Rmc

“Ready mix concrete is concrete whose components are proportioned away from the construction site for delivery to the construction site by the truck in a ready-to-use-condition.”

In 1909, the residents of Sneridan, Wyoming could have witnessed the birth of Ready Mix concrete industry.

Prior to World War I, concrete was produced in stationery plant mixer hauled to construction sites in dumps trucks.

In India RMC was first initially was used in 1950 during the construction sites of Dams like like BhakraNangal, Koyna. At the construction the transportation of concrete is done by either manually or mechanically using ropeways &buckets or conveyor systems.

Transit Mixer in late 1950’s

Requirement for higher grades of concrete

Correct accountability ingredients

Rapid development of infrastructure industry

Increased demand of concrete

Possibility of manufacture of desired grades

Mega project demands higher output

Timely supply of reliable concrete

Raw Materials are:-

1. Water

2. Additives

3. Cement

4. Aggregate

5. Air

Aggregates, which make up roughly 60% to 75% of ready mix concrete’s volume, are obtained from quarries and aggregate banks.

Additives are solid or liquid chemical substance that can be added to readymix concrete before or during preparation.

·Most commonly used additives either improve a hardened concrete’s durability or reduce a concrete’s water content in an effort to shorten setting times.

No others material rivals cement’s important in the mix; it’s the ingredient that gives concrete its strength.

The most widely used cements are gray Portland type 1 and PozzolonaPortland type 2.

Following are the equipment’s required in R.M.C

1. Batching plant

2. Silos

3. Belt Conveyor

4. Transit mixer

Batching plants are classified as

1. Manual

2. Semiautomatic

3. Fully automatic

While transporting concrete to a site, the cement mixer never stops revolving at a speed of two to six rotations per minute.

PHASE TIME PERIOD

IN YEARS

CEMENT

CONSUMPTION

IN %

VOLUME OF

R.M.C PER

YEAR

PHASE I 1992-2010 5-10% of cement

consumption

20 million cubic

meter/RMC/year

PHASE II 2020-2050 20-25% of cement

consumption

70 million cubic

meter/RMC/year

PHASE III 2050 Onwards 25-40% of cement

consumption

100 - 150 million

cubic

meter/RMC/year

Quality assurance

Elimination of manual errors

Mass production of concrete possible

Water cement ratio maintained

Reduced material wastage

Labour cost saved

Design mix as per IS standards resulting in standard deviation and improved characteristics.

The materials are batched at a central plant, and the mixing begins at that plant

Generation of additional road traffic; furthermore, access roads, and site access have to be able to carry the weight of the truck and load.

Concrete's limited time span between mixing and going-off