Mordern Concrete RMC With Photos

8/3/2019 Mordern Concrete RMC With Photos

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Ready Mix ConcreteReady Mix ConcreteByBy

ErEr.N..N.KalidossKalidoss B.Tech.B.Tech.


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Ready Mix ConcreteReady Mix Concrete

A concrete whose constituents are weigh batched at aA concrete whose constituents are weigh batched at acentral batching plant, mixed either at the plant itselfcentral batching plant, mixed either at the plant itselfor in truck mixers, and then transported to theor in truck mixers, and then transported to theconstruction site and delivered in a condition ready toconstruction site and delivered in a condition ready to

use, is termed as READY MIXEDuse, is termed as READY MIXEDCONCRETE(RMC)CONCRETE(RMC)

Enables the places of manufacture and use of concreteEnables the places of manufacture and use of concretebeing separated and linked by suitable transportbeing separated and linked by suitable transport

operationoperation..


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ApplicationsApplications

This technique is useful in congested site orThis technique is useful in congested site or

diverse work Places and saves the consumerdiverse work Places and saves the consumerfrom the botheration of procurement, storagefrom the botheration of procurement, storage

and handling of concrete materialsand handling of concrete materials

Ready mix concrete is produced under factoryReady mix concrete is produced under factory

conditions and permits a close control of allconditions and permits a close control of all

operations of manufacture and transportation ofoperations of manufacture and transportation offresh concretefresh concrete


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SPECIFICATIONSSPECIFICATIONS

Quality of ready mix concrete is generallyQuality of ready mix concrete is generallyspecified in terms of two systemsspecified in terms of two systems

Performance parametersPerformance parameters

Prescriptive specificationPrescriptive specification


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Performance parametersPerformance parameters

It is the best way to order ready mixed concreteIt is the best way to order ready mixed concrete

because RMC producer, who is expert in thebecause RMC producer, who is expert in the

field, would design an economical mix with thefield, would design an economical mix with the

desired propertiesdesired properties

The RMC producer accepts the responsibility forThe RMC producer accepts the responsibility for

the design of the mixture for the desiredthe design of the mixture for the desiredperformanceperformance


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Perspective SpecificationsPerspective Specifications

Purchaser specifies aggregate size, slump,Purchaser specifies aggregate size, slump,

air content, cement content, or weight ofair content, cement content, or weight ofcement per cubic meter of concrete,cement per cubic meter of concrete,maximum water content and admixturesmaximum water content and admixtures

requiredrequired..

The purchaser accepts the responsibilityThe purchaser accepts the responsibility

for concrete strength and its performance.for concrete strength and its performance.


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ORDERING OF CONCRETEORDERING OF CONCRETE RMC is ordered and supplied by volumeRMC is ordered and supplied by volume

(cum) in a freshly mixed and unhardened(cum) in a freshly mixed and unhardenedstatestate

When ordering concrete, 5 to 10 percentWhen ordering concrete, 5 to 10 percentmore concrete than estimated from amore concrete than estimated from avolumetric calculation is orderedvolumetric calculation is ordered

This will account for the wastage, overThis will account for the wastage, overexcavation, spreading of forms, some ofexcavation, spreading of forms, some ofloss of entrained air, settlement of wetloss of entrained air, settlement of wet

mixture and change in volumemixture and change in volume


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PROPORTIONING OF RMCPROPORTIONING OF RMC

The proportioning of an RMC aims atThe proportioning of an RMC aims at

obtaining the properties, such asobtaining the properties, such asworkability, strength, durability andworkability, strength, durability andappearanceappearance

The following basics of a good concrete mix shouldThe following basics of a good concrete mix should

be considered while proportioning RMCbe considered while proportioning RMC

Concrete aggregates should be clean,Concrete aggregates should be clean,strong and durable.strong and durable.


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PROPORTIONING OF RMCPROPORTIONING OF RMC

Fly ash or other supplementaryFly ash or other supplementarycementitiouscementitious materials added tomaterials added toRMC, which enhance concreteRMC, which enhance concrete

propertiesproperties

Admixtures are commonly used toAdmixtures are commonly used to

improve the rate of setting andimprove the rate of setting andstrength of development of concretestrength of development of concrete


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Production of RMCProduction of RMC

There are three principal categories of RMCThere are three principal categories of RMC

Transit Mixed ConcreteTransit Mixed Concrete

Shrink Mixed ConcreteShrink Mixed Concrete

Central mixed concreteCentral mixed concrete


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TRANSIT MIXED CONCRETETRANSIT MIXED CONCRETE

It is also called truck mixed or dry batchedIt is also called truck mixed or dry batchedconcreteconcrete

All the ingredients are charged directly inAll the ingredients are charged directly inthe truck mixer .the truck mixer .

Most of the water usually batched at theMost of the water usually batched at theplantplant


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There are three options for truck mixedThere are three options for truck mixedconcreteconcrete

Concrete mixed at the job site:Concrete mixed at the job site:

Concrete mixed in the yard or centralConcrete mixed in the yard or central

batching plantbatching plant

Concrete mixed in transit:Concrete mixed in transit:


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Concrete mixed at the job site:Concrete mixed at the job site:

While traveling to the job site the drum isWhile traveling to the job site the drum is

turned at agitating speed (slow speed).turned at agitating speed (slow speed).

After arriving at the job site, the concreteAfter arriving at the job site, the concrete

is completely mixed. The drum is thenis completely mixed. The drum is thenturned for 70 to 100 revolutions, or aboutturned for 70 to 100 revolutions, or about5 minutes, at mixing speed.5 minutes, at mixing speed.


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TRANSIT MIXED CONCRETETRANSIT MIXED CONCRETEConcrete mixed in the yard or centralConcrete mixed in the yard or central

batching plantbatching plant

The drum is turned at high speed or 12The drum is turned at high speed or 12--1515

rpm for 50 revolutions.rpm for 50 revolutions.

This allows quick check of batch. TheThis allows quick check of batch. The

concrete is then agitated slowly whileconcrete is then agitated slowly whiledriving to the job sitedriving to the job site


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Concrete mixed in transit:Concrete mixed in transit:

The drum is turned at medium speedThe drum is turned at medium speed

or about 8 rpm for 70 revolutionsor about 8 rpm for 70 revolutionswhile driving to the job site. .while driving to the job site. .


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SHRINKSHRINK -- MIXED CONCRETEMIXED CONCRETE

Concrete that is partially mixed in a stationaryConcrete that is partially mixed in a stationary

plant mounted mixer and then discharged intoplant mounted mixer and then discharged into

the drum of truck mixer for completion ofthe drum of truck mixer for completion ofmixingmixing feelingfeeling


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CENTRALCENTRAL-- MIXEDMIXED

CONCRETECONCRETE

Central mixed concrete batch plants include aCentral mixed concrete batch plants include a

stationary, plant mounted mixer that mixes thestationary, plant mounted mixer that mixes the

concrete before it is discharged into a truck mixerconcrete before it is discharged into a truck mixer

TypesTypes--Tilt drum mixer, horizontal shaft paddle mixer,Tilt drum mixer, horizontal shaft paddle mixer,

pan mixer, and slurry mixer.pan mixer, and slurry mixer.


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MIX MOBILESMIX MOBILES

MixMix-- mobile plants or plantsmobile plants or plants--on wheels are truckon wheels are truckmounted, volumetric batching and continuous mixingmounted, volumetric batching and continuous mixingunits which often supply small volume or specialtyunits which often supply small volume or specialty

pourspours

Offer the convenience of freshly mixed concrete inOffer the convenience of freshly mixed concrete in

fairly prcised quantities.fairly prcised quantities.


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DELIVERY OF RMCDELIVERY OF RMC

Ready mix concrete can be delivered to theReady mix concrete can be delivered to theconstruction site in truckconstruction site in truck-- mounted, rotatingmounted, rotating

drum mixersdrum mixers..

Truck mixers have a revolving drum with theTruck mixers have a revolving drum with the

axis inclined to horizontalaxis inclined to horizontal..

To load or charge the raw materials from aTo load or charge the raw materials from a

transit mixed plant or central mixed plant intotransit mixed plant or central mixed plant intothe truck, the drum must be turned very fast inthe truck, the drum must be turned very fast inthe changing direction.the changing direction.


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DELIVERY OF RMCDELIVERY OF RMC

After the concrete is loaded and mixed, itAfter the concrete is loaded and mixed, it

is normally hauled to the job site with theis normally hauled to the job site with thedrum turning at the speed of less than 2drum turning at the speed of less than 2

rpm. .rpm. .

The truck mixer having front dischargeThe truck mixer having front discharge

units are more popular than the traditionalunits are more popular than the traditionalone having rear discharge unitsone having rear discharge units


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INSPECTION AND TESTINGINSPECTION AND TESTING

Since RMC is a manufactured product, specificSince RMC is a manufactured product, specific

control tests and evaluations are required duringcontrol tests and evaluations are required during

the manufacturing process to producethe manufacturing process to produce

predictable high quality concretepredictable high quality concrete

Some of the important properties of concreteSome of the important properties of concretethat are measured by basic quality control teststhat are measured by basic quality control tests

are strength,temperature,slump, air content,are strength,temperature,slump, air content,and unit weightand unit weight


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INSPECTION AND TESTINGINSPECTION AND TESTING

Concrete producer to agree to supplyConcrete producer to agree to supply

concrete in accordance with relevantconcrete in accordance with relevantnational codes.national codes.

Any agreement between the producer andAny agreement between the producer anda purchaser should include definition ofa purchaser should include definition of

the basis of purchase.the basis of purchase.


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THANK YOUTHANK YOU

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Mordern Concrete RMC With Photos