marl soil

Chulmin Jung, Antonio Bobet, and Nayyar Zia Siddiki 1

A SIMPLE METHOD TO IDENTIFY MARL SOILS Chulmin Jung, Ph.D., P.E., Geotechnical Specialist, Civil & Architectural Department 1, Samsung Engineering, 467-14, Samsung SEI Tower, Dogok-2dong, Gangnam-gu, Seoul, 135-856, Korea. Tel: +82-2-2148-2315, Fax: +82-2-3458-4015, e-mail: [email protected] (Corresponding Author)

Antonio Bobet, Ph.D., Professor, School of Civil Engineering, Purdue University, West Lafayette, IN 47907-1284, U.S.A. Tel: (765) 494-5033, Fax: (765) 496-1364, e-mail: [email protected]

Nayyar Zia Siddiki, M.S., P.E., Geotechnical Field Operation Supervisor, Office of Geotechnical Engineering, Indiana Department of Transportation, 120 S. Shortridge Rd., Indianapolis, IN 46219-0389, U.S.A. Tel: (317)610-7251, Fax: (317) 356-9351, e-mail: [email protected].

Submission date: Nov. 1, 2010 Word Count: 7111 words (Text only: 3861 words, and 8 Figures and 5 Tables: 3250 words)

TRB 2011 Annual Meeting Paper revised from original submittal.


ABSTRACT An experimental investigation was carried out to propose a simple, practical method, to identify marl soils in the laboratory and to classify the soils. The percentage of calcium carbonate (CaCO3) of the soil was determined with three different methods: (1) TGA (Thermo-Gravimetric Analysis); (2) “sequential” LOI (Loss on Ignition); and (3) chemical reaction following ASTM C 25. The sequential LOI test has the advantage that both organic and calcium carbonate content of the soil can be determined with a conventional furnace. X-Ray Diffraction (XRD), pH, and Atterberg limits tests were also conducted. The percentage of CaCO3 determined from the sequential LOI tests agreed very well with those from the TGA tests and from the chemical tests. No correlation was found between the percentage of CaCO3 and organic content in the soil. As the organic content of the soil increases, the liquid limit (LL) increases, and the plasticity of the soil increases. As the CaCO3 content of the soil increases, the LL of the soil decreases and the soil becomes less plastic. The geotechnical engineering properties of marl soils depend on organic content and CaCO3 content, and so the soils should be classified in terms of both organic content and calcium carbonate content. KEYWORDS: Classification, Calcium carbonate, Marl, Organic content, Sequential LOI, Soil index properties.



INTRODUCTION Marl soil deposits are encountered in the Midwest of the US, including the states of Indiana, Illinois, Michigan, and Ohio (1-4). The term marl has been used in the regional area to designate carbonate-rich, light gray to almost white silts and clays formed by precipitation of calcite at the bottom of lakes or swamps (1-3). The marl soils sometimes contain noticeable amounts of fine sand (3). The marl deposits are encountered often below highly organic soil or peat deposits (2) and contain shell fragments (3). The marl soil is classified as an organic soil in accordance with the Ohio DOT soil classification system (4). According to the Indiana DOT soil classification system, a soil with a calcium carbonate content of 26 to 40 % is classified as Marly soil while a soil with a calcium carbonate content larger than 40 % is classified as Marl (1); the Indiana DOT uses chemical tests, following ASTM C 25, to determine the calcium carbonate content in the soil. Both Marly soils and Marls fall into the ASSHTO soil class A-8 (1). Marl soils typically have low dry density, very high moisture content and low shear strength. This makes them “problem soils” that are unsuitable for pavement subgrade, may be prone to slope instability and have low bearing capacity. Given all these issues, it is somewhat surprising that very limited work has been done in the Midwest on these soils.

The term marl or marl soil is used with somewhat different meanings in different fields. In agriculture, marl is defined as a limnic soil that, moist, has a color value of 5 or more and reacts with dilute HCL to produce CO2 (5). It usually has an organic content of 4 to 20 %, and is classified as an organic soil (5). In engineering geology and geotechnical engineering, terms such as calcareous soil, carbonate soil and marl soil have been used to designate a mixture of fine-grained soils and carbonate minerals (6-13).

The carbonate content of a soil changes its geotechnical engineering properties. It affects the soil index properties such as the Plastic Limit (PL), the Liquid Limit (LL), the Plasticity Index (PI), and the activity of the soil (9-10), the peak frictional angle (9), the residual frictional angle (12), the effective cohesion (9), and permeability (9). With increasing carbonate content, the LL, PL, PI, and activity of the soil decrease, the friction angle increases while cohesion and permeability decrease. In other words, as the carbonate content increases, marl soils tend to show less plastic behavior. The results however were obtained from soils with no organic content. In other words, the origin of the soils investigated was different from that of marl soils encountered in the Midwest of the US. Marl soils, at least in the Midwest, have organic matter typically in the range of 3 to 25%.

The paper focuses on the identification and classification of marl soils with low to moderate organic content, which are thought to be more representative of the soils in the Midwest. It also provides recommendations for alternative methods to determine the content of calcium carbonate and organic matter. The initiative for the work came from the need of the Indiana DOT (INDOT) to have a workable classification and accurate and yet economical laboratory tests to determine the composition of the soils, and thus the work has been conducted on samples collected in the State of Indiana.

SOIL SAMPLING Three INDOT road construction projects, for which marl soil samples had been preserved by geotechnical engineering companies during the design phase, were chosen as the source of the soil samples. The samples were not protected from loss of moisture, but the values reported here are taken from the original geotechnical investigation. Table 1 contains: (1) site number; (2) road construction project; (3) INDOT designation number of road project; (4) time when the



geotechnical investigation was completed. Sites (1) and (3) are located in Kokomo, Howard County, about 50 miles north of Indianapolis, Indiana, and Site (2) is located in Randolph County, about 60 miles east of Indianapolis. Ten soil samples were selected at each site, each from a different borehole. Table 2 shows the location of each of the selected samples, the moisture content obtained from the original investigation and the SPT (Standard Penetration Test) blow count at the depth of the sample for sites (1), (2) and (3), respectively.

At site (1), the samples were taken at depths of 4.5 ft to 16.5 ft below the ground level (Table 2). The natural moisture content ranged from 26% to 60%, with an average value of 40%. The SPT values were very small, which indicates a very soft soil, typical of the marl deposits encountered in Indiana. At site (2) the depth of the samples ranged from 6 to 20 ft below the ground level, and the natural moisture content ranged from 29 % to 126 %, with an average value of 70%. The in-situ SPT blow count ranged from 0 to 8 with an average value of 4. At site (3), the depths of the samples were between 7 and 19 ft, and had a natural moisture content from 19 to 76 %, with an average of 51%. The in-situ SPT blow count ranged from 0 to 4, with an average value of 2.

TEST METHODOLOGY The calcium carbonate content of the soil samples was determined using three different methods: (1) TGA (Thermo-Gravimetric Analysis); (2) “sequential” LOI (Loss on Ignition); and (3) chemical reaction in accordance with ASTM C 25 (14). XRD, pH, and Atterberg limits tests were also conducted on the soil samples collected. All tests were completed in December, 2008.

Thermo-Gravimetric analysis TGA (Thermo-Gravimetric Analysis) tests were performed on all the thirty soil samples collected. The tests were done to determine the content of calcium carbonate in the soil. A TGA-2050 (manufactured by TA Instruments), Thermo-Gravimetric analyzer, was used for the study. Ten milligrams of soil were placed in the furnace of the analyzer and then heated in a nitrogen gas at a rate of 10 °C/min from room temperature to 1000 °C. The weight loss curve of the soil with temperature was obtained from the test. In the range of 650 to 800 °C, calcium carbonate (CaCO3) decomposes into calcium oxide (CaO) and carbon dioxide (CO2). As a consequence, the calcium carbonate content in a soil sample may be determined from the weight loss of the soil between 650 and 800 °C.

“Sequential” Loss on Ignition (LOI) Method Loss on Ignition (LOI) tests were conducted to determine the organic content and calcium carbonate content in the soil. In geotechnical engineering LOI tests have been used to measure organic content, heating the soil up to 455 °C, in accordance with AASHTO T 267-86 (15). In this study, the LOI test was extended in an attempt to determine the calcium carbonate content in the soil, and as a simpler alternative to the chemical tests (discussed later). The procedure for the “sequential” LOI is as follows: First, the mass of the crucible is measured. Then, a soil sample with a mass of 10 to 15 grams is placed inside the crucible. The soil is dried in an oven at 110°C for 24 hours. After drying, the mass of the crucible and soil is measured and the crucible and the dried soil are placed into a furnace for six hours at a temperature of 455°C (note that this is the temperature used to burn the organics in a soil, according to AASHTO T 267-86). The crucible with the soil is then removed from the furnace, placed into a desiccator, allowed to cool, and the mass is measured. The crucible and the soil are again placed into the furnace for six additional



hours at a temperature of 800°C (this is the temperature of decomposition of calcium carbonate). Finally the mass of the crucible and the soil is measured. The organic content (O.C.) of the soil sample is:

110 455

110 crucible

M MO.C. (%) 100

M M

(1)

where M110 is the mass of crucible and oven-dried soil before ignition at 455°C; M455 is the mass of crucible and soil after ignition at 455°C; and Mcrucible is the mass of the crucible. The percentage of calcium carbonate in the soil is:

455 8003

110 crucible

100 M M% CaCO 100

44 M M

(2)

where M800 is the mass of the crucible and soil after ignition at 800°C.

Chemical test The chemical tests follow ASTM C25 (14) that specifies a procedure to determine the neutralizing capacity of a calcareous material. About two grams of soil are placed into a 500-mL Erlenmeyer flask. 25 mL of 1.0 N hydrochloric acid (HCl) solution is added into the flask. About five minutes after the addition of the 1.0 N HCl solution the excess acid in the flask is titrated with 0.5 N sodium hydroxide (NaOH) solution using phenolphthalein as indicator. The volume of NaOH solution required for the titration of the excess acid is measured. The calcium carbonate content in the soil is:

1 1 2 23

5.0045(V N V N )% CaCO 100

W

(3)

where V1 is the volume of the HCl solution used; N1 is the normality of the HCl solution; V2 is the volume of the NaOH solution required for titration of the excess acid in mL; N2 is the normality of the NaOH solution; and W is the weight of the soil sample in grams. Note that the value obtained with the above equation is not the percentage of calcium carbonate (CaCO3), but the percentage of calcium carbonate equivalent (C.C.E.). This is so because other carbonate species such as magnesite and dolomite as well as calcite (CaCO3) can react chemically with the 1N HCl solution. In other words, the chemical test describes the amount of all carbonate species in terms of C.C.E.

XRD test X-Ray diffraction (XRD) tests were performed to identify calcium carbonate as one of the minerals present in the soil. The tests were conducted on the fraction of the soil that passed No. 200 sieve. A SIMENS D500, an X-Ray diffractometer, was used for the study. From the XRD test results, the presence of calcium oxide, CaO, calcium hydroxide, Ca(OH)2, or calcium carbonate, Ca(CO)3, can be identified. Note that with this test the minerals can be identified, but the test cannot provide a quantitative estimate of the mineral in the soil.



pH test The pH of the marl soil samples was measured in accordance with ASTM D 4972-01 (14) to establish, if possible, a correlation between the calcium carbonate content of the soil and its pH. Ten grams of air-dried soil that passed through a No. 10 sieve were mixed with 10 mL of water. One hour after mixing, the pH of the soil was measured using a calibrated pH meter.

Atterberg limits test Atterberg limits tests were performed according to ASTM D 4318 (14). The soil that passed through a No. 40 sieve was used for the determination of the PL and LL. TEST RESULTS Tables 3 to 5 include a summary of the results of all the tests for sites (1), (2), and (3), respectively. Each table includes, for each soil sample: (a) color of the dry soil; (b) plastic limit (PL); (c) liquid limit (LL); (d) plasticity index (PI); (e) USCS classification; (f) moisture content; (g) percentage of organic matter; (h) pH; (i) CaCO3 from XRD test results; (j) percentage of CaCO3 determined from TGA tests; (k) percentage of CaCO3 from sequential LOI tests; and (l) percentage of CaCO3 from chemical tests in accordance with ASTM C 25. In the tables, a value in parentheses means that the value was obtained from the original geotechnical investigation.

The PL of the soil samples ranged from 14 to 58, the LL from 25 to 85, and the PI from 0 to 48. The LL and PI are plotted on the Casagrande plasticity chart in FIGURE 1. From the chart, the soils are classified as CL, CH, or MH, depending on their LL and PI (Tables 3 to 5).

FIGURE 2 plots the result of the TGA test on soil sample No. 1-1. The weight of the soil decreases sharply in the range of 650 and 800 °C. This is within the range where CaCO3 decomposes into CaO and CO2, and so the weight loss represents the CaCO3 content. The figure also includes the derivative of the weight loss with respect to time, which shows a clear peak at about 750 °C. The sharp decrease of the weight of the soil between 650 and 800 °C is also observed on all other soil samples. The percentage of CaCO3 ranged between 12 and 76 % with an average value of 35 % (Tables 3 to 5). The percentage of CaCO3 in the soil that was determined from sequential LOI tests ranged from 11 % to 78 %, with an average value of 35 %. Results from the three different methods are compared in FIGURES 3 and 4. FIGURE 3 provides a comparison between CaCO3 determined from the sequential LOI test and from TGA. The figure shows a very good agreement between the two methods. FIGURE 4 plots results from chemical tests and TGA. The CaCO3 content from the chemical tests is slightly smaller than from the TGA. This is expected because other matter, in addition to CaCO3 may be burnt during the tests. The differences however are small and so the CaCO3 content determined from the two methods is comparable. FIGURES 3 and 4 thus show that the results from the three methods are comparable.

XRD tests were performed to identify the presence of calcium carbonate (CaCO3). The XRD tests detected CaCO3 in all soil samples except No. 1-5 and No. 3-4 (Tables 3 to 5). No other carbonate species were found. The false negatives (No. 1-5 and No. 3-4) may be due to sensitivity of the equipment, considering that the CaCO3 content in the two soil samples was 12 %, the lowest value measured in this study. From the results, it seems that at least a 10% CaCO3 or more in the soil is needed for the XRD test to detect the mineral. The sequential LOI test was also used to provide the organic content (O.C.) of the soils, which ranged from 1.2 % to 17.3 % with an average value of 6 % (Tables 3 to 5). No correlation has been found between CaCO3 and organic content.



Tables 3 to 5 also provide the natural moisture content of the soil samples that was obtained from the original geotechnical investigation. The natural moisture content ranged from 19 % to 126 %, with an average value of 54%. FIGURE 5 compares the organic content of the soil with the natural moisture content. As one can see, the natural moisture content increases with the organic content. This result is consistent with findings from others (16-17). pH tests were performed on all soil samples. The pH ranged between 6.96 and 7.60 with an average value of 7.34 (Tables 3 to 5). The pH is compared with the percentage of CaCO3 in FIGURE 6. The results suggest a general trend of increasing pH as the calcium carbonate in the soil increases. There is however significant scatter, which is thought is due to soil variability.

The LL is plotted with organic content in FIGURE 7. From the figure, it is clear that the LL of the soil increases with organic content. The result is expected (e.g. 16, 18-19). FIGURE 8 plots the PI of the soil with the CaCO3 content. From the figure, it seems that the PI tends to decrease with CaCO3. There is however no clear correlation, which suggests that other soil characteristics play an important role. Lamas et al. (9) reported that soil plasticity decreased with increasing CaCO3 and a strong correlation was found between soil indices and CaCO3 content. It should be noted that Lamas et al. (9) used soil samples that did not contain organic matter. Based on all experiments, it can be concluded that the soil indices depend, to a large extent, on the CaCO3 content when the soil does not contain any organic matter, but this trend becomes much weaker when the soil contains organic matter because the organic matter significantly affects the soil indices. As a result, the geotechnical characteristics of marl soils depend on their organic content, to the largest extent, and on their CaCO3 content.

SUMMARY AND CONCLUSIONS An experimental investigation was carried out to propose a practical method to identify and classify in the laboratory marl soils in the state of Indiana and to investigate the geotechnical engineering properties of the marl soils. Soil samples were taken from three INDOT road construction projects. Ten soil samples were collected from ten different boreholes at each project, and so a total of thirty soil samples were collected and tested. The percentage of calcium carbonate (CaCO3) in the soil was determined using three different methods: (1) TGA (Thermo-Gravimetric Analysis); (2) “sequential” LOI (Loss on Ignition); and (3) chemical reaction in accordance with ASTM C 25. In addition, XRD, pH, and Atterberg limits tests were performed.

The percentage of CaCO3 determined from the sequential LOI tests agreed very well with those from the TGA tests and from the chemical tests (ASTM C 25). pH tests showed that as CaCO3 increases, the pH of the soil increases; the tests however showed large scatter and so pH tests alone cannot be used to accurately determine the calcium carbonate content in a soil. No correlation was found between CaCO3 and organic content. A strong correlation however was observed between natural moisture content and organic content and between LL and organic content. As the organic content of the soil increases, the LL increases, or the plasticity of the soil increases. It was also found that as the CaCO3 content of the soil increases, the LL of the soil decreases, or the soil becomes less plastic.

From all test results, the following can be concluded: (1) any of the three methods: chemical, TGA or LOI, can be used to determine the CaCO3 content of the soil; (2) the sequential LOI test can be used, as a simple method, to determine the CaCO3 content of the soil; and (3) the geotechnical characteristics of the marl soils depend on organic content and on CaCO3 content, and so the soil description should provide both the organic and the calcium carbonate contents. A soil classification such as that of the Indiana DOT that provides a denomination for the soil as a



function of the calcium carbonate content, with the addition of the organic content, seems appropriate.

ACKNOWLEDGEMENT The work presented (SPR 3227) was supported by the Joint Transportation Research Program administered by the Indiana Department of Transportation and Purdue University. The contents of this paper reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein, and do not necessarily reflect the official views or policies of the Federal Highway Administration and the Indiana Department of Transportation, nor do the contents constitute a standard, specification, or regulation. The authors are grateful to the Federal Highway Administration/ Indiana Department of Transportation/ Joint Transportation Research Project for supporting this research. In addition the authors would like to thank H.C Nutting (Cincinnati, OH) Company and Patriot Engineering and Environmental Inc. for their contribution and collection of the soil samples used for laboratory tests, and to Ms. Janet Lovell, the Laboratory Manager of the School of Civil Engineering at Purdue University, who performed the chemical, TGA, and XRD tests for the project.



REFERENCES 1. Geotechnical Manual. Indiana Department of Transportation, Indianapolis, 2008. 2. Geotechnical Manual. Illinois Department of Transportation, Springfield, 1999. 3. Uniform Field Soil Classification System. Michigan Department of Transportation, Lansing,

2009. 4. Specifications for Geotechnical Explorations. Ohio Department Transportation, Columbus,

2010. 5. Soil Taxonomy. United States Department of Agriculture, Washington D.C., 1999. 6. Aiban, S. A. Strength and compressibility of Abqaiq marl, Saudi Arabia. Engineering

Geology, Vol. 39, 1995, pp. 203-215. 7. Bellair, M., and Pomerol, L. Tratado de Geología, Vol. 1. Limusa, Mexico, 1980. 8. Datta, M., Gulhati, S. K., and Rao, G. V. Engineering behavior of carbonate soils of India and

some observations on classification of such soils. In: K.D. Demars and R.C. Chaney (Editors), Geotechnical Properties, Behavior, and Performance of Calcareous Soils. ASTM Special Technical Publication 777, 1982, pp. 113-140.

9. Lamas, F., Irigaray, C., and Chacón, J. Geotechnical characterization of carbonate marls for the construction of impermeable dam cores, Engineering Geology, Vol. 66, 2002, pp. 283– 294.

10. Pazza, N., Lamas, F., Irigaray, C., and Chacón, J. Engineering geological characterization of neogene marls in the southeastern Granada Basin, Spain. Engineering Geology, Vol. 50, 1998, pp. 165–175.

11. Pettijohn, F. Sedimentary Rocks. Harper and Row, New York, 1975. 12. Tsiambaos, G. Correlation of mineralogy and index properties with residual strength of

Iraklion marls. Engineering Geology, Vol. 30, 1991, pp. 357-369. 13. Shaqour, F.M., Jarrar, G., Hencher, S., and Kuisi. M. Geotechnical and mineralogical

characteristics of marl deposits in Jordan. Environmental Geology, Vol. 55, 2008, pp. 1777-1783.

14. ASTM International Annual Book of ASTM Standards. ASTM International, West Conshohocken, PA, 2010.

15. Standard specifications for Transportation Materials and Methods of Sampling and Testing. 28th ed. AASHTO, Washington, D.C., 2008.

16. Huat, B.B., Asadi, A., Kazemian, S. Experimental investigation on geomechanical properties of tropical organic soils and peat. American Journal of Engineering and Applied Science Vol. 2 No. 1, 2009, pp. 184-188.

17. Jarrett, P. M. Testing of Peats and Organic Soils: A Symposium Sponsored by ASTM Committee D-18 on Soil and Rock, Toronto, Canada, 23 June 1982.

18. Malkawi, A.I., Alawneh, A.S. and Abu-Safaqah, O.T. Effects of Organic Matter on the Physical and the Physicochemical Properties of an Illitic Soil. Applied Clay Science, Vol. 14, 1999, pp. 257-278.

19. Odell, R.T., Thornburn, T.H., Mckenzie, L.J., “Relationship of Atterberg limits to some other properties of Illinois soils”, Proceedings of the Soil Science Society of America, Vol. 24, No. 4, 1960, pp. 297–300.



FIGURE 1 Classification of marl soils according to Casagrande plasticity chart.

FIGURE 2 Weight loss and weight loss rate obtained from TGA on soil sample No. 1-1.



FIGURE 3 Comparison between % CaCO3 from LOI and TGA tests.

FIGURE 4 Comparison between % CaCO3 from ASTM C 25 and those from TGA tests.



FIGURE 5 Correlation between natural moisture content and organic content.

FIGURE 6 Correlation between pH and % CaCO3 determined from TGA tests.



FIGURE 7 Correlation between liquid limit and organic content (%).

FIGURE 8 Correlation between plasticity index and % CaCO3 determined from TGA tests.



TABLE 1 Source of Soil Samples

Site INDOT construction project INDOT

Designation No. Time of geotechnical

investigation

1 US Highway 31 Kokomo Bypass Marl Delineation - main lane project

Des. 0700338 April, 2008

2

State Road 1 Rehabilitation. Beginning at US Highway 36 and extending north 8.6 miles to State Road 32 in Randolph County

Des. 0013810 May, 2008

3 US Highway 31 Kokomo Bypass Marl Delineation - contract 1c project

Des. 0600337 Nov., 2007



TABLE 2 Location and properties of selected samples

Site Sample No. Depth (ft) W/C of soil

(%) SPT N

Site (1)

1-1 6.0-7.5 60 0

1-2 7.5-9.0 25 0

1-3 6.0-7.5 32 0

1-4 9.0-10.5 43 0

1-5 4.5-6.0 58 0

1-6 13.5-15.0 - 0

1-7 15-16.5 26 2

1-8 7.5-9.0 35 0

1-9 9.0-10.5 36 0

1-10 12.0-13.5 42 0

Site (2)

2-1 18.5-20.0 126 2

2-2 8.5-10.0 94 1

2-3 8.5-10.0 67 3

2-4 6-7.5 58 4

2-5 8.5-10.0 - 3

2-6 6-7.5 29 3

2-7 13.5-15.0 49 8

2-8 18.5-20.0 34 0

2-9 8.5-10.0 95 7

2-10 13.5-15.0 76 6

Site (3)

3-1 9-11 59 3

3-2 7-9 47 2

3-3 7-9 38 3

3-4 17-19 76 2

3-5 11-13 75 2

3-6 9-11 75 2

3-7 9-11 19 4

3-8 7-9 51 2

3-9 7-9 43 0

3-10 9-11 26 2



TABLE 3 Test Results from site (1) soil samples

Sample No.

Color PL LL PI Soil type

Natural M/C

O.C. (%) (LOI)

pH CaCO3 (XRD)

CaCO3 (%)

TGA LOI ASTM C25

No. 1-1 Light gray

(26) (41) (15) CL-ML (60) 2.5 7.47 Yes 46 47 (33)

No. 1-2 Light gray

- - - (25) 1.6 7.44 Yes 35 34 31

No. 1-3 Light gray

- - - (32) 2.5 7.26 Yes 39 36 (40)

No. 1-4 Light gray

- - - (43) 4.8 7.43 Yes 28 27 22

No. 1-5 Brown 30 73 43 CH (58) 9.2 6.96 No 12 14 6

No. 1-6 Brown 24 49 25 CL - 8.5 7.28 Yes 18 20 10

No. 1-7 Light gray

- - - (26) 1.3 7.16 Yes 35 32 28

No. 1-8 Light gray

24 43 19 CL (35) 3.0 7.41 Yes 35 37 (32)

No. 1-9 Light gray

15 32 17 CL (36) 1.5 7.17 Yes 35 33 (31)

No.1- 10 Light gray

- - - (42) 3.0 7.37 Yes 30 28 (25)




Sample No. Color PL LL PI Soil typeNatural

M/C O.C. (%)

(LOI) pH

CaCO3 by XRD

CaCO3 (%)

TGA LOI ASTM C25

No. 2-1 Light gray

50 73 23 MH (126) 17.3 7.51 Yes 45 41 41

No. 2-2 Light gray

- - Non-

plastic (94) 7.0 7.58 Yes 76 78 73

No. 2-3 Light gray

- - Non-

plastic (67) 7.3 7.56 Yes 76 74 64

No. 2-4 Light gray

39 66 27 MH (58) 5.0 7.47 Yes 44 40 (52)

No. 2-5 Light gray

27 45 18 CL-ML - 5.2 7.60 Yes 46 44 (42)

No. 2-6 Light gray

- - - (29) 16.5 7.58 Yes 53 51 15

No. 2-7 Light gray

14 26 12 CL (49) 2.2 7.41 Yes 39 45 (40)

No. 2-8 Light gray

22 38 16 CL (34) 2.4 7.43 Yes 32 34 (32)

No. 2-9 Light gray

40 59 19 MH (95) 9.7 7.52 Yes 46 46 (40)

No.2- 10 Brown 27 56 29 CH (76) 8.2 7.20 Yes 18 17 12




Sample No.

Color PL LL PI Soil typeNatural

M/C O.C. (%)

(LOI) pH

CaCO3 by XRD

CaCO3 (%)

TGA LOI ASTM C25

No. 3-1 Light gray

27 50 23 CL-CH (59) 4.4 7.54 Yes 37 37 29

No. 3-2 Brown 39 60 21 MH (47) 6.2 7.31 Yes 21 21 -

No. 3-3 Brown 30 52 22 MH (38) 4.9 7.31 Yes 21 23 -

No. 3-4 Brown 44 68 24 MH (76) 15.5 7.00 No 12 11 8

No. 3-5 Brown 32 60 28 MH (75) 9.0 7.19 Yes 18 18 -

No. 3-6 Brown 58 85 27 MH (75) 11.5 7.23 Yes 16 15 9

No. 3-7 Light gray

- - (19) 1.7 7.27 Yes 32 32 -

No. 3-8 Light gray

18 38 20 CL (51) 3.8 7.47 Yes 41 43 39

No. 3-9 Light gray

- - (43) 1.8 7.27 Yes 35 33 -

No.3-10 Light gray

17 25 8 CL (26) 1.2 7.23 Yes 35 35 28


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