12 M i.sc'e llaneorrs-M iscellancous
tools such a.s mixing pans, spoon.s, NOTE }-Maximum dry unir weighr ob-
NOTE l-When using molds having a straightedge, tllter paper, balances. etc. tained from a compaction test performed in
:ight of 177.8 mm (7.0 in.) (see Figure l), a 4-in. (101.6 mm) diamerer mold may be
spacer disk height of 61.37 mm (2.416 in.) slightly greater than the maximum dry unir
needed to obtain a thickness of compacted r,veight obtained from compaction in rhe 6-in.
recimen that conforms to the thickness: 5. SAMPLE (152.4 mm) compaction mold or CBR mold.
16.43 mm (4.584 in.) of specimens in T 99
rd T 180. 5.1 The sample shatl be handlerl and 6.2 Bearing Rario for a Range of
specimerr(s) for compaction shall be pre- Water Conrent. Using rhe 6.8 kg (15
,_ ftayruns7-fi rarnmer as speci- pared in accordance with the procedures lb.) specimens prepared as described in
red in either T 99 or T 180. given in T 99 or T 180 for compaction Section 5.1, determine
4.4
Apparatus for Measuring Expan-
the optimurn
in a 152.4-mm (6-in,) rnold except as fol- moisture content and maximum dry den-
ion-This consists of a swell plate with lows: sity in accordance with. the compaction
djustable stem (Figure l) and a tripod 5.1.1 If all material passes a 19 mm method specihed, either T 99 (Method
upport for a dial indicator (Figure 1). (r/.-in.) sieve, the entire gradation shall
'he swell plate is made of metal, 149.2 D) or T 180 (Method D) excepr rhat
be used for preparing specimens for com- the CBR molds shall be used and each
: 1.6 mm (57/s ! 'lru in.) in diameter paction wirhout modification. If there is specimen shall be penetrated for CBR
nd is perforated with 1.6 mm ('/ro in.) material retained on rhe l9 mm ('/u-in.) determination- In addition, the complete
iameter holes. The tripod used to sup- sieve, the material retained on the 19
,ort the dial indicator is arranged to.fit moisture-density relationship for 25-
mm (r/.-in.) sieve shall be removed and blow and l0-blow per layer compactions
n-e mold extension collar. replaced by an equal amount of material shall be developed and each test speci-
4.5 Indicarors---Two dial indicators: passing the 19 mm (r/,-in.) sieve and men compacted shall be penetrated. Per-
ach indicator shall have a 25 mrn ( I in.) retained on the 4.75-mm (No. 4) sieve form all compaction in CBR molds. [n
hrow and read to 0.02 mm (0.001 in.). obtained by separation frorn porrions of cases where the specified unit weight is
4.6 Surclwrge Weights-One annu- ,
the sample not otherwise used for testing. at or near 100 percent maximum dry unit
ar metal weight with a center hole ap- 5.1.2 Bearing Ratio at Optimum Wa- weight, it will be necessary to include
rroximately 54.0 mrn (2tls in.) in diame- ter Contenl. From a sample weighing 35
er and
a compactiye effort greater than 56-
several slotted or split metal kg (75 lb.) or more, select a representa- blows per layer (NOTE 4).
veighrs, all 149.2 t 1.6 rnm (57/s ! tlro tive portion weighing approximately I I
n' diameter and each weighing 2.27 kg (25 lb.) for a moisture-density tesr
"r NOTE L-A semilog plot of dry
kg (5 * 0.10 lb)
unit
t -.04 (Figure l) and divide the remainder of the sample to weight versus compactive effort usually gives
NOTE 2). obtain 3 representative porrions weighing a straight line relation when compactive effort
approximately 6.8 kg (15 lb.) each. in fi-lb/ftr is plotted on rhe tog scale. This typc
NOTE 2-When using split weights, the 5.1.3 Bearing Ratio for a Range of of plot is useful in establishing rhe compacrivc
+ 0.0a kg. (5
nass of the pair shall be 2.27 effort and nurnber of blows per layer needed
Water Conrent. From a sample weighing
: 0. t0 tb.),
250 lb. (113 kg) or more, seleo ar least to bracket the specified dry unit weight and
water content range-
4.7 Penetration Piston-A metal
5 representative portions weighing ap-
proximately 6.8 kg (15 lb) each for use
riston of circular cross-section having a 6.2.1 If the soaked CBR is ro be
Jiameter of 49.63 t 0.13 mm (1.954 *
in de-veloping each compaction curve.
determined, take a representative sample
1.005 in.) (1935 mmz, area :3 in.]) and of the material, for the determination of
;lot less than 102 mm (4 in.) long (see moisture, at the beginning of compaction
Figure I ). 6. IUOISTURE.DENSITY
. of each specimen and another sample of
4.8 Device-A compres-
Loading RELATION the remaining material after compaction
sion-type apparatus capable of applying of each specimen. Use T 265 to deter-
a urriformly irtcreasing load up to 10000 6.1Bearing Ratio at Optimum Water mine the moisture content. [f the un-
Ib (44.5kN) at a rate of 1.3 mnr (0.05 in.) Conrent. Using the II kg (25 lb.) portion soaked CBR is to be detennined, take a
per min., used to force the penetration prepared as describecl in Section 5.1, moisture content sample in aciordance
piston into the specimeri. determine the optimum moisture content with T 99 qr T 180 if the average mois-
4.9 Soaking Tank-A soaking tank and maximum dry density in accordance ture content is desired.
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TABLE OF MEASUBEMENTS
TF.IPOO FO8 DETHMINING EXPANSION SURCHAFGE I SpaC=a OISC
MATERIAL
OIMENSION A I c o
SIEEL
ElriGlx
I sreer_ .
OIMENSION I
n'
mm.
MEiRrC. rl:2llr.llI
i 56 'ir9'. 3Z i4604i5O.B l69B I;S.a |:9.0tiA
IOLEFAT{CE. mnr I
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- IOLERAAICE. rn. ffi:E';;6li:'iri
I
I. PROCEDURE (l5 lb.) portions prepared in Section in contact with the filter paper. Clamp
5.1.2 with sufficient water to obrain the to the mold and
the perflorated base plate
7.1 Bearing Ratio at Optimum Wa- optimum moisture content determined in attach the collar. Weigh the mold and
er Content. Section 6.1. specimen to the nearest 5 g (0.01 lb.).
7.L.1 Normally, 3 specimens must 7.1.4 Compact one of the portions 7.1.7 Compact the other two (6.8 kg)
)e compacted so that their compacted of soil-water mixture into the mold in 3 (15 lb.) portions in accordance with the
lenslties range from 95 percent (or equal layers to give a total compacted procedure in Sections 7 .1.4 through
ower) to 100 percent (or higher) of the depth of about 127 mm (5 in.) compact- 7.1.6, except that an intermediate number
maximurn dry density determined in Sec- ing each layer with the lowest selected of blows per layer should be used to
tion 6.1. number of blows in order to give a com- compact the second specimen and the
pacted density of 95 percent or less of highest number of blows per layer shall
NOTE S-Generally about 10, 30, and 65 the maximum density. be used to compact the third specifien.
blows per layer are suitable for compacting 7,1.5 Deterrnine the moisture con- 7.2. Beanng Ratio for a Range of
specimens l, 2, and 3, respectively. More tent of the material being compacted at Water Content.
than 56 blows per layer are generally required
to mold a CBR specimen to 100 percent of
the beginning and end of the compaction 7.2.1 Prepare specimens in accor-
procedure (2 samples). Each moisture dance with Section 6,2. Perform all com-
the maximum dry density determined by T
sample shall weigh at least I00 g for paction in the CBR molds. Each speci-
99 (Method D); this is due to the sample for
the moisture-density test being reused, while fine-grained soils and 500 g for coarse- men used to develop the compaction
th, 'ample for the CBR specimen is mixed grained soils. Determination of moisture curyes for the lO-blow,25-blow. and 56-
tu ,ompacted only once. content shall be done in accordance with blow per layer compactive efforts shall
NOTE 6-Some laboratories may prefer T 265, Laboratory Determination of be penetrated. [n cases where the speci-
to test only one specimen, which would be Moisture Content of Soils. fied unit weight is at or near 100 percent
compacted to rnaximum dry density at opti- 7,1.6 Remove the extension collar, maximum dry unir weight, it will be
mum moisture content as determined by T 99. and using a straightedge, trim the com- necessary to include a compactive effort
pacted soil even with the top of the mold. greater than 56 blows per layer
7.1.2 Clamp the mold to rhe base Surface irregularities should be patched
plate, attach the extension collar and with small-sized material. Remove the
weigh to the nearest 5 g (0,01 lb.). lnsert spacer disk, place a coarse filter paper
the spacer disk into the mold and place on the perforated base plate, inverl the
8. SOAKING
a coarse filter paper on top of the disk. mold and compacted soil and place on
7.1.3 Mix each of the three 6.8 kg the filter paper so the compacted soil is
E.l Place the swell plate with adjust-
able stem on the soil sarnple in the rnold
and apply sufficient annular weights to
aoo produce an intensity of loading equal to
the mass of the subbase and base courses
and surfacing above the tested material,
2.26 kg (t 5 lb.) but in no case shall
the mass be less than 4.54 kg (10 lb.).
H0 coireclto E.2 Place the tripod with dia! indica-'
er rtourl(0 corrccrEo Loro v^L!,ct
a
l7 O.t ti. 2[HCtr^rlo^. tor on top of the mold and make an
I
initial dial reading.
ir* 8.3 Immerse the mold in water to
3 allow free access of water to top and
U bottorn of the specimen. During soaking,
I
i soo
orrtcrfo Loao Y^LUtt
maintain the water level in the mold and
o the soaking tank approximately 25.4 mm
Ar o.l tx. Pf xErraTrotr
v (1.0 in.) above the top of the specimen.
.J
t Soak the specimen 96 hours (4 days).
: 200
: NOTE 7-A shorter irnmcrsion period (not
3 less than 24 hours) may be used for soil-
aggregate materials that drain readily if tests
show that the shorter perid does not affect
the test results. For some clay soils, a soaking
period greater than 4 days may be required.
lGrJs rEO Ofi6r Ht roR concrvE -UPvMo
txlpf ff CUR/Et
8.4 At the,end of 96 hours, make a
,fnaTlrrloi- lxcxt final dial reading on the soaked speci-
mens and calculate the swell as a percent-
FIGURE 2 Correction of Stress-strain Cuvres age of the initial sample length:
1'193 IvlE.I.I{ODS OF SA|.-IPLING AND TESTING 377
Percint swell = der of the surcharge weights shall then instances, the initial penetration takes
fhange in length in be placed around the pision place without a proportional increasc in
in. during soaking \., r rv\
n rL/v 9.2 Seating Prsron-Seat rhe pene- the resistance to penetration and the
4.584 in. tration piston with a l0 lb. (44 N) load. curve may be concave upward. To obtain
then set both the penerration dial indica- thc tnre stress-strain relationships, cor-
8.5 Remove the specimens from the tor and the load indicator to zero.
soaking tank, pour the water off the top
rect the curye having concave upward
9.3 Application of l-oad-Apply the shape near the origin by adjusting rhe
and allow to drain downward for 15
loads to the penetration piston so the location of the origin by exrending the
minutes. Care shall be taken not ro dis-
rate of penetrarion is uniform at 1.3 mm straightline portion of the stress-srain
turb the surface of the specimens during
(0.05 in.) per minute. Record the load curve downward until it intersects the
removal of the water. After draining, when the penetration is 0.64, l.Z'1, l.gl, abscissa (See dashed lines).
remove the surcharge weights and perfo-
2.54, 5.08, and 7.62 mm (0.025, 0.050, 10.2 California Bearing Rario-The
rated plates.
0.075, 0.100, 0.150, 0.200, and 0.300 conected load values shall be determined
NOTE 8-The specimens may be weighed
in.). Load readings at penetrations of for each specimen at 2.54 and 5.08 mm
after draining when it is desired to determine 10.16 and 12.70 mm (0.a0O and 0.500 (0.10 and 0.20 in.) penetrarion. Califor-
the average wet density of the soaked and in.) may be obtained if desired. nia Bearing Ratio values are obtained in
drained material. percent by dividing the corrected toad
NOTE 9-The moisrure conrenr of the values at 2.54 and 5.08 mm (0.10 and
upper 25 mm (1.0 in.) may be determined 0.20 in.) by the standard loads of 1000
after testing if desired. Moisrure samples shall
9. PENETRATION TEST weigh at lcast l0O g for frne-grained soils
and 1500 psi (6.9 and 10.3 Mpa), rcspec-
tively, and multiplying these ratios by
and 500 g for granular soils.
100.
9.1 Application of Surcharge-Place
a surcharge of annular and slotted
Corrccted load value
weights on the specirnens equal to that CBR =
Standard Load
x 100
_ sed during soaking. Tb prevent dis- IO. CALCULATIONS
placement of soft materials into the hole 10.2.1 The CBR is generally se-
of the surcharge weights, seat the pene- 10.1 Stress-Strain Curve-Plor rhe lected at 2.54 mm (0.10 in.) penetration.
tration piston after one surcharge weight stress-strain (resistance to penetration- If the ratio at 5.08 mm (0.20 in.) pcnetra-
has been placed on rhe specimen. After depth of penetration) curve for each spec- tion is greater, the test shall be rerun. If
seating the penetration piston the remain- irnen as shown in Figure 2. In some the check test gives a similar result, the
rt3
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Not' t'-suEn"8c = 50 lb' soalirs r.d P.n.r.tion. Atl sempkr so.k.d lo9 .0d borrcm rour d.ys. A silnpr.s comprrcd i. 5 ta),.G, to-lb. h.mrrEa rE-ir drop in cBR
FIGURE 4 Deterrnining cBR for water content Range and Minimum Dry Unit Weight
ratio at 5.08 mm (0.20 in.) penerrarion 10.4 Design CBR for Warer Content 11. REPORT
shall be used. Range-Plot the data from the tests at
103 Design CBR for One Water the three compactive efforts as shown 11.1
Content Only-Using the data obtained
The reporr shall include the lol:
in Figure 4. The data plotted as shown lowing information for each specimen:
f-^rn the 3 specimens, plot rhe CBR-Dry represents the response of the soil over ll.f .1 Compaction effort (number of
.*^rsiiy as Molded relation as shown in the range of water content specified. Se- blows per layer).
Figure 3. The design CBR may then be lect the CBR for reporting as the lowest ll.l.2 Dry density as molded pct.
determined at the desired percentage of CBR within the specified water conrent 11.1.3 Moisture content as molded
the rnaximum dry density, normally the range having a dry unit weight between Pct.
minimum percentage compaction per- the specified minimum and the dry unit .4 Swell (percent of
11.f original
mitted by the agency's compaction spgci- weight produced by cornpaction within
length) pcr.
fications. 11.1.5 California Bearing Ratio pct.
the water content range.
^;'