A SIMPLIFIED METHOD FOR IDENTIFYING THE PREDOMINANT CLAY MINERAL IN SOIL by Eugene C. Mojekwu, B.S. in C.E. A THESIS IN CIVIL ENGINEERING Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirement for the Degree of MASTER OF SCIENCE IN CIVIL ENGINEERING Approved Accepted December, 1979
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A SIMPLIFIED METHOD FOR IDENTIFYING THE
PREDOMINANT CLAY MINERAL IN SOIL
by
Eugene C. Mojekwu, B.S. in C.E.
A THESIS
IN
CIVIL ENGINEERING
Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirement for the Degree of
MASTER OF SCIENCE
IN
CIVIL ENGINEERING
Approved
Accepted
December, 1979
ACKNOWLEDGMENTS
I am deeply indebted to Dr. Warren K. Wray for his guidance
and counseling during this research. I am also grateful to Dr.
C.V.G. Vallabhan for his advice and useful criticisms.
Grateful acknowledgment is also made to the Civil Engineer-
ing Department of Texas Tech University for providing me with
financial support during this research.
Sincere appreciation is also extended to the following soil
sis, and infrared analysis. These available methods are frequently
laborious, expensive, lengthy and require expensive,intricate equip-
ment that is, in general, too sophisticated and expensive to be
found in the ordinary commercial soils testing laboratory.
1.2 Purpose and Scope of Thesis
The purpose of this study is to find a simplified method of
identifying the predominant clay mineral in a soil. The correla-
tion chart developed by Pearring (9) and Holt (3) offered a simple
1
way of doing this except thatcation exchange capacity (CEC) is one
of the required parameters. Since the CEC is not typically evalua-
ted in normal practice, a simplified way to evaluate CEC was needed
without using the expensive equipment normally required to do so.
The Atterberg limits are easily obtainable and usually performed
and, hence, the objective of this study was to investigate the possi-
bility of a relation between CEC and Atterberg limits as a way to
avoid using the conventional tedious means of cation exchange capa-
city determination.
When the final relationship between CEC and Atterberg limits
was determined, a check of the overall method was made. The approach
was to arbitrarily identify some samples using the above method in
conjunction with Pearring-Molt correlation chart and then compare the
results to clay mineral identifications, on the same samples accom-
plished by X-ray diffraction analysis.
1.3 Review of Literature
The review of literature pertaining to this study v/as made
and is presented under the three headings: (1) Expansive Soils,
(2) Atterberg Limits, and (3) Available Methods for Clay Mineral
Identification.
1.3.1 Expansive Soils
The expansive soil problem has long instigated a lot of inves-
tigations which began as early as 1931 (3). Terzaghi (13) was the
first to look into the problem of expansive soils. In his work,
he concluded that swell is directly related to the electrical charge
on the clay mineral and the surface tension of the water it contains.
Since Terzaghi (13), other important contributions have been
made in the area of swelling soils and researchers (3, 13, 14, 22,
51) generally tend to agree that soil expansion is related to the
type and amount of clay mineral, the hydration rate of the adsorbed
ions, the amount of exhangeable cations the negatively charged min-
eral is capable of adsorbing (cation exchange capacity), and the a-
nount and composition of the pore water.
3
1.3.1-A The Effect of Clay Minerals on Expansion: Clay
minerals are the primary cause of soil volume changes (swelling and
shrinking). It has been reported that clay minerals are commonly
crystalline and contain chiefly silicon, aluminum, oxygen and water (12).
According to the combinations in which these constituents occur,
most of the minerals can be divided into three major groups: smec-
tite (montmorillonites being the most abundant), illite, and kaoli-
nite. Terzaghi and Peck (12) reported that these minerals have the
same laminated crystalline structure but wery different surface ac-
tivities. They also reported that kaolinites are the least active,
followed by illites. Smectites, they reported, are the most active
and have the capacity to swell by taking water molecules directly
into their space lattice. This type of swelling is referred to as
intramicellar swelling. The other type of swelling, intermicellar
swelling, occurs between clay minerals and is exhibited by all clay
minerals.
1.3.1-B The Effect of lons on Expansion: Terzaghi and
Peck (12) reported that the surface of ewery soil particle carries
a negative electric charge. These negative charges, they reported,
attract the positive ions (or cations) in the adsorption complex.
These cations have been found to have appreciable effect on the
expansive character of clay. It is reported, by Holt (3), that
cations have varying hydration rates. In his work, Baver (14)
concluded that ions with the least ionic radii have the greatest
hydration rates and, thus, cause the greatest swell.
1.3.1-C The Relationship Between CEC and Expansion:
As Terzaghi and Peck reported, the surface of every soil particle
carries a negative electric charge. The intensity of the charge
depends largely on the mineral. Minerals are said to have high or
low surface activity, depending on the intensity of the charge.
The negatively-charged soil particle attracts cations which
have migrated from the surrounding liquid into the adsorbed layer
(water located within the charge's influence). These attracted
cations can be replaced by other cations that may migrate to the ad-
sorption complex (13).
The sequence of the replacing power of the common cations has not
yet been resolved. Way (15) concluded that the sequence of the repla-
cing power of the common cations was: sodium (Na), potassium (K),
calcium (Ca), magnesium (Mg), and ammonium (NH4). This means, for
instance, that ammonium will more easily replace calcium than
calcium will replace ammonium. However, as the study in cation re-
placeability was expanded, it became obvious that there was no univer-
sal replaceability series. The series varied depending on the experi-
mental conditions, on the cations involved.and on the type of clay
material (15).
The ease with which a cation replaces another depends on a number
of factors. As Grim (15) reported, the ability of a cation to replace
another increases as the concentration of the replacing cation is in-
creased. He also said that the nature of the valence of the cations
influence replaceability in that, all other things being equal, cations
with higher valences have greater replacing power and are more diffi-
cult to displace when already on the clay. For cations with the same
valence, he reported, replacing power depends on hydrated size; the
smaller the hydrated size of the ion, the greater the replacing power.
Grim also noted that replaceability depends on the nature of the anion
in the replacing solution. For instance, replaceability of sodium
cation from montmorillonite by calcium cation varies depending on
whether calcium sulphate or calcium hydroxide is used [sulfate (S0-~)
and hydroxide (0H~) are the anions involved].
The process of cations replacing other cations on the surface
of an active material, for example clay, is known as base exchange.
The amount of cations that the surface of the soil is capable of ad-
sorbing and exchanging is known as the cation exchange capacity, mea-
sured in milliequivalents (meq) per lOOg of sdil. A wery active surface
adsorbs more exchangeable cations. A high cation exchange capacity
value thus indicates a high surface activity and, thus, a high swell
potential. Grim (15) reported that montmorillonite, the most active
clay mineral, has CEC values in the range of 80-150 milliequivalents
per lOOg. The second most active, illite, has values ranging from
10 to 40 meq per lOOg and the least active, kaolinite, has a range of
3 to 15 meq per lOOg. These values, however, are for pure minerals
which are seldom found in nature.
1.3.1-D The Effect of Pore Water on Expansion: Water is a
known prerequisite for swelling. Yong and Warkentin (22) reported
that increases in the salt content of the pore water reduces swelling,
especially when monovalent ions prevail in the pore water. According
to Holt (3), water sorption follows the process of osmosis. If the
concentration in the pore water of the soil matrix is less than
that of the surrounding pore water sorption takes place, followed
by swelling. Adding salt to the surrounding pore water reduces its
concentration and, hence, swelling.
1.3.2 Available Clay Mineral Identification Methods
Many methods are presently available for identifying clay min-
erals in a soil in order to better assess its potential for shrink-
swell activity. The methods commonly used include X-ray diffraction,
chemical analysis, electron microscope resolution, differential ther-
mal analysis, gravimetrical analysis, and infrared analysis.
The available methods are frequently laborious and time consum-
ing and require expensive and intricate equipment that is, in general,
too sophisticated and expensive to be found in the ordinary commercial
soils testing laboratory.
In 1968, Pearring devised two parameters to aid in empirically iden-
tifying the predominant clay mineral in lateritic soils. The first para-
meter he called Cation Exchange Activity (CEAc) and defined as the ratio
of the cation exchange capacity to the percent clay content. The second
parameter he established was termed "Activity Ratio" and defined as the
ratio of the plasticity index to percent clay. This parameter is a mod-
ified "Skempton's Activity Ratio." Skempton (23) defined his activity
ratio as the ratio of the plast city index to the percent clay fraction.
Percent clay fraction as used by Skempton is the percentage by weight of
the whole sample that is less than 2vi. Pearring recognized the fact that
particles coarser than 2y impart some degree of plasticity to the soil and
defined percent clay content as the percent less than 2y of the soil
material passing the No. 200 sieve.
With the above two parameters, a correlation chart was devel-
oped to aid in identifying the common clay minerals of montmorillo-
nite (smectite), illite, kaolinite, halloysite, and attapulgite
(Figure 1). The horizontal and vertical lines of the several clay
mineral zones show the approximate ranges for the cation exchange
activities and activity ratios of the minerals making up the zone.
Pearring showed that this chart is applicable to lateritic soils
as depicted by the regression curve, A of Figure 1. In 1979, Holt
(3) further extended the correlation chart to include the montmoril-
lonite mineral group as shown by line B of Figure 1.
The parameter, cation exchange activity, is dependent on the
cation exchange capacity as well as the percent clay content. The
cation exchange capacity is an expensive and lengthy parameter to
obtain, and a quick and inexpensive way of doing this is needed to
help simplify the Pearring-Holt method even further.
1.3.3 Atterberq Limits
In 1911 Atterberg (16) proposed four different soil consis-
tencies for agricultural purposes. The consistencies proposed were
sticky, plastic, soft, and harsh. Casagrande (17) in 1932 modified
these consistencies for engineering purposes. He said that soil can
be divided into four states of consistency, namely, solid, semi-
solid, plastic and liquid. The boundary between the solid and semi-
solid state is the shrinkage limit. The boundary between the semi-
solid state and the plastic state is the plastic limit and the
boundary between the plastic state and the liquid state is the
liquid limit.
Atterberg's work was primarily concerned with the plasticity
of soil. He noted that the plasticity of soil was directly affected
by the presence of organic matter. Since Atterberg, researchers have
found that soil plasticity not only depended on the presence of or-
ganic matter, but also on the size, quantity, and type of predominant
clay mineral, water content, and the type of exchangeable cations
(3, 14, 23).
o < Ul o
o < Ul «9 < X u X UJ
< o
2.0
1.5
1.0
1.8
0.6
0.4
0.2
0.1
IN
HALLOYSITE
MONT
TERSTRATIFIED
/
A /
/ ILLH / CHLOR
/ KAOLI
/lORILLON
j
'E ITE IITE
TE
\.r»
/
/
ATTA
/
/
PULQ ITE
i
i f
i
0.1 0.2 0.4 0.6 0.8 1.0
ACTIVITY (Ac)
1.5 3.0
FIGURE 1 CORRELATION OF CATION EXCHANGE ACTIVITY, ACTIVITY RATIO, AND CLAY MINERALS OF MONTMORILLONITIC AND LATERITIC SOILS (AFTER PEARRIN6 (9) AND H0LT(3))
8
Holt (3), reported that while coarse-grained particles have no
plastic properties, flat-surfaced particles have a high degree of
plasticity and spherical grains exhibit a limited amount of plasti-
city. Hareens, et al., (3), concluded in their work that particle
size less than l.Oy (O.OOlmm) have pronounced effects on the liquid
and plastic limits which, in turn, highly influence plasticity.
The amount of clay particles have also been reported to in-.
fluence plasticity. Skempton's (23) work clearly depicts this
phenomenon. He found that the plasticity index increases as the
percentage clay fraction increases. In his work, Baver (14), also
concluded that plasticity increases as the percentage of clay frac-
tion increases and mathemetically expressed plasticity as a function
of the amount of clay thus:
Plasticity Index = 0.6 x (% clay) - 12 (1.1)
The rate at which plasticity increases, as percent of clay
increases, is dependent on the activity of the soil. Activity,
as defined by Skempton (23) is the ratio of the plasticity index
to the percentage by weight of the whole sample finer than 2y. As
is evident from Figure il, one can reasonably expect an active soil
to exhibit a higher plasticity than a soil that is relatively less
active. In support of Skempton's work, it has been reported (3)
that soils containing montmorillonite, the most active mineral,
exhibit higher plasticity than soils containing the same percen-
tage of kaolinite and illite.
As regards to the effect of ions on plasticity, Holt (3) re-
ported that soils saturated with univalent ions, generally, have
more plasticity than soils saturated with divalent ions.
The Atterberg limits, since their time of introduction, have
gained widespread acceptance as necessary parameters for engineering
knowledge related to soil properties. The procedures as originally
outlined by Atterberg have been greatly refined and specified in
sufficient detail so that persons anywhere can do the tests with
relative ease and in exactly the same manner. Some of the apparatus
100
UJ o fr UJ QL
x* UJ o
I -co <
80
60
40
20 -
\ 1 r (CLAY ACTIVITIES IN BRACKETS)
SHELLHAVEN (1.33)
LONDON CLAY (0.95)
WEALD CLAY (0.63)
HORTEN (0.42)
J-20 40 60 80
CLAY FRACTI0N«2Mm), PERCENT
100
FIGURE 2. RELATIONSHIP BETWEEN PLASTICITY INDEX AND CLAY FRACTION (AFTER SKEMPTON (23))
10
and procedures specified by the American Society of Testing and Mater-
ials (ASTM) have been found (24, 25, 26) to not be entirely satisfac-
tory because of excessive dependence on operator skill and judgment.
Extensive research by Ballard and Weeks (24) led to their conclusion
that plastic limit results reported on a single sample varied more be-
tween operators than results reported by a single operator. Thus, a
single operator has consistently reproducible results. Dawson (26) re-
searched and reported that liquid limits performed in accordance with
the ASTM method D423-59 varied considerably between laboratories and
in a particular case ranged from 58 to 71 percent. The results are,
however, reproducible within each laboratory. The works of Dawson,
Ballard and Weeks show that the plastic limit is more reproducible
between operators than the liquid limit, and, hence, the plastic
limit is a more dependable consistency parameter. Suggestions have
been made by researchers (24, 25, 26, 27, 28, 29) for changes of
techniques presently used for determining Atterberg limits, but as ,
of now the ASTM methods are still standard.
1.4 Definition of Terms
The aim of this section is to prevent unnecessary expansion
of the text and to eliminate confusion in the use of scientific •
terms.
The definitions that follow are as found in literature and
are those considered to be most acceptable and offer a source of
ready reference for the reader.
Absorption: The taking up of water by clay particles through capillary suction (3).
Activity Ratio (Ac): The ratio of the plasticity index to the percentage clay content (23). In this manuscript the percentage clay content is defined as the per-centage less than 2y of the soil material passing the U.S. No. 200 sieve (9).
n Adsorbed Layer:
Adsorption:
Adsorption Complex;
Cation Exchange:
Cation Exchange Activity (CEAc):
Caton Exchange Capacity (CEC):
Clay:
Clay Minerals:
Exchangeable Cation
Water located within the zone of influence created by the negative charge on a soil particle.
The adhesion of water molecules on the surface of clay minerals by the process of chemical bonding (3).
The adsorption complex is constituted by the attracted cations that enter the adsorbed layer.
The interchange between a cation in solution and another cation on a surface active material (3).
The ratio of the cation exchange capacity to the percentage clay content (9). Percent clay content is as defined in activity ratio.
The total amount of exchangeable cations that a soil is capable of adsorbing, measured in milliequiva-lents per 100 grams of soil.
The soil particles smaller than 2y which arederived from the chemical decomposition of rock. It consists, chiefly, of clay minerals but small amounts of quartz, feldspar, organic matter, soluble salts and amorphous materials are also present.
The extremely small crystalline hy-drous aluminum silicates found in clay material. Clay minerals com-prise a small family of minerals of which the most abundant are kaolinite, halloysite, illite, chlorite, vermi-culite,and smectite (the most abundant of this group is montmorillonite (9).
A cation that is capable of being exchanged with another cation in an adsorption complex.
12
Liquid Limit (LL): The water content, expressed as a percentage of the weight of the dry soil, at the boundary between the liquid and plastic states. The water content at this boundary is defined as the water content at which a groove, Imm wide, cut in the soil sample with a standard gooving tool, closes for a length of 1/2-inch when a brass dish containing the soil is dropped 25 times, at the rate of 2 drops per second, through a distance of 1 cm on a standard hard rubber base.
Plastic Limit (PL) The water content, expressed as a percentage of the dry weight of the soil at which the soil becomes crumbly and ceases to be plastic. The water content is defined as the water content at which the soil just begins to break apart and crumble when rolled, by hand, into threads one-eighth of an inch in diameter.
Plasticity Index (PI):
X-Ray Diffrac-tion Analysis
The difference between the greater moisture content of the liquid limit and the less moisture content of the plastic limit. It is de-fined as the range in water con-tents through which the soil remains in the plastic state.
A technique used to identify clay minerals. It can be applied to clay mineral identification through the application of Bragg's Law (37) which states that:
where.
nx = 2dsinø
n = order of relection
X = wave length of X-ray beam
d = distance between two like planes
e = angle of diffraction.
The distance, d, can be calculated and used to identify the predominant clay mineral when the wave length, X, and the angle of diffraction, e, are known
CHAPTER 2.
rWERIALS AND TEST METHODS
2.1 Materials
The undisturbed soil samples, taken from depths of 1 to 11 feet,
were obtained from practicing geotechnical engineering firms and tes-
ting laboratories located in a number of Texas cities. The cities
As is evident from Table 5, the correlation equation method
identifies the same clay mineral as the other, more sophisticated
and more expensive methods. The correlation equation can, thus,
be authoritatively said to be a viable and simplified aid in clay
mineral identification.
3.3.4 Summary
The work of first Pearring and then Holt have shown that the
activity ratio and the cation exchange activity of a soil can be
useful in identifying the predominant clay mineral in the soil.
Their work has been further simplified by this study which shows
that the tedious step of determining cation exchange capacity can
be eased by a relationship between cation exchange capacity and
plastic limit. This relationship, which is limited to plastic
limits in the range of 13.97% to 32.5%, is expressed as:
1.17 CEC = (PL) (3.7)
CHAPTER 4.
CONCLUSIONS AND RECOMMEflDATION
4.1 Conclusions
Three important conclusions may be reached from an investigation
of the data obtained under the testing conditions of this study:
(a) The Peech method using an inexpensive spectrophotometer produces reliable measurements of cation exchange capa-city as evidenced by its comparison to flame photometer results.
(b) A strong relation exists betv;een the cation exchange capa-city and the plastic limit for all soils tested. This re-lationship can be approximated, for soils with plastic limits in the range of 13.97% to 32.5%, by the expression:
CEC = (PL)^-"^^ (3.7)
(c) This expression can be used in conjunction with the Pear-ring and Holt Correlation Chart to easily and quickly identify the predominant clay mineral in a soil.
4.2 Recommendation
It is recommended that additional research be undertaken to
extend the applicability of the correlation equation to soils with
plastic limits outside the range of 13.97% to 32.5% used in this
investigation.
30
LIST OF REFERENCES
!• Chen, F. H., Foundations on Expansive Soils, Elsevier Scientific Publishing Co., New York, NY, 1975, p. 123, pp. 263-270.
2. Franzmhier, D. P., and Ross, S. J., "Soil Swelling: Laboratory Measurement and Relation to Other Soil Properties," Pro-ceedings, Soil Science Society of America, Vol. 32, No. 4., July-August, 1968, pp. 573-577.
3. Holt, J. E., "A Study of the Physio-Chemical, Mineralogical, and Engineering Properties of Fine-Grained Soil in Relation to Their Expansive Characteristics," Dissertation presented to Texas A&M University, College Station, Texas, in 1967 in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy.
4. Jones, D. E., and Holtz, W. G., "Expansive Soils—The Hidden Disaster," Civil Engineering-ASCE, Vol. 43, No. 8, New York, NY, August, 1973, pp. 49-51.
5. Jumikis, A. R., Soil Mechanics, D. Van Nostrand Co., Inc, Prince-ton, New Jersey, 1966, pp. 67-69.
6. Lytton, R. L., "The Characterization of Expansive Soils in Engi-neering," Presented at the December 1977, American Geophy-sical Union Conference, held at San Francisco, CA, pp. 63.
7. McKeen, R. G., "Characterizing Expansive Soils for Design" Pre-sented at the October, 1977, Joint Meeting of the Texas, New Mexico and Mexico Sections of ASCE, Albuquerque, NM, pp. 23.
8. Mitchell, J. K., Fundamentals of Soil Behavior, John Wiley & Sons, Inc, New York, New York, 1976. pp. 169-185.
9. Pearring, J. R., "A Study of the Basic Mineralogical, Physical-Chemical, and Engineering Index Properties of Laterite Soils," Dissertation presented to Texas A&M University at College Station, Texas, 1968, in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy.
10. Peech, M., "Determination of Exchangeable Cations and Exchange Capacity of Soils - Rapid Micromethods Utilizing Certrifuge and Spectro-Photometer," Proceedings, Soil Science Society of America, Vol. 1, 1945, pp. 25-38.
11. Van Der Merwe, D. H., "The Prediction of Heave from the Index and Percentage Clay Fraction of Soils," The Civil Engineer in South Africa, June, 1964, pp. 103-107.
31
32 12. Terzaghi, K., and Peck, R. B., "Soil Mechanics in Engineering
Practice," John Wiley & Sons, Inc, New York, NY, 1948, pp. 10-13.
13. Terzaghi, K., "The Swelling of Two Phse Systems," Colloid Chemistry (J. Alexander), Vol. 3, D. Van Nostrand Co., New York, NY, 1931, pp. 65-88.
14. Baver, L. D., Soil Physics, John Wiley & Sons, Inc, New York, NY,
1956.
15. Grim, R. E., Clay Mineraloqy, McGraw-Hill, 1953, pp. 188-224.
16. Atterberg, A., "Die Plastizitat der Tone," Internationale Mittei-lungen fur Bodenkunde, Vol. 2., 1912, pp. 149-188.
17. Casagrande, A., "Research on the Atterberg Limits of Soils," Public Roads, Vol. 13, No. 8, 1932.
18. Wray, W. K., "Development of a Design Procedure for Residential and Light Commercial Slabs-on-Ground Constructed Over Ex-pansive Soils," Dissertation presented to Texas A&M Univer-sity at College Station, Texas, 1978, in Partial Fulfill-ment for the Degree of Doctor of Philosophy.
19. Bowles, J., "Engineering Properties of Soils and Their Measure-ment," McGraw-Hill Book Company, New York, NY, 1979, pp. 4U51.
20. Seed, H., Woodward, R. J., and Lundgren, R., "Fundamental Aspects of the Atterberg Limits," Proceedings, Soil Mechanics and Foundation Division, ASCE, SM6, November, 1964, pp. 75-104.
21. Moum, J., and Rosenqvist, I., "On the Weathering of Young Marine Clay," Proceedings, Fourth International Conference on Soil Mechanics and Foundation Engineering, London, Vol.l, 1957, pp. 77.
22. Yong, R. N., and Warkentin, B. P., Introduction to Soil Behavior, The MacMillan Company, New York, NY, 1966.
23. Skempton, A. W., "The Colloidal Activity of Clays," Proceedinqs, Third International Conference on Soil Mechanics and Founda-tion Engineering, Vol. 1, Switzerland, 1955, p. 57.
24. Ballard, G. E. H., and Weeks, W. F., "The Human Factor in Deter-mining the Plastic Limit of Cohesive Soils," Materials Re-search and Standards, MTRSA, Vol. 3., No. 9, September, 1963, pp. 726-729.
25. Sowers, G. F., "Introduction," Proceedinqs of the ASTM Symposium on Atterberg Limits, Special Technical Publication (STP), No. 254, pp. 159.
33
26. Dawson, R. F., "Investigations of the Liquid Limit Test on Soils," Proceedings of the ASTM Symposium on Atterberq Limits, Special Technical Publication (STP), No. 254, pp. 199-195.
27. Mitchell, J. E., "Liquid Limit Results from Various Types of Groov-ing Tools," Proceedings of the ASTM Symposium on Atterberg Limits, Special Technical Publication (STP), No. 254, pp7 197-200.
28. Morris, M. D., Ulp, R. B., and Spinna, J. R., "Recommendation for Changes in the Liquid Limit Test," Proceedinqs of the ASTM Symposium on Atterberq Limits, Special Technical Publication (STP), No. 254, pp. 202-211.
29. Nuyens, T. A. E., and Kockaeitz, R. F., "Reliable Techniques for Determining Plastic Limit," Materials Research and Standards, Vol. 7, No. 7, 1967, pp. 295-299.
30. Eden, W. J., "Use of a One-Point Liquid Limit Procedure," Proceed-ings of the ASTM Symposium on Atterberg Limits, Special Tech-nical Publication (STP), No. 254, pp. 168-75.
31. Harter, R. D., "Reaction of Minerals with Organic Compounds in Soil," Chapter 20, Minerals in Soil Environment, Editors Dixon, J. B., and Weed, S. B., Soil Science Society of Ameri-ca, Madison, WI, 1977.
32. Ensminger, L. E., and Gieseking, J. E., "The Adsorption of Proteins by Montmorillonite Surfaces: Ethylene Glycol," Soil Science Society of America, Vol. 51, 1941, pp. 125-132.
33. Kown, B. T., and Ewing, B. B., "Effects of the Counter-Ion Pairs on Clay lon-Exchange Reactions, Soil Science of America, Vol. 108, 1969, pp. 231-240.
34. DeSilva, J. A., and Loth, S. J., "Cation Exchange Reactions, Elec-trokinetic and Viscometric Behavior of Clay-Organic Complexes," Soil Science Society of America, Vol. 97, 1964, pp. 63-76.
35. Hocking, R. R., and Leslie, R. N., "Selection of the Best Subset in Regression Analysis," Technometrics, Vol. 9, 1967, pp. 531-540.
36. LaMotte, L. R., and Hocking, R. R., "Computational Efficiency in the Selection of Regression Variables," Technometrics, Vol. 12, 1970, pp. 83-93.
37. Resnick, R., and Halliday, D.. "Physics," John Wiley & Sons, Inc, New York, NY, 1966, pp. 1140-1143.
APPENDIX A
COUNTIES, GEOLOGY, AND CLIMATE OF THE CITIES AND THE DEPTHS FROM WHICH SOIL SAMPLES WERE OBTAINED
34
35
Sample No.
001-01
003-01
004-01
005-01
008-01
010-01
011-01
012-01
013-01
015-04
017-04
021-04
026-02
028-02
029-02
030-02
033-02
035-02
036-03
038-03
040-03
041-03
042-03
044-03
046-03
047-03
048-03
049-07
050-07
055-05
057-05
058-05
059-05
061-05
Location (City)
Sugarland, TX
Deer Park, TX
Deer Park, TX
Houston, TX
Houston, TX
Houston, TX
Port Arthur, TX
Port Arthur, TX
Amarillo, TX
Amarillo, TX
Amarillo, TX
Amarillo, TX
Port Arthur, TX
Nederland, TX
Winnie, TX
Groves, TX
Beaumont, TX
Nederland, TX
Dallas, TX
Irving, TX
Dallas, TX
Crowell, TX
Crowell, TX
Arlington, TX
Arlington, TX
Amarillo, TX
Amarillo, TX
Bryan, TX
Bryan, TX
Whitehouse, TX
Diboll, TX
Hemphill, TX
Diboll, TX
Jefferson, TX
County(ies)
Fort Bend
Harris
Montgomery
Harris
Harris
Harris
Jefferson
Jefferson
Potter/Randall
Potter/Randall
Potter/Randall
Potter/Randall
Jefferson
Jefferson
Chambers
Jefferson
Jefferson
Jefferson
Dallas
Dallas
Dallas
Foard
Foard
Tarrant
Tarrant
Potter/Randall
Potter/Randall
Brazos
Brazos
Smith
Angelina
Hemphill
Angelina
Jefferson
Depth (feet)
0.5
3.0
9.5
4.5
3.5
11.5
2.5
9.0
2.5
15.0
5.0
10.0
2-4
1-4
7-9
8-10
4-6
6-8
0.5-1.0
3-4
4-5
4-5
6-7
2-3
2-3
1-2
9-10
6-8
1-4
3-5
5-7
1-3
5-7
3-5
36 Sample
No.
062-05
063-05
065-05
068-06
069-06
071-06
072-06
073-06
074-06
075-06
077-06
078-08
080-08
081-08
084-08
085-08
086-08
087-08
Location (City)
Hemphill, TX
Lufkin, TX
Jefferson, TX
San Antonio, TX
San Antonio, TX
San Antonio, TX
San Antonio, TX
San Antonio, TX
New Braunfels, TX
New Braunfels, TX
Universal City,
Waco, TX
Corpus Christi,
Abilene, TX
Abilene, TX
Bartlett, TX
Corpus Christi,
Austin, TX
TX
TX
TX
County(ies)
Hemphill
Angelina
Jefferson
Bexar
Bexar
Bexar
Bexar
Bexar
Comal
Comal
Bexar
McClennan
Nueces
Taylor
Taylor
Williamson
Nueces
Travis
Depth (feet)
5-7
1-3
8-10
7.5-8.5
4-5
7.5-8.5
1-2
7.5-8.5
7.5-8.5
2.5-3.5
10-11
5-6.5
3-5
6.5-8
6-7.5
1.5-3
8-9.5
4-5
Anqelina County
Geology:
Climate:
37
The geological formation from which most of the soils in the Angelina County are derived belong to the Mio-cene period of the Tertiary era.
The greater part of the deposits in the area consist of gray, white, and blue sands. The principal bed underlying these sands, and the one probably forming the greater proportion of the whole group, is a heavy bed of dark-blue clay.
No weather bureau stations are located within the limits of this county, nor are there any stations having records covering a sufficient time to have established normals. The average temperature of 67.0°F and average precipitation of 39 inches for Trinity, which is a country adjacent to Angelina, could well be typical values for Angelina County.
Bexar County
Geology:
Climate;
The soils of Bexar County developed over cherty lime-stone. The soils consist of one or more formations that contain limestone, chalky limestone, chalk, shaly clay, marly clay, sandy clay, calcareous clay, sand, and sandstone.
Rainfall in Bexar County is fairly well distributed throughout the year. Evaporation is high and rain-fall seldom wets below the root zone. This has caused great leaching of calcium carbonate from upper zones of some soils but not from their lower horizons. Con-sequently, many of the soils have a layer in which calcium carbonate has accumulated.
Brazos County
Geology:
Climate:
Brazos County has soils that have a large number of parent materials which include old sediments deposited by floodwaters of the Brazos River, alkaline to weakly calcareous clay, sand clay, water lain unconsolidated loamy sands, acid shaly clay and acid sandy clay loam.
Brazos County has a warm temperature, humid, continen-tal climate. Annual precipitation which averages 30 inches, is relatively uniform throughout the county. Droughts of varying duration and severity occur in summer. They are the result of a high rate of evapor-ation, low humidity, and low water-holding capacity of the soils.
Comal County
Geology;
Climate;
In addition to the alluvial and coalluvial material occurring in the valleys, the rocks which make up the soils in this area are largely of marine sedi-mentary origin.
Mean annual temperature is about 67°F, while mean annual precipitation is about 28 inches.
38
Chambers County
Geology:
Climate;
Old alluvium and marine sediment laid down by ancient streams and the Gulf of Mexico are the main parent materials of most soils in this county. These materials consist primarily of clay and sandy clay mixed with some clay loam, silt and sand.
The climate of Chambers County is humid subtropical and is characterized by warm summers. The proximity of the Gulf of Mexico and the bays results in a pre-dominantly marine climate. Average annual tempera-ture is 77.7°F. Rainfall is abundant, averaging 51.55 inches annually.
Dallas County
Geology:
Climate:
The soils and subsoils of Dallas County are charac-teristically calcareous.
Warm, temperate climate. The summers are long, with rather high temperatures during most of the time. The winters are short and mild. Mean temperature is 64.9°F. Mean annual precipitation is 38.04; this is fairly well distributed throughout the year.
Foard County
Geology: The soils of Foard County developed in residuum de-rived from permian shale, permian sandstone, permian limestone, and permian gypsum; in sandy and clayey outwash, or acient alluvium, and recent alluvium.
Foard is underlain by the geological formation known as the permian red beds. This red bed consists of sediments that, according to geologists, were laid down in an old sea some 200 million years ago.
Climate: Foard County has a subhumid, warm temperate, conti-nental-type climate. The permian rocks have been broken down into residuum, from which soils have formed, by temperature changes and by the action of water. A wetter climate in past geologic ages was responsible for the disposition of the parent mater-ial of all of the soils formed in outwash and allu-vium. Water has leached calcium carbonate from the profile of the sandy soils and moderately coarse textured soils. Also, rainwater has moved clay particles downward in this profile.
Wind, too, is an outstanding factor in the develop-ment of soils in the area. It deposited sand over the pre-existing permian red beds.
Fort Bend County
Geology: Fort Bend County soils are of three geologic for-mations--lissie (range from sands to sandy clays), beaumont (overlies the lissie in areas between streams contains limy clay, sandy clays, clayey sands, and fine sands) and recent (mainly calcar-eous materials deposited by the Brazos River).
Geology: In Harris County the parent material consists of un-consolidated sediment of holocene, pliestocene, and pliocene age. In general, the soils are sedimentary and consist of material that has been deposited by water. In some areas, terrace or beach deposits of non-calcareous unconsolidated material range from sand to clay. Some of the soils developed from calcareous clayey sediment.
Climate: Humid, warm and moist.
Hemphill County
Geology: Most of the soils of Hemphill County formed on de-posits of the Cenozic era. The thick deposits of the High Plains or Ogallala were deposited in the Tertiary period. The soils are alkaline to calcar-eous, loamy and sandy earths.
Climate: Warm and semi-arid. Soil development has been re-tarded by low rainfall in the county.
39
40
Jefferson Countv
Geology: Old alluvium and marine sediments laid down by ancient streams and the Gulf of Mexico are the chief parent materials of most soils in this country.
The materials consist primarily of clay and sandy clay mixed with some clay loam, silt and sand. They ori-ginated from a multitude of soils, rocks, and unconsol-idated sediments that existed throughout the flood plains of the ancient streams.
Climate: Jefferson County has a mixture of tropical and temper-ate climate.
McClennan County
Geology: The soils of McClennan County are underlain by many parent materials, viz, marine sediments of marl, chalk, or calcareous clay; marine sediments of fri-able marl or chalk; old alluvial sediments of calcar-eous clay; and soils of stream terraces.
Climate: Warm, temperate, humid continental climate. The summers are long, with rather high temperatures much of the time. The winters are short and mild.
Navarro County
Geology: Navarro County soils formed in five kinds of parent materials, namely: (a) clay and marl, (b) limestone caps over clay, (c) clay and shale, (d) sandy clays to clayey sediment, or old alluvium, and (3) recent alluvium.
Climate: Navarro County has a humid, subtropical climate. Rainfall is fairly evenly distributed throughout the year and averages 36.96 inches annually. Summer tem-peratures are hot and winter temperatures are mild. The mild climate has promoted rapid soil development,
Nueces County
Geology: The geologic materials from which the soils of this county formed are Beaumont clay and material of the lissie formation and of the recent epoch. The recent materials are alluvial sediments of streams and eloian sands that were blown from beaches along the Gulf of Mexico.
Climate: The climate in Nueces County is intermediate between that of the humid, subtropical region to the north-east along the coast of Texas and that of the semi-arid region to the west and southwest.
41
Smith County
Geology:
Climate:
The subsoils in this county have been derived from beds of heavy clay, calcareous clays, and alluvial deposits.
The climate of Smith County is characterized by rela-tively mild winters and long, warm summers, with a gradual transition from one season to the other.
The mean precipitation of 38 inches is well distri-buted throughout the year.
Tarrant County
Geology:
Climate:
The parent materials of the soils in this county are calcareous clays, lime carbonate, soft chalky material, and hard limestones.
Summers are long and winters are short. Mean annual temperature is 65°F, of summer, 82.2°F; and, that of fall, 66°F. Rainfall in this county is distributed throughout the year, but somewhat unevenly.
Taylor County
Geology:
Climate:
Parent material in Taylor County consists of permian shale and clay, permian sandstone, recent deposits of alluvium, outwash from cretaceous formations, and clayey sediment over limestone.
Taylor County lies roughly on the boundary between the humid climate of East Texas and the semi-arid climate of the west and north.
Some soils in the county have accumulated a lot of calcium carbonate caused by water leaching the solu-ble material to a certain depth.
Because Taylor County has mild winters and hot summers, micro organisms continuously decompose residue from plants and animals. This contributes to the high or-ganic content found in some Taylor County soils.
42
Jravis County
Geology:
Climate:
The soils of Travis County are formed in several kinds of parent material. In the western part of the county, the parent material was mainly limestone, dolomite, interbedded limestone and marl, and clay. In the cen-tral part of the county, it was chalk, marl, limestone and marly limestone. In the eastern part of the county it was clay, chalky marl, and silty clay. Along the Colorado River the parent material was alluvium.
Travis County has a humid, subtropical climate. Win-ters are usually short and mild; summers are long, with hot days and warm nights.
Randall Count.y
Geology:
Climate:
The parent materials of the soils of Randall County are dominantly strongly calcareous and moderately alkaline, unconsolidated sandy and silty clay mater-ial. It was derived mostly from loessal deposits and from rocky mountain outwash.
Precipitation, temperature and wind have been important in the development of soils of Randall County. The wet climate of past geologic ages influenced the deposition of parent materials. Later, rainfall was limited, and it seldom wet below the root zone.
Williamson County
Geology:
Climate:
In Williamson County, there are three major soil pro-vinces, each of which is underlain by a characteristic variety of rock formation; namely, the blackland prairie underlain by marl of very highly calcareous clays and chalks; the East Texas timber country, underlain by sands and sandy clays containing no carbonate of lime; and the Grand Prairie, underlain by clays.
Moderately humid and warm-temperate. It is continen-tal in type and is characterized by irregularity of rainfall, sudden changes in temperature, and a com-paratively dry atmosphere. Mean annual temperature is 67.2°F and mean annual precipitation is 31.80 inches.
APPENDIX B
SIMPLIFIED PROCEDURE FOR DETERMINING CATION EXCHANGE CAPACITY USING
A SPECTROPHOTOMETER (AFTER PEECH (10))
43
44
The cation exchange capacity of a soil may be determined by com-
parative means in the standard spectrophotometer device. This simpli-
fied procedure is:
1. Place 10 grams of clay soil in a beaker and 100 ml of neutral
1N_ ammonium acetate (NH^Ac) is added. The solution is allowed to
stand overnight.
2. Filter the solution of Step 1 by washing through No. 42 filter
paper with 50 ml of NH^Ac
3. Wash the material retained on the filter paper of Step 2 with
two 150 ml washings of isopropyl alcohol, using suction. The isopropyl
alcohol wash fluid should be added in increments of approximately 25 ml
and the sample allowed to drain well between additions. Discard wash
solution.
4. Transfer the soil and filter paper to a 800 ml flask. Add 50
ml MgClo solution and allow to set at least 30 minutes, but preferably
24 hours.
5. Under suction filter the fluid resulting from Step 4. Store in
stoppered flask.
6. Prepare a standard curve by using lOyg of NH^-N/ml standard
solution in a 50 ml volumetric flask. Adjust the volume to approxi-
mately 25 ml, add 1 ml of 10% tartrate solution, and shake. Add 2 ml
of Nessler's aliquot with rapid mixing. Add sufficient distilled
water to bring the total volume to 50 ml. Allow color to develop for
30 minutes.
7. Repeat Step 6 for 1.0, 2.0,4.0 and 8.0 ml of aliquots of
standard solution (Note: 72.2yg, 57.70yg, 28.88yg, 14.44yg and 7.22yg
of aliquots were used in this investigation.)
45
8. Insert the standard solution form Steps 6 and 7 into the
spectrophotometer. Record readings and plot the transparency read-
ings against the corresponding NH^-N/mL strengths to construct a
standard curve. (The spectrophotometer is calibrated before hand
with 1 ml of 10% tartrate, 2 ml Nessler and distilled water.)
9. Extract 2.0 ml of sample aliquot (wash solution of Step
5) and add 25 ml of distilled water in a 50 ml volumetric flask.
Add 1 ml of 10% tartrate and shake. Add 2 ml of Nessler's aliquot
with rapid mixing. Add sufficient distilled water to bring the
total volume to 50 ml. Let the solution stand for 30 minutes and
then insert into the spectrophotometer and record the transparency
reading:
10. Typical calculations:
Weight of dry soil = 10.85 gm
Spectrophotometer = 78.6%
= 44yg/g from standard curve.
Conversion:
44yq 50ml^ 50ml^ x "" x "* x IQQom 2ml/aliquotc ^ 1 ml ^ 10.85gm lOOOyg/mg ^ 14mg/meq ^ '"^^m
= 36.21 meq/lOOgm.
total volume of solution from Step 9
volume of MgCL^
^volume of sample aliquot.
APPENDIX C
DETERMINATION OF ATTERBERG LIMITS
46
LIQUID LIMIT
The liquid limit was determined in accordance with the ASTM D423-66.
47
ratus
(a)
(b)
(c)
(d)
(e)
(f)
• •
Evaporating dish
Spatula
Liquid limit device
Grooving tool
Containers (moisture cans)
Balance.
Sample:
About 100 g of so i l from the thoroughly mixed portion of the
material passing the No. 40 sieve:
Procedure:
1. Adjust the liquid limit device.
2. Place soil in evaporating dish and mix with 15 to 20 ml of
distilled water by alternately and repeatedly stirring, kneading, and
chopping with a spatula. Make further addition of water in increments
of 1 to 3 ml. Thoroughly mix each increment of water with the soil,
as previously described, before adding another increment of water.
3. Place a portion of the mixture in the liquid limit device
cup above the spot where the cup rests on the base, when enough water
has been added to produce a consistency that will require 30 to 35
drops of the cup to cause closure. With the spatula, level the soil
and at the same time trim it to a depth of 1 cm at the point of maxi-
mum thickness, care being taken to prevent entrapment of air in the
mass. Divide the soil in the cup by firm strokes of the grooving
48
tool along the diameter through the centerline of the cam follower
so that a clean, sharp groove of the proper dimensions will be formed.
4. Lift and drop the cup by turning the liquid limit device
crank, at the rate of 2 rps, until the two halves of the soil cake
come in contact at the bottom of the groove along a distance of 1/2
inch. Record the number of drops.
5. Remove a slice of soil approximately the width of the spatula,
extending from edge to edge of the soil cake at right angles to the
groove and including that portion of the groove in which the soil
flowed together, and place in a suitable tared container. Weigh
and record the weight. Over-dry the soil in the container to a con-
stant weight at 230 ± 9F and reweigh as soon as it has cooled. Re-
cord this weight. Record the loss in weight due to drying as the
weight of water.
6. Transfer the remaining soil from the cup to the evaporating
dish. Wash and dry cup and grooving tool, and reattach the cup to
the device in preparation for the next trial.
7. Repeat the above operation for at least two additional
trials, with the soil collected in the evaporating dish, to which
sufficient waster has been added to bring the soil to a more fluid
condition. The object of this procedure is to obtain samples of
such consistency that the number of drops required to close the
groove will be above and below 25. The number of drops should be
less than 35 and exceed 15. The test shall always proceed from the
dryer to the wetter condition of the soil.
8. Calculation:
(a) Water Content, W^ =
(weight of water/weight of oven dry soil) x 100
49
(b) Plot a "flow curve" representing the relationship
between water content and corresponding number of
drops on a semilogarithmic graph with the water
content as abscissae. The flow curve is a straight
line drawn as nearly as possible through the plotted
points.
(c) The water content corresponding to the intersection
of the flow curve with the 25-drop ordinate is the
liquid limit, reported to the nearest whole number.
50 PLASTIC LIMIT
Plastic limit was determined in accordance with ASTM D424-59.
Apparatus:
(a) Evaporating dish
(b) Spatula
(c) Surface for rolling - A ground-glass plate or piece
of glazed or unglazed paper on which to roll.
(d) Containers
(e) Balance.
Procedure:
1. Place about 15 g of the air-dried soil sample passing the No.
40 sieve in an evaporating dish and thoroughly mix with distilled water
until the mass becomes plastic enough to be easily shaped into a ball.
Take about 8 g of this ball for the test sample.
2. Squeeze and form the 8 g test sample into an ellipsoidal-
shape mass. Roll this mass between the fingers and the ground-glass
plate or a piece of paper lying on a smooth horizontal surface with
just sufficient pressure to roll the mass into a thread of uniform
diameter throughout its length. The rate of rolling shall be between
80and90 strokes/min, counting a stroke as one complete motion of the
hand forward and back to the starting position again.
3. When the diameter of the thread becomes 1/8-in., break the
thread into six or eight pieces. Squeeze the pieces together between
the thumbs and fingers of both hands into a uniform mass roughly ellip-
soidal in shape, and reroll. Continue this alternate rolling to a
thread 1/8-in. in diameter, gathering together, kneading and rerolling,
until the thread crumbles under the pressure required for rolling and
the soil can no longer be rolled into a thread. The crumbling may
occur when the thread has a diameter greater than 1/8-in. This shall
51
be considered a satisfactory end point, provided the soil has been
previously rolled into a thread 1/8-in. in diameter.
4. Gather the portions of the crumbled soil together and place
in a suitable tared container. Weigh the container and the soil and
record the weight. Oven-dry the soil in the container to constant
weight at 230 ± 9F. Record this weight. Record the loss in weight
as the weight of the water.
5. Calculate the plastic limit, expressed as the water content
in percentage of the weight of the oven-dry soil, as follows:
Plastic limit = (weight of water/weight of oven-dry soil) x 100.
APPENDIX D
HYDROMETER ANALYSIS TEST
PROCEDURE
52
53
Grain size analysis of the less than No. 200 sieve material was
accomplished by the hydrometer using the ASTM D422-63 procedure.
Apparatus
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
Procedure
• •
Balance
Stirring apparatus
Hydrometer (152 H model)
Sedimentation cylinder
Thermometer
Water bath
Beaker
Timing device.
•
1. Take exactly 50 g of oven-dry, well-pulverized soil and mix
with 125 cu cm of 4 percent sodium metaphosphate solution. The 4 per-
cent solution can be prepared by adding 40 g of dry sodium metaphos-
phate to 1000 cu cm of water. This solution should be freshly mixed,
but, in many cases, should not be over 1-month old.
2. Allow the mixture to stand for about 16 hours. Transfer the
mixture to a special dispersion cup and add distilled or dimineralized
water until the cup is more than half full. Stir for a period of 1
minute.
3. Immediately after dispersion, transfer the soil-water slurry
to the glass sedimentation cylinder and add distiller or demineralized
water until the total volume is 1000 ml.
4. Using the palm of the hand or a rubber stopper over the open
end of the cylinder, turn the cylinder upside down and back for a period
of 1 minute to complete the agitation of the slurry. At the end of 1
minute set the cylinder in a convenient location and take hydrometer
54
readings at the following intervals of time, or as many as may be
needed; 2, 5, 15, 30, 60, 250, and 1440 minutes.
5. When it is desired to take a hydrometer reading, carefully
insert the hydrometer about 20 to 25 secs before the reading is due
to approximately the depth it will have when the reading is taken.
As soon as reading is taken, carefully remove the hydrometer and
place it with a spinning motion in a graduate of clean distilled or
demineralized water. Readings shall be taken at the top of the menis-
cus formed by the suspension around the stem, since it is not possible
to secure readings at the bottom of the meniscus.
6. After each reading, take the temperature of the suspension
by inserting the thermometer into the suspension.
7. Calculat ions:
(a) Calculate percentage of soil remaining in suspension
for hydrometer 152 H as follows:
P = (Ra/w) X 100
where a = correction factor to be applied to the hydro-
meter reading (listed in most lab manuals)
R = corrected hydrometer reading
= actual -zero reading + C^
(C. = temperature correction; listed in most soil laboratory manuals)
apd w = oven-dry weight of soil in a total test sample
represented by weight of soil dispersed, grams.
(b) The diameter of a particle corresponding to the percentage
indicated by a given hydrometer shall be calculated ac-
cording to Stoke's law:
55
D =/[30n/980 (G-G^)] x L/T
which may be written as:
D = K / L/T
where
G = Specific gravity of soil particles
G^ = Specific gravity (relative density) of
suspending medium
n = Coefficient of viscosity of suspending medium.
D = Diameter of particle, mm
K = Constant depending on temperature of suspension
and specific gravity of the soil particles
(values are listed in most soil laboratory
manuals).
L = Distance from the surface of the suspension to
the level at which the density of the suspension
is being measured, cm. This distance is known
as effective depth and is listed in most soil
laboratory manuals.
T = Interval of time from beginning of sedimenta-
tion to the taking of the reading, min.
8. When the hydrometer analysis is performed, a graph of the test
results shall be made, plotting the diameters of the particles on a loga-
rithmic scale as the abscissa and the percentages smaller than the corres
ponding diameters to an arithmetic scale as the ordinate.
APPENDIX E
TEST DATA FOR CATION EXCHANGE CAPACITY (CEC), ATTERBERG LIMITS (PLASTIC LIMIT (PL) AND LIQUID LIMIT (LL), AND PLASTICITY INDEX
56
Sample No.
001-01
003-01
004-01
005-01
008-01
010-01
011-01
012-01
013-04
015-04
017-04
021-04
026-02
028-02
029-02
030-02
033-02
035-02
036-03
038-03 040-03
041-03
042-03
044-03
046-03
047-03
048-03
049-07
050-07
055-05
057-05
058-05
059-05
061-05
LL
28.80
25.40
34.43
53.31
34.30
36.20
43.96
32.00
44.30
36.70
47.97
32.42
53.94
51.42
62.80
30.29
82.42
43.15
47.60
72.20 41.40 *
48.35
28.95
49.56
57.60
52.13
35.33
39.80
72.72
52.80
59.12
62.70
65.80
33.67
PL
18.48
15.48
15.79
19.32
17.01
16.39
18.46
15.23
23.10
19.37
19.18
14.95
17.06
25.11
20.70
16.66
30.94
18.41
18.84
31.17
20.49
21.63
13.97
22.84
24.30
19.89
15.05
16.70
22.37
22.59
20.02
20.83
21.49
15.55
PI
10.32
9.42
19.64
33.99
17.30
19.81
25.30
16.77
21.20
17.18
28.79
17.47
35.54
26.31
42.08
13.34
51.48
24.74
28.76
41.03
20.91
26.72
14.98
26.72
33.30
32.24
20.28
23.10
50.35
30.21
39.10
41.87
44.31
18.12
CEC
20.20 17.66
29.20
48.40
35.90
23.24
27.57
23.52
52.40
27.87
26.34
19.40
35.43
36.70
50.30
26.66
44.87
38.90
54.95
49.00
38.40
28.70
16.23
34.50
51.24
43.56
31.24
27.75
46.54
20.29
42.20
32.00
34.64
22.54
57
58
Sample No.
062-05
063-05
065-05
068-06
069-06
071-06
072-06
073-06
074-06
075-06
077-06
078-08
080-08
081-08
083-08
084-08
085-08
086-08
087-08
LL PL PI CEC
46.88
60.00
32.40
50.05
51.85
52.57
74.27
54.80
22.00
55.45
54.84
38.75
54.48
32.19
81.06
31.90
44.38
61.53
38.46
18.95
20.12
16.67
22.59
20.39
18.53
32.52
18.36
14.34
24.80
21.61
18.31
18.26
17.97
29.57
13.33
18.02
25.10
21.79
27.93
39.88
15.73
27.46
31.46
34.04
41.75
36.44
7.66
30.65
33.23
20.44
36.22
14.22
51.57
18.57
26.36
34.90
16.55
36.20
32.80
15.94
30.00
34.14
31.56
72.80
18.90
24.80
50.00
26.70
23.20
27.14
28.20
58.40
34.40
49.00
50.00
29.10
APPENDIX F
SUBROUTINE "INPUT"
59
60 SUBROUTINE INPUT
IMPLICIT REAL*8(A-H,0-Z,$)
DIMENSIØN D(6)
CØMMØN|BLK2|Z'(80),1FMT(180),NVAR, MØD,CHK
DATA END|'END'|
READ(5,1FMT) (D(I),I=1,NVAR),CHK
IF (CHK.EQ.END) RETURN
X=D(1)
Z(1)=DL0G10(X)
B=D(2)
Z(2)=DL0G10(B)*3.25
C=D(3)
Z(4)=DL0G10(P)*2.19
RETURN
END
Note: Z(l) is the dependent variable
Z(2), Z(3), Z (4) are the independent variables. The Z vectors
used in this investigation are not standard but depend on the
nature of the problem.
APPENDIX G
PROCEDURE FOR REMOVING ORGANIC MATTER FROM SOIL
61
62
Apparatus:
(a) 600 ml glass beaker
(b) Clorox
(c) Hydrochloric acid {HCÍL)
(d) pH meter.
Procedure:
1. Pour about 450 ml of clorox (sodium hypochlorite) into beaker.
Check pH (should be about 12-13).
2. Add HCA a little at a time, with constant mixing, until pH
becomes about 9.
3. Place enough soil in the solution. Allow soil to remain in
beaker for about 30 minutes, with occasional stirring.
4. Filter solution through No. 42 Whatman filter paper.
5. Wash soil with distilled H2Q until wash solution registers