Soil and Soil Aggregates

VOLUME I - SOIL AND SOIL AGGREGATES TEST 1

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Sampling Aggregates

SIGNIFICANCE

FORMULA

to determine the availability and suitability of the largest single constituent entering into the construction

NOTES influences the type of construction from the standpoint of economics and governs the necessary material control to ensure durability if the resulting structure, from the aggregate standpoint

from flowing aggregate stream (bins or belt discharge) fom converyor belt from stockpiles or transportation units from roadway (bases & subbases) Preparation of Disturbed Soil Samples for Test Mechanical & Specific Gravity 9.5mm-0.5kg; 25mm-2kg; 50mm-4kg; 75mm-5kg/for hydrometer & sieve analysis: passing 2mm-110g for sandy; 60g for silty or clayey; for SG 60°C retained at at 2mm sieve-Coarse: 25g volumetric flask; 10g bottle Physical Test separate passing 2mm using 0.425mm; passing 0.425mm for limits tests Moisture Density Relations separate remaining portion of sample using 4.75mm or 19mm sieve/Compaction Test Thin-walled Tube Sampling of Soils for relatively undisturbed soils samples suitable for not permitted - bottom discharge bits/jetting through an laboratory tests for structural properties open-tube sampler to clean out the borehole sampling elevation Preparation of Undisturbed Soil Samples using any drilling equipment that provides clean hole for density, permeability, consolidation & other shear for Test before insertion of thin walled tubes/both natural density test/done in humid room & moisture content are preserved Reducing Field Samples of Aggregates to Method A - mechanical splitter; Method B - Quartering; fine aggregates drier that saturated-surface-dry condition Testing Size Method C - miniature stockpile use Method A; free moisture - use Method B or C

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Determination of Moisture Content

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Particle Size Analysis of Soils

ratio of the weight/mass of water in the soil ti the MC=[(W1-W2)/(W2weight/mass of the dry soil after it has been dried to Wc)]x100 constant weight/mass at a temperature of 110±5°C determination of particle size distribution in soils by sieve, hydrometer or a combined analysis

gravel +2mm; sand -2mm +0.075mm; silt - Hygroscopic Moisture 0.075mm +0.002mm; clay -0.02mm

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HM = (wt. of air-dried - wt. of oven-dried)/wt. of ovendried

W1-container+wet soil; W2-container+dry soil; Wc-container

9.5mm-0.5kg; 25mm-2g; 50mm-4g; 75mm-5g / portion passing 2mm or 0.425mm (No.40) - Hydrometer 100g for sandy soil; 50g for silty or clayey soil; Hygroscopic Moisture Determination - 10g Correction on mass of air-dried sample = 100/(100+%HM)

TEST

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Amount of Material Finer than 0.075mm Sieve

9

Determination of Liquid Limit

SIGNIFICANCE

FORMULA

NOTES

Percentage of Soil in Suspension for Hydrometer A (152H)

P = (Ra/Ws)x100

R - corrected hydrometer reading; Ws - dry weight/mass of soil dispersed; a - constant that varies w/ Gs

Percentage of Soil in Suspension for Hydrometer B(151H)

P = [1606(R-1)a/Ws]x100

Diameter of Particle in Suspension

D = √[30nL/980(Gs-Gm)T]

Gs-a; 2.95-0.94; 2.85-0.96; 2.75-0.98; 2.65-1.00; 2.55-1.02; 2.45-1.05; 2.35-1.08 D-max particle diameter (mm); -coefficient of viscosity; Ldistance of surface of suspension to center of volume of hydrpometer (cm) ; period of sedimentation (minutes); Gsspecific gravity of soil particles; Gm-specific gravity of suspending medium dry at 110±5°C, weigh nearest 0.1%; add water & agitate; pour water over the nested sieve (1.18mm over 0.075m) until clear; dry & weigh

can be separated much more efficiently and completely by %passing 0.075mm by wet wet sieving prior dry sieving; AASHTO T 27 sieve = (orig dry - dry after washing)/orig dry

lowest moisture content at which soil will flow upon the application of very small shearing force; LL - moisture content corresponding to 25 blows 10 Determination of Plastic Limit and Plasticity Index Plastic Limit minimum moisture content at which soil can be readily molded without breaking or crumbling Plasticity Index indicates compressibility; high P.I. = high compressibility / lower permeability 11 Determination of Shrinkage Limit of Soil between semi-solid & solid stated states; highest moisture content of which the mass attains its maximum volume but continues to lose weight/mass

%Moisture = [(W1-W2)/W2]x100

W1-wet; W2-dry

PL = [(Wa-Wb)/Wb]x100

Wa-crumbled; Wb-dry

12 Determination of Specific Gravity of Soil

Gavg=1/[(R1/100G1)+(P1/1 R1-% etained on 4.75mm sieve; P1-%passing 4.75mm sieve; 00G2)] G1-specific gravity of retained; G2-specific gravity of passing

ratio of the weight/mass in air of a given volume of a material to the weight/mass in air of an equal volume of water at a stated temperature

PI = LL - PL SL = w-[(V-Vo)/Wo]x100 w=[(wet-dry)/dry]x100

Gs=WsGtx/[Ws+(Wa-Wb)]

13 Compaction Test / Moisture Density Relation Test of Soil

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w-moisture content; V-volume of wet soil pat; Vo-volume of oven-dried soil pat; Wo-wt/mass of oven-dried soil pat

Gs-specific gravity of soil; Ws-mass of oven-dried soil, Wamass of pycnometer+water at T1; Wb-mass of pycnometer+water+soil at T1; Tx-temperature of contents; Gtx-density of distilled water at Tx

TEST Compaction

14 Determination of Density of Soil In-place by the Sand Cone Method Density Field Density Test 15 California Bearing Ratio Test

16 Unit Weight/Mass Determination in Aggregates 17 Determination of Organic Impurities in Sands of Concrete

18 Effect of Inorganic Impurities in Fine Aggregates on Strength of Mortar

19 Soundness Test by the use of Sodium or Magnesium Sulfate

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SIGNIFICANCE

FORMULA

NOTES

application of energy and addition of water as lubricant; results in reduction of pore spaces and increase of density by rearrangement of particle grains; mass becomes more stable and impermeable; attain maximum stability; makes fill impervious

w=[(A-B)/(B-C)]x100; W=[W1/(w+100)]x100; optimum moisture contentvertex of the curve; max dry density-corresponding density of optimum moisture content

w-% of moisture on oven-dry mass; A-container+wet soil; Bcontainer+dry soil; C-container; W-dry mass of compacted soil; W1-wet mass of compacted soil; ¶ using 2.5kg rammer & 305mm drop (5.5lb/12");

weight/mass per unit volume control test in embankment construction to ensure highway specs - not less adequate compaction than 95% determination of the bearing ratio of soil when compacted and tested in laboratory condition by comparing the penetration load of the soil to that of a standard material; measuring resistance of soil to penetration used in volumetric-gravimetric calculations determines the presence of injurious organic compounds natural sands which are to be used in cement mortar or concrete; furnish warning that further tests are necessary before approval significant in making a final determination of the acceptability of fine aggregates for Portland Cement Concrete (AASHTO M6); applicable only to samples which produce darker color when tested for Organic Impurities

determines the resistance of aggregates to disintegration by saturated solutions of sodium sulfate or magnesium sulfate; to eveluate soundness of aggregates subject to weathering action

if darker, perform effect of organic impurities on the strength of mortar

450g sample; 3%NaOH solution; reference color/ fill 130ml sample, add 3%NaOH solution up to 200mL; stopper, shake & allow to settle for 24hrs

compressive strength = max load/cross-sectional area; strength ratio = unwashed/washed

use sample from (17); wash until NaOH has been removed; test using phenolphthalein or litmus; stength comparison at 7 days (3 batches unwashed & 3 batches washed - mold 3 2" cube per batch); consistency = 100±5; 23±1.7°C; 600g cement/360mL water sodium sulfate soln - 350g anhydrous salt/L water or 750g decahydrate salt/L water; SG=1.54-1.174 ¶ magnesium sulfate soln - 1400g heptahydrate/L water; SG=1.295-1.174; ¶ 5 cycles of immersion & drying; 12.7mm depth @ 21±1°C

TEST 20 Mortar Strength Test

SIGNIFICANCE

FORMULA

to determine compressive strength of hydraulic cement and mortars; used to predict the strength of concrete

flow - resulting increase in average base diameter of the mortar mass (%)

6 speciments: 500g cement; 1,375g sand; 242mL water (230 mL for air-entraining)

compressive strength = max load/cross-sectional area;

NOTES 1part cement:2.75part sand ¶ water-cement ratio = 0.485 for portland cement; 0.460 for air-entraining portland cement ¶ flow = 110±5

21 Determination of Specific Gravity and Absorption of Fine and Coarse Aggregate Bulk Specific Gravity generally used for calculation of the volume occupied by aggregate in various mixtures (portland cement concrete, bituminous concrete) that are proportioned & analyzed on an absolute volume basis Absorption change in the weight of aggregate due to water absorbed in the pore spaces within the constituent particles Fine Aggregates 1kg; 110±5°C; immersion; 15-19hrs; slump @ surface-dry BSG=A/(B+S-C) Abs=[(S- A-dry sample in air; B-pyc+water; C-pyc+sample+water; Scondition/ 500g to pycnometer+water; 23±1.7°C, weigh/ A)/A]x100 saturated surface-dry 110±5°C for 1±1/2hr, weigh Coarse Aggregates BSG = A/(B-C) Abs=[(B- A-dry sample in air; B-saturated surface-dry in air; C-saturated A)/A]x100 in water 22 Abrasion Test evaluates the structural strength of coarse aggregate; Abrassion loss, abrasive charge - consist of cast-iron spheres or steel spheres indicates quality as determined by resistance to impact & %wear=(original volumeapprox. 46.8" Ø & each weighing 390 & ___g/ 30-33 rpm; 500 wear retained in sieve No. rev/ separate by 1.70mm (No. 12) coarser that 1.70mm dry at 12)/original volume 105-110°C

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