Mixed Concrete (RMC) is the concrete delivered at site or into
a purchaser's vehicle, in a plastic condition and requiring no further
treatment before being placed in the position in which it is to set
and harden. RMC was introduced in the early 1930s in the United Kingdom
and has since been in usage in the west. In developed countries its
usage has been over 70%. In India, the concept was introduced only
in the early 1990s. And usage is around 5-6% of the total concrete
requirement in the country.
As Dr Visvesvarayya was quoted saying, in the journal 'The
Master Builder' (Volume 1, No. 4, July-August '99): "The Indian
construction system has to get into the practice of using the maximum
out of the performance that the concrete mix can give. While they
start using the maximum advantage, then they will find RMC the best."
Advantages of RMC
- Structure constructed with RMC is likely to function in a more predictable
manner because of known concrete strengths and uniformity of concrete
- Assured quality of raw material.
- Assured and uniform quality of required grade of concrete, even
- Better finishing due to pumpable mix.
- Control on Water
-Cement ratio is maintained.
- Due to the highly workable and cohesive mix, less chance of segregation/lumping
and consequent absence of honeycombs in the concrete.
- Lower labour and supervisory efforts.
- Better supervision of Concrete from the RMC supplier at the construction
- Environment friendly.
- Multi-transportation of raw materials, for concrete, eliminated.
- Quicker construction through continuous mechanized operations.
- Eliminates need for ordering and storing Cement, Sand and other
aggregates at the site.
- Eliminates space constraint problems for storage.
- Timing for setting of concrete can be decided to suit site or weather
- Wastage reduced due to bulk handling.
Suppliers of RMC in
L & T
Suppliers of RMC Equipment
Ocmer Truck Mixers
Ajax Fiori Engineering (ORU)
Varieties of RMC
Condensed Silica Fume Concentrate
Fibre reinforced Concrete
Temperature controlled Concrete
Future of RMC in India
Projected that the 5% usage will reach 45% by 2020.
Insistence on the use of RMC by all major
Present forward integration will turn into
more individual business units.
Disadvantages of RMC
- More expensive than
Site Mixed Concrete (SMC). SMC is at least 20% cheaper.
- RMC attracts Sales Tax, as a product.
- Congestion and traffic snarls could play spoilsport.
Problems faced by
Lower level of awareness of the benefits of RMC
Acceptance of the concept
High Sales Tax
Variable Cement prices
Traffic restrictions on Transit Mixers
Shortage of trained manpower
RMC - What they say
" As far as the superiority
of technology is concerned, no doubt , it (RMC) is one of the
best technologies, that should be adopted in all construcion
activities " - Professor B Bhaskara Rao of Centre
for Symbiosis of Technology Environment and Management.
"It (RMC) is an ideal solution to many
of the problems we face. What is lacking is awareness.
We have to educate our engineers in the government departments.
" - Kantharaju of Karnataka State Building Centre.
Text : Hemantha Kumar Pamarthy Picture : V Ganesan