ready mix concrete
TRANSCRIPT
Ready Mix Concrete
MADE BY-MD. RAFI SAJJADSTUDENT AT CIVIL & ENVIRONMENTAL ENGINEERING DEPT .ISLAMIC UNIVERSITY OF TECHNOLOGY (IUT).
READY MIX CONCRETE PLANT
Ready Mix Concrete - Definition
“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.”
History
The first concrete mixed off site and delivered to a construction site was effectively done in Baltimore, United States in 1913 just before the Fist World War.
The first concept of transit mixer was also born in 1926 in the United States.
In 1939, the first RMC plant was installed in United Kingdom and in 1933 first specification on RMC was published in United Kingdom.
Transit Mixer in late 1940’s
• In Bangladesh RMC was first used in 1993 by CONCORD.
• RMC was successfully established sometime after 1998 in Bangladesh, especially at Dhaka and Chittagong.
• As per the available record up to 2010, there are around 76 RMC plant major cities with a total capacity of around 1200 CuM/hr, producing 1.8 million cubic meter of concrete per year.
History
READYMIX CONCRETE FACTORY IN BANGLADESH
The Ready-Mix concrete producing companies in Bangladesh are as follows:•Navana RMC •Amin Mohammad Foundation •Bestec Ltd. •BDCL. Concord Ready-Mix & Concrete Products Ltd. •MIR concrete products Ltd. •Advanced Development & Technology Ltd. •Bashundhara Technology Ltd •ABC Ltd. •GBB (Gulbox Bhuiyan Ltd). •Abdul Monem Ltd.•Crown Readymix•Sah Readymix•Sana Kalyan songstha Readymix•NDE Readymix
Need for Ready Mix concrete
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
By using RMC it is possible to increase work speed manifold as an RMC plant can produce around 30,000 cft of concrete a day, while a traditional mixture machine can hardly produce 1,000 cft of paste.
RMC Manufacturing
• Aggregates
• Additives
• Water
• Cement
• Air
Raw material used to produce concrete
AggregatesAggregates, which make up roughly 60% to 75% of ready-mix concrete’s volume, are obtained from quarries and aggregate banks.
AdditivesAdditives are solid or liquid chemical substances that can be added to ready-mix 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.
WaterThis is the mix’s vital fluid, which sets of a chemical reaction when it comes into contact with the cement.
RMC Manufacturing
CementNo other material rivals cement’s importance in the mix; it’s the ingredient that gives concrete its resistance. Although types II and IV are also employed, the most widely used cements are gray Portland type I and Pozzolana Portland type C-2.
Concrete mixingDuring the mixing phase the different components come together to produce a uniform mass of concrete. Mixing time is registered from the moment material and water are poured into the cement mixer, and it begins rotating.
RMC Manufacturing
While transporting concrete to a site, the cement mixer never stops revolving at a speed of two to six rotations per minute.
After producing ready mix concrete, utmost care must be given to the quality of concrete during transportation to the site. The following factors for transportation should be kept in mind:
Travel distance: Since the concrete setting time is very much related to the time, so time distance between loading and pouring is very much important. For Dhaka city, it is very much important because of too much traffic jam and broken and dame road. Large travel time may hamper the quality of concrete.Transit mixers: These are the vehicles which carry ready mix concrete from bathing plant to site. So every transit mixers should be in good condition and tested before carrying.
RMC Manufacturing
Weather condition: As a tropical country weather is a considerable factor for transportation of ready mix concrete. Mainly in summer season ready mix concrete should be transported with caution.
Ready Mix Concrete vs.
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.
Ready Mix Concrete vs.
Site Mix Concrete
Ready Mix Concrete vs.
Site Mix Concrete
You don’t have to stock materials and watch over them. There’s no worry about pilferage as the concrete is directly supplied to your site when you need it.
Risk of pilferage of raw materials is high. Housekeeping could be poor due to piles of stocks lying at the site
Ready Mix Concrete vs.
Site Mix Concrete
Raw materials are chosen after strict quality checks
Quality of raw materials is manually checked. Or not checked at all.
Ready Mix Concrete vs.
Site Mix Concrete
Large quantities of concrete can be ordered. This allows you to upgrade yourself and handle projects of any size.
Takes more time. Repeated mixing needs to be done for large quantities as the mixer will be too small to handle the requirement.
Ready Mix Concrete vs.
Site Mix Concrete
No wastage of raw materials at your site. Everything is pre-mixed at our plants, based on your needs.
High wastage of raw materials due to manual mixing.
Ready Mix Concrete vs.
Site Mix Concrete
No hassle of managing labour on site. We supply ready-to-use concrete. Our well-equipped technical crew will handle the pouring and patching of concrete at the site.
Involves the use of labourers for mixing the concrete on site. Management of labour means more time, efforts and money.
Ready Mix Concrete vs.
Site Mix Concrete
Safe work practices – no disruption in your schedule.
Highly unsafe. Unskilled and untrained labourers may work carelessly resulting in dangerous working condition
Disadvantages Of Ready Mix Concrete
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
In general, the use of Ready mix concrete is beneficial to users from all angles: Better quality Higher speed Better durability and savings in labor .
CONCLUSION
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