concrete

1. Presented By :- Suman
dandapat
75121027
TH
PRESENTATION
ON
HIGH STRENGTH CONCRETE

2. Contents
History of concrete
Introduction of concrete
Type of concrete
High Strength Concrete (HSC)
Properties of HSC
Materials for HSC
Application of HSC

3. History of Concrete
Roman Pantheon, finished 128 AD,
still the largest unreinforced solid
concrete dome.
The word concrete comes from the Latin
word "concretus" (meaning compact or
condensed).
The earliest large-scale users of concrete
technology were the ancient Romans.
e.g.- The concrete dome of
the Pantheon is the world's largest
unreinforced concrete dome.

4. Introduction to concrete
Concrete mix
 A building material made from a
mixture of broken stone or gravel ,sand ,
cement and water , which can be poured
into mould and forms a stone-like mass
on hardening.
 It is strong in compression and very
weak in tension.
 Composition of concrete are cement ,
water, Aggregates and Chemical
admixtures(if needed).

5. Types of Concrete
Normal Concrete
High Strength Concrete
High Performance Concrete
Air Entrained Concrete
Light Weight Concrete
Self Compacting Concrete

6. High Strength Concrete
 High-Strength concrete has a Compressive Strength greater
than 40 Mpa.
 High Strength Concrete is made by Lowering the Water
Cement (W/C) ratio to 0.3 or Lower.
 Due to Low W/C ratio it causes problem of placing to over
come from this super plasticizer used.

7. Properties of HCS
 High workability, high durability and high ultimate strength .
From the general principles behind the design of high-strength
concrete mixtures, it is apparent that high strengths are made
possible by reducing porosity, inhomogeneity, and micro cracks in
the hydrated cement paste and the transition zone.
Consequently, there is a reduction of the thickness of the interfacial
transition zone in high-strength concrete.
For very high-strength concrete where the matrix is extremely dense,
a weak aggregate may become the weak link in concrete strength.

8. Materials of HSC
Cement
 Almost any ASTM Portland cement type can be used to obtain concrete
with adequate rheology and with compressive strength up to 60 MPa.
 In order to obtain higher strength mixtures while maintaining good
workability, it is necessary to study carefully the cement composition
and fineness and its compatibility with the chemical admixtures.
 Experience has shown that low-C3A cements generally produce
concrete with improved rheology.

9. Aggregate
 In high-strength concrete, the aggregate plays an important role on the
strength of concrete.
 Extreme care is necessary, therefore, in the selection of aggregate to be
used in very high-strength concrete.
 The particle size distribution of fine aggregate that meets the ASTM
specifications is adequate for high-strength concrete mixtures.
 If possible, Aitcin recommends using fine aggregates with higher
fineness modulus (around 3.0).

10. Guidelines for the selection of materials
 The higher the targeted compressive strength, the smaller the maximum
size of coarse aggregate.
 Up to 70 MPa compressive strength can be produced with a good coarse
aggregate of a maximum size ranging from 20 to 28 mm.
 To produce 100 MPa compressive strength aggregate with a maximum
size of 10 to 20 mm should be used.
 To date, concretes with compressive strengths of over 125 MPa have
been produced, with 10 to 14 mm maximum size coarse aggregate.

11.  Using supplementary cementations materials, such as blast-furnace slag,
fly ash and natural pozzolans, not only reduces the production cost of
concrete, but also addresses the slump loss problem.
 The optimum substitution level is often determined by the loss in 12- or
24-hour strength that is considered acceptable, given climatic conditions
or the minimum strength required.
 While silica fume is usually not really necessary for compressive
strengths under 70 MPa, most concrete mixtures contain it when higher
strengths are specified.

12. Application of HSC
In bridges , use of HSC Reduces the number of beams
supporting the slab.
 Use of HSC in Column decrease the Column Size.
Use of HSC in Column decrease amount of steel
required for same column.
In high rise building , use of HSC increases the Floor
area for rental Purpose.

13. Example of use of HSC Bridge
Vidyasagar Setu,Kolkata,India

14. Joigny Bridge, Paris

15.  In Vidhya Sagar Setu bridge, because of use of HSC instead of NSC
increases the span between two column and strength.
In Joingy bridge,NSC is replaced by HSC because of which volume
of concrete decreases by 30%.

16. Thank you...