1. Concrete
Er. Jagadiswar M. Shrestha
SDE, Department of Irrigation

2. is an artificial stone having basic
ingredients of cement, sand and coarse
aggregate.
can be obtained by mixing together the
above ingredients with water and
allowing the product to cure for
hardening
Concrete

3. Concrete
 is very popular construction material having
high strength and flexibility in shape and
size for the construction.
 is considered to be superior to any other
construction materials in terms of the
durability, corrosive resistance, greater fire
resistance etc.

4. Quality of concrete
Depends upon
Quality of its ingredients
 cement, coarse and fine aggregates, water, admixtures etc
Concreting process
checking before concreting
 formwork condition properly whether it is on exact
required alignment as per drawings or not
 reinforcing bar as per design & drawing
 detailing of reinforcing bars
 proper installation of electrical pipes
 proper sizes of cover blocks at top, bottom and ends
proportioning the ingredients, mixing,
transporting, placing, compacting, curing etc

5. Quality of its ingredients
 Cement
 guaranteed by the manufacturer
 suitable cement should be chosen
 Aggregates
 usually available in locally and can vary to any extent in
many of their properties.
 very essential to know more about the aggregate
 Water
 potable water can be used
 Admixtures
 Used for special purposes
 Need special knowledge or advise from manufacturer

6. Concreting Process
 Batching
 Mixing
 Transporting
 Placing
 Compacting
 Curing

8. 8

10. Compaction

12. Concreting Process
 Batching
 by weight is preferable
 If batched on volume basis, use measurement boxes in
units of 35 liters which is the capacity of one 50 kg bag
of cement
 cement should be batch only by weight and preferably
by whole bags
 aggregates shall be used with measurement box
 correction for bulking of aggregates is necessary

13. Concreting Process
 Mixing
 Use mixing machine.
 Avoid hand mixing
 When it is unavoidable hand mixing should be done on
an impervious plate-form. In the case of hand mixing,
mix cement and sand first and then add aggregates.

14. Concreting Process
 Transporting
 Manually by pan for short distance
 By trolley horizontally or vertically
 By dumper with cover for mass concrete in short
distance
 By transit mixture for long distance and ready mixed
concrete (RMC)
 Avoid drying out, segregation and setting during
transportation.

15. Concreting Process
 Placing
 Place concrete in its final position before setting starts
 avoid segregation of materials by pouring with short
distance without disturbance of the forms
 lay concrete in suitable layers without any break of
continuity
 Pour the concrete upto construction joint as per design
if provided

16. Concreting Process
 Compacting
 use internal (needle) vibrator for thick concrete
 use external (plate) vibrator for thin concrete
 avoid over vibration
 apply vertically the needle without moving and never
use needle as nearby transporter of concrete
 check props (supports) of the formwork while
compacting

17. Concreting Process
 Curing
 keep concrete moist by ponding or plastic curing over
floor
 keep concrete moist by jute wrapping on column
or vertical wall
 apply curing preferably for 10 days minimum

18. Thank you for your kind attention