This document provides an overview of concrete, including its history and types. It focuses on high-strength concrete (HSC), describing how it is made with a low water-cement ratio and additives. Guidelines are given for selecting materials for HSC to achieve different compressive strengths. The differences between normal strength concrete and HSC are outlined. Applications of HSC include reducing column sizes in buildings and bridges and increasing floor area in high-rise buildings. Examples are given of bridges that used HSC to decrease volume and increase spans.
2. • HISTORY OF CONCRETE
• INTRODUCTION TO CONCRETE
• TYPES OF CONCRETE
• HIGH STRENGHT CONCRETE
• GUIDLINES FOR THE SELECTION OF MATERIALS
• DIFFERENCE B/W NSC AND HSC
• APPLICATION OF HSC
3. HISTORY OF CONCRETE:
• The word concrete comes
from the Latin word
"concretus" Which means
compact or condensed.
• German archaeologist
Heinrich Schliemann
found concrete floors,
which were made of lime
and pebbles, in the royal
palace of Tiryns, Greece,
which dates roughly to
1400-1200 BC.
Outer view of the Roman Pantheon Dom
4. INTRODUCTION TO CONCRETE:
• A building material
made from a mixture
of broken stone or
gravel, sand, cement,
and water,which can
be poured into moulds
and forms a stone-like
mass on hardening.
• It is strong in
compression and very
weak in tension.
5. TYPES OF CONCRETE:
• Normal concrete
• High Strength Concrete
• High Performance Concrete
• Air Entrained Concrete
• Light Weight Concrete
• Self Compacting Concrete
• Shotcrete
6. HIGH STRENGHT 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 0.35 or lower.
• Due to low w/c ratio it causes problem of placing
,to overcome from this superplasticizer used.
7. Materials for High-Strength Concrete:
Cement:
•Almost any ASTM portland
cement type can be used to
obtain concrete with compresive
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.
8. Aggregate:
• In high-strength concrete, the aggregate
plays an important role on the strength
of concrete.
• The low-water to cement ratio used in high
strength concrete causes densification in
both the matrix and interfacial transition
zone, and the aggregate may become the
weak link in the development of the mechanical
strength
9. Methods Of Making HSC:
• Use of admixture
• Use of cementitious agg
• Seeding
• High speed slurry mixing
10. Guidelines for the selection of materials:
• The higher the targeted compressive strength,
the smaller the maximum size of coarse
aggregate.
• Up to 70 MPacompressive strength can be
produced with a good coarse aggregate of a
maximum size ranging from 20 to 28 mm. •
• To produce 100 MPacompressive strength
aggregate with a maximum size of 10 to 20 mm
should be used.
11. Differences Between NSC and HSC:
• In normal strength concrete, the
microcracks form when the compressive
stress reaches ~ 40% of the strength. The
cracks interconnect when the stress
reaches 80-90% of the strength
• The fracture surface in NSC is rough.The
fracture develops along the transition zone
between the matrix and aggregates.
Fewer aggregate particles are broken.
• The fracture surface in HSC is smooth.
12. APPLICATION OF HSC:
• Use of HSC in column section decreases
the column size.
• Use of HSC in column decreases amount
of steel required for same column.
• In high rise building, use of HSC increases
the floor area for rental purpose.
• In bridges,use of HSC reduces the
number of beams supporting the slab.
13. Example of use of HSC in bridges
Vidya Sagar Setu Bridge,Kolkatta,India
15. • In joingy bridge,NSC is replaced
by HSC because of which volume
of concrete decreases by 30%.
• In vidhya sagar setu
bridge,because of use of HSC
instead of NSC increases the
span between two column and
strenght.
16. avg is code ===IAJS3-BQCRN-VG399-ALCOU-USHQH-K
