This document discusses concrete technology and provides information on various topics related to concrete construction. It begins with an overview of concrete admixtures and their classification. It then discusses ready mix concrete and includes information on quality control measures in concrete projects. The document also covers common defects in concrete, repair methods, and different varieties of concrete. It concludes with sections on concreting under extreme conditions and the past, present, and future of concrete.

1. ADVANCED BUILDING CONSTRUCTION-IX
CONCRETE TECHNOLOGY
RISHABH JAIN
B.ARCH(9THSEM)
1/16/FPA/B.ARCH/005
2

2. TABLE OF CONTENTS
1. CONCRETE ADMIXER
2. READY MIX CONCRETE(RMC)
3. QUALITY CONTROL IN CONCRETE CONSTRUCTION
4. DEFECTS AND REPAIR IN CONCRETE
5. VARITIES OF CONCRETE
6. CONCRETING UNDER EXTREME CONDITION
7. CONCRETE:PAST,PRESENT,FUTURE

3. CONCRETE ADMIXTURES
Concrete admixtures (additives) enhances the properties of concrete
for applications in construction with special requirements.
 Ingredient added to concrete batch immediately before or during
mixing concrete
Retard or accelerate time of initial setting.
Increase strength
make a poor concrete better.

4. CLASSIFICATION
CHEMICAL ADDMIXERS MINERAL ADDMIXERS
 improve the quality of
concrete
 more economical
 reduce permeability
 increase strength
ADDMIXERS
MISCELLANEOUS
SUPER
PLASTICIZERS
PUMPING
WATER
PROOFING
AIR
ENTRAINING
WATER
REDUCING
OR
PLASTICIAING
RETRADING
ACCELERATING
 delay in the
setting time of
concrete
 lower water content
 DECREASE WATER
CEMENT RATIO
 REDUCE WATER REQUIRMENT
 INCREASE WORKABILITY
 INCREASE LONG TERM STRENGTH
 HIGH SLUMP RATE
 reduces segregation
 Improves properties of
hardened concrete
 improve workability, ease of
placing, better resistance to
frost action and reduction in
bleeding

5. DAMP CARE CW 300/L
Air Entraining Admixture PASAND - 38/KG
Sikacim Waterproofing Compound - 80/KG
FOSROC Admixture Concrete Mortar -150/KG
Dr. Fixit Raincoat Waterproofing Coating -340/UNIT
SOME OF THE ADDMIXERS
ARE :

6. READY - MIX - CONCRETE (RMC)
• Manufactured in a factory or within a batching plant based on the standard
required specifications.
• The prepared concrete mix is then taken to the work site within transit mixers
mounted over a truck.

7.  The transit time from the time of preparation
of concrete to the delivery site, will result in
loss of workability.
 Traffic during the transit of concrete can
result in setting of concrete.
 The formwork and placing arrangement must
be prepared in advance in large area as the
concrete can be bought in larger amounts.
ADVANTAGE DISADVANTAGE
 mixture formed is precise and of higher quality.
 Better handling and proper mixing practice will help to
reduce the consumption of cement
 The concrete mixed is used with high versatility.
 make use of bulk concrete instead of bags of cement
 Cement saving will conserve the energy and the resources.
 less environmental pollution.
 chances of human errors is reduced.
 Petrol and diesel consumed is less thus noise and air
pollution is reduced.
RMC
Transit mixed concrete Shrink mixed concrete Central mixed concrete
 concrete is partially mixed in the
plant mixer and then balance mixing
is done in the truck
 concrete is thoroughly mixed
before loading into the truck
mixer.
 water are charged
directly into the truck
mixer
Concrete mixed at job site
Concrete mixed in transit
While being transported towards the
destination, the drum is revolved at a slow
The drum speed is kept
medium during the transit time

10. QUALITY CONTROL IN CONCRETE CONSTRUCTION
For the building structure to be durable, more strength and also for
aesthetic, accomplishing a quality concrete is of supreme importance.
By little variation in water to cement ratio, strength drops very much
HOW TO DETERMINE THE QUALITY OF CONCRETE ?
 Properties of the cement used in the concrete.
 Mixing of the concrete
 Slump of the concrete.
 Vibration/Compaction of the concrete
 Control of water addition.
 Sampling and testing

11. TEST TO QUALITY CONTROL
Tests on Fresh Concrete
• The Slump test
• The Compacting Factor Test
Tests on Hardened Concrete
• Compression Test
• Tensile Strength Test
(Split Cylinder Test)
• Flexural Strength Test
SLUMP
TEST
COMPACTING
FACTOR TEST
COMPRESSION TEST
TENSILE STRENGTH TEST
FLEXURAL TEST

12. DEFECTS AND REPAIR IN CONCRETE
DEFECTS IN CONCRETE
Causes for Defects in Concrete Structures
Damage due to marine environments.
Movement of concrete due to physical characteristics.
Damage due to chemical attack
Damage due to fire, floods, earthquakes, cyclones etc.
construction defects.
errors in structure design,
Defects due to the quality of raw materials.
Defective workmanship.
Excessive use of water in the concrete mix is the largest single source of
weakness.

13. TYPE
OF
DEFECTS
CRACKING
CRAZING
OR
PATTERN
CRAKING
BLISTERING
DUSTING
OR
CHALKING
 improper mix design, insufficient
curing,
 contraction joints,
 unsuitable sub-grade etc.
 use low water – cement ratio
and maximize the coarse
aggregate in concrete mix
 admixtures
 rapid hardening of top
surface of concrete due
to high temperatures
 excess water content
or due to insufficient
curing.
CAUSES PREVENTION
 proper curing
 protection to the
surface from rapid
temperature changes
formation of hollow
bumps of different sizes
on concrete surface due
to entrapped air under
the finished concrete
surface
 excessive vibration
 presence of excess
entrapped air in mix or
due to improper finishing
 Excessive evaporation of
water on the top surface
formation of
closely spaced
shallow cracks
in an uneven
manner
 Covering the top surface
which reduces evaporation
 good proportion of
ingredients in concrete
formation of fine and
loose powdered concrete
 excess amount of water
 fine particles like cement or sand
will rise to the top causes dust at
the top surface.
 use low slump concrete
 water reducing
admixtures

14. CURLING
SCALING
AND
SPALLING
EFFORESCENSE
When a concrete slab is
distorted into curved shape
by upward or downward
movement of edges or
corners
 differences in moisture
content or temperature
between slab surface (top)
and slab base (bottom).
 use low shrink
concrete mix,
 provide control joints,
 provide heavy
reinforcement at
edges
 provide edges with
great thickness.
shrink before top surface
shrink before BOTTOM surface
formation of deposits of salts
on the concrete surface.
Formed salts generally white in
color. It is due to the presence
of soluble salts in the water
which is used in making
concrete mix.
 When concrete is
hardening, these
soluble salts gets lifted
to the top surface by
hydro static pressure
and after complete
drying salt deposits are
formed on the surface.
 using clean and pure
water for mixing,
 using chemically
ineffective aggregates
concrete surface gets
deteriorated and flaking
of concrete occurs.
 penetration of water
through concrete surface.
This makes steel gets
corroded and spalling or
scaling may occurs.
 inadequate curing
 use of lo strength concrete
 adding air
entrainment
admixtures,
 proper finishing and
curing,
 providing good
slope to drain water
coming on to the
surface etc.

15. REPAIRS IN CONCRETE
Materials for Repairing
1)Portland cement:
 Repairs are tend to be made with a high concentration of
cement which will make the finished repair appear darker
than the parent concrete.
 White Portland cement helps to lighten the colour.
2)Aggregate and sand:
Preferably the same as used in the original mix
3)Gauging liquid:
generally water with a polymeric material such as styrene
butadiene rubber (SBR), polyvinyl acetate (PVA) or an acrylic
material. These improve the cohesion and adhesion of the
repair to the parent concrete

16. Repairing of Honeycombed Concrete:
Repair of cracks
 main function of concrete in the cover zone is to protect the steel reinforcement
from corrosion, cracks in floor slabs can generally be filled with a cement paste.
 To repair a concrete wall you will need an epoxy repair kit.
Repair of blow holes
 A technique called “Bagging in: is used to repair
excessive blow holes in the surface of concrete. This
technique involves using a hessian pad to rub a cement
paste into the holes.
 The repair mix is normally made from a 1:4 mix of
cement and fine grade sand (silver sand is often used)
with sufficient water
 FIRST REMOVE THE honeycombed concrete AND BRUSH TO
REMOVE DUST
 prepare the replacement concrete 1:2 combination of Portland and
white cement.
 liquid should be added such that the mixture is just moist

17. VARIETIES OF CONCRETE
SOME OF THE VARIETIES OF CONCRETE ARE AS FOLLOWS -
Normal Strength Concrete OR Plain concrete (P.C.C) :
 produces normal strength concrete.
 basic ingredients — concrete, sand and aggregate
— using the 1:2:4 ratio
 no reinforcement ,good in compression only
 construction of the pavements and the buildings
Reinforced Concrete :
 reinforcement is introduced to
bear the tensile strength
 Buildings, bridges and roadways
rely on reinforced concrete.

18. Prestressed Concrete :
 bars or the tendons used in the concrete is
stressed before the actual service load
application
 Once the concrete sets and harden, the
structural unit will be put in compression.
 This phenomenon of prestressing will make
the lower section of the concrete member to
be stronger against the tension.
 Hence the prestressing units are made at site
and assembled at site. These are used in the
application of bridges, heavy loaded
structures, and roof with longer spans.

19. Precast Concrete :
 elements can be made and cast in the factory as per
the specifications and bought to the site at the time of
assembly
 advantage of acquiring speedy construction
 As the manufacturing is done at site, quality is assured
 Precast concrete is used for:
o Concrete blocks
o Precast walls
o Staircase units
o Poles
OTHER VARIETIES OF CONCRETE ARE -
 GRC
 High-Density Concrete
 Self – Consolidated Concrete
 Glass Concrete
 Decorative Concrete , etc

20. Concreting Under Extreme Conditions
1. Concrete Work- Hot and Cold Climates
Temperature control of concrete ingredients.
 Aggregates- stored under shade or cooled by water
 Water- used in the form of ice or in near freezing temperatures.
 Cement- Temperature restricted to 77O C
 Temperature of concrete at the time of placement should be below
40 OC.
 The mixing time should be held at minimum
 Period between mixing and delivery should be kept to a minimum.
 reinforcements should be kept cool by spraying with cold water first.
If possible, concreting may be restricted to evenings and nights.
 PRECAST ELEMENTS MAY BE USED

21. 2. Under-water Concreting
Precast members are to be preferred

22. 3. CONCRETE IN WEAK SOIL/LOW DENSITY
Pile foundations
A slender, structural member consisting steel or concrete or
timber.
• It is installed in the ground to transfer the structural loads to soils
at some significant depth below the base of the structure.

23. PAST ,PRESENT AND FUTURE OF CONCRETE
PAST
 Crushed rocks that were sometimes burned to change their chemical makeup
 Water
 Sand
 Gravel or small stones
 LIME
The ingredients were combined to make a crude cement mortar; when stones
were added to the mixture, the resulting materials could be used to build walls,
create durable pathways and to help construct the primitive houses of the time
period.

24. PRESENT
 Today, concrete is used in almost every type of construction used materials in
residential, industrial and commercial construction.
 Concrete floors and foundations are the standard throughout the
construction industry due to its durability and strength
 Builders depend upon concrete to provide strong and reliable support for
bridges, buildings, walls, dams and many other construction projects.
 New research in the fields of chemistry and engineering has created a
number of breakthroughs that are likely to make concrete even more useful
for future generations.

25. FUTURE
 Carbon negative concrete formulations actually absorb carbon dioxide from the
environment during curing, making them an outstanding choice for green-friendly
building.
 Self-healing concrete incorporates specially developed bacterial colonies to repair gaps
and breaks that develop on the surface over time.
 The increasing availability and popularity of 3-D printing is also likely to boost demand for
concrete; developing a system by which entire buildings can be printed using concrete.

26. BIBLOGRAPHY
 theconstructor.org
 CONCRETEISBETTER
 WIKIPEDIA
 SLIDE SHARE
 GOOGLE IMAGES
 USBR.GOV