Fly Ash Presentation Readymix Brunei
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WELCOME INTRODUCING FLY ASH INTO READYMIXED CONCRETE 7 May 2015 Presented By: James Wong Sales & Marketing Manager +673.729 5733 [email protected]
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Transcript of Fly Ash Presentation Readymix Brunei
WELCOME
INTRODUCING FLY ASH INTO READYMIXED CONCRETE
7 May 2015
Presented By:James Wong
Sales & Marketing Manager +673.729 5733 [email protected]
What Is ‘Fly Ash’?
It started more than 2,000 years ago…The ash generated from Volcanoes was used extensively in the construction of Roman structures. Colosseum is a classic example of durability achieved by using volcanic ash.This is a building constructed 2,000 years ago and still standing today!
What Is ‘Fly Ash’?
Fly ash has a high amount of silica and alumina in a reactive form. These reactive elements complement hydration chemistry of cement.
When cement reacts with water, we say that hydration of cement has began.
On hydration, cement produces C-S-H Gel.
However, one more compound is produced on hydration that is so different in behaviour. It is non other than the Calcium Hydroxide Ca(OH)2.
In construction industry, it is generally referred to as Free Lime.
Why Fly Ash?
Why Fly Ash?
Aggressive environmental agents like water, sulphates, CO2 attack this free lime leading to deterioration of the concrete.
Why Fly Ash?
Fly ash, on itself, can not react with water. It needs free lime, produced on hydration of Portland cement, to trigger off its Pozzolanic effect.
Once it is triggered, it can go on and on!
Definition: A pozzolan is defined as a siliceous or siliceous and aluminous material that in itself possesses little or no cementitious value, but that will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds having cementitious properties
Why Fly Ash?
In simple words, all this means a much longer life for our concrete structure.
Concrete Performance
Specific benchmarks have been set up to evaluate the performance of concrete with respect to durability—mainly Strength and Permeability. This means to produce a durable and long lasting concrete, it must posses: -
High strength And
Low permeability
Concrete Performance
Fly ash makes concrete denser, and hence less permeable, mainly by : -o Reducing water demand in
concreteo Improving microstructure of
concreteAt the same time, fly ash improves long term strength of concrete due to the continued Pozzolanic reaction as discussed earlier.
What Is ‘Fly Ash’?
Fly ash is a fine powder produced as a product from industrial plants using pulverized coal or lignite as fuel.
o It is the most widely used pozzolan siliceous or aluminosiliceous in nature in a finely divided form.
o They are spherical shaped “balls’’ finer than cement particles.
What Is ‘Fly Ash’?
Source of Fly Ash
o Class F is fly ash produced from burning anthracite or bituminous coal,
o Class C is produced from the burning of sub-bituminous coal and lignite.
Comparison between different classes of Fly Ash & OPC
o Class F is low in lime, under 15 percent, and contains a greater combination of silica, alumina and iron (greater than 70 percent) than Class C fly ash.
o Class C fly ash comes from coals which may produce an ash with higher lime content — generally more than 15 percent often as high as 30 percent. Elevated CaO may give Class C unique self-hardening characteristics.
The fly ash from the boilers where mechanical collectors are used is coarser than fly ash from electrostatic precipitators
o The color varies from light to dark grey depending upon its carbon contents
o The quality of fly ash varies from source to source
o Fly ash particles are small, they effectively fill voids
Physical Aspect
Shape effects water requirement o Spherical particles create ball
bearing effect that improves its flow properties & reduce water requirement
Benefits of Fly Ash in Concrete
Effects of particle Size o Higher Pozzolanic re-activity due
to its fineness
Particle in raw Fly Ash range mostly from 1 – 100 micron
o Particles under 10 micron: early strength (7 & 28 days)
o10 – 45 micron: late strength up to 1 year
oAbove 45 micron: inert & act as filler
Benefits of Fly Ash in Concrete
Hydrationo Hydration of Fly Ash does not
begin until about 7 dayso Late hydration is important for
mass concreting
Benefits of Fly Ash in Concrete
Setting & HardeningFly ash provides additional strength(Reactive silica in Fly Ash)+(Calcium Hydroxide) = additional C-S-H = reduction in permeability & improved Durability
Benefits of Fly Ash in Concrete
Calcium Silicates from cement react with water to form C-S-H & CHC-S-H is principal strength giving compound, acting like a “sponge’ absorbing variety of ions
Strength & Durabilityo Strength is combination of 3
factors: Dilution + Physical + Chemical
o Physical effect is increase in strength due to filler effect
o Chemical effect is increase in strength due to pozzolanic reaction
o Improved interfacial transition zone (ITZ) microstructure
Benefits of Fly Ash in Concrete
Important for development of strength & durability propertiesPrevention of moisture loss is important : (a) when W/C ratio is low (b) when cement has a high rate of strength development & © when concrete contains mineral admixturesMoisture loss from concrete surface specially for thin elements, relatively high in hot & dry climate
Importance of Curing
Quote by: Nicholas Edward, Ready Mix USA, 19 February 2010
Fly Ash Is GREEN, Not Gray
Growth of cement usage leads to greater production of CO2 which is one of the major cause of global warming
Cement industry contributes 5% of total anthropogenic CO2 emission globally
Green Energy
Global Coal Consumption
http
://w
ww
.eia
.gov
/
Balingian Power Plant (Mukah, Sarawak)
Nearest Source
Bintulu Port
Balingian Fly Ash market
Approved Fly Ash Importer
READYMIX EXPERIENCE
READYMIX EXPERIENCE
READYMIX EXPERIENCE
Client: Indramas Sdn BhdProject: UBD Sport Complex Phase 2Quantities: 470 m³Date: 21 April 2105Start: 4:45pm, 21 April 2015End: 0045am, 22 April 2015
READYMIX EXPERIENCE
READYMIX EXPERIENCE
All ready with RCB Team at site by 4:30 pm
READYMIX EXPERIENCE
First discharge: 4:45pm
READYMIX EXPERIENCE
As at: 7:35pm
READYMIX EXPERIENCE
As at: 11:58pm
READYMIX EXPERIENCE
Continuous monitoring by RCB Technical Manager
READYMIX EXPERIENCE
READYMIX EXPERIENCE
24 hours
READYMIX EXPERIENCE
7 days
READYMIX EXPERIENCE
7 days
READYMIX EXPERIENCE
7 days
READYMIX EXPERIENCE
Test Results
READYMIX EXPERIENCE
Test Results
READYMIX EXPERIENCE
Test Results
READYMIX EXPERIENCE
Test Results
More local testing @ BHC
READYMIX EXPERIENCE
Around the world
Ghatghar Dam But the Ghatghar Roller Compacted Concrete Dam was a unique project in all respects. For the upper dam, 65% fly ash was used with 35% Portland cement. The result was much better than expected.So Fly Ash was increased to 70% with only 30% of Portland cement!! Of course, this was possible due to the roller compacting technology employed and definitely not be advised for other regular structures. Though, it is amazing to see how the younger one turns into the Big Brother and carries the elder one in his arms!!
Around the world
Burg-Al-Khalifa, Dubai
http://www.slideshare.net/jojikulangara/burj-khalifamode-of-construction
SUMMARY – WHY FLY ASH
It delays the heat of hydration and hence reduces the thermal cracks in concrete
It improves the workability of concrete It makes the mix homogeneous and hence reduces
segregation and bleeding The concrete finish is improved due to perfectly
spherical fly ash particles The concrete permeability is substantially reduced
which enhances the life of the structure Fly ash contributes to the long term strength in
concrete
CLOSING
PROCEED TO DEMO VENUE
NEXT
SAFETY BRIEFINGo Wear proper PPEso Watch out for moving vehicleso Keep within safety zoneo Do not wander awayo Emergency Meet Point – Back to hallo If unsure, ask RCB Personnel
Sentral for Lunch
