of Concrete Presented by Chuck Curry ABCs of Concrete What is concrete Where does it come from How is it used Is it all the same wwwconcretepipeorg wwwconcretepipeorg Early History ID: 741665
Download Presentation The PPT/PDF document "www.concrete-pipe.org ABCs" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
www.concrete-pipe.org
ABCs of Concrete
Presented by
Chuck CurrySlide2
ABCs of Concrete
What is concrete?Where does it come from?How is it used?Is it all the same?.
www.concrete-pipe.orgSlide3
www.concrete-pipe.org
Early History Ancient Egyptians
Mix mud & straw to make bricks
Discover lime & gypsum make better binders…
3Slide4
www.concrete-pipe.org
Early History
Great Pyramids
3,000 BC
Held title of tallest man-made structure for 3,800 years!
4Slide5
www.concrete-pipe.org
Early History
Ancient Chinese
Mix water, rice and lime
Use mortar to bind bricks…
5Slide6
www.concrete-pipe.org
Early History
Great Wall of China
3,000 BC
13,000 miles
6Slide7
www.concrete-pipe.org
Improving Practices Roman Empire
Pozzolans discovered
Extensive use of hydraulic lime
7Slide8
www.concrete-pipe.org
Improving Methods
The Pantheon
Largest Unreinforced
Concrete Dome.
8Slide9
www.concrete-pipe.org
Setbacks Knowledge lost with fall of Rome
400 AD
Not “discovered” again for 1200 years!
9Slide10
www.concrete-pipe.org
The Renaissance
Renaissance Period
Scientific method
Manufacturing
Engineering
Importance of recipesSlide11
www.concrete-pipe.org
Importance of Recipes
Mix Designs
Consistency
Repeatability
Increased Confidence in PerformanceSlide12
www.concrete-pipe.org
Industrial Methods
“But if the Sand be not very sharp, then you may put a greater quantity of Sand, for Morter which hath its due proportion of Sand, is stronger than that which hath less Sand in it, altho' some think otherwise.”
- Joseph Moxon, 1678Slide13
www.concrete-pipe.org
Industrial EraRefinement of cement
Consciousness of aggregates
Scientific method
Engineering
EfficiencySlide14
www.concrete-pipe.org
Industrial Methods
Specialization
Knowledge of intended use
Mixes specific to use
Cost of mixesSlide15
www.concrete-pipe.org
Modern EraPrinciple components
Primary applications
Range of use
What and when?Slide16
www.concrete-pipe.org
Key Benefits
Widely Available
Rock and sand is everywhere!
Economical
Rock and sand generally cheap!
Continued strength gain
Self-healing properties
Relatively easy to makeSlide17
www.concrete-pipe.org
How to Make Concrete?
Rock (Coarse Aggregates)
Sand (Fine Aggregates)
Water
Cement
Add Admixtures, when needed
Mix
sounds simple enough…Slide18
www.concrete-pipe.org
How To Make a Car:Make a Body
Add 4 Wheels
Install Engine
Paint
sounds simple enough…Slide19
All The Same Right?
www.concrete-pipe.orgSlide20
www.concrete-pipe.org
Concrete is not Concrete!
Proportions of materials
Ratio of water to cement
Types of aggregates
Types of admixtures
All have an effect!Slide21
www.concrete-pipe.org
Effects of…More rock versus more sand
Cement quantity and w/c ratio
Smooth versus angular
Types of fly ash
Types of admixturesSlide22
www.concrete-pipe.org
Types of Concrete
Wet cast
Dry Cast
Flowable
Self-CompactingSlide23
www.concrete-pipe.org
Wet CastSlump Concrete
Old Days:
Achieved with high w/c ratios
Today:
Often achieved with lower w/c ratios and Water reducing admixturesSlide24
www.concrete-pipe.org
Wet CastSlide25
www.concrete-pipe.orgSlide26
www.concrete-pipe.orgSlide27
Wet Cast Properties
Pros Portable
More Dense
Lower Permeability
Lower Absorption
Nicer Finish
Cons
Longer Curing Time
Slower Form Cycle
Delayed QC
Formwork
Manpower
www.concrete-pipe.orgSlide28
www.concrete-pipe.org
Wet Cast – Common Uses
Slumps ‘generally’ 1-9” slump
Major Infrastructure – Dams, Highways
Buildings – Columns, footings, beams
Architectural – Panels, facades
Cast-in-place - Curbs, inlets, manholes
Transport – Roads, sidewalks, sleepers
Drainage – Pipe, box culverts, etc.
Residential – Drives, patios, etc.Slide29
www.concrete-pipe.org
Dry Cast
Zero Slump Concrete
Cast and Strip – Mass Production!
Lower w/cm ratioSlide30
www.concrete-pipe.org
Dry Cast
Old Days:
Tamping – Too slow. Obsolete.
Today:
Vibrational Compaction
Vibromac
Packerhead
CentrifugalSlide31
www.concrete-pipe.org
Dry Cast
Vibrational Compaction
Denser, faster, surface issues
Packerhead
Less dense, fastest, aesthetic, weaker
Vibromac
Part vibration and packing pressure
Centrifugal
Most dense*, slower, high maintenance
* (of modern methods)Slide32
www.concrete-pipe.orgSlide33
www.concrete-pipe.orgSlide34
www.concrete-pipe.orgSlide35
www.concrete-pipe.orgSlide36
www.concrete-pipe.orgSlide37
www.concrete-pipe.org
Picture of dry cast slump cone?Slide38
Dry Cast Properties
Pros
Shorter Curing Time
Rapid Form Cycle
Earlier Shipping
Automated
Mass Production!
Cons
Less Dense
Less Aesthetic
More Energy Req’d
Duplication of Errors
www.concrete-pipe.orgSlide39
www.concrete-pipe.org
Dry Cast – Common Uses
Concrete Block
Pavers
Storm and Sanitary Drainage
Concrete Pipe
Concrete Box Culverts
ManholesSlide40
www.concrete-pipe.org
Flowable High Fly Ash Content
Not Structural
Typically used as backfill
Voids in trenches
Abandoned pipelines
Little to no vibrationSlide41
www.concrete-pipe.orgSlide42
www.concrete-pipe.org
Self-Compacting Concrete(SCC)
Spread not Slump
Cement/Admix suspends aggregate
Fills the containerSlide43
www.concrete-pipe.orgSlide44
SCC Properties
Pros No vibration
Less energy
Less time
Less manpower
Complex structures
Fewer voids
Cons
High admix (cost)
Critical proportions
Interaction of admixes
www.concrete-pipe.orgSlide45
www.concrete-pipe.org
SCC – Common Uses
Manholes & Inlets
Utility Vaults
BMPs
RehabilitationSlide46
www.concrete-pipe.orgSlide47
www.concrete-pipe.org
Chemical AdmixturesWater Reducers
Reduce Water Content by 5-10%
Increase Strength
Decrease Porosity
Increases Workability
Improves FinishSlide48
www.concrete-pipe.org
Chemical AdmixturesHigh Range Water Reducers
Reduce Water Content > 10%
Significant early and final strengths
Increased flow without segregation (rheoplasticity)
Helpful where vibration inhibitedSlide49
www.concrete-pipe.org
Chemical AdmixturesAir Entrainment
Increases air content
Evenly distributed
Increases Durability, esp. to freeze/thaw cycles
Reduces StrengthSlide50
www.concrete-pipe.org
Chemical AdmixturesRetarders
Increase set time
Good for long pours in hot weather
Extended transportSlide51
www.concrete-pipe.org
Chemical AdmixturesAccelerators
Decrease set time
Increase early strength
Used in cold weatherSlide52
www.concrete-pipe.org
Chemical Admixtures
Corrosion Inhibitors
Inhibit attacks on reinforcing steel
Marine environments
Heavy salt use (northern roads)Slide53
www.concrete-pipe.org
Chemical Admixtures
Ensure Proper Dosage
Possible Mix Time Changes
Negative Synergies
How do different admixes interact?
Do you want to find out the hard way?Slide54
www.concrete-pipe.org
Methods of Mixing Many available. Important to remember goal of mixing:
Homogenous mixtures
Uniform batches
Tolerances – RecipesSlide55Slide56Slide57Slide58Slide59
www.concrete-pipe.org
What Concrete Would Be Best? Manhole Riser
Low Leakage Limit
Exposed to Freeze/Thaw
Wet Cast with Entrained AirSlide60
www.concrete-pipe.org
What Concrete Would Be Best? Bridge Beams
High Cementitious Contents
Multiple Steel Layers
SCCSlide61
www.concrete-pipe.org
What Concrete Would Be Best? Storm Drain Pipe
Mass Production
Dry CastSlide62
www.concrete-pipe.org
Recap
Value of Concrete
Types of Concrete
Similarities / Differences
Range of Use / Applications
Importance of Recipes
Effects of Admixtures
Application drives Selection!Slide63
QUESTIONS?
www.concrete-pipe.org