Compaction Data Handbook

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Compaction data handbook

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INGERSOLL-FiAND

' ; C O N S T B U C T J P N E Q U IP M E t ir



PREFACE

In to day ’s construction industry “ Com paction” plays a moreimportant role than it ever has before. During the past years,industry has learned a great deal about the importance andeffects of Compaction. As insignificant as it may seem, this onephase of construction represents the very foundation of theconstruction industry. Today’s projects around the globe demand effective densification of soils to support greater loads fornew highways, airports, dam and building foundations. Moderntechnology has answered the call with the introduction of

vibratory compaction which has proved to be the most effectivemethod and tool f or soil densification.

This text has been prepared to acquaint you with a workingknowledge of soil reactions and the application of compactionequipment. The text presented herein concerns the basic concepts relating to the requirements of soil densification, but alsoshould alert you to the numerous factors involved in soilcompaction.

Ingersoll-Rand CompanyCompaction DivisionIngersoll DriveShippensburg, PA 17257 U.S.A.

INGERSOLL-RAND®CONSTRUCTION EQUIPMENT

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F i g u

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CHAPTER I

From the beginning herds of cattle and flocks of sheep wereused effectively as a method of soil compaction. The timesyielded to the methods which were available in preparation of

earth fill to make way for primitive roadways.

Horse and oxen-drawn rollers for road building were constructed by approximately the 18th century. Steam rollers wereconstructed in France in the middle of the 19th century. Thesmooth steel wheel roller emerged, driven by steam powerwhich proved impractical.

Figure 1-2

Soon after, with the introduction of the internal combustion

engine, smaller power plants were available and became mostpopular.

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The United States was the pioneer in the development of soilcompaction engineering. The first sheepsfoot rollers, which

were designed for use in earth dam construction, were developed in California in the years 1904 to 1906. At that time, itwas still customary to move earth masses by means o f carts orsimilar vehicles drawn by horses and mules. Therefore, the firstsheepsfoot rollers were likewise horse or mule-drawn.

In the field of road construction it was found at an early stagethat pavements laid on non-compacted highway embarkmentswere damaged in a short time and became uneven because of

soil settlements. For this reason, road construction has becomeand continues to be the greatest field of application of soilcompaction engineering.

The principles and methods of soil compaction evolved in theUnited States have also been widely applied in other countries.The organizations in the United States had to deal with theoretical and practical studies of soil compaction problems withthe various road authorities, such as the Federal Bureau of

Public Roads and the Highway Department of the individualstates. Moreover, such studies were also made by the Corps ofEngineers, which is charged with dam construction, flood regulation, military airfield construction, etc., and by the Bureau ofReclamation, which is a federal government organization dealing with irrigation projects, that has built many of the largestdams in the United States.

Vibratory compaction o f soils began to come into use in Germany in the early 1930’s in connection with the construction ofthe motorway system. The first types of vibratory compactorswere the self-propelled 1.5 ton base plate type compactor andthe caterpillar type compactor, weighing about 25 tons, whichwas manufactured by the Losenhausenwerk. The first self-propelled and tractor towed vibrating rollers were constructedin the 1940’s (Fig. 1-3).

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Nevertheless, tractor driven plate compactors have provenunfeasible and were quickly replaced with hand held or self-

propelled type equipment.

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CHAPTER II

MATERIALS

SOIL TYPES

Steel, concrete and wood are easy construction materials with

which to work because they are of homogeneous, uniformcomposition. As such, their behavior can be predicted. Soil is

just the opposite. In its natural state, soil is rarely uniform andcan only be studied and worked by comparing it to a similartype with which previous experience has been gained. To accomplish this, soil types first must be classified.

Rock was formed by three different means. Igneous rockssolidified from molten masses; sedimentary rocks formed inlayers settling out of water solutions; and metamorphic rockswere transformed from material of the first two by heat andpressure. Time, chemistry, and weather have attacked theserocks and have worn much of their surfaces down into soft“ seas” o f minute particles — the soil. These have been wellmixed by glaciers, wind, water, gravity, and man. Decayingplant and animal matter have further complicated the soilpicture by contributing organic material to the mixture.

The embankment builder is only concerned with five basic soiltypes: gravel, sand, silt, clay and organic matter.

GRAVEL is any rock-like material down to 1/8 inch in particlediameter. But the larger particles are called stones, and thosesingle particles larger than 10 inches are boulders.

SAND has mineral grains below 1/8 inch down to 0.002 inches.

It could be coarse or fine sand, but it feels grainy and itsstrength is not affected by wetting. In general, it is called

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granular material because the grains have little attraction foreach other. This leaves the soil with no dry strength. Granular

material can be vibrated into a dense form because the particles jiggle themselves about until they find the most compact grainarrangement, thereby minimizing voids. Granular material doeshave internal friction due to this “ stacking” o f the particles.

SILT is very fine sand that presents a floury appearance whendry. If pure, silt will settle out of muddy water and leave itclear. Although the particle size is 0.002 inches and smaller, itis still granular material. But silt compacts very poorly, has next

to no dry strength because of lack of cohesion between thegrains and is easily pulverized when in dry lumps. All granularmaterial permits ready passage of groundwater and is, therefore, permeable.

C L A Y is the finest size soil material. It consists of microscopiccolloidal scale-like particles which give clay its plastic properties. In a moist condition, clay becomes very sticky and maybe rolled into a ribbon. Clay particles have much attraction foreach other and thus clay is a cohesive material. It has a highdry strength, low erosion, good workability, and it compactsreadily. But clay has no internal friction and is, therefore,subject to slides. It also is susceptible to shrinkage and/orswelling. It is low in permeability since water has difficultyflowing through the tight particle pattern held by the surfacetension bond o f the natural moisture.

ORGANIC MATTER is partly decomposed vegetable or otherpreviously living matter. It appears as peats, organic silts, ororganic clays. They are generally soft, odorous upon heatingand appear fibrous, black, or very dark brown. Organic materialshould not be considered for fill material since it will decompose further, leaving voids.

Therefore, we may break our soil types into two groups, cohesive material and non-cohesive. The cohesive soils will have

the characteristic of sticking together. Examples would be clay,coarse clay sediment, loamy sand, and sandy clay. The non-

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cohesive soils take on the appearance of graded sand, gravel,sand mixtures, sand stone and crusher run material.

Generally, the soil types are found in nature in some mixedproportion. Care should be taken in placing fill embankments tomake the most advantageous use of soil properties.

SOIL MIXING

Mixing soils at the borrow or on the job is closely allied with

moisture. It is the key step that makes subsequent operationseasy or difficult. Best results come not from soil of any onepredominant type, but from good sensible mixtures of two ormore classifications of soils if they are readily available. Herethe contractor and the engineer can work closely together in acooperative effort to develop a superior end product.

In a coarse grained sand, for example, fine grain sand should beadded to improve the density since the smaller grains willdistribute themselves among the spaces between the largergrains and thereby reduce the amount of voids. If possible, clayshould be added as binder.

In every clayey material, granular soil should be added toprovide internal friction, prevent slides, and make possible abetter choice of compaction equipment. Gravel and stones bearup well, although they do not compact well, are unstable, and

may damage some compacting equipment. In general, plasticmaterials are more workable but have less bearing capacitywhile granular materials lend stability due to internal frictionand good strength.

If the soils to be mixed appear together in the same borrow pitin different layers, they often can be handled economically byshovel or belt loader. The machines, working against a mixedface, mingle the different materials directly as they dig and load

them into the hauling units.

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More generally, the different soils will come from separatesources of borrow and must be mixed thoroughly with the fill

before compacting. It is poor practice to make alternate lifts ofthe different materials. They should be dumped out and mixedtogether long and well, generally by harrows.

An hour’s time spent in processing is worth 3 to 5 hours o frandom rolling. Dozing serves to level out and spread the loosematerial; back-dozing provides a pulverizing effect. Graderblading for evenness of layer thickness is important, for thenthe compaction equipment can give the entire area the same

number of passes to reach uniform density throughout. Withdifficult, lumpy soil, other equipment often must be broughtinto play such as heavy disk harrows, field cultivators, or rotarytillers.

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Using the table show n be low w e can see the various soil co m

binations utilized and their classification symbol.

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SOIL PROPERTIES

The following terms refer to properties and characteristics of

various soil materials. To understand compaction techniques,one must he acquainted with the various terms employed in theindustry. Once the basic terms are understood, selection of thecorrect compaction tool can be made easier.

SHEAR RESISTANCE

The soil’s ability to resist movement or slippage when subjectedto an imposed load or to pressure from static or impactcompaction may be defined as shear resistance. This resistancecomes about from the friction between the soil particles. Thereis also resistance in cohesion — this happens when the soil particles resist pulling away from each other. Such resistance is veryapparent in clay when the elasticity is very high. The cohesionin rough sand and gravel particles by comparison is very low.

In observing Fig. II-2, the measure of the shear resistance of a

soil would be its degree o f resistance to particles sliding overeach other. The rate at which the material is subjected to

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movement will be dependent upon the applied force, the internal friction between the soil particles and the cohesion of the

material. Therefore, one should be able to recognize material ofa high shear resistance and a low shear resistance. A looselygraded non-plastic granular material, easily compactable, couldbe classified as having low shear resistance. On the other hand, aclay material which is very elastic and difficult to compactcould be classified as having high shear resistance. Case inpoint:—the more force required to shear the soil material fromadjoining soil particles the higher will be the shear resistance.

ELASTICITY

As the term implies, elasticity is a soil’s ability to returnapproximately to its original form after the applied load isremoved. Soils o f this type are very undesirable in constructionand road building. For example, as automobiles and trucks rollover a road surface the base material gives way to the subjectedload and rebounds upon removal, continually flexing, whicheventually causes breakdown of road surface.

COMPRESSIBILITY

As a volume o f material is acted upon by a downward fo rce, the

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voids within the material are decreased and take on less volume. As a result, the soil particles becom e forced together more

closely and remain together after the downward force has beenremoved. In some cases a measurement of soil density ispossible by equating the soil’s compression to the given load.

CAPILLA RY ACTION

The capillary action refers to a soil’s ability to absorb anddissipate water. The molecular surface forces, acting upon theinterfaces between the water and surfaces of the soil particles,

produce the capillary action in the voids of the soil mass. Thewater between the particles forms an elastic bond. The capillaryforces acting between the soil particles can be overcome byapplying compression and shear forces.

PERMEABILITY

The permeability of a soil is the rate at which water is permittedto flow through the soil from gravitational forces or water

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pressure. In compaction, this is a very important factor. Themoisture must be permitted to flow through the material inorder to reach the optimum moisture for satisfactory com

paction density. Many times water may saturate an area withlittle or no penetration into the depth of the soil. A soil of thisnature is not very permeable and will probably need to be tilledin order to satisfactorily compact at the correct moisturecontent.

SHRINKAGE

Shrinkage is usually limited to the finer grain of soils in which

the water content is reduced by means of evaporation. Differentsoils grow and shrink at different rates. Usually, clay materialsshrink a great deal whereas sand and gravel only shrink slightly.Material which expands and contracts a great deal, such as clay,offers an undesirable base for supporting surfaces. Soils may befully compacted, but as water penetrates, the material expandsand as the water evaporates, the material contracts causingflexibility and damage to the surface area. This is extremelycritical on rigid surfaces such as concrete highways or buildingswhich are incapable of absorbing any flexing motion.

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CHAPTER III

SOIL TESTING

Testing is an important factor of determining whether or notcompaction is, in a given soil, being achieved. The soil specifications outline the best combinations of achieving a givendensity for the various soils utilized in construction operations.There is no advantage if specifications and testing is by-passed,needless compactive effort may be the result.

The soil specifications pave the way to the various soil combinations and moisture content to arrive at the maximum densityfor a given soil. There are several ways of testing for soil density

which were originally developed back in 1933 by R. R. Proctor.It was he who established the relationship between the soilmaterial to be compacted and its maximum density whichrelated to a condition called optimum moisture content. A soilis not a solid mass; it contains particles of water and air betweenthe soil particles. Excessive water does not allow the material tobond; insufficient water does not allow the particles to slidetogether with the least resistance. Therefore, both excessivewater and insufficient water will produce unsatisfactory results.

OPTIMUM MOISTURE

The optimum moisture for a given soil is established in thelaboratory. This is the amount of water required for a given soilto reach maximum density. The correct amount of water isnecessary in order for the soil particles to slide together intotheir formation with the least resistance. A series of soil samplesare compacted at different moisture contents and plotted on a

graph as shown (See Page. 18).

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18

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The graph is plotted in dry weight (lbs./cubic foot againstmoisture content—% by dry weight). The series of tests beginssomewhere below optimum moisture point. A curve is thenplotted, comparing the soil density at the different moisturelevels. The optimum moisture content is the highest point onthe curve which maximum density of the tested soil hasreached. Unfortunately, this density cannot be assimilated100% under field conditions due to the variance of materials.Therefore, field densities are established and based on laboratory tests and are normally a reduced version. For example, ifmaximum density under laboratory conditions is 131 lbs./cubic

foot, specifications may require jobsite compaction at 90% forsatisfactory results.

The moisture content affects various soils differently. Granular

material tends to have a wider range to changes in the moisturecontent. On the other hand, material of silt and clay contenttend to be more sensitive to the range o f moisture content.

PROCTOR TEST

A standard proctor soil test isconducted as follows:

A soil sample is takenfrom the job location andplaced in a containerequal to 1/30 cubic foot. A 5-1/2 pound weightwith a striking face of 3.1square inch is dropped 12inches for 25 blows oneach of the three equallayers. The soil material isthen weighed, less themold, and recorded as wetweight/cubic ft.

The material is then ovendried for 12 hours in order toevaluate the water content.

5£ LB 2 5 Blows PerLayer

Compaction Force12,400 ft. lbs.

Soil Sample

So Cu. Ft.

3 Layers

STANDARD AASHO

F i gu r e I I I -3

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The modified Proctor test is done in much the same way,except a 10 pound hammer is used and dropped from a distance

of 18 inches for 25 blows. The material is contained in acontainer 1/30 cu. ft. and five equal layers. The compactioneffort produced is 56,200 foot pounds while the standardProctor test produces 12,400 foot pounds. The modified test isnormally used in testing materials for higher shearing strengthwhich would probably be used in supporting heavier loads.

n 2 5 Blows Per

Layer

Compaction Force56,200f t . lbs .

Soil Sample

30 Cu. Ft.

5 Layers

MODIFIED AASHO

Figure III-4

After compaction, it is necessary to determine if the density o fthe compacted fill meets the specification. This has been accomplished by testing an exact in-place volume of the soil. To

determine the exact volume of sample soil, there are two basicmethods:

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FIELD TESTS

,b f t Γ . 7S SÀV sec. 3

_ F ederal Pro jec t Ni

J j ELl

O rW

Sample taken from .

FIELD DENSITY

Material Removed from Test Hole

Wet Weight Dry Weight Loss Weight M.C. (%) =(Loss + Dry Wgt.) X 100

6/1 Sf>7 V ■<&/ / ° · 9

B. Wgt. contro l sand, jar and cone ---------

C. Wgt. contr ol sand, jar and cone after u

D. Wgt. sand to fi ll ho le and cone ---------

E. Wgt. sand to fi ll cone _____________

F. Wgt. sand to fil l hole ______________

Material Replaced in Test Hole

________ /7 -3 /

mitG. F (Wgt. sand to fil l hole)

Density of Control Sand

H. DRY WGT. (Soil From Te st Hole)

G. (Volume of Hole)

I. Field Density

+ Z 3 .Volume of Hole Q · Ô T Í Ô

34 W o = /2 3 *

I.k (o · S ' %OPTIMUM MOISTURE: Fi. u f ^

PROCTOR DENSITY: Lob. ^ S' ^

Field7 Z H ?

' X 100 - %CompactionProctor Density CONTROLL ED MOISTURE DENSITY

ASTM DESIGNATION 37-/5 6-7 —Wgt. Mold & Moist. Soil (M + Sw) z+.Z 7 Ζ Τ Ι Γ ZS-hO Z S teZ z¥-.9o 2 S. SgWgt. Mold (M) i+.SZ / ¥ . 5T ΙΨ. S i ι ψ . ς τ /+ÉÍL /ψ.5'1Wgt. Mois t. Soil (Sw) /OZI n o 3 // 02. II. OS _ u 0 2 . / /· f éWet Density '« /f t. 3)

1*1-2. m . o /¥?■ O /ÏL.S Ιψ ψ .ο /¥S- οDry Density (» /f t.3) 13¥·.? 137-0 I3S. O 131. O / 3 6 SWgt. Wet Soil & Can 1 / 7 / 1173 /2S· / l / l o m o 1 2 * 0Wgt. Dry Soi 1& Can 11 V-S5 n + n r 12 .01 t t + b US-3 LZ- / /Wgt. Loss 2.3 3>z * 2 . 3 ZWgt. Can b 52. b S i <eS2. f e i l e s z ££•2-

H t l + t o ■ v u ¥-$3·Moisture Content (%) y - .b s b - ç s 7 5 F ¥ 9S 7 -oS 7 / 0

Note: Density (* /f t. 3 ) Wet = Sw X 30 ( 4■ Mold) or Sw X 13.33 (6 ■ Mold)

Density Wet v in n OPERATOR'S SIGNATURE —_—, ______________________________

D . n. it y , . / , , 3 , D(y = * ' » O ' A j,ASTM DESIGNATION 0-698 - Run*oil tests w ith 5*5 lb. ho-------* « ,. 1 1 2 - REVIEWED AND APPROVED BY

Method A 4" mold - 4. Material 3 equal layers, 25 blows per layer.

Method B 6 “ mold —4. Material 3 equal layers, 56 blows per layer.

Method C 4 “ mold. Material coarser than 3/4 " shall be replaced by on equal amount passing 3/4 " & retained on the «4.

3 equal layers, 25 blows per layer.

Method D 6 " mold. Material coarser than 3/4 " sha ll be replaced by an equal amount passing 3/4 " & retained on the # 4.5 equal layers, 56 blows per layer.

ASTM DESIGNATION D-1557-Run all t est s with 10 lb. hammer dropped 18"

Method A 4" mold —4. Material 5 equal layers, 25 blows per layer.

Method B 6 " mold - 4. Material 5 equal layers, 56 blows per layer.

Method C 4" mold. Material coarser then 3/4 " shall be replaced by an equal amount passing 3/4 " & retained on the » 4.


Method D 6* mold. Material coarser than 3/4 " shall be replaced by an equal amount passing 3/4 " & retained on the » 4.


* 4" mold = 1/30 cu. ft. (0.0333) - 6 " mold = 1/13.33 cu. ft. (0.075)

Typical Field worksheet

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(a) Liquid—In the liquid procedure, water from a calibrated vessel is forced into a rubber balloon in the hole.

The amount of water used equals the sample’s in-placevolume. The disadvantages in the liquid method arebreakage of the balloon and freezing of the water inwinter. (Fig. III-5).

(b) Sand—In the sand cone method (most popular), thehole from which the soil sample was removed is filledwith measured dry sand of uniform known density—

from a graduated bottle—the dry weight volume is thenknown (Fig. III-6).

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Figure III-6

The disadvantages lie in the discomfort of working withsand in windy areas and the moving of 100 pound bagsof sand and bottles around the test site, plus the degreeo f human error.

Samples are then cut from this exact-volume sample,

weighed, and oven-dried to obtain the water content.

This is then plotted and checked against the specifications for required density.

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NUCLEAR SOIL DENSITY TESTING

This type of testing is conducted with an instrument designed

to measure the bulk density and moisture of soil. The measuringprobe uses a radioactive source in combination with geiger tubesto measure either density or moisture.

Cou r tesy o f Cam pbe l l Pac i fi c Nuc lea r Co rp .

Figure III- 7

An external dete cto r probe is inserted into the soil to thedesired depth. Basically, gamma rays being emitted from thedetector probe are absorbed by the soil and water atoms. Thedenser the soil and the more water present, the more rays areabsorbed. Therefore, fewer rays manage to reach the instrument

detector to be counted. Thus, the denser the soil, the lower thecount rate will be.

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Figure III-8

We may think of soil as a shield against the gamma rays beingemitted by the detector probe or being similar to light from aglowing lamp. The light rays diminish in strength as we moveaway or strengthen as we come closer. In this case, the rays areimpeded by the density of the soil.

Advantages o f the nuclear field test method are that it:(1) Is non-destructive; does not disturb in soil structure.

(2 ) Reduces the personal element that is involved in co n

ventional test procedures, thereby increasing the consistency of density and moisture test results.

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NUCLEAR DENSITY/MOISTURE

FIELD TEST DATA

ROUTE _

DATE __

J O /

TYPE MATERIAL

SECTION _

TEST NO. .

OPTIMUM MOISTURE .

3 B6 A

OPERATOR _

MODEL NO. .

MAXIMUM DENSITY J

J S . I -n SP- 54.

COMPACTOR NAME FREQUENCY RANGE OPERATING FREQUENCY

STANDARD COUNT REMARKS

DENSITY MOISTURE "Rolled w/th1. 27/33 1. 99/5- /Zoo VPrt x - x2. 27 OOO 2. ? ? s / S P - S M 3. 2 b ? 4 l 3. 9 6 7 44.

27//Z4.

7 9 Z 45. 2.6 963 5. 9706,Total /3S/55 Total * 9 2 3 0Avg. 2.703/ Avg. 9 W 6

TEST NUMBER 1. 2. 3. -· 5. 6.

STATION /76 +37 /76+45OFFSET 2 .' o f f £

ELEVATION — — —

DEPTH /X* 6 "

DENSITY COUNT * / & 0 7S Λ οDENSITY

COUNT RATIO 177 /· W 257 /· f/7WET

DENSITY PCF /29oo 127.00 /3/· So /25.00MOISTURE COUNT 6 3 5 — 6 77 —

MOISTURE

COUNT RATIO

* 3 7 — —

MOISTURE PCF S-5e> — —

DRY DENSITY 120. So US- 5o /22 ./o //S. bo% MOISTURE II. (o /0-1 /2 . 3 /o . /% MAXIMUM

DENSITY 97. z / Õ 0 . o Î V .7

Typical Field worksheet

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(3 ) Provides a means o f performing density tests on largesized aggregate base courses and on frozen material

which are difficult to handle by other test methods.

(4) Saves money, over the long pull, because o f its greaterspeed and closer quality control. It also eliminatesseveral conventional field test procedures requiringmore trained personnel, and the new method createsless interference to the contractor’s operations.

A disadvantage o f nuclear testing is the possibility o f radiation

exposure to the operator. However, individual radiation exposure can be maintained within the Atomic Energy Commission’s safety levels by exercising ordinary caution.

To sum up, the process of compaction is a mechanical effort toget soil particles in as close an arrangement as possible, therebyminimizing the water and air in the voids. This way, soil is at itsmaximum density. By a series o f trials in the laboratory, somewater content is reached that will give this condition. This isthen duplicated in the field, with proper compaction equipmentselection, required density may be achieved.

VISUAL TESTS

It is not always possible to have accurate test data available,therefore, one should have some idea of what to look for. Fromprevious experience we know that too little moisture can haveas unsatisfactory results as too much moisture. Also, in the

classification of soils, it is beneficial to recognize the soil typeso we may proceed with the proper selection of compactionequipment.

A simple method most often employed in the industry is topack a soil sample by hand into the shape and size of a golf ball.

After the shape is achieved, placed the ball between the indexfinger and thumb.

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Figure HI-9

If the material shatters into fairly uniform fragments, the soil isclose to the optimum moisture.

If the material weeps in your hand or does not break butflattens out, the soil is over optimum moisture. When the soilcannot be formed into a ball or is difficult to shape, it isprobably under optimum and moisture must be added.

F i gu r e I I I -l 0



In order to help classify the soil, roll a sample by hand into athin roll about 1/8 inch in diameter. If you have no problemrolling the material into this shape, the soil is usually plastic andextra care must be exercised when attempting to compact.Ideally, we are looking for material that cannot be rolled intothe 1/8” diameter, which means it is less plastic and moredesirable for compacting.

A method for determining the amount o f coarse and finematerial is to place a soil sample into a glass of water. Shakethoroughly and allow to settle for IV 2 minutes. If the water

clears during this time, the material is very granular with verylittle if any plastic material or fines. In the event the water ismuddy or cloudy, there is a high percentage of cohesive orplastic soil. Several types of soil will generate this condition. Agood indication would be the clay material which will usuallyrequire soil manipulation.

F i gu r e I I I -l 1

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COMPACTION METHODS

Knowing what types of soil are to be compacted are useful todetermine what piece of equipment should be selected to do the

jo b. The Soil-Selection Guide may be used for making roughfield checks without any apparatus, but should not eliminatethe standard tests for positive confirmation.

SOIL SELECTION GUIDE

GRA NUL A R SOILS, PLA STIC (COHESIVE) WH A T TO LOOK FOR FINE SANDS, SILTS SOILS, CLAYS

Visual appearance andfeel.

Coarse grains can be

seen. Feels gritty whenrubbed between f ingers.

Grains cannot be seenby naked eye. Feelssmooth and g reasywhen rubbed betweenfingers.

Movement of water in

the spaces.When a small quanti tyis shaken in the palmof the hand, wa ter w i l l

appear on the surfaceof the sample. Whenshaking is stopped,

water gradual ly disappears.

When a small quanti tyis shaken in the palmo f the hand, i t w i l l

show no signs of watermoving out of thevoids.

Plast ic i ty when moist . Very l i t tle or no plast i c i t y .

Plastic and sticky. Canbe rol led.

Cohesion in dry state. Lit t le or no cohesivestrength in dry state.

Wi l l crumble and f lakereadi ly.

Has a high driedstrength. Crumbles

w i t h d i f f i cu l t y andflakes slowly in water.

Sett lement in water. Will settle out of suspension wi thin anhour.

W ill stay in suspensionin water for severaldays unless i t f locculates.

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CHAPTER IV

COMPACTION EQUIPMENT

Compaction equipment does its job in any one of four principalways, or combinations of them:

1. Static weight

2. Kneading action

3. Impact

4. Vibration

Static-weight compactors are surface rollers of either thesmooth-steel-wheel or pneumatic-tired type.

Tandem rollers are those that have two or three rolls in line.The rolls are actually steel drums that can be filled with ballastto increase their weight. If a roller is described as “ 14-20 tons” ,

F igu r e I V -1

31



it means that the minimum deadload weight of the machine is14 tons and that the rolls can be ballasted with material such as

water or wet sand to give a maximum total weight of 20 tons. Itshould be kept in mind that although total weights of tandemrollers can be greater than three-wheel rollers, their unit pressures tend to be less because the greater contact surface of therolls will spread the load over a larger area.

Three wheel rollers have two rear wheels and a front steeringwheel. The narrow rear wheels and the wide front wheel may be

either spoked or ballastable. The three wheel roller is quitemaneuverable but tends to leave deep ruts in granular soils dueto the concentration of load in the narrow wheels.

Both types have rather slow running speeds and have questionable safety for operation near the edges of high, steep-sidedhills.

Steel rollers of the tandem or three-wheel type are effective

most generally on soils of a more granular nature where thecrushing effect of their static weight can be best employed.However, loose sands may not support the heavier rollers.

32



A steel roller’s compactive effort is lessened in material o fgranular-plastic or plastic-granular nature. That’s because the

heavy rollers create crushing at the top of the layer withdiminishing effectiveness down to the lower parts of the lift,even in shallow thicknesses.

For plastic material, steel rollers tend to have a bridging effect.This means that the roller will squeeze material from the highspots to the lows, but the material moved will not be compacted. Steel rollers also have a plowing effect. This createsplastic waves ahead of the rolls and also results in a springing upof material behind them.

Steel-wheel rollers can be used effectively to level off high spotsafter sheepsfoot, vibratory or pneumatic-tired rollers have donetheir work, but traction is very limited with this type ofcompaction.

Pneumatic-Tired Rollers

Pneumatic-tired rollers are also surface rollers, but in additionthey apply the principle o f kneading action. They are eitherself-propelled or towed and are of two types—those with smalltires and those with large tires.

Figure IV-3

33



Rubber tired Rollers generally have two tandem axles with fourto nine wheels each. The wheels are arranged so that the rear

ones will run in the spaces between the front ones, theoreticallyleaving no ruts. The chassis of the vehicle is also a container forsolid or liquid ballast. The weights carried may be varied to suitthe material being compacted.

The individual wheels may be a knee-action type mountings toavoid omissions of low spots or bridging on highs. Wheels mayalso be mounted slightly out of line with the axle, giving them a

weaving action and the name “ wobble whee l” . This condition

improves the kneading action.

Pneumatic-tired rollers cannot be overloaded with ballast ormoved at excessive speeds. Such faulty operation will give morecoverage but will result in extra tire and bearing wear, thusincreasing maintenance costs.

Small-tire compactors provide the same unit surface pressure aslarge-tire units with less overall weight on the material beingcompacted. They provide more crushing of lumps and do notpush whole masses before them or cause lateral displacement.Disadvantage lies in poor flotation in loose materials, slipping ofself-propelled units in very wet soil, and about a 6-in. maximum

F i gu r e I V -4

34



depth of compactive effectiveness, with density only on theupper layers and soil bridging.

Large-rubber-tire rollers will work on most types of soils. Theycover a bigger unit-pressure area and have a deeper effect on soilmovement (due to less lateral support, percentage wise) than dosmall-tire units, but still are restricted to shallow compaction.The expense is in their operation since they require the righttype tractor to pull them and they must make a greater numberof passes to get complete coverage of the spaces between thewheels. Their best use is in test or “ proo f” rolling.

When considering a large-tire roller for general compactionwork, the contractor should check the econom ics o f getting thesame unit loadings in other types of compaction equipment.

There are at least four ways used to express the compactingability of pneumatic rollers. They are: (1) gross weight ofvehicle; (2) wheel or tire load; (3) weight per inch of tire width;and (4) tire inflation pressure. The problem is complex becauserubber, unlike the steel roller, is flexible and low tire air

pressure allows an oval surface contact area to enlarge. Thisdiminishes the effect of total load by giving larger weightdistribution and, consequently, lower unit ground pressure.Note, on some units tire pressure may be varied while thevehicle is working.

Accordingly , gross-weight ratings mean nothing unless thenumber of wheels, tire size, and inflation pressures are known.

SHEEPSFOOT ROLLERSFor cohesive materials (clays and silty clays), sheepsfoot orpadfoot rollers are used. The typical sheepsfoot roller can beself-propelled or towed, and compacts with a kneading actionon the soil. These units generally range in weight from 2 tons to20 tons and vary in coverage width normally between 30 and100 inches. The feet or pads can be of various shapes and arenormally less than 10 inches in length.

The sheepsfoot compactor is usually most effective on liftsbetween 10 and 12 inches in compacted thickness, and operated

35



on the theory that the feet will compact the lower layers of thesoil first and work toward the surface in successive passes until,

when completely compacted, the soil will yield no further andthe roller will “ walk o ut” o f the lift. Because the feet penetratethe lift and compact within it, they affect the soil particles in alldirections. It is not necessary that the roller drum touch thesurface, since the total load is transmitted to the soil by the feetin small areas at high concentrations.

In some cases sheepsfoot rollers will bridge over the soil at theoutset, but this bridging stops after several passes. They doexpose more soil surface to the air for evaporation of moisture,causing crusting. Their penetrating feet pulverize lumps in thesoil. They work well by causing lateral particle movementbeneath the surface, thus blending coarse and fine materialsmore thoroughly. On the other hand, sheepsfoot rollers shouldnot be used in graded aggregate or stone bases since there theywill cause segregation.

IMPACT COMPACTORS

When a compaction unit has very low frequency and a very highamplitude it is classed as an impact compactor even though itdoes have a somewhat vibrating effect. Generally, these are

hand held tampers or rammers and are used in small areas orconfined spaces.

Figure IV-5

36



Figure IV-6

Also available are rammers with a self-contained gasoline enginethat makes the entire unit jump up and down. Guided by anoperator, a 125-lb. machine can deliver an 1150-lb. blow to theground surface.

VIB RA TOR Y COMPACTORS

A vibratory compactor functions by producing a dynamic forceinto the ground with a series of rapid impacts. Soil particlestend to stack by nesting in void spaces between other grains.When shaken or vibrated, the soil grains will shift themselvesinto the tightest arrangement. If the particles are dry, frictionmay impede their flow or shifting. If the material is too wet,water will take up the voids since water is not compressible. Thecorrect amount of water will lubricate the movement of the soilwith least resistance into maximum density. This is known as

optimum moisture point. Maximum density at optimum moisture can be achieved by all the previously mentioned com

37



pactors but it will require more time and expense to achieve.The success of vibratory compactors lies in the ability to com

pact a wide range of soils in deeper lifts and less time thanconventional expensive methods.

There are two principal classes of vibratory compaction equipment—drum rollers and plate tampers.

A. DRUM ROLLERS A drum roller will impart vibrations into the soilthrough a steel drum. An eccentric shaft is usually

housed within the center axis of the drum and supported by bearings at each end o f the shaft. As the shaft

Figure IV - 7

rotates at a given speed, the drum assembly is displacedfrom the neutral axis within the suspension system. The

drum assembly rebounds against the ground surfacewith a force generated by the eccentric shaft and static

38



Figure IV-8

weight of the assembly while traveling along the ground.Drum compactors may be self propelled with a rubbertired tractor unit, driven individually as tandem drummachines or may be towed behind a tractor. Pad footdrum compactors are equipped with tamping feet,welded to the circumference of the drum surface. Thetamping feet function in a manner similar to a sheepsfoot roller but afford a dynamic force in addition to the

kneading of the soil material (Fig IV-8).

B. PLATE COMPACTORS A plate compactor is individually vibrated by aneccentric shaft driven mechanically or hydraulically.The eccentric is affixed to the vibrating plate. As theeccentric shaft rotates, a force imparts which causes the

plate to rebound against the ground surface. Simultaneously the compactor is vibrated in a forward or reverse

39



direction. The vibrating plate may normally be guidedindividually by hand and is suitable for compactingbottoms of trenches, confined areas and steep slopes.

Figure IV-9

One of many advantages of vibratory compaction is that it

keeps the compacted surface fairly well sealed against evaporation o f internal moisture and also against entrance o f newwater. This crusting effect permits rapid resumption of work

after rain. Due to the penetrating effect of the vibrations, thiscrusting does not prevent uniform compaction through theentire lift as is the case with crusting under a static roller.

In compacting granular material, some number (frequency) of

blows in a given period gets it down faster and tighter thanfewer blows o f a heavier order (amplitude). The combination o f

40



frequency and amplitude of vibrations get varying results withdifferent soils, depending on grain size, distribution and mois

ture, since every material has its own frequency rate (or resonance). Vibrations vary from 1,000 per minute in some compaction machines to 5,000 per minute in others and it is moreeconomical to use a machine that will vibrate closest to thesoil’s resonant frequency.

Figure IV -10

There are two schools of thought regarding resonant frequency.One claims that since the resonance factor of various granularmaterials determines their compactability and the depths to

which compaction will be effective, then before going aheadwith the selection of a dynamic compactor it is best to have acompetent laboratory run a set of vibratory compaction tests.The other viewpoint is that such tests are only necessary forplant foundations where the structure will contain vibratingmachinery. On highways or airports where the embankment issubjected to impact loads, or in dams where the stress is static,no laboratory vibration tests are needed. However, a full scaletest-trial on the job is always in order before any equipment isfinally chosen.

41





CHAPTER V

FUNDAMENTAL S OF VIBRA TORY COMPACTION

The following are basic fundamentals of vibratory compaction

equipment. In the pages that follow we attempt to give simpleexplanations of some of the concepts and terminology commonly encountered in the field of vibratory compaction. Thismaterial is geared and only intended to furnish basic familiaritywith this type equipment.

Soil compaction, through vibration, is accomplished by:—

(A) The movement of soil particles reducing the internal

friction and repositioning to produce the maximumdensity or least amount of air voids.

Figure V-l

43



(B) The influence of the impact generated by the vibratingdrum or plate against the ground, and the static weight

which presses the drum or plate against the earth.

Each compactor must be equipped with an eccentric shaftnecessary to produce the vibratory action . The eccentric shaft ismerely a body which rotates about any axis other than one atits center of mass. This exerts an outward force called centrifugal force upon the axis which restrains it from moving in astraight line.

One common analogy on how centrifugal force is produced:

Suppose you secure a one pound weight to the end of astring and begin whirling it in a circle. The tug you feel onthe string is the centrifugal force you have generated by

its rotation.

44



Figure V-3

The faster you whirl, the more force will be felt on thestring. If you increase the weight on the end of the stringwe will also experience a higher force. The centrifugal forcewe have generated is relative to the weight of the off-centermaterial, distance of the weight to the center of rotation,and the velocity at which this weight rotates.

Every vibratory compactor produces centrifugal force which isgenerated by this eccentric shaft, the amount of force is predetermined by limiting the size of eccentric and the speed ofrotation. The eccentrics are designed to match the weight o f thevibrating member which in effect is a ratio of the weight of the

vibrating drum to that of the springborne frame. The centrifugalforce created by the eccentric shaft will have little effect with-



out the proper drum frame weight to keep the drum pressedagainst the soil during vibration. As the eccentric shaft rotates,

the centrifugal force generated is directed in a 360° forcepattern.

Figure V-4

The centrifugal force acts inside the drum or baseplate. Thisforce is not equal to the dynamic force which is being dealt tothe underlying soil. Very often the centrifugal force is mistakenfor dynamic force. The frequency (V.P.M.) amplitude andweight of the vibrating drum, plus the properties of the soil willbe dependent on the results of dynamic force generated. Thisforce is not an exact measurement of compaction effort, butgives an approximate value with the variance of soil material.

The dynamic force may be accurately measured by pressurecells under the vibrating drum. The centrifugal force generatedby the vibrating drum is then added to the static working

weight of the drum assembly exerted on the ground to make upthe applied drum force.

46



Therefore, we can clearly see that without this static weightfrom the drum and frame weight, we would not be able toeffectively retain the drum against the soil. The ratio of eccentric force to drum and frame weight is carefully designed toproduce the most efficient penetration into the soil. The vibrating member (drum) is always isolated from the main frameassembly by utilizing rubber shock mounts symmetricallylocated on each end of the vibrating drum. The static weight hasa large influence on the compaction effort since the energy as

well as the momentum from the vibrating drum is directlyproportional to the weight when the frequency and amplitudeare constant.

WHAT AB OUT FREQUENCY A ND AM PLITUDE

The velocity at which the eccentric shaft rotates is referred to asits frequency. Each machine is designed to operate at a predetermined frequency for maximum efficiency, since this ishow we generate maximum drum force. The frequency level is

47



level is broken down into a low range (500-1000) and a mediumrange of (1000-3000) and a high range (3000-5000) vibrations

per minute (V.P.M.). As the eccentric shaft rotates at the prescribed frequency developing centrifugal force, the drumassembly is displaced from the rest position and is restrainedwithin the isolation system. The total vertical distance that thevibrating drum or baseplate travels is called the amplitude. Theamplitude is a direct function of the drum weight and make upof the eccentric shaft. The amplitude is also determinate uponthe elasticity and tamping properties of the soil.

Figure V-6

The frequency and amplitude of a machine will predetermine itsmost effective application. As an example, if our requirementapplication is for compaction of a highly elastic material wewould normally require a high amplitude and low frequency toaccomplish this. The reason for this choice is to break down the

highly resistant cohesive material; consequently, a high amplitude is more desirable to penetrate a material of this nature.

48



Another example would be the compaction o f bitum inous basesand other types of asphalt surfaces which would require the use

of high frequency and low amplitude for satisfactory results onthese materials.

SOIL REACTIONS

Vibratory rollers operate with a rapid succession o f impactsagainst the soil. These impacts are generated by the rotatingeccentric to produce forces and pressures which transmit intothe soil. Each load cycle generates a stress wave which decreases

intensity as it travels further from the vibrating drum. Eachwave characteristics is dependent upon the properties of thesoil. Various soils will react differently when subjected to vibration. The purpose of vibration is to set the soil particles intoa state of motion almost as a fluid. The soil is broken down andsubjected to shear between the particles as the material isgradually rearranged during compaction. Soil particles inmotion slide against each other and eventually settle out,

F i gu r e V -7

49



keeping themselves together in a densely packed state. Themovement of soil will be greatest when the vibratory drum is

operating closest to the natural frequency of the vibrator-soilsystem.

IMPACT PER FOOT

As a vibratory compactor rolls over the ground surface, a seriesof blows is delivered to the ground surface, which is generatedby the vibrating drum. The drum rebounds against the groundduring the period of time it takes to apply. Slower travel speedswill compact heavier lifts more effectively due to the longer

time duration. Generally, 2-3 MPH is considered the mosteffective travel speed for most applications.

Figure V-8

Example: An SP-56 operating at 1,825 VPM traveling at 3 MPHwill produce approximately 7 impacts per foot.

1,825 VPM 60 min . ,3 MPH (5,280 ft/m ile) 1 hour imPacts per foot

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GROUND FORCE

If we wish to determine ground force exerted from the vibrating

drum our applied drum force must be divided over the length ofthe drum.

Example: An SP-56 has a drum applied force of 53,800 lbs.(24,404 kgs.) acting on the soil, the drum width is 84 inches(2134 mm).

Ground Force = — = 640 lbs. per lineal inch (pli)

Ground Force — ^ S‘ = 11.44 kg. per linear mm.2,134 mm

SUMMARY

In field applications it is difficult to determine the actual forcesbeing generated into the ground. Many figures are published oncentrifugal and dynamic forces employed by various com

pactors, these values are no assurance of the forces dealt intothe soil. Many factors can alter the effect of compaction in thesoil. The frame weight is responsible for holding the drumagainst the soil, if the frame is too light the energy by theeccentric shaft will be dissipated upward, if the frame is tooheavy the amplitude may be considerably effected. The drumconstruction can also effect compaction, the drum shell mustnot be allowed to flex under load, otherwise a degree of energywill be absorbed by drum deflection. Therefore frequency,

amplitude, frame weight and drum construction all tend toinfluence the compactive effort. The amount of time or impactper unit distance is governed by the travel speed of the compactor. The travel speed and number of passes influence theamount of production as illustrated in Chapter VI. Our ob

jective is to establish the maximum travel speed with the fewestpasses to achieve a required density.

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/



CHAPTER VI

PRODUCTIVITY

With any compaction device it is very important to be able tomeasure the expected amount of material able to be compactedduring a specified period o f time. Because o f unknown factors

of the soil material, this production rate cannot always beaccurately predetermined, but by making certain assumptions,one can arrive at a reasonably close estimate o f compactionoutput. Following is a simple formula for determining production.

p _ D X T x L X CP

where P = production in com pacted soil volume per hourD = drum widthT = compaction unit travel speedL = lift thicknessC = conversion factorP = passes required to achieve density

When working with the foot-pounds system, the following unitsof measure would apply. Drum width would be expressed in

inches, compaction unit travel speed in miles per hour, liftthickness in inches, and the conversion factor required to makethe sum of inches multiplied by miles per hour multiplied byinches equal to cubic yards per hour would be 1.36.

When working in metric units (the meter-kilogram system), different units of measure are required. Drum width is expressed inmillimeters, travel speed in kilometers per hour, lift thickness incentimeters, and the conversion factor is 0.01.



Let’s now examine one specific example for each system. First,we are using an SP-56 operating at a speed o f three miles per hourand compacting a fourteen inch thick lift (compacted thickness)in three passes. What is our production rate?

„ , „ _______ . DXTXLXCProduction Rate ( P.R. ) = ------------------

D = drum width —84 inches

T = travel speed = 3 miles per hour

L = lift thickness =14 inches

C = conversion factor = 1.36

P = passes = 3

therefore p R = <84>X<3)X, 14)X(Τ.ββ) = 1599compacted

cubic yards per

hour.

Suppose now we have an SPF-56 compacting a twenty centimeter

thick lift (compacted thickness) of cohesive material with two

passes at five kilometers per hour. What is our rate of compac

tion?

Production Rate ( P.R. ) = DXTg LxC

D = drum width = 2134 centimeters

T = travel speed = 5 kilometers per hour

L = lift thickness = 20 centimeters

C = conversion factor =0 .01

P = passes = 2

thus P.R. = (2134)X(5)X(20)X(0.01)= ^ compactedcubic meters per

hour

However, no compaction device is 100 percent efficient on an ac

tual job. A certain amount of time is required to change travel

direction, to start and stop, and a certain amount of production is

lost because of required overlap between side by side passes.

Therefore it is necessary to take into account some factor for effi

ciency. This is to some degree variable, but experience has shown

54



us that our self-propelled vibratory compactors have an efficiency factor ( E.F. ) of 85 percent.

Employing this efficiency correction with our previous exampleswe find that we can reasonably expect an SP-56 operating at aspeed of three miles per hour to compact a fourteen inch thick liftin three passes at the rate of:

1599 cubic yards per hourX85% E.F. = 1359 compacted cubicyards per hour.

Similarly the SPF-56 using two passes to compact a 20 centimeter lift at a speed of five kilometers per hour would, whenconsidering actual efficiency, perform at the rate of:

1067 cubic meters per hourX85% E.F. = 907 compacted cubicmeters per hour.

Based on this information, the contractor, engineer, or salesrepresentative can fairly accurately predetermine how much com

paction equipment is required to efficiently com pact the materialbeing placed by the hauling equipment, and he can betterschedule his equipment on the entire job.







APPLICATION DA TA

To intelligently approach and select proper compaction equip

ment, one must recognize several factors; the type of soil beingcompacted, the moisture content and equipment selection.

Various soils require different types o f compaction equipmentto satisfy the soil system. To aid in the selection of equipment,refer to the Compaction Selection Chart (Fig. VI-1), UnifiedSoil Classification (Fig. II-l) and Machine Specifications (Fig.

VI-2). The Compaction Selection Chart will assist in abasic selection. The Soil Classification Chart will further definethe composition of the soils you will encounter under standard

classifications. Machine Specifications will furnish informationas to approximate machine production and soil application inconjunction with the Unified Soil Classification System. Bear inmind, this information is only a guide; fluctuations in a soilsystem or other variables may require altering a selection.

Let us take a hypothetical case:—

A project requires compaction o f a silty gravel and sandmaterial in 12-14 inch lifts and production of approximately 10,000 cubic yards per 8 hour day. Referring to theCompaction Selection Chart under Sand-Silt-Gravel we findseveral machines capable of this compaction requirement.The determining factor will be the amount of productionrequired.

Let’s go a step further and refer to the Unified Soil Classifi

cation Chart—the silty, gravel and sand mixture is describedunder “ Secondary” and classified as a (GM) material. Referto the machine specifications, observing the productionrange. Our requirement is 10,000/8 or 1250 cu/yds/hr.

The SP-56DD appears to meet production requirements andsoil classification as shown. Once we have selected the unitwe may further calculate our production rate for the job.

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Following is the example of calculating the production ratefor the SP-56DD in this hypothetical case:

Drum Width — 84 inchesTravel Speed = 3 miles per hourLift Thickness = 14 inchesConversion Factor = 1 .3 6PassesEfficency Factor

= 3= 0.85

Production Rate =

P.R. =(84)X(3)X(14)X(1.36)

3 X 0.85

Production Rate ( P.R. ) = 1359 compacted cubic yards per hour

Let’s assume an eight hour day:

1359 cu. yd/hr.X 8 hr. = 10,872 cubic yards per day

Therefore, we can clearly see that we are able to meet ( and evenexceed) the required production rate with the SP-56DD. L et ’s goone step further and compute the cos t to operate the SP-56DD.

OPERATING COST

Operating cost is an indirect fixed cost which includes theexpenditures for repairs and maintenance, the costs for fuelsand lubricants, and the expense for an equipment operator. Thefollowing assumption are made.

1. Repairs and maintenance costs are determined byconsidering a fixed cost equal to eight percent of the initial purchase price of the machine under normal conditions and dividing this figure by the base value of 1000hours between maintenance intervals. The resultingcost is the estimated repair and maintenance costs perhour of equipment operation.

2. Fuel costs are quick ly com puted by multiplying the

fuel consumption rate in gallons per hour times theaverage cost per gallon of fuel.

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3. Lubrication costs are figured at a consum ption o f 1/8gallon per hour at whatever cost per gallon is appropriate.

4. Operator’s wage should be determined from local payscales.

Let’ s use the SP-56DD from the preceeding productivity exampleto estimate the operating cost per cubic yard of material compacted. F irst compute the maintenance costs as suggested. Thendetermine the hourly fuel and lubricants costs. Add to thesecosts the actual hourly equipment operator’s rate for a totaloperating cost.

Take the total operating cost per hour and divide it by the production rate in cubic yards per hour. The answer, then, is the actual cost per cubic yard of material compacted. Keep in mind,however, that these costs are estimated. Different areas may experience variations from these values and adjustments should bemade accordingly.

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SUMMARY

These examples are guides which are intended to point you inthe right direction. Poor soil conditions may bring about unsatisfactory results even though the equipment selection wascorrect and the soil itself required altering. Proper equipmentselection is imperative to ensure economical and effective compaction results, but their is no exact method of pre-determiningthe results of soil compaction prior to actual field testing withthe unit. Soil testing is one of the factors that make it possibleto actually establish the full benefit of densification throughvibration. We are still learning about the effects of vibration insoil compaction and must conclude that there is not a fixedprocedure for compaction assignments. As we move forward intime, new technologies in compaction methods emerge whichoffer new, efficient techniques to serve the construction industry.

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APPENDIX

CUBIC MEASURE

1 Cubic Yard = 27 Cubic Feet = .7645 Cubic Meter1 Cubic Foot = 1.728 Cubic Inches = .02832 Cubic Meter1 Cubic Meter = 35 .314 Cubic Feet = 1.308 Cubic yd.1 Cubic Centimeter = .061 Cubic Inch

MEASURES OF LENGTH

1 Mile = 1,760 yds. = 5,280 ft. = 1.609 Kilometers1 Yard = 3 ft. = 36 inches = .9144 meters1 Foot = 12 inches = .3048 meters = 304.8 millimeters1 Inch = 2.54 centimeters = 25.4 millimeters1 Kilometer = .6214 miles1 Meter = 3.2808 feet = 1.093 yards = 39.37 inches1 Centimeter = .3937 inches1 Millimeter = .03937 inches

SQUARE MEASURE

1 Square Kilometer = .3861 sq. miles = 247.1 acres1 Square Meter = 10 .764 sq. feet = 1.196 sq. yards.1 Square Centimeter =.155 sq. inches1 Square Millimeter = .00155 sq. inches.1 Square Mile = 2.5899 sq. kilometers1 Square Yard = .836 Square meters

1 Square Foot = .0929 Square Meters

LIQUID MEASURE

1 U.S. Gallon

1 British Imperial Gallon

1 Cubic Foot1 Liter

= .1337 cubic feet = 231 cubic inches= 4 qts. = 8 pints = 3.785 liters.= 1.2009 U.S. Gallons = 277.42 cu.inches= 7.48 U.S. Gallons= .2642 U.S. Gallons = 1.0567 U.S.

Qt.

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MEASURE OF WEIGHT

IT on (short) = 2000 lb.

1 Ton (long) = 2240 lb.1 Metric Ton = .9842 Ton (long) = 2204 .6 lbs.1 Pound = 16 ounces= .4536 kg.

GRADE CHART

Percent Degrees Percent Degrees

5 2° 52’ 45 24° 14 ’

10 5° 43 ’ 50 26° 34’

15 8° 32’ 55 28° 49 ’20 11° 19 ’ 60 30° 58 ’25 14° 2 ’ 65 33° 1’

30 16° 42 ’ 70 35°35 19° 17’ 75 36° 52’

40 21° 48 ’ 80 38° 40’

b_Percent grade is c or the amount of vertical rise relative tohorizontal distance travelled expressed in terms of percent.

_bThe angle of the grade in degrees is tan B = c or equivalent to thetangent trigonometric function of the product of the adjacent sideand the base o f the triangle.

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DEFINITIONS

AASHO

Adhesion

Aggregate

Amplitude

AppliedDrum Force

ASTMBasalt

Base

Binder

Caliche

Capillarity

CentrifugalForce

CIMA

— The American Association o f State HighwayOfficials

— A property of soil which causes the particlesto stick together.

— Stone or gravel which has been crushed andscreened to various sizes for use in concrete,asphalt, or other road surfaces.

— The total vertical distance the vibratingdrum or plate is displaced from the rest orneutral position from the eccentric moment.

— The sum of forces exerted against the groundfrom the static working weight of the drumassembly and the centrifugal force generated bythe eccentric shaft.

— American Society for Testing and Materials.— A finely grained dense igneous rock usuallyblackish gray in color.

— The first or foundation course in pavementconstruction usually consisting o f aggregate.

— A material made up of fines which hold graveland crushed stone together.

— Soil material which consists of layers ofweathered deposits bonded by carbonates suchas lime.

— A property of soils which allows themovement o f water upward or laterally.

— The force generated by the vibration-inducing mechanism at the stated frequency.

— Construction Industry Manufacturers Association.

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-

Clay

Cohesion

Compaction

Compression

Consolidation

Density

Double Amplitude

DynamicForce

Elasticity

Expansion

Frequency

Gradeability

— Soil material composed of microscopicparticles derived from the decomposition of

rock.

— A property o f soil or asphalt which bonds theparticles together.

— A volume change produced artificially by amom entary load application.

— A volume change produced by application ofa static external load.

— A volume change that is achieved naturallywith the passage o f time.

— Weight per unit volume of a soil or othermaterial.

— The total peak to peak vertical movem ent percomplete vibrating cycle of the drum in a freely

suspended condition.

— The force generated by the vibration inducingmechanism at a stated frequency.

— A characteristic of a material which allowsdeformation when subjected to a load but toreturn to original configuration after removal ofthe force.

— An increase in volume in soil usuallyresulting from increase in moisture content(swell).

— The number of complete cycles of thevibrating mechanism in a vibratory compactorper minute.

— The ability of a machine to climb a grade at a

constant velocity (usually expressed in percent).

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Granular

Gravel

Gumbo

Hardpan

Humus

Impervious

Lift

Loam

Nominal Amplitude

Non-Vibra tingWeight

OperatingWeight

OptimumMoisture

— Soil particles which do not have internalcohesive forces, but rather get their strength

from friction.— Cohensionless aggregate with particle sizesfrom 3.0 to 0.8 inches.

— A material identified by a soapy or waxyappearance when wet.

— A layer of material which is extremely denseand fine-grained with a minor amount of

cohesive material.— Organic material formed by thedecomposition o f vegetation.

— Resistant to the flow of water.

— Newly deposited material graded to a specificthickness.

— A material which is cohesive with a particle

size ranging from .01 to .05 mm.

— One-half of Double Amplitude, and the termpreferred by CIMA to evaluate vibratory compactors.

— The static weight measured at the drum(s)minus the Vibrating Weight.

— The gross machine weight with fullmechanical operating systems, plus a full tankof fuel, plus a half sprinkler tank of water, if soequipped, plus a 175 lb. (80 kg) operator.

— The exact amount of water necessary to coatand lubricate each soil particle so the maximum

density for any compaction effect may be obtained.

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Pass — A one-way trip or passage of the machine. Around trip in the same path is two passes.

Permeability

Plasticity

Sand

Shearing

Resistance

Shrinkage

Silt

SprungWeight

UnsprungWeight

VibratingWeight

— A characteristic of a soil which allows water

to flow through it by gravity.

— The ability of a soil to be molded and formedwithout cracking or rupturing the soil mass.

— A cohesionless aggregate o f round or angularfragments with particle sizes between 2 and .05mm.

— A soil’s ability to resist sliding againstadjacent particles when a force is applied. Friction and cohesion determine shear resistance.

— Volume change produced by capillarystresses during drying of a soil.

— Soil material composed of particles between.05 and .005 mm in diameter.

— Preferred term is Non-Vibrating Weight.

— Preferred term is Vibrating Weight.

— The weight of all the intentionally vibratedparts at each roll.

NOT E: Many o f the definitions contained above are representativeof the terms and definitions established by CIMA, and assuch will be standard throughout the compaction industry.

Documents

Compaction Data Handbook