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SHRI SHANKARPRASAD AGNIHOTRI COLLEGE
OF ENGINEERING, WARDHA
MIX DESIGN PROCEDURE OF READY MIX CONCRETE
DEPT. OF CIVIL ENGG.
PRESENTED BY :-
MISS. MINAL LONKAR MAM
MISS. HARSHALI KOPARKAR
Ready-mix concrete (RMC) is a ready-to-use
material, with predetermined mixture of Cement,
sand, aggregates and water.
The Idea of Ready Mix Concrete (RMC) was first
introduced by Architect Jurgen Heinrich Magens, he
got his patent of RMC in Germany in 1903.
In 1907, he discovered that the available time for
transportation could be prolonged not only by cooling
fresh concrete but also by vibrating it during
The first concrete mixed off site and delivered to a
construction site was effectively done in Baltimore,
United States in 1913, just before the First World
The first concept of transit mixer was also born in
1926 in the United States. In 1939, the first RMC
plant was installed in United Kingdom and in 1933.
Between the years 1950 and 1980 considerable
growth of RMC took place in the United States.
In India RMC was first initially was used in 1950
during the construction sites of Dams like Bhakra
• The increasing availability of special transport
vehicles, supplied by the new and fast growing
automobile industry, played a positive role in the
development of RMC industry.
Better quality concrete is produced.
Elimination of storage space for basic
materials at site.
Elimination of Procurement / Hiring of
plant and machinery.
Wastage of basic materials is avoided.
MATERIALS REQUIRED FOR RMC
1. AGGREGATE :
Aggregates are the important constituents in
concrete. They give body to the concrete,
reduce shrinkage and effect economy. The
mere fact that the aggregates occupy 70-80 per
cent of the volume of concrete.
Aggregates are divided into two categories from
the consideration of size
• Coarse aggregate
• Fine aggregate
The size of the aggregate bigger than
4.75 mm is considered as coarse aggregate and
aggregate whose size is 4.75 mm and less is
considered as fine aggregate.
2. CEMENT :
Cement is a binder material which
sets and hardens independently, and can bind
other materials together.
Cement is made up of four main
dicalcium Silicate (2CaO SiO2),
tricalcium silicate (3CaO SiO2),
tricalcium acuminate (3CaO Al2O3),
tetra-calcium aluminoferrite (4CaO Al2O3
these compounds are designated as C2S,
C3S, C3A, and C4AF.
where C stands for calcium oxide (lime), S for
silica and A for alumina, and F for iron oxide.
Small amounts of uncombined lime and
magnesia also are present, along with alkalis
and minor amounts of other elements.
• Air-entraining admixtures (mainly used in
concrete exposed to freezing)
• Water-reducing admixtures, plasticizers
(reduce the dosage of water while maintaining
• Retarding admixtures (mainly used in hot
weather to retard the reaction of hydration)
• Accelerating admixtures (mainly used in cold
weather to accelerate the reaction of hydration)
• Super plasticizer or high range water-reducer
(significantly reduce the dosage of water while
maintaining the workability)
• Miscellaneous admixtures such as corrosion
inhibiting, shrinkage reducing, coloring, pumping
Fly ash is a by-product from coal-fired
electricity generating power plants.
The fly ash is generally used in the
concrete in the following ways.
As partial replace for cement.
As partial replacement for sand.
As simultaneous replacement for both
cement and sand.
The pH value of water should be in
between 6.0 and 8.0 according to IS
rice husk / hull ash (RHA)
Today, rice is grown and harvested on
every continent except Antarctica.
The majority of all rice is produced in
India, China, Japan, Indonesia, Thailand,
Burma, and Bangladesh. Asian farmers’
accounts for 92-percent of the world's total
More than 550 million tons of rice is
produced annually around the globe.
That rice husk are used in RMC to
Storage of materials - Silos, containers
Measuring and recording equipment
Electrical, hydraulic and pneumatic
Conveying systems (belt / screw
Thorough mixing of the materials is essential
for the production of uniform concrete. The
mixing should ensure that the mass
becomes homogeneous, uniform in colour
and consistency. There are three methods
adopted for mixing Ready Mix Concrete.
Following are the three types of mixing
process of RMC
1. Transit Mixed (or "truck-mixed") Concrete
2. Shrink Mixed Concrete
3. Central Mixed Concrete
TRANSIT MIXED(OR "TRUCK-MIXED") CONCRETE:-
While ready mixed concrete can be delivered to the
point of placement the overwhelming majority of it is
brought to the construction site in truck-mounted,
rotating drum mixers.
Truck mixers have a revolving drum with the axis
inclined to the horizontal.
Inside the shell of the mixer drum are a pair of blades
or fins that wrap in a helical (spiral) configuration from
the head to the opening of the drum.
The concrete is loaded and mixed, it is normally
hauled to the job site with the drum turning at a speed
of less than 2 rpm.
NEEDS TO BE SPECIFIED BY CONSUMER FOR RMC
Characteristic strength or grade (N/mm2)
Target workability or slump in mm required
Exposure conditions for durability
Maximum water to cement ratio
Minimum cement content
Maximum aggregate size
Type of cement
Mineral admixture and its proportion
CHECKS BY CONSUMER BEFORE ORDERING THE RMC
Calibrations of all measuring devices and
Mode of operation of plant should
preferably be fully automatic and not
Quality of materials proposed to be used.
Adequacy of quantity of materials used.
INSPECTION OF CONSUMER
The concrete quality produced in RMC
plant is highly consistent with low
It provides a high degree of overall
strength of hardened concrete and the
performance of the structure at a later
RMC operations are highly mechanized
and fully controlled through electronic
controls and hence reduce the
• Concrete technology