Dr' Larry Muszynski

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SOILS AND CONCRETE
Dr. Larry Muszynski RNK 327
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• Soils

• Structural integrity of a building depends on the
  material that supports its foundations.
• Type of soil
• Non problem soils
• Problem soils
• Subsurface investigation
• destructive
• non-destructive

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• Bearing capacity of the soil
• Soil compaction methods
• Effects of groundwater
• Dewatering methods
• Foundations
• Shallow
• Pile

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• Laboratory Experiments

• Three Soils and Concrete Labs
• Concrete Mix Design
• Lab Demonstration
• Preliminary Information
• Mixing
• Plastic concrete testing
• Hardened concrete testing
• Soil Classification
• Sieve analysis
• Atterberg test
• Soil Compaction
• Proctor test

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• Natural soil deposits

• Soil composition
• large and small particles
• weathering of rocks and decay of vegetation
• Igneous rocks
• fine grained - slow cooling
• Basalt, rhyolite, andesite
• coarse grained - fast cooling
• Granite, diorite, gabbro

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• Sedimentary formed by accumulation of sediments
• Shale- clay or silt most abundant?
• Sandstone -quartz
• Limestone-Calcium carbonate (soft and hard
  versions)
• Tabby buildings
• Dolomites - limestone Mg.
• Metamorphic formed by heat and pressure
• granite gt gneiss
• basalt gt schist
• sandstone gt quartzite
• shale gt slate
• limestone gt marble

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• Weathering of rock
• mechanical
• temperature changes
• frost action
• rainfall, running water
• wind erosion
• chemical
• oxidation
• carbonation
• leaching
• hydrolysis
• solution

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Weathering Profile
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• Igneous rocks
• granite gt silty sands
• basalts gt clayey soils
• Sedimentary rocks
• shales gt clays and silts
• sandstones gt sandy soil
• limestone gt coarse or fine grained soils
• Metamorphic rocks
• gneiss gt silty sands
• slate gt clayey soils
• marble gt fine grained soils
• quartzite gt coarse grained soils

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SOIL EXPLORATION
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• METHODOLOGY

• Reconnaissance
• preliminary examination including
• geologic data-
• topographical information
• groundwater table information
• underground utilities
• Borings - drilling holes in the ground
• Sampling - removing soil from the hole
• Testing - characteristic properties of the soil

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• Borings

• Auger - not good for soft clay or coarse sand
• Test pits -excavations into the earth to permit
  visual inspection of soil strata
• Advantages
• relatively fast
• inexpensive
• clear picture of soil strata
• gtDisadvantages
• -depth of observation (10- 15 ft.)
• -high groundwater table

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• Con't

• Core borings - drill into soil and/or rock with a
  core drill bit.
• Core removed with soil or rock core intact,
• Soil or rock removed for further testing
• soil rock tested for compressive strength and
  permeability.

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• Contractor

• Decisions
• boring spacing
• 50 - 100 ft. for multistory buildings
• 100 - 200 ft. for single story buildings
• 500 - 1000 ft. for highways.
• boring depths
• boring should go deeper than the depth of
  unsuitable soil into suitable or compacted soil.
  (Footing width)
• for tall structures borings should go into bedrock

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• Sampling

• Removing samples from bored holes - every 5 ft.
  in depth of the boring hole.
• disturbed
• auger and wash borings
• core borings
• soil grain analysis, liquid limit, plastic limit,
  specific gravity and compaction.
• undisturbed
• test pit "carving"
• "Shelby tube" extraction
• strength, compressibility and permeability

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• Groundwater table

• Soil bearing capacity reduced when the water
  table is near the the footing.
• Reduction in foundation stability
• structures float out of ground (high ground water
  table)
• hazardous or toxic waste landfills -
  contamination
• Location of water table
• existing wells
• boring holes
• level to which groundwater rises in a boring hole
  is the groundwater elevation in that area.

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• Testing

• Standard Penetration test
• Cone Penetration test

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• Standard Penetration Test
• (SPT)

• Cohesionless soil- cohesive soil
• Split spoon sampler
• 2" o.d. x 1-3/8" i.d tube, 18 to 24 in long
• split longitudinally
• 140 lb hammer falling 30" to drive spoon 18" into
  the soil
• No. of blows required to penetrate each of the
  three 6-inch increments is recorded separately.
• Standard penetration resistance value (N-value)
  is the number of blows required to penetrate the
  last 12-inches, N in blows/ft)
• Remove "disturbed" sample for further testing

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• Con't

• SPT results affected by overburden pressure
• effective wt. of overlying soil.
• Correction factor, C(n)
• Three methods
• Cn 0.77(log (20/po)
• Ncorr N Cn

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Cohesionless Soil

• Relative Density N(corr)-value
• Very loose 0-4
• Loose 4-10
• Medium 10-30
• Dense 30-50
• Very Dense gt50

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Cohesive Soil

• Consistency N(corr) Value
• Very soft lt2
• Soft 2-4
• Medium 4-8
• Stiff 8-15
• Very stiff 15-30
• Hard gt30

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• Cone Pentration Test
• (CPT)

• Mechanical cone penetrometer
• 60 degree angle
• 1.41 in. base diameter
• 1.55 sq. in. base area
• Static cone test
• pushed by hydraulic jack
• Dynamic cone test
• pushed by blows of a drop hammer
• Penetration resistance measured and recorded as a
  function of depth of soil penetrated

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• Con't

• Depth increments of 8 inches
• Rate of penetration of 2-4 ft./min
• CPT data
• cone resistance
• friction resistance
• friction ratio

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• Seismic Refraction

• Seismic waves velocity - soil rock density
• sound waves
• explosive charge
• hammer/steel plate arrangement
• detectors - geophones
• time of arrival vs. distance
• velocity and depth -
• v 800 ft/s in loose sand
• v 20,000 ft/sec in granite

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• Electrical Resistivity

• Wenner 4-probe electrode
• Soils rock of different densities
• different electrical resistivities
• resistivity affected by moisture content
• Resistivity vs. spacing
• initial straight line - constant soil resistivity
• second straight line resistivity of second
  layer and intersection gives depth of the boundry
  between the two layers.

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• Con't

• Electrical resistivity
• depth of strata
• type of soil
• depth of groundwater
• locate masses of dry sands, gravel rock.
• Disadvantages of both techniques
• subjective nature of data and interpretation
• subsurface picture may not be accurate

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• Soil Exploration Records

• Example boring map -
• Boring log sheet -
• Geologic profile -
• RINKER HALL MAP AND LOG SHEETS

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SOIL CLASSIFICATION
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METHODOLOGY

• Soils categories type and size
• cohesionless
• gravel (2 mm)
• sand (0.1-2 mm)
• silt (0.005 - 0.1 mm)
• cohesive
• clay (less than 0.005mm)
• organic
• unacceptable (color and odor)

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• Grain size categories
• coarse grained
• coarser than 0.075 mm or 200 sieve
• Granular (gravel and sand)
• fine grained
• finer than 0.075 mm or 200 sieve
• silts and clay

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Grain size analysis

• Sieve analysis (ASTM D422)
• Grain size distribution curve - graph
• Median size (D50)
• diameter of soil particles at which 50 passes
• average particle size
• Effective size (D10)
• diameter of soil particles at which 10 passes
• permeability related

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Atterberg Limits - ASTM D4318
States of Consistency for cohesive soils
- water
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Soil Classification Systems

• AASHTO Soil Classification System
• ASTM (Unified Soil Classification System)

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Unified Soil Classification System Coefficients

• Coefficient of Uniformity
• C(u) D60/D10
• Coefficient of Curvature
• C(c) (D30)2/ D60D10
• These coefficients are used to distinguish
  between clean gravel and clean sands, having less
  than 5 fines(passing 200 sieve)
• Footnote c and d, and meaning of CL-ML

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Liquid Limit 55 Plastic Limit 50
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Soils Classification Review
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Lab 1

• Sieve analysis test
• Sieves 10, 20, 40, 60, 100 or 140, 200,
  Pan
• Approximately 500 - 1000g soil
• 10 minute shake time
• Data sheet
• Calculate Median size - D50, effective size -
  D10, D60 and D30 for coefficient of uniformity
  and coefficient of curvature determinations.

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• Liquid Limit Test
• Drop device and grooving tool
• Approx. 150g dry soil passing 40
• Add water in 20 ml increments
• Record number of drops (2 drops per second)
  required to close ½ wide groove
• Less than 5 too wet start over
• Greater than 35- too dry add water
• 1 sample 25-35 drops and one between 15 and 25
  and all three between 15 and 35
• Determine water content in percent based on o.d.
  dry soil
• Data sheets

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Plastic Limit Test
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Review

• Lab Review and data
• Sieve test
• 140 0.106 mm
• Liquid limit
• Plastic limit
• Example problems
• Homework problems

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Soil Classification
Sieve No.
Passing
PI
14
27
19
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2
4
6
No. 4

100

100

100

No. 10

92

100

100

No. 40

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100

92

No. 100

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No. 200

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62

90

LL

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72

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PL

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45

19



AASHTO A-2-6(0) A-7-5(18)
A-6(17) ASTM SC MH CL
Clayey sand Elastic silt Lean
clay
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Components of Soil

• Solid, liquid and gas solids, water and air
• Block Diagram of Soil Components
• Figure 3-10 in book.
• V(t) V(v) V(s)
• V(v) V(a) V(w)
• Three new (Volume) parameters for soil
  characterization
• void ratio, e V(v)/V(s)
• porosity, n V(v)/V(t) 100 expressed as a
• degree of saturation, S V(w)/V(v)100
  expressed as a

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• Parameters based on (Weight)
• water content w W(w)/W(s)100 expressed as a
• Unit weight(wet) ? W(t)/V(t)
• W(t) W(s) W(w)
• V(t) V(s) V(w) V(a) V(s) V(v)
• Unit wt. (dry) ?(d) W(s)/V(t)
• Specific gravity of solids
• G(s) W(s)/V(s)?(w)
• ?(w) 62.4 pcf (Unit weight of water)

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Permeability, Capillarity Compressibility

• Permeability - movement of water through the soil
• Capillarity - rise of water in soil at the water
  table
• Compressibility - Settlement resulting in a
  volume decrease of soil under load
• immediate settlement - hours of a few days
• cohesionless or granular soils
• consolidation settlement - over a period of time
• primary consolidation - cohesive soils

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Compactness Relative Density

• Relative Density based on
• Voids ratios
• Loosest condition
• Densest condition
• In-place
• Unit weight
• Loosest condition
• Densest condition
• In-place

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SOIL COMPACTION STABILIZATION
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METHODOLOGY

• Compaction
• compression of soil by mechanical means expelling
  air.
• Rapid by heavy compaction rollers
• increases soil density and
• increases soil strength
• decreases soil permeability
• decreases amount of settlement
• inexpensive way of improving the overall
  properties of the soil

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• Compaction quantified by
• soils dry unit weight
• calculated from wet unit weight and moisture
  content
• Optimum moisture content
• Maximum dry unit weight
• Laboratory compaction test (Plastic Soils?????)
• Standard Proctor - ASTM D698
• Modified Proctor- ASTM D1557

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Relative Density Cohesionless Soils

• Relative Density based on
• -Voids ratios
• Loosest condition e(max)
• Densest condition e(min)
• In-place (e)
• -Unit weight
• Loosest condition ?(min)
• Densest condition - ?(max)
• In-place - ?

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Lab Test

• Description of proctor compaction device
• Standard, 5.5 hammer weight
• 3 x 25 blows from 1-ft height 12,375
  ft-lbs/cu.ft.
• Modified, 10- hammer weight
• 5 x 25 blows from 1.5-ft height 56,250
  ft-lbs/cu.ft.
• Specifications for compaction testing equipment
• Test Designation
• Standard or Modified
• Method
• Soil Particle size

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• Soil sample as received?
• Unified designation maximum dry unit weight
  range
• 5 samples - 5 different water contents?
• Each sample placed in compression mold with
  collar
• compacted in layers
• specified distance
• specified number of blows per layer
• remove collar and trim
• weigh and determine - wet unit weight
• remove soil and determine moisture content - oven
  dry
• calculate dry unit weight using formula
• Plot data dry unit weight versus moisture
  content
• Determine Max dry unit weight and Optimum
  moisture content

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Problems to Do

• Page 160-161
• No. 1, 5, and 6.

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Field Compaction

• Equipment
• Smooth wheel roller
• Sheepsfoot roller
• Pneumatic roller
• Vibratory roller
• Dynamic Compaction

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Field Compaction Test Methods
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In-Place Soil Unit Weight Test

• Density of soil in-place by drive cylinder method
• ASTM D2937 or AASHTO T 204
• Unit weight of soil in-place by the sand-cone
  method
• ASTM D 1556 or AASHTO T 191
• Unit weight of soil in-place by the
  rubber-balloon method
• ASTM 2167 or AASHTO T 205
• Unit weight of soil and soil-aggregate in-place
  by nuclear methods
• ASTM D 2922

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Field Control of Compaction

• Specify in-place dry unit wt.
• Test in-place compacted layer
• of Std. Proctor compaction (90-95 typically
  acceptable)
• in-place dry unit wt./max lab dry unit wt. X 100
• Contract document
• of required compaction
• min. number of field dry unit wt tests
• max thickness of layers to compaction
• methods to obtain max. dry unit wt.(proctor)
• methods to obtain in-place unit wt.(sand-cone,
  nuclear density meter)

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Compaction Specifications

• Work-Type specification
• contractor what to do and how to do it
• Lowest bid
• Method A
• Performance based specification
• contractor must achieve a certain degree of
  compaction based on lab data.
• Most common
• Method B and C

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• Soil Stabilization

• Soil improvement
• Mechanical
• new soil added to and mixed with natural soil
• compacted
• Chemical
• adding a chemical to natural soil followed by
  mixing compacting
• portland cement (7-14)
• road bases
• lime- plastic soils like clays to control volume
  expansion
• GeoSynthetics

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• Con't

• Fly ash - byproduct of coal combustion
• cementing value
• Geosynthletics
• geotextiles
• geogrids
• geonets
• geomembranes