Viewers, please understand that every abode in modern
days need concrete to safe build it.
That is what everybody wants -a quality concrete. RMC an old concept (1930),
but now it is commercially available in many countries. Many RMC dealing
agencies are functioning for providing QA/QC certification , technical audit
& regulatory framework around the world. And as such the ready-mix plant
providers now must providing quality concrete as per requirement of the real
estate purchasers in dry and wet state.
It can be used without tears now. The framework is
described in this blog for better
usability of RMC.
Concrete is a heterogeneous mix prepared namely by
Cement and / or Cementitious materials
Fine and Coarse Aggregates Water
Chemical Admixture
Other additives (as per requirement of concrete types)
About Ready Mix Concrete RMC
Quality based ingredients of concrete are mixed in proportions as per design requirement by:
Hand mixing – usually at
scattered places, in small quantity and O&M works.
Mechanical and hand
mixing
- for small jobs, usually at scattered
places, in small quantity and O&M works.
Mechanical means using prime movers (
initial source of motive power) - usually at scattered places, in large
quantity and O&M works in large
quantities- onsite operations.
Mobile mixing units on trucks using prime movers -
usually at scattered places, in large quantity and rehabilitation works.
Mixing at centralized batching and mixing plant and transporting the mixed concrete in wet or dry state to the workplace. These types of concrete can be used for.
Project based
requirement – At places within a project only (mixing unit used for
project operations)
Commercial based requirements – At other project -
mostly for real estate projects ( the projects above the ground) having
different owners / purchasers with different mix design and requirements. RMC
fulfils this commercial requirement.
(Ready-mix concrete (RMC) is concrete that is manufactured in a batch plant,
according to a set engineered mix design. Ready-mix concrete is normally
delivered in two ways.
First is the barrel truck or in–transit mixers. This type of truck
delivers concrete in a plastic state to the site.
Second is the volumetric concrete mixer. This delivers the ready
mix in a dry state and then mixes the concrete on site….Wikipedia)
RMC
History
Mainly concrete is a composite of Cementing material, Fine aggregates, Coarse Aggregates and Water. This concrete was initially prepared by manual mixing and used to become the part of the designed structure. The concrete manufactured this way had to be used within the final setting conditions of the concrete.
With advanced research the concrete started mixing with on-
site
mechanical and electrical means.
Further research on the use of cementitious materials and
admixtures made the concrete to set at desired time that is beyond its normal setting time. The increase in setting time made the way to transport the concrete with dumpers, carts etcetera to a longer distance from the batching and mixing place. With coming up of transit mixers, the large, scattered project site started using concrete manufacturing from batching plants located at a central place or at several places in the project area. The concrete production at such plant remained limited to the demand of the project area. The project areas where it was not possible to manufacture concrete at site used ready mixed concrete from the central batching and mixing plant.
Concrete batching and mixing plats began commercial production at various place to fulfil the demand of other several small and bigger areas in private sectors and public sectors.
Now this RMC is very much in advances stage, and it has become a concrete manufacturing industry to fulfil the concrete requirement of various mix designs at various places including dense cities. Later with the further advancement and with the help of computer science, the RMC is widely used at the construction sites ( within the reach of RMC plants).
The history search for RMC says it was patented in 1903 (GERMANY), developed for commercial use in USA from 1917 to 1926, and around 1930 it was used for construction practices in European countries.
Some RMC dealing agencies are as below for QA/QC
certification , technical audit & regulatory framework.
USA -
NRMCA - National Ready Mixed Concrete Association
Europe
- ERMCO – European Ready Mixed Concrete
The RMCAO – Ready Mixed Concrete
Association of Ontario, Canada.
RMC
in India
The concept of RMC came to India in 1950’s and was well
used in hydro projects at Ramganga Dam and Yamuna Project in UP( 1969 – 1976) and other states. IS: 2946 was published in 1968 for RMC
(The first commercial ready-mixed concrete (RMC) facility in
India was set up in 1992.
Ready Mixed Concrete Manufacturers’ Association (RMCMA) was established in 2002 for QA/QC certification , technical audit & regulatory framework.
RMCMA had introduced audit-based Quality Scheme for Ready Mixed Concrete in December 2008. Later, the scheme came under the joint ownership of RMCMA & QCI.
The scope of the scheme was further changed and it is now
jointly managed by the Quality Council of India (QCI) and
Building Materials & Technology Promotion Council (BMTPC) under the Ministry of Housing and Urban Poverty Alleviation, Government of India.
Jointly these parties are working as third-party organization.
The Purchaser- First Party
RMC facility operator – Second party
MTPC & QCI – Third Party
IS 4026 code was first published in 1968 and was
subsequently revised in 1976 and 2003 (Reaffirmed in 2017)
for the RMC use in
India.
Indian Standard RMC Code
The Indian
Standard READY-MIXED CONCRETE — CODE OF PRACTICE (Second Revision) IS:4926 -
2003 , Reaffirmed in 2017 considers the following points for RMC : ( excerpts from the code)
Rationalization
of definitions and addition of definitions for more terms.
Requirements
for materials brought in line with IS 456:2000 ‘Plain and reinforced concrete —
Code of practice’.
Minimum
testing frequencies introduced for aggregates and water.
Basis of
supply modified to bring it in line with IS 456:2000 ‘Plain and reinforced
concrete — Code of practice’.
Transportation
time made uniform to 2 hours.
Requirement
of temperature of concrete deleted.
Sampling
procedure has been modified.
Tolerance
limits for workability have been modified.
A clause on
non-compliance has been included.
A detailed
clause on production and delivery including plant safety and maintenance and
environmental considerations has been included.
A detailed
clause on quality control has been included.
A detailed
clause on order processing and training has been included.
Detailed
provisions on calibration and weighing equipment accuracy has been introduced
as Annex E, in the code.
The provisions in the code are supported from the good
practices and as such it should be endeavored to remain in
touch with the good practices being followed to date
elsewhere.
Summery Points on RMCC
RMC is a
concrete mixed at central place and transported to required pour sites.
The history
search for RMC says it was patented in 1903 (GERMANY), developed for commercial
use in USA from 1917 to 1926, and around 1930 it was used for construction
practices in European countries.
Concrete is
heterogenous product, but as the particle size of coarse aggregates reduces the
homogeneity of concrete increases.
Concrete
contents include Cement & SCM, CA, FA, Water and Chemical Admixtures
RMC production control agencies exists the world
over.
In India,
RMC was in use at state level after 1950. And IS 4926: 1968 provided the
necessary guidelines.
In India
RMCMA along with QCI and BMTPC provide RMC for commercial use now.
The Indian
Standard READY-MIXED CONCRETE — CODE OF PRACTICE (Second Revision) IS:4926 -
2003, Reaffirmed in 2017 provides necessary guidelines.
RMC Ready Mix Concrete
QA Quality Assurance
QC Quality Control
UHPC Ultra High-Performance
Concrete
O&M Operation and
Maintenance
IS Indian Standard
BMTPC Building Material and
Technology Promotion Council
QCI Quality Council of India
RMCMA Ready mix Concrete
Manufacturer’s Association – India
FA Fine Aggregates
CA Coarse Aggregates
SCM Supplementary
Cementitious Material
The
available framework for RMC, shall boost the confidence of purchaser, for a
better-quality RMC.
