Key Parameters for the Strength Control of Lime

7/24/2019 Key Parameters for the Strength Control of Lime

http://slidepdf.com/reader/full/key-parameters-for-the-strength-control-of-lime 1/7

Key Parameters for the Strength Control of LimeStabilized Soils

Nilo Cesar Consoli, Ph.D.1; Luizmar da Silva Lopes Jr.2; and Karla Salvagni Heineck3

Abstract: The addition of lime is an attractive technique when the project requires improvement of the local soil. The treatment of soils

with lime finds an application, for instance, in the construction of pavement base layers, in slope protection of earth dams, and as a support

layer for shallow foundations. However, there are no dosage methodologies based on rational criteria as exist in the case of the concrete,

where the water/cement ratio plays a fundamental role in the assessment of the target strength, and in the case of soil–cement technology,

where the voids/cement ratio is shown to be a good parameter for the estimation of unconfined compression strength. This study,

therefore, aims to quantify the influence of the amount of lime, the porosity, and the moisture content on the strength of a lime-treated

sandy lean clay soil, as well as to evaluate the use of a water/lime ratio and a voids/lime ratio to assess its unconfined compression

strength. A number of unconfined compression tests and measurements of matric suction were carried out. The results show that the

unconfined compression strength increased linearly with the increase in the lime content as well as with the reduction in porosity of the

compacted mixture. The change in moisture content has not presented an obvious effect on the unconfined compression strength of

mixtures compacted at the same dry density. It was shown that, for the soil–lime mixture in an unsaturated state which is usual for

compacted fills, the water/lime ratio is not a good parameter for the assessment of unconfined compression strength. In contrast, the

voids/lime ratio, defined as the ratio between the porosity of the compacted mixture and the volumetric lime content, is demonstrated to

be the most appropriate parameter to assess the unconfined compression strength of the soi-lime mixture studied.

DOI: 10.1061/ ASCE0899-1561200921:5210

CE Database subject headings: Lime; Compacted soils; Compression tests; Soil stabilization.

Introduction

The improved characteristics of compacted soils resulting from

lime utilization may be very important to some geotechnical en-

gineering applications such as canal lining, pavement structures,

and engineered fills Transportation Research Board 1987; Car-

raro 1997; Consoli et al. 2001. Several methodologies were es-

tablished in the last 50 years Hilt and Davidson 1960; Eades and

Grim 1966; Rogers et al. 1997 in order to determine the needed

amounts of lime required for modification of soil characteristics

and introduce adequate strength and durability to the use. Such

methodologies intend to establish a threshold value, supposed to

chemically satisfy the soil demand for lime, which has often been

suggested as the starting content to adopt for construction expe-

diency purposes. In spite of the numerous applications, there are

no dosage methodologies for the assessment of a target strength,

based on rational criteria as in the case of the concrete technol-

ogy, where the water/cement ratio plays a fundamental role. The

need for such dosage results from the fact that soil lime shows a

complex behavior that is affected by many factors, for example,

the physical–chemical properties of the soil, its porosity, and the

amount of lime and moisture content at the time of compaction

Mitchell 1981; Transportation Research Board 1987; Brown

1996; Consoli et al. 2001, 2008.This study, therefore, aims to quantify the influence of the

amount of lime, the porosity, and the moisture content on the

strength of a lime-treated sandy lean clay, as well as to evaluate

the use of a water/lime ratio and a voids/lime ratio to assess its

unconfined compression strength.

Experimental Program

The experimental program was carried out in three parts. First,

the geotechnical properties of the soil and lime were character-

ized. Next, the minimum amount of lime required for full stabi-

lization, based on the modified initial consumption of lime ICL

Rogers et al. 1997 was established. A number of unconfined

compression tests and measurements of matric suction were then

carried out as discussed below.

Materials

The results of the soil characterization tests are shown in Table 1

and the grain-size curve is shown in Fig. 1. This soil is classified

as sandy lean clay CL according to the Unified Soil Classifica-

tion System. Dry hydrated lime CaOH2 was used as the ce-

1Associate Professor, Dept. of Civil Engineering, Federal Univ. of Rio

Grande do Sul, Av. Osvaldo Aranha, 99, 3. Andar 90035-190 Porto AlegreRio Grande do Sul, Brazil corresponding author. E-mail: consoli@

ufrgs.br2Ph.D. Student, Federal Univ. of Rio Grande do Sul, Rio Grande do

Sul, Brazil. E-mail: luizmar [email protected] Professor, Federal Univ. of Rio Grande do Sul, Rio Grande

do Sul, Brazil. E-mail: [email protected]

Note. Associate Editor: Anand J. Puppala. Discussion open until

October 1, 2009. Separate discussions must be submitted for individual

papers. The manuscript for this paper was submitted for review and pos-

sible publication on July 31, 2007; approved on November 25, 2008. This

paper is part of the Journal of Materials in Civil Engineering , Vol. 21,

No. 5, May 1, 2009. ©ASCE, ISSN 0899-1561/2009/5-210–216/$25.00.

210 / JOURNAL OF MATERIALS IN CIVIL ENGINEERING © ASCE / MAY 2009

J. Mater. Civ. Eng., 2009, 21(5): 210-216



menting agent. Its slow gain of strength requested the adoption of 28 and 90 days as the curing times. The specific gravity of thelime grains is 2.49.

For the characterization tests, distilled water was used, but formolding specimens for the compression tests, tap water was used.

Modified Initial Consumption of Lime

The minimum amount of lime required for full stabilization,

based on the modified ICL Rogers et al. 1997, was establishedwith the basis on the interpretation of pH tests carried out on soilwith lime added—water proportions of 1:3 mixtures. A curveshowing the variation of pH due to lime addition is presented inFig. 2. Analyzing Fig. 2, using the modified asymptotic ICL in-terpretation, it can be observed that 3% was the minimum amountof lime for soil stabilization.

Methods

Molding and Curing of Specimens

For the unconfined compression tests, cylindrical specimens50 mm in diameter and 100 mm high, were used. After the soil,

lime and water were weighed, the soil and lime were mixed untilthe mixture acquired a uniform consistency. The water was thenadded continuing the mixture process until a homogeneous pastewas created. The amount of lime for each mixture was calculatedbased on the mass of dry soil and the target moisture content.

After mixing sufficient material for one specimen, the mixturewas stored in a covered container to avoid moisture losses before

subsequent compaction. The time it took to prepare mix andcompact was always less than 1 h. Two small portions of themixture were also taken for moisture content determination.

The specimen was then statically compacted in three layersinto a 50 mm diameter by 100 mm high split mold, which waslubricated, so that each layer reached the specified dry density.The top of each layer was slightly scarified. After the moldingprocess, the specimen was immediately extracted from the splitmold, and its weight, diameter, and height measured with accura-cies of about 0.01 g and 0.1 mm. The samples were then placedwithin plastic bags to avoid significant variations of moisture con-tent. They were cured in a humid room at 23 2°C and relativehumidity above 95% for 28 or 90 days.

The samples were considered suitable for testing if they metthe following tolerances:• Dry density d within 1% of target value;• Moisture content within 0.5% of the target value;• Diameter within 0.5 mm; and• Height within 1 mm.It is important to point out that the dry density d of the speci-

mens was calculated as the dry mass of the soil and lime dividedby the total volume of the sample. In order to keep the dry densityd of the specimens constant with increasing lime content, asmall portion of the soil was replaced by lime. As the specificgravity of the lime grains 2.49 is smaller than the specific grav-ity of the soil grains 2.81, for the calculation of void ratio andporosity, a composite specific gravity based on the soil and limepercentages in the specimen was used.

Unconfined Compression Tests

Unconfined compression tests have been used in most of the ex-perimental programs reported in the literature in order to verifythe effectiveness of the stabilization with lime or to access theimportance of influencing factors on the strength of lime-treated

soils. One of the reasons for this is the accumulated experiencewith this kind of test for concrete. The test is also simple and fast,while being reliable and cheap.

However, it is known that, when using soil lime as a com-pacted layer over a low bearing capacity soil, the system failureusually happens under tensile stresses at the base of the improvedlayer Consoli et al. 2008. It would then seem more reasonable touse the tensile strength as a direct measure of the soil–limestrength. However research has shown that the soil-lime tensilestrength typically ranges between 9 and 14% of the unconfinedcompression strength Ingles and Metcalf 1972, Consoli et al.2001. Because of this relationship, as well as the advantages of

Table 1. Physical Properties of the Soil Sample

Properties Values

Liquid limit 24%

Plastic limit 15%

Plasticity index 9%

Specific gravity 2.81

Medium sand 0.2 diameter 0.6 mm 12.6%

Fine sand 0.06 diameter 0.2 mm 41.1%

Silt 0.002 diameter 0.06 mm 42.0%

Clay diameter 0.002 mm 4.3%Effective diameter D10 0.0036 mm

Uniformity coefficient C u 33

Fig. 1. Grain-size distribution

Fig. 2. ICL test results

JOURNAL OF MATERIALS IN CIVIL ENGINEERING © ASCE / MAY 2009 / 211

J. Mater. Civ. Eng., 2009, 21(5): 210-216



the above-mentioned test, the unconfined compression test has

therefore been adopted as the most convenient means to investi-

gate the effect of different variables on the soil-lime strength.

An automatic loading machine, with maximum capacity of

50 kN and proving rings with capacities of 10 and 50 kN and

resolutions of 0.005 and 0.023 kN, respectively, were used for the

unconfined compression tests. The rate of displacement adopted

was 1.14 mm /min.

After curing in a humid room for 27 or 89 days, the specimens

were submerged in a water tank for 24 h for saturation and to

minimize suction, bringing the total curing time to 28 or 90 days.The water temperature was controlled and maintained at

23 3°C. Immediately before the test, the specimens were taken

out of the tank and dried superficially with an absorbent cloth.

The unconfined compression test was then carried out and the

maximum load reached by the specimen recorded. As acceptance

criteria, it was stipulated that the individual strengths of three

specimens, molded with the same characteristics, should not de-

viate by more than 10% from the mean strength.

Matric Suction Measurements

At their molding moisture contents, all the specimens tested were

in an unsaturated state and a certain level of suction may be

present. The suction measurements aimed to verify its magnitudeand examine if there was significant variation between specimens

of different porosities and lime contents.

The measured suction was the matric suction, i.e., that arising

from the capillary forces inside the sample. It was measured using

the filter paper technique Marinho 1995. The filter paper used

was Whatman No. 42. Its initial moisture content, in the air, dried

state, is approximately 6%, which allows measurements of suc-

tion from 0 to 29 MPa. The calibration equations for this filter

paper are those presented by Chandler et al. 1992.

The matric suction measurements were performed on samples

after failure in unconfined compression tests.

Program of Unconfined Compression TestsThe unconfined compression tests constituted the main part of this

research. The program was chosen in such a way as to evaluate,

separately, the influences on the mechanical strength of the arti-

ficially lime-cemented soil, of the lime content, the porosity, the

molding moisture content, the water/lime ratio, and the voids/lime

ratio.

The molding points for the program of unconfined compres-

sion tests are shown in Fig. 3 along with the compaction curves

with and without lime addition for the usual efforts of the Proc-

tor test standard and modified, and the saturation curves of 89

and 100%.

The molding points were positioned in two lines; a vertical

line Points A1, A2, A3, and A4, called Line A, with the samemoisture content and different dry densities, and a horizontal line,

called Line B Points B1, B2, A3, and B4, with the same dry

density but different moisture contents. Table 2 presents the val-

ues of dry density and moisture content for all the points.

The position of the molding points in Fig. 3 was chosen con-

sidering possible field conditions. Each point of the A line was

molded with five different lime percentages Li: 3, 5, 7, 9, and

11%. The points of the B line were molded with the same per-

centages as noted above. These percentages were chosen consid-

ering the Brazilian and international experience with soil lime

Mitchell 1981; Consoli et al. 2001, 2008, both in experimental

and practical work. Because of the typical scatter of data forunconfined compression tests, for each point three specimenswere tested.

Results

Effect of the Lime Content, Molding Moisture,and Porosity

Figs. 4 and 5 show data for the molding points on the Line A

=14% . Figs. 4a and b show the raw data and the fitted linesfor the unconfined compression strength as a function of the limecontent Li for, respectively, 28 and 90 days of curing. It can beobserved that the lime content has a reasonable effect on thestrength of this soil lime. It can be seen that the unconfined com-pression strength increases approximately linearly for both cur-ing periods with the increase in the lime content. The linesshown in Fig. 4 are best fit lines. Another feature that can be seenin Figs 4a and b is the increase in the rate of strength gain withlime content, represented by the gradient of the fitted line, withthe increase of the dry density. Such increase in the rate of strength gain is clearer for 90 days of curing. This indicates thatthe effectiveness of the lime is greater in more compacted mix-tures and longer curing periods. In Fig. 4b, a small deviationfrom linearity can be verified, when the unconfined compressionstrength increases more rapidly at first and then nearly flattens outessentially for smaller values of dry density.

Fig. 5 shows how the porosity affects the unconfined compres-sion strength of the soil lime studied. The unconfined compres-sion strength increases linearly with the reduction in porosity of

Fig. 3. Compaction curves and unconfined compression program of

tests

Table 2. Characteristics of Molding Points

Point d kN/m3 %

A1 16.0 14.0

A2 17.0 14.0

A3 18.0 14.0

A4 18.8 14.0

B1 18.0 10.0

B2 18.0 12.0

B3 18.0 16.0


J. Mater. Civ. Eng., 2009, 21(5): 210-216



the compacted mixture. This beneficial effect of a decrease inporosity has been reported by several researchers Ingles andMetcalf 1972; Consoli et al. 2006, 2007. The mechanism bywhich the reduction in porosity influences the soil-lime strength isrelated to the existence of a larger number of contacts.

Fig. 6 presents the unconfined compression strength for a cur-ing period of 28 days as a function of the moisture content forspecimens with the same dry density Line B. Generally, thestrength values are not affected by the moisture content for thesoil studied here.

The process of submerging the specimens for 24 h before theunconfined compression tests was found to be satisfactory to en-sure a high and repeatable degree of saturation. An average de-gree of saturation of 80% was obtained for specimens after

submersion, irrespective of the initial porosity or cementitiousmaterial content. The values of suction measured were low withvalues ranging from about 3 up to 8% of the unconfined compres-sion strength. The suctions in the samples at the peak strength aretherefore, likely to be insignificant relative to the strengths beingmeasured, allowing suction to be eliminated as a variable in theanalysis.

Effect of Water/Lime Ratio „a / Li …

From the data plotted in Fig. 6 for the 3 to 11% lime contents,Fig. 7 was plotted, which shows the unconfined compression

strength as a function of the water/lime ratio a /Li defined as

the water mass divided by the lime mass. It can be seen that it isnot possible to establish a relationship between these two factors,once an unique unconfined compression strength is related to arange of water/lime ratios see lime content 3% in Fig. 7.

Studies in soil–cement Horpibulsuk et al. 2003 in which thehigh moisture contents were sufficient for the pores of the

0

100

200

300

400

500

600

700

800

900

1000

2 3 4 5 6 7 8 9 10 11 12

Li (%)

q u

( k P a )

γd = 16.0 kN/m3

: qu = 10.1Li + 173.5 (R 2

= 0.95)

γd = 17.0 kN/m3

: qu = 12.6Li + 292.7 (R 2

= 0.97)

γd = 18.0 kN/m3

: qu = 20.5Li + 422.2 (R 2

= 0.97)

γd = 18.8 kN/m3

: qu = 19.8Li + 543.7 (R 2

= 0.93)

(a)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2 3 4 5 6 7 8 9 10 11 12

Li (%)

q u

( k P a )

γd = 16.0 kN/m3

: qu = 18.8Li + 282.6 (R 2

= 0.70)

γd = 17.0 kN/m3

: qu = 32.8Li + 435.2 (R 2

= 0.91)

γd = 18.0 kN/m3

: qu = 38.7Li + 712.4 (R 2

= 0.93)

γd = 18.8 kN/m3

: qu = 62.3Li + 914.9 (R 2

= 0.94)

(b)

Fig. 4. Variation of unconfined compression strength with lime con-

tent: a 28 days of curing; b 90 days of curing

0

100

200

300

400

500

600

700

800

900

1000

30 31 32 33 34 35 36 37 38 39 40 41 42

η(%)

q u

( k P a )

Li = 3% : qu = -42.45η + 1940 (R 2

= 0.99)

Li = 5% : qu = -44.88η + 2060 (R 2

= 0.99)

Li = 7% : qu = -46.90η + 2163 (R 2

= 0.99)

Li = 9% : qu = -47.61η + 2211 (R 2

= 0.99)

Li = 11% : q u = -52.34η + 2412 (R 2

= 0.99)

(a)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

30 32 34 36 38 40 42 44

η(%)

q u

( k P a )

Li = 3% : qu = -76.7η + 3470 (R 2

= 0.99)

Li = 5% : qu = -87.9η + 4011 (R 2

= 0.98)

Li = 7% : qu = -94.8η + 4321 (R 2

= 0.99)

Li = 9% : qu = -100.8η + 4598 (R 2

= 0.98)

Li = 11% : q u = -107.2η + 4857 (R 2

= 0.98)

(b)

Fig. 5. Variation of unconfined compression strength with porosity:

a 28 days of curing; b 90 days of curing

Fig. 6. Effect of molding moisture content on the unconfined com-

pression strength 28 days of curing


J. Mater. Civ. Eng., 2009, 21(5): 210-216



samples to be predominantly water filled, the water content wouldreflect the amount of voids. In such a case, the water/cement ratiowas found to be a useful parameter in the analysis of the strengthdevelopment of the materials, as happens in concrete, where theamount of water again reflects the amount of voids in the mortar.In the present study, the voids are only partially filled by waterand there is not, therefore, a unique relationship between the

voids and the amount of water. Therefore, for the soil lime in theunsaturated state, as is usual in engineering practice, a relation-ship between porosity and lime content should be more appropri-ate in the analysis and control of its mechanical strength.

Effect of Voids/Lime Ratio

Fig. 8 presents the unconfined compression strength as a functionof the voids/lime ratio defined by Eq. 1

V v

V Li=

Absolute volume of voids water + air

Absolute volume of lime 1

The data presented in Figs. 8a and b are, for the Line A

=14% , respectively, for 28 and 90 days of curing. No correlationcan be observed between this ratio and the unconfined compres-sion strength qu of the soil lime studied.

Figs. 8a and b distinguish the plotted points by their limecontents. It can be readily seen that points with the same voids/ lime ratio but obtained by different combinations of lime contentand densification show distinctly different strengths.

Figs. 9a and b appear to show that increasing lime contentfrom 3 to 11% has a moderate effect on unconfined compressionstrength while increasing compaction reducing the volume of voids has a major effect. Examining Figs. 9 and 10, it can beseen that the rates of change of unconfined compression strength

0

100

200

300

400

500

600

700

800

900

2 4 6 8 10 12 14 16 18 20 22 24

Vv / VLi

q u

( k P a )

Li= 3%

Li= 5%

Li= 7%

Li= 9%

Li= 11%

(a)

0

250

500

750

1000

1250

1500

1750

2000

2 4 6 8 10 12 14 16 18 20 22 24

Vv / VLi

q

u

( k P a )

Li= 3%

Li= 5%

Li= 7%

Li= 9%

Li= 11%

(b)

Fig. 8. Variation of unconfined compression strength with voids/lime

ratio: a 28 days of curing; b 90 days of curing

0

100

200

300

400

500

600

700

800

900

1

60 64 68 72 76 80 84

Vv (cm3)

q u

( k P a )

Li = 3% : qu = -22.1Vv + 1986 (R 2 = 0.98)

Li = 5% : qu = -23.5Vv + 2114 (R 2 = 0.99)

Li = 7% : qu = -24.3Vv + 2203 (R 2

= 0.99)

Li = 9% : qu = -24.7Vv + 2253 (R 2

= 0.99)

Li = 11% : qu = -27.4Vv + 2481 (R 2 = 0.99)

(a)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

58 62 66 70 74 78 82 86

Vv (cm3)

q u

( k P a )

Li = 3% : qu = -39.7Vv + 3549 (R 2

= 0.99)

Li = 5% : qu = -45.7Vv + 4104 (R 2

= 0.98)

Li = 7% : qu = -49.9Vv + 4467 (R 2 = 0.98)

Li = 9% : qu = -52.3Vv + 4710 (R 2

= 0.98)

Li = 11% : qu = -54.6Vv + 4901 (R 2

= 0.98)

(b)

Fig. 9. Relationship between voids volume and unconfined compres-

sion strength: a 28 days of curing; b 90 days of curing

Fig. 7. Variation of unconfined compression strength with water/lime

ratio 28 days of curing


J. Mater. Civ. Eng., 2009, 21(5): 210-216



with voids volume V v and the inverse of the lime volume

1 /V Li are substantially different. A way to make the variationrates of V

v and 1 /V Li compatible is through the application of a

power to one of them. It was found that for the relationship be-tween unconfined compression strength and voids/lime ratio theoptimum fit could be obtained applying a power equal to 0.06 to

the parameter V Li as shown in Fig. 11. A good correlation coef-ficient of determination— R2 =0.97 and 0.98, respectively, for 28and 90 days of curing can be observed between V

v/ V Li

0.06 and

the unconfined compression strength qu of the soil lime studiedsee Eqs. 2 and 3, respectively, for 28 and 90 days of curing

qukPa = 4.23 109 V v

V Li0.06

−3.89

2

qukPa = 4.15 1010 V v

V Li0.06

−4.29

3

Fig. 12 shows that when using all the data for 28 days of curing plotted together for Lines A and B, a good fit is still ob-tained coefficient of determination— R2 =0.96 can be observed

between V v / V Li0.06 and the unconfined compression strengthqu of the soil lime studied

qukPa = 5.13 109 V v

V Li0.06

−3.93

4

So, the use of the voids volume of the compacted mixturedivided by the lime volume, adjusted by an exponent 0.06 for thesoil and lime used in the present research to assess the uncon-fined compression strength in the soil-lime mixtures studiedherein is valid for all considered moisture contents. The resultspresented in this paper, therefore, suggest that using the voids/ lime ratio as represented by the voids volume of the compacted

mixture divided by the lime volume adjusted by an exponent thatprobably varies depending on the soil and lime used—but possi-bly not depending on curing time same exponent for curing timesused—28 and 90 days, the engineer can choose the amount of lime and the compaction effort appropriate to provide a mixturethat meets the strength required by the project at the optimumcost. The voids/lime ratio can also be useful in the field control of soil-lime layers. Once a poor compaction has been identified, itcan be readily taken into account in the design, through the qu

versus voids/lime ratio curve, and adopting corrective measuresaccordingly such as the reinforcement of the treated layer or thereduction in the load transmitted.Fig. 11. Adjusted voids/lime ratio 28 and 90 days of curing

Fig. 12. Adjusted voids/lime ratio 28 days of curing—all data

0

100

200

300

400

500

600

700

800

900

1000

0.04 0.08 0.12 0.16 0.20 0.24 0.28 0.32

1 / VLi (cm3

)-1

q u

( k P a )

γd = 16.0 kN/m3 : qu = 135.9(1/VLi)-0.29 (R 2 = 0.99)

γd = 17.0 kN/m3 : qu = 241.7(1/VLi)-0.22 (R 2 = 0.95)

γd = 18.0 kN/m3

: qu = 336.6(1/VLi)-0.24

(R 2

= 0.97)

γd = 18.8 kN/m3

: qu = 448.4(1/VLi)-0.19

(R 2

= 0.92)

(a)

0

250

500

750

1000

1250

1500

1750

2000

0.03 0.06 0.09 0.12 0.15 0.18 0.21 0.24 0.27 0.30

1 / VLi (cm3

)-1

q u

( k P a )

γd = 16.0 kN/m3

: qu = 196.7(1/VLi)-0.36

(R 2

= 0.84)

γd = 17.0 kN/m3

: qu = 313.6(1/VLi)-0.36

(R 2

= 0.96)

γd = 18.0 kN/m3

: qu = 542.0(1/VLi)-0.28

(R 2

= 0.98)

γd = 18.8 kN/m3

: qu = 657.3(1/VLi)-0.33

(R 2

= 0.99)

(b)

Fig. 10. Relationship between the inverse of lime volume and un-

confined compression strength: a 28 days of curing; b 90 days of

curing.


J. Mater. Civ. Eng., 2009, 21(5): 210-216



Conclusions

From the data presented in this paper, and bearing in mind thelimitations of this study, the following conclusions can be drawn:• For the lime contents studied here, the unconfined compres-

sion strength increased approximately linearly with an increasein the lime content.

• The reduction in the porosity of the compacted mixture greatlyimproves the strength. It was shown that the unconfined com-pression strength increased approximately linearly with a re-

duction in the porosity of the compacted mixture.• It was found that there is no relationship between the uncon-

fined compression strength and the water/lime ratio for thematerial studied.

• The voids/lime ratio, defined by the voids volume of the com-pacted mixture divided by the lime volume, adjusted by anexponent 0.06 for the soil and lime used in the present re-search has been shown to be a more appropriate parameter toevaluate the unconfined compression strength of the soil–limemixture studied. It is probable that this exponent will be afunction of the materials soil and lime used.

Acknowledgments

The writers wish to express their gratitude to CNPq/MCTProjects Nos. 301869/2007-3, 501468/2008-0, and 558474/ 2008-0 and PRONEX-FAPERGS Project No. 04/0841.0 fortheir financial support to the research group.

Notation

The following symbols are used in this paper:

a mass of water;a /Li water/lime ratio;

C u uniformity coefficient;

D10 effective diameter;Li mass of lime;qu unconfined compression strength;

R2 coefficient of determination;S degree of saturation;

V Li volume of lime;V v

volume of voids;d dry density; porosity; and

moisture content expressed in relation to the sumof dry soil and lime.

References

Brown, R. W. 1996. Practical foundation engineering handbook ,

McGraw-Hill, New York.

Carraro, J. A. H. 1997. “Use of industrial residues in the stabilization of

a residual soil.” MSc thesis, Federal Univ. of Rio Grande do Sul,

Porto Alegre, Brazil in Portuguese.Chandler, R. J., Crilly, M. S., and Montgomery-Smith, G. 1992. “A

low-cost method of assessing clay desiccation for low-rise buildings.”

Proc. Inst. of Civ. Eng. (UK), 922, 82–89.

Consoli, N. C., Foppa, D., Festugato, L., and Heineck, K. S. 2007. “Key

parameters for strength control of artificially cemented soils.” J. Geo-

tech. Geoenviron. Eng., 1332, 197–205.

Consoli, N. C., Prietto, P. D. M., Carraro, J. A. H., and Heineck, K. S.

2001. “Behavior of compacted soil-fly ash-carbide lime-fly ash mix-

tures.” J. Geotech. Geoenviron. Eng., 1279, 774–782.

Consoli, N. C., Rotta, G. V., and Prietto, P. D. M. 2006. “Yielding-

compressibility-strength relationship for an artificially cemented soil

cured under stress.” Geotechnique, 561, 69–72.

Consoli, N. C., Thomé, A., Donato, M., and Graham, J. 2008. “Loading

tests on compacted soil–bottom ash–carbide lime layers.” Proc. Inst.

Civil Eng., Geotech. Eng., 1611, 29–38.Eades, J. L., and Grim, R. E. 1966. “A quick test to determine require-

ments for lime stabilization.” Highway Research Record. 139, High-

way Research Board, Washington, D.C., 61–72.

Hilt, G. H., and Davidson, D. T. 1960. “Lime fixation in clayey soils.”

Highway Research Record. 262, Highway Research Board, Washing-

ton, D.C., 20–32.

Horpibulsuk, S., Miura, N., and Nagaraj, T. S. 2003. “Assessment of

strength development in cement-admixed high water content clays

with Abram’s Law as a basis.” Geotechnique, 534, 439–444.

Ingles, O. G., and Metcalf, J. B. 1972. Soil stabilization—Principles

and practice, Butterworths, Melbourne, Australia.

Marinho, F. A. M. 1995. “Suction measurement through filter paper

technique.” Proc., Unsaturated Soils Seminar , UFRGS, Porto Alegre,

Brazil, 111–125 in Portuguese.

Mitchell, J. K. 1981. “Soil improvement—State-of-the-art report.”

Proc., 10th Int. Conf. on Soil Mechanics and Foundation Engineer-

ing, Stockholm, Sweden, 509–565.

Rogers, C. D. F., Glendinning, S., and Roff, T. E. J. 1997. “Lime modi-

fication of clay soils for construction expediency.” Proc. Inst. Civil

Eng., Geotech. Eng., 1253, 242–249.

Transportation Research Board. 1987. “Lime stabilization—Reactions,

properties, design, and construction.” State of the Art Rep. No. 5,

Transportation Research Board, Washington, D.C.


Key Parameters for the Strength Control of Lime

Documents

Transcript of Key Parameters for the Strength Control of Lime