Processing & Properties of Floor and Wall Tiles.pptx
GGBS
1. Changing the face of concrete
Avinash Shaw
Department of Civil Engineering
NIT Durgapur
Prof. A. K. Samanta
2. Ground-Granulated Blast-furnace
Slag
Sometimes, also referred to as
GGBFS
Obtained by quenching molten
iron slag from a blast furnace
in water or steam, dried and
ground into a fine powder
5. What are its
physical properties?...
Particle size - 0.1 to 40 microns
Specific Surface Area – 400-600 m2/kg
Relative Density – 2.85-2.95
Bulk density –Loose - 1.0–1.1 tonnes/m3
Vibrated - 1.2–1.3
tonnes/m3
pH (T = 20 °C in water) – 9 to 11
6. Ma i n l y two u s e s
Production of quality-improved slag
cement, namely Portland Blast Furnace
Cement (PBFC) and High-Slag Blast-
Furnace Cement (HSBFC)
Production of ready-mixed or site-batched
durable concrete.
7.
8.
9. Durability
• Provides protection against both sulphate
attack and chloride attack.
• Effectively replaced Sulfate-Resisting Portland
Cement (SRPC) on the market for sulfate
resistance because of its superior
performance and greatly reduced cost
• Useful against chloride attack in reinforced
concrete in marine environments and in road
bridges where the concrete is exposed to
splashing from road de-icing salts.
10. Durability
• use of GGBS in such instances will
increase the life of the structure by up to
50% had only Portland cement been used,
and precludes the need for more expensive
stainless steel reinforcing.
• also routinely used to limit the temperature
rise in large concrete pours, which prevents
the occurrence of micro cracking.
12. Appearance
• The near-white color of GGBS cement
permits architects to achieve a lighter colour
for exposed fair-faced concrete finishes, at
no extra cost.
• Also produces a smoother, more defect free
surface, due to the fineness of the GGBS
particles.
• GGBS cement prevents the occurrence of
efflorescence, the staining of concrete
surfaces by calcium carbonate deposits.
15. Powerfloating
As GGBS concrete stays plastic for a longer
time than Portland cement concrete, this
enables the contractor to achieve a very flat
finish.
16. Strength
• GGBS cement has a higher ultimate strength
than concrete made with Portland cement.
• Higher proportion of the strength-enhancing
calcium silicate hydrates (CSH) than
concrete made with Portland cement only,
and a reduced content of free lime, which
does not contribute to concrete strength.
• Doubles its 28-day strength over a period of
10 to 12 years.
17. Strength
Typical strengths of 35 N concrete (N/mm2)
GGBS % 7 day 28 day 56 day
0 32 42 43
20 30 43 45
35 27 43 47
50 23 40 44
19. Sustainability
• GGBS is a by-product of steel manufacturing
process, its use in concrete is recognized by
LEED.
• It significantly reduces the embodied CO2 of
the structure.
20. Working with GGBS Concrete
• Fresh concrete containing GGBS has better
mobility characteristics, arising from the
consistent fineness and particle shape of the
GGBS powder, and from its slightly lower
relative density.
• The smoother surface texture and glassy
surface of GGBS particles also helps to
improve workability.
21. Placing, Compacting and Pumping
• Easier to place the concrete into formwork
and easier to compact by mechanical
vibration.
• Less liable to segregation during transport
and handling.
• Pumping is also easier, due to the slightly
lower relative density and better flow
characteristics.
22. Water Demand
• Less of the mixing water(3–5% lower) is
adsorbed onto the surface of the GGBS
particles, as they are smoother and glassy.
23. The rate of early age strength gain of
GGBS concrete is greatly improved by
higher curing temperatures
A temperature increase from 20 to 40°C is
sufficient to increase the early strength
GGBS concrete by a factor of two to
four.
24. This graph illustrates that as the in-situ curing temperature increases, any
delay in strength development that may arise as a result of increasing the %
of GGBS may be negated by the increase in temperature.
25. Water in GGBS concrete takes slightly
longer to combine chemically to form
hydration products, thus making GGBS
concrete a little more sensitive to poor
curing.
For GGBS contents of up to 60%, curing
periods as recommended in IS 326 and BS
8110 for Portland cement concretes are
sufficient. For higher GGBS contents, these
periods may need to be extended.
Notes de l'éditeur
The two images above show colour difference between concrete that contains GGBS and that does not contain GGBS on a median barrier in Tipperary
Boyne Bridge M1 motorway Concrete Piers contain GGBS, resulting in a lighter more aesthetic appearance. The Mary McAleese Boyne Valley Bridge is a cable-stayed bridge in County Meath, Ireland.
LEED-Leadership in Energy and Environmental Design is a suite of rating systems for the design, construction, operation, and maintenance of green buildings, homes and neighborhoods.
