Advance Construction

TechnologyPrepared By:Darshan Parakhiya (IU1551190008)

Guided By:Prof. Umang Sheth

Ready Mix Concrete

Contents

• Introduction• Background• Components• Material used in RMC• Application of RMC• Advantages & Limitations of RMC• Research paper• Case study• Comparison • Conclusion

Introduction• As per the Indian Standard Specification IS

4926:2003,”Concrete mixed in a stationary mixer in a central batching and mixing plant or in a truck-mixer and supplied in fresh condition to the purchaser either at the site or into the purchaser’s vehicles.”

• Ready-mix concrete (RMC) is a ready-to-use material, with a predetermined mixture of cement, sand, aggregates and water.

• RMC is a type of concrete manufactured in a factory according to a set recipe or as per specifications of the customer, at a centrally located batching plant.

• Most of ready mixed concrete is currently manufactured under computer controlled operations and transported and placed at project sites using sophisticated equipment and methods.

Background

• The Idea of Ready Mix Concrete (RMC) was first introduced in Germany in 1903.

• In India RMC was first time used for Bhakhranagal Dam Project in 1953

• The first concrete mixed off site and delivered to a construction site was done in Baltimore, United States in 1913.

• The first RMC Plant was setup in Pune, India in 1993.

Components of RMC Plant

• Batching Plant: Inline Bins oRaw materials like fine &

coarse aggregates are stored in bins called as “INLINE BINS” where the trucks carrying fine and coarse aggregate can dump the material easily.

Silos oCement & Fly ash are stored in an

airtight container called as “Silos”. The required quantity of cement & fly ash is extracted by the silos.

Screw Conveyer Belt oCement and Fly ash are fed to

holding hopper with the help of a screw conveyer. A heavy duty cement screw conveyor is fixed in an inclined position to convey the cement from Manual Feeding Hopper to Cement Hopper.

Type of Batching plants As per BIS 4926-2003• CP 18 – 16cum/hr . • CP 30 – 30cum/hr . • M1 - 56cum/hr . • M3 - 64cum/hr

• Transit Mixers • Transit mixers are made to transport and mix concrete up

to the construction site. The discharge of concrete is done from rear side of the Transit mixer.

• Concrete Pumps • A concrete pump is a machine

used for transferring liquid concrete by pumping.

• Vibrator • A vibrator is a mechanical

device to generate vibrations to remove the air voids in concrete and for proper compaction of concrete.

PLANT LAYOUT

BATCHING PLANT

Transit Miller

Material used in RMC

• Aggregate• Coarse Aggregate• Fine Aggregate

• Cement• Fly ash• Water

AGGREGATE :• Aggregates are the important materials in concrete. They

give body to the concrete, reduce shrinkage and effect economy. The mere fact that the aggregates occupy 70-80 % 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.

CEMENT :• Cement is a binder material which sets and hardens

independently, and can bind other materials together.• Cement is made up of four main compounds,

• Daicalcium Silicate (2CaO SiO2),• Tricalcium silicate (3CaO SiO2),• Tricalcium aluminate (3CaO Al2O3),• Tetra-Calcium aluminoferrite (4CaO Al2O3 Fe2O3).

• 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.

FLY ASH :• The coal used in plants is mainly composed of combustible

elements such as carbon, hydrogen and oxygen and non combustible impurities (10 to 40%) usually present in the form of clay, shale, quartz, feldspar and limestone.

• The size of fly ash ranges from 1.0 to 100 micron & the average size is around 20 microns.

WATER :• The pH value of water should be in between 6.0 and 8.0

according to IS 456-2000.

Application of RMC• Foundation• Building• Highway• Bridge• Walkway• Retaining• Airport• Tunnels

• Canals• Pile Foundation• Water tank• Shear wall• Kerb• Dams• Power Plant

Advantages of RMC• Better quality concrete is produced. • Elimination of storage space for basic materials at site. • Elimination of Hiring 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. • No wastage on site • Environment friendly

Limitations 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 the vehicle creates a problem if the

proper dose of admixture is not given. • Labours should be ready on site to cast the concrete in

position to vibrate it and compact it. • Concrete's limited time span between mixing and going-off

means that ready-mix should be placed within 90 minutes of batching at the plant.

Research Paper

Title : Manufacturing of concrete from ready mix concrete plantAuthors : D.V.Sweta, V.V.S.Sravankumar, Dr.K.RajashekarSubjects : Manufacturing, CostKeywords : Concrete, Fly Ash, aggregates, Super Plasticizer, durability and Compressive StrengthPublication Date : 11, November-2014

Abstract• This paper summarizes the results of various physical properties

conducted on the aggregates, cement, fly ash, concrete and the effect of replacement of cement by fly ash (15%, 20% and 30%) on the compressive strength to provide sound concrete for the purpose of utilization in various civil engineering constructions like buildings, dams, bridges etc. Our study includes the mix designs of fly ash blended concrete and compressive strength test on concrete cubes to know the performance of the concrete.

• It is the material of choice where strength, durability, impermeability, fire resistance and abrasion resistance are required. Several design mixes were prepared, cured and tested for compressive strength properties.

• The results are analysed and compared with standard concrete and conclusions made on how best the fly ash can be utilized to give optimum results. The results indicate that, as the total replacement level of OPC in concrete using blend of OPC + FA increases, the strength with respect to control mix increases up to certain replacement level and thereafter decrease.

Case study• Company : RIM Concrete PVT. Ltd., Rajkot.• Client : Takshal Devlopers,

SHREENATHJI Tower, Kalawad Road, Rajkot.

• Work : Concreting of 75’*62’*4” Slab Required Transit Miller : 14 nos.

• Duration : 1 day

Comparison between RMC & Site Mix Concrete

Consistent Quality- concrete is made in high tech batching plants in a computerized environment.

Quality is inconsistent because concrete is hand mixed.

Construction in double quick time. Manual mixing is time consuming. Projects take longer time to finish.

There’s no worry about to stock materials and watch over them.

Risk of pilferage of raw materials is high. Housekeeping could be poor due to piles of stocks lying at the site

Large quantities of concrete can be ordered. Takes more time. Repeated mixing needs to be done for large quantities as the mixer will be too small to handle the requirement.

No wastage of raw materials at site. Everything is pre-mixed at RMC plants, based on Client’s needs.

High wastage of raw materials due to manual mixing.

No hassle of managing labor on site. Involves the use of laborers for mixing the concrete on site. Management of labor means more time, efforts and money.

Safe work practices – no disruption in the schedule.

Highly unsafe. Unskilled and untrained laborers may work carelessly resulting in dangerous working condition

Conclusion• Ready Mix Concrete is a modern technique of production of

concrete in large quantities away from the actual site of placing.

• RMC is very useful in cities where demand of concrete is very high and construction sites are in congested areas, where mixing on site is not possible.

• The Supervisory and labour costs associated with production of RMC is less, and the quality of concrete is high.

• RMC is suitable for huge industrial and residential projects where time plays a vital role.

Thank You !!!