ASTM D6276-99a(2006)
(Test Method)Standard Test Method for Using pH to Estimate the Soil-Lime Proportion Requirement for Soil Stabilization
Standard Test Method for Using pH to Estimate the Soil-Lime Proportion Requirement for Soil Stabilization
SIGNIFICANCE AND USE
The soil-lime pH test is performed as a test to indicate the soil-lime proportion needed to maintain the elevated pH necessary for sustaining the reactions required to stabilize a soil. The test derives from Eades and Grim.3
Performance tests are normally conducted in a laboratory to verify the results of this test method.
This test method will not provide reliable information relative to the potential reactivity of a particular soil, nor will it provide information on the magnitude of increased strength to be realized upon treatment of this soil with the indicated percentage of lime.
This test method can be used to estimate the percentage of lime as hydrated lime or quicklime needed to stabilize soil.
Agricultural lime (crushed limestone) will not stabilize soil.
Note 1—Notwithstanding the statements on precision and bias contained in this test method: The precision of this test method is dependent on the competence of the personnel performing it and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D 3740 are generally considered capable of competent and objective testing. Users of this test method are cautioned that compliance with Practice D 3740 does not itself ensure reliable testing. Reliable testing depends on several factors; Practice D 3740 provides a means of evaluating some of those factors.
SCOPE
1.1 This test method provides a means for estimating the soil-lime proportion requirement for stabilization of a soil. This test method is performed on soil passing the 425-m (No. 40) sieve. The optimum soil-lime proportion for soil stabilization is determined by tests of specific characteristics of stabilized soil such as unconfined compressive strength or plasticity index.
1.2 Some highly alkaline by-products (lime kiln dust, cement kiln dust, and so forth) have been successfully used to stabilize soil. This test method is not intended for these materials and any such product would need to be tested for specific characteristics as indicated in .
1.3 This test method is used to determine the lowest percentage of lime that results in a soil-lime pH of 12.4.
1.4 Lime is not an effective stabilizing agent for all soils. Some soil components such as sulfates, phosphates, organics, and so forth can adversely affect soil-lime reactions and may produce erroneous results using this test method.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D6276–99a (Reapproved 2006)
Standard Test Method for
Using pH to Estimate the Soil-Lime Proportion Requirement
for Soil Stabilization
This standard is issued under the fixed designation D6276; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope* D421 Practice for Dry Preparation of Soil Samples for
Particle-Size Analysis and Determination of Soil Con-
1.1 This test method provides a means for estimating the
stants
soil-limeproportionrequirementforstabilizationofasoil.This
D653 Terminology Relating to Soil, Rock, and Contained
testmethodisperformedonsoilpassingthe−425-µm(No.40)
Fluids
sieve.Theoptimumsoil-limeproportionforsoilstabilizationis
D1193 Specification for Reagent Water
determined by tests of specific characteristics of stabilized soil
D1293 Test Methods for pH of Water
such as unconfined compressive strength or plasticity index.
D2216 Test Methods for Laboratory Determination of Wa-
1.2 Some highly alkaline by-products (lime kiln dust, ce-
ter (Moisture) Content of Soil and Rock by Mass
ment kiln dust, and so forth) have been successfully used to
D3740 Practice for Minimum Requirements for Agencies
stabilize soil. This test method is not intended for these
Engaged in theTesting and/or Inspection of Soil and Rock
materials and any such product would need to be tested for
as Used in Engineering Design and Construction
specific characteristics as indicated in 1.1.
D4753 Guide for Evaluating, Selecting, and Specifying
1.3 This test method is used to determine the lowest
Balances and Standard Masses for Use in Soil, Rock, and
percentage of lime that results in a soil-lime pH of 12.4.
Construction Materials Testing
1.4 Lime is not an effective stabilizing agent for all soils.
E11 Specification for Wire Cloth and Sieves for Testing
Some soil components such as sulfates, phosphates, organics,
Purposes
and so forth can adversely affect soil-lime reactions and may
E145 Specification for Gravity-Convection And Forced-
produce erroneous results using this test method.
Ventilation Ovens
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety and health practices and determine the applica-
3.2 Refer to Terminology C51 for definitions of terms
bility of regulatory limitations prior to use.
relating to lime.
2. Referenced Documents 3.3 Refer to Terminology D653 for terms relating to soil.
2 3.4 Definitions of Terms Specific to This Standard:
2.1 ASTM Standards:
3.4.1 buffer solution—a solution of specific pH value used
C51 TerminologyRelatingtoLimeandLimestone(asused
to calibrate the pH meter.
by the Industry)
3.4.2 free lime—lime in a soil-lime mixture that has not
C977 Specification for Quicklime and Hydrated Lime for
dissociated into calcium and hydroxyl ions.
Soil Stabilization
3.4.3 hydrated lime—lime that is predominately calcium
hydroxide (Ca(OH) ) or a mixture of calcium hydroxide and
magnesium oxide (MgO) or magnesium hydroxide
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland (Mg(OH) ).
Rock and is the direct responsibility of Subcommittee D18.15 on Stabilization and
3.4.4 lime—a general term which, for the purpose of this
Admixtures.
test method, includes hydrated lime and quicklime.
Current edition approved May 1, 2006. Published June 2006. Originally
3.4.5 lime content—the ratio expressed as a percentage of
approved in 1998. Last previous edition approved in 1999 as D6276–99a.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the mass of lime to the dry mass of soil.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.4.6 lime stabilization—addition of lime to a soil in suffi-
Standards volume information, refer to the standard’s Document Summary page on
cient quantities to promote long-term pozzolanic reactions that
the ASTM website.
result in strength gain and permanent improvement in stability.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6276–99a (2006)
Textural improvement alone, such as reduced plasticity, is 6.1.1 A balance or scale for determining the mass of soil
often referred to as “modification.” Modification can be ef- and lime having a minimum capacity of 600 g and meeting the
fected by lime addition rates less than those required for requirements of Specification D4753 for a balance or scale of
stabilization and may not be permanent. 0.01 g readability.
3.4.7 pH—thenegativelogarithmoftheeffectivehydrogen- 6.2 Sieve—A 425-µm (No. 40) sieve, conforming to the
ionconcentrationorhydrogen-ionactivity,ingramequivalents requirements of SpecificationE11.
per litre. The pH values range from 0 to 14; where pH 7 6.3 Plastic Bottles—Six 150-mL (or larger) plastic bottles
represents neutrality, pH values less than 7 indicate increasing with tight-fitting screw caps.
acidity, and pH values greater than 7 indicate increasing 6.4 A pH Meter—A pH meter equipped with reference
alkalinity. electrode and low-sodium error glass pH-sensitive electrodes
3.4.8 quicklime—lime that is predominately calcium oxide (or combination electrode) and a meter capable of displaying
(CaO) or calcium oxide in association with magnesium oxide 0.01 units pH at 0.2 pH accuracy over a range from 0 to 14.
(MgO). 6.5 Drying Oven—Oven conforming to requirements of
3.4.9 stabilization—a process to improve the engineering Specification E145.
properties of soils at a site. 6.6 Miscellaneous Equipment—An airtight, moisture-proof
container for preserving the moisture content of the soil;
4. Summary of Test Method
mixing tools and scoops for use in preparing test specimens.
4.1 Aseries of specimens is prepared containing a range of
7. Reagents and Materials
percentages of lime content in soil. Measurements of pH are
made on slurries of the specimens to determine the minimum
7.1 Water—Reference to water shall be understood to mean
lime content of the soil-lime mixture to obtain a pH of at least Type II reagent water conforming to Specification D1193.
12.4.
Store the water in a tightly capped container; boil and cool the
4.2 The pH of at least 12.4 achieved in this test method
water immediately before use.
results from free lime remaining in the soil-lime mixture.
NOTE 2—If the pH of the site water to be used is highly acidic (<6) or
Normally, the pH of the specific lime being used for soil
highly basic (>9) test results should be checked against a specimen made
stabilization should be determined and used as the indicator
up with site water rather than Type II water.
pH.
7.2 Buffer Solution—Use a buffer solution having a pH of
5. Significance and Use 12, either commercially available or prepared in accordance
with Test Methods D1293.
5.1 The soil-lime pH test is performed as a test to indicate
7.3 Hydrated Lime—Only fresh lime meeting the require-
the soil-lime proportion needed to maintain the elevated pH
ments of Specification C977 may be used.
necessary for sustaining the reactions required to stabilize a
7.4 Quicklime—Only fresh lime meeting the requirements
soil. The test derives from Eades and Grim.
of Specification C977 may be used.
5.2 Performance tests are normally conducted in a labora-
tory to verify the results of this test method.
8. Safety Hazards
5.3 This test method will not provide reliable information
8.1 Quicklime becomes hot when mixed with water. Use
relative to the potential reactivity of a particular soil, nor will
protective gloves when handling containers of soil-quicklime-
it provide information on the magnitude of increased strength
water mixtures.
to be realized upon treatment of this soil with the indicated
8.2 Hydrated lime and quicklime are strong caustics and
percentage of lime.
may cause severe irritation of skin, eyes, and mucous mem-
5.4 This test method can be used to estimate the percentage
branes. Appropriate safety equipment such as heavy rubber
of lime as hydrated lime or quicklime needed to stabilize soil.
gloves,protectiveeyewear,andaplasticapronshouldbeworn
5.5 Agricultural lime (crushed limestone) will not stabilize
when handling lime. Ensure that adequate ventilation (or a
soil.
respirator) is provided.
NOTE 1—Notwithstanding the statements on precision and bias con-
9. Technical Hazards
tained in this test method: The precision of this test method is dependent
onthecompetenceofthepersonnelperformingitandthesuitabilityofthe
9.1 Limereadilyabsorbswaterandcarbondioxidefromthe
equipment and facilities used. Agencies that meet the criteria of Pra
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