READY MIX CONCRETE

R MC
GUIDE:
B.S.RAKESH REDDY M.TECH

PRESENTED BY:
B.SRINIVAS (19QA1A0145)
D.MADHUSUDAN (19QA1A0109)
K.SARITHA (19QA1A0121)
R.SHIVA KUMAR (19QA1A0138)
CONTENTS:
 INTRODUCTION
 NECESSITY OF RMC
 RMC IN INDIA
 MATERIALS REQUIRED FOR RMC
 EQUIPMENT REQUIRED
 TEST ON FINE AGGREGATES AND COARSE AGGREGATES
 TESTS ON WATER
 MIX DESIGN
 MERITS OF RMC
 DEMERITS OF RMC
 CONCLUSION
 INTRODUCTION:
• Ready Mix Concrete (RMC) is a specialized material in
which the cement aggregates and other ingredients are
weigh-batched at a plant in a central mixer or truck mixer,
before delivery to the construction site in a condition ready
for placing by the build.
• The use of the RMC is facilitated through a truck-mounted
'boom placer' that can pump the product for ready use at
multi-storied construction sites. A boom placer can pump the
concrete up 80 meters.
• RMC is preferred to on-site concrete mixing because of the
precision of the mixture and reduced worksite confusion.
• It facilitates speedy construction through programmed
delivery at site and mechanized operation with
consequent economy.
 NECESSITY:
Normally the concrete operation carried out in India , is of site mixed, which is having some disadvantages which are
shown below:
• Quality assurance not guaranteed.
• Constant control on aggregates for size, shape & grading not exercised on site.
• Strict water-cement ratio not exercised.
• Wastage of materials.
• Manual operation.
• Storage of aggregates and cement.
• Blocking of roads / approaches.
Wastage of concrete
• Dust pollution

Manual operation
Storage of materials Blocking of roods
RMC is the perfect solution for the above disadvantages and offers
the following advantages by its usage, which makes it necessary as a
part of the construction:
• Generally speaking, the quality of concrete will be superior than site mixed concrete.
• However, it will greatly depend on the controls and checks exercised at site and at
RMC producer's plant. RMC PLANT
• There is a considerable wastage of materials on site due to poor storage conditions and
repeated shifting of the mixer location. This is prevented if RMC is used.
• In most cities, the plot area is barely sufficient to store reinforcement steel, formwork,
concrete and other construction materials.
• Using RMC can cause less congestion and better housekeeping on the site resulting in
efficient working environment.
• Obtaining RMC at site can reduce supervision and labour costs which would otherwise
be required for batching and mixing of concrete at site.
• Many sites in cities, house their work force on the site itself to reduce the time and cost
of daily travel
• This creates unsafe and unhygienic conditions on the site as well as for the surrounding
areas. This will reduce to a certain extent if RMC is utilized.
RMC IN INDIA:
In India RMC was first initially was used in 1950 during the construction sites of
Dams like Bhakra Nangal, Koyna. At the construction the transportation of
concrete is done by either manually or mechanically using ropeways & buckets
or conveyor systems.

RMC at Pune in the year 1991. However, due to various pit falls and problems
this plant did not survive for long and was closed. Within a couple of months in
the year 1993, two RMC plant were set up in Mumbai to commercially sell RMC
to the projects where they were installed.

These plants were later allowed to sell RMC to other projects also. Thus RMC
was successfully established sometime after 1994 in India.

As per the available record up to 2003, there are around 76 RMC plant in 17
cities with a total capacity of around 3875 CuM/hr, producing 3.8 million CuM
of concrete per year.
 Table1.1:Number of RMC plants and their capacities in leading
metropolitan cities of India.
 
Metro No. of Plants Capacity
(M3 / hr)
Mumbai and Navi 15 835
Mumbai
Bangalore 13 550
Delhi 11 660
Chennai 11 480
Hyderabad 7 350
 Materials REQURIED FOR RMC :

 Aggregates:

Fine Aggregates Coarse Aggregates

Above 4.75
Below 4.75mm
 CEMENT:
 ADDMIXTURES
 WATER IN CONCRETE:

The pH of water should be in between 6.0 to 8.0 according to IS:456-2000

 EQUIPMENT REQUIRED:
 Batching plant
The principal functional elements of every stationary concret production Plant comprises of the
following:
• Storage of materials - Silos, containers and bins.
• Batching arrangement.
• Measuring and recording equipment.
• Mixing equipment.
• Control systems.
• Electrical, hydraulic and pneumatic drives .
• Conveying systems (belt / screw conveyors).
 TRANSIT MIXER:

Capacities of transit mixers

Normal Capacity 4 to 12 CuM
Hydraulic Driver of Mixer Separate engine or driven by truck engine
Water tank capacity 192 to 2000 liters
Mixer trucks Twin axles for 2 CuM capacity
Three axles for 6 to 7 CuM capacity
Three/ four axles for 8 to 10 CuM capacity
Semi trailer for 10 to 12 CuM
 TEST ON FINE AGGREGATES AND COARSE AGGREGATES:

 SEIVE ANALYSIS:

• A gradation test is performed on a sample of aggregate in a laboratory. A typical sieve analysis involves a nested
column of sieves with wire mesh cloth (screen).
• The size of the average particles on each sieve then being analysis to get the cut point or specific size range captured
on screen.
• The results of this test are provided in graphical form to identify the type of gradation of the aggregate.
 SPECIFIC GRAVITY:
In Concrete technology, Specific gravity of aggregates is made use of in design calculations of concrete mixes. With the
specific gravity of each constituent known, its weight can be converted into solid volume and hence a theoretical yield of
concrete per unit volume can be calculated.
 BULK DENSITY TEST:

 When dealing with aggregates it is important to know the voids that presents between the aggregate
particles, so that we decide whether to fill them with finer aggregate or with cement paste.
 We all know that the Density we often deal with equals the mass divided by the volume, when using
this law to measure the density of aggregates the volume we use is the volume of aggregate + the
volume of the voids, and in this case we get a new quantity called the Bulk Density.
 Bulk Density = Mass of the aggregate \ Volume of aggregate particles with voids between them.
 TESTS ON WATER:

pH Value
Chloride
Sulphite
Nitrite
 MIX DESIGN:
The procedure for designing concrete mix as per new code is highlighted using
an M20 concrete.

Design stipulations for proportioning

a. Grade designation: M20
b. Type of cement: OPC 43 grade, IS 8112
c. Max. Nominal size of aggregate. : 20 mm
d. Minimum cement content: 300 kg/m3
e. Maximum water cement ratio: 0.55
f. Exposure condition: Mild
g. Degree of supervision: Good
h. Type of aggregate: Crushed angular aggregate
i. Maximum cement content: 450 kg/m3
j. Chemical admixture: Not used
 MERITS OF RMC:

 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.
 Labour associated with production of concrete is eliminated.
 Time required is greatly reduced.
 Noise and dust pollution at site is reduced.
 Organization at site is more streamlined.
 Durable & Affordable.
 No storage space required either for raw materials or for the mix.
 Lower labour and supervisory cost.
 No wastage at site.
 Environment friendly.
 Availability of concrete of any grade.
 DEMERITS OF RMC:

Need huge initial investment.

Not affordable for small projects (small quantity of concrete).
Needs effective transportation system from R.M.C to site.
Traffic jam or failure of vehicle creates problem if proper dose of retarder is
not given.
Labours should be ready on site to cast the concrete in position to vibrate it
and compact it.
 CONCLUSION:
• The concrete quality produced in RMC plant is highly consistent with low deviation order.
• RMC operations are highly mechanized and fully controlled through electronic controls
and hence reduce the probability of errors in various operations.
• It is also environment friendly and brings down pollution due to dust at construction can
also be accelerate with the use of RMC. The use RMC in civil construction is widely
adopted throughout the world.
• The beginning made in India is in tune with the developments outside and RMC uses
provide numerous benefits to the consumers.
• The advantages of RMC are particularly evident in construction projects with aggressive
exposure conditions.
• Ready mix concrete has gained acceptance in Indian industry due to several advantages
including quality control and overall economy.
THANK
YOU…!