A Concrete Proposal ….for you !

Concrete can be grouped under various  headings depending upon how we look at it:

A. Whether it has been cast at site or cast previously somewhere else:

1.Cast in situ:

Most of the concrete done at site falls under this group. The formwork is erected and concrete poured in the form work and later on centering or shuttering is removed .

2.Pre-cast:

2.1 Man hole covers, Lintels , Cover blocks are cast in the yard and then shifted to the location and placed in position.

2.2.Entire columns, wall panels & slabs are cast at the factory & transported to the site and installed.

2.3 Preacast prestressed ( Pre-tensioned or Post-tensioned ) girders for long span bridges or flyovers are cast either at the yard or factory , transported to the site and erected in position.

PRECAST PRE-STRESSED POST- TENSIONED ELEMENTS OF THE LONG SPAN GIRDERS FOR THE FLYOVER.
PRECAST
PRE-STRESSED
POST- TENSIONED ELEMENTS OF THE LONG SPAN GIRDERS FOR THE FLYOVER.

TENDONS COMING OUT FROM THE PRE-STRESSED POST -TENSIONED GIRDERS. [ TENSION YET TO BE APPLIED ]
TENDONS COMING OUT FROM THE PRE-STRESSED POST -TENSIONED GIRDERS.
[ TENSION YET TO BE APPLIED ]

B. Whether it has been mixed fresh at site or has been mixed  somewhere else and then shifted to the site:

1.Mixed at site:

This is the traditional method where cement, sand & aggregate are stored at site .Proportioned, mixed,shifted & placed at the desired element.

TRADITIONAL TILTING DRUM CONCRETE MIXER AT SITE  [ 1/2 BAG  CAPACITY ]
TRADITIONAL TILTING DRUM CONCRETE MIXER AT SITE
[ 1/2 BAG CAPACITY ]

MEDIUM CAPACITY BATCHING PLANT BEING USED AT A CONSTRUCTION SITE
MEDIUM CAPACITY BATCHING PLANT BEING USED AT A CONSTRUCTION SITE

2.Mixed at a central batching plant:

This is the comparatively new method where cement, sand & aggregate are stored ,proportioned and mixed at a batching plant, shifted to the site by transit mixers & placed at the desired element.

TRANSIT MIXER AND CONCRETE PUMP BEING USED FOR CONCRETING
TRANSIT MIXER AND CONCRETE PUMP BEING USED FOR CONCRETING

C. Whether ingredients have been proportioned by volume or by weight:

1. Volumetric batching:

2.Weight batching

WEIGH BATCHER for proportioning the sand & aggregate by weight.
WEIGH BATCHER for proportioning the sand & aggregate by weight.

D. Whether the ratio of ingredients has been decided by imperial methods or by scientific analysis  :

1.Nominal mix:
2.Design mix:

E. Whether the ratio of ingredients has been decided by imperial methods or by scientific analysis  :

1.Lean concrete
2.Rich concrete

F. Whether the concrete is fluid or it is quite rigid :

1.Pumpable concrete
2.Dumpable concrete

G. Whether the concrete is fresh or it is quite old :

1.Green concrete
2.seasoned concrete

H. Whether the concrete is plain or reinforced or prestressed :

1.Plain cement concrete
2.Reinforced cement concrete
3.Prestressed concrete

For bring the discussion to the present tense, all the columns above the basement were cast as follows :

1.Nominal mix of 1:1.5:3
2.Mixing done at site
3.Volumetric mixing was used
AUTHOR with his team at a construction site.
AUTHOR with his team at a construction site.
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