READY MIX CONCRETE

READY MIX CONCRETE
INTRODUCTION
HISTORY
OBJECTIVES
READY MIX CONCRETE VS SITE MIX CONCRETE
MATERIALS REQUIRED
AGGREGATE
CEMENT
WATER
ADMIXTURES
EQUIPMENTS REQUIRED:
Silos
Mixers
Tilting drum mixer
Pan mixer
Twin shaft mixer
Control Room
Aggregate Batcher
Conveyors
GRADES OF CONCRETE
RATIOS OF CONCRETE MIX
MAINTAIN THE QUALITY OF CONCRETE
Advantages of Ready-Mix Concrete
Disadvantages of Ready-Mix Concrete
TRANSPORTATION
TRANSIT MIXED CONCRETE
CENTRAL MIXED CONCRETE
SHRINK MIXED CONCRETE
MARKET SURVEY

1. READY MIX CONCRETE

2. INTRODUCTION Ready-mix concrete (RMC) is a ready-to-use material, with predetermined mixture of cement, sand, aggregates and water. The Idea of Ready Mix Concrete (RMC) was first introduced by Architect Jurgen Heinrich Magens , he got his patent of RMC in Germany in 1903. It is manufactured in a cement factory, or specifically known as the batching plant , according to a given set of proportions, and then delivered to a work site, by truck mounted with mixers. This results in a precise mixture, allowing specially developed concrete mixtures to be implemented on construction sites. Each batch of ready-mixed concrete is tailor-made according to the specifics of the contractor and is delivered to the contractor in a plastic condition, usually in the cylindrical trucks often known as "cement mixers”. 2 RMC being delivered to a site and put to work

3. INTRODUCTION The increasing availability of special transport vehicles, supplied by the new and fast growing automobile industry, played a positive role in the development of RMC industry. Ready mix concrete is sometimes preferred over on-site concrete mixing because of the volume it can produce with precision of proportion of mixtures and also due to reduced work site confusion. RMC is manufactured under controlled operations. The performance of a concrete mix can be altered by use of admixtures. Concrete has a limited lifespan between batching / mixing and curing. This means that ready-mixed concrete should be placed within 30 to 45 minutes of batching process. It has a long life span on use, when compared to other products of a similar use, like road ways. 3 A mini Ready-mix Concrete plant

4. HISTORY Ready mix concrete was first patented by the German architect Jurgen Heinrich Magen in 1903. Despite this discovery, attempts to supply the building trade did not take off until the late 1920’s. This was successfully achieved by the new range of used trucks which were fitted with a drum to move the concrete during transportation. The first ready mix company to set up in the UK took place in 1930, and it was only later on in the 1960’s that a successful network of concrete firms had established themselves in the construction industry. In India Ready Mix concrete plant was launched in 2010. Lack of proper manuals, higher initial costs than conventional site mixed concrete, high initial investments for installation of automatic batching plants and also lack of awareness were the major causes that led to an initial set back to Ready Mix concrete industry. But in India about 3% of the total cement produced is utilized in Ready Mix concrete plant against 70% of the cement produced being utilized in UK and US. In today’s construction market, read ymix concrete is used on a daily basis. The professional services of Base Concrete are used for the specialist and quality concrete mixes which are produced. 4 For construction companies, ready mix concrete reduces labor costs and increases the amount of space they have on-site.

5. OBJECTIVES To produce better quality of concrete Elimination of storage space for basic materials at site. Elimination of Procurement / Hiring of plant and machinery. To avoid wastage of basic materials.

6. READY MIX CONCRETE SITE MIX CONCRETE Consistent Quality – concrete is made in high tech bathing plants in a computerized environment. Quality is inconsistent – because concrete is hand mixed. Construction is double quick time. Manual mixing is time consuming. Projects take longer time to finish. Raw materials are chosen after strict material check. Quality of raw material is manually checked, or not checked at all. Large quantities of concrete can be ordered. This allows to handle projects of any size. Takes more time. Repeated mixing needs to be done for large quantities a the mixer will be too small to handle the requirement,. No wastage of raw materials at site. Everything is premixed at plants, based on the needs. High wastage of raw material due to manual mixing. No hassle of managing labour on site. Involves the use of labourerd for mixing of concrete on site. There is no worry about pilferage. Risk of pilferage of raw materials is high.

7. 7 MATERIALS AGGREGATE ADMIXTURE CEMENT WATER COARSE FINE MINERAL CHEMICAL MATERIALS REQUIRED

8. 8 8 AGGREGATE :- FINE AGGREGATE:- Aggregate whose size is 4.75 mm and less is considered as fine aggregate. COARSE AGGREGATE:- The size of the aggregate bigger than 4.75 mm is considered as coarse aggregate. CEMENT:- OPC (ORDINARY PORTLAND CEMENT):- Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum. PPC(PORTLAND POZZOLANA CEMENT):- PPC cement is generally used for plastering, brick masonry and waterproofing works.  PPC has a lower heat of hydration and it is prone to fewer cracks compared to OPC.  PPC has lower strength than OPC but PPC provides better workability and finishing than OPC. WATER:- The pH value of water should be in between 6.0 and 8.0 according to IS 456-2000.

9. 9 9 ADMIXTURES :- CHEMICAL ADMIXTURES:- Air-entraining admixtures (mainly used in concrete exposed to freezing) Water-reducing admixtures, plasticizers (reduce the dosage of water while maintaining the workability) Retarding admixtures (mainly used in hot weather to retard the reaction of hydration) Accelerating admixtures (mainly used in cold weather to accelerate the reaction of hydration) Super plasticizer or high range water-reducer (significantly reduce the dosage of water while maintaining the workability) NATURAL ADMIXTURES:- The fly ash is generally used in the concrete in the following ways. As partial replace for cement. As partial replacement for sand. As simultaneous replacement for both cement and sand.

10. EQUIPMENTS REQUIRED: Silos:- Cement and fly ash are stored in a airtight container called Silos. The required amount of cement and fly ash is extracted by the silos. Due to the sensitivity of cement and the cement supplement to moisture, this is always an enclosed system. Silo Diameter is 2800/3200/3500 mm. Shell Thickness 5 mm Bottom Cone Section 6 mm Thick Top Shell in 5 mm Thick.

11. EQUIPMENTS REQUIRED: Mixers:- The center of the concrete batching plant is the mixer. There are three types of mixer: - Tilting drum mixer:- They are fast and efficient, but can be maintenance-intensive since they include several Moving parts that are subjected to a heavy load. Pan mixer Pan mixers are generally lower capacity mixers at about 4 to 5 yd3 and are used at precast concrete plants. Twin shaft mixer The twin shaft mixer can ensure an even mixture of concrete and large output with high quality. It consist of mixer, with Counter rotating shafts, delivers fast mixing action and rapid discharge. Tilting Drum Mixer Pan Mixer Twin Shaft Mixer

12. EQUIPMENTS REQUIRED: Control Room:- The programmable controller can control the production process with high reliability and stability. It can control the unloading ingredients, mixing and automatic control of the whole process of the concrete. Aggregate Batcher:- The aggregate batching system includes aggregate supply system, weighing system and electrical control system. The feeding device is driven by conveyor belt. Conveyors:- Conveyor Systems are mechanical devices or assemblies that transport material with minimal effort. While there are many different kinds of conveyor systems, they usually consist of a frame that supports either rollers, wheels, or a belt, upon which materials move from one place to another.

13. A B C D E F G H I J K L M N O P Aggregate Delivery Aggregate receiving hopper Aggregate Storage Conveyor Belt Cementitious material Storages Weigh Hopper Cement Delivery Mixer Admixtures Ready Mix Truck With Returned Concrete Recycled Water Reclaimed Aggregates Pump Water Storage Concrete Loaded in Ready Mix Truck Control Room

14. GRADES OF CONCRETE Source

15. 15 Classification Grade RATIOS OF CONCRETE MIX Applications Ordinary M10 1:3:6 PCC (Plain Cement Concrete) e.g. Levelling course, bedding for footing, concrete roads, etc. M15 1:2:4 PCC e.g. Levelling course, bedding for footing, concrete roads, etc. M20 1:1.5:3 RCC (Reinforced Cement Concrete) e.g. Slabs, beams, columns, footings, etc. (for mild exposure) Standard M25 1:1:2 RCC (Reinforced Cement Concrete) e.g. Slabs, beams, columns, footings, etc. M30 1:0.75:1.5 RCC e.g. Slabs, beams, columns, footings, etc. M35 1:0.5:1 RCC e.g. Slabs, beams, columns, footings, etc. M40 1:0.25:0.5 RCC e.g. Pre-stressed concrete, slabs, beams, columns, footings, etc. M45 As per Mix Design RCC e.g. Runways, Concrete Roads (PQC), Prestressed Concrete Girders, RCC Columns, Prestressed beams. M50 As per Mix Design RCC e.g. Runways, Concrete Roads (PQC), Prestressed Concrete Girders, RCC Columns, Prestressed beams. M55 As per Mix Design RCC e.g. Prestressed Concrete Girders and Piers. High Strength M60 - M80 As per Mix Design RCC work Where high compressive strength is required such as high rise buildings, long span bridges, ultra-thin white topping, etc. and constructions in aggressive environment e.g. Spillways of dams, coastal construction.

16. TO MAINTAIN THE QUALITY OF CONCRETE : Ready-mix trucks, used for transportation of concrete should clean prior to loading each time. The compression machine which used to finding out compressive strength should be checked regularly. To ensure the quality of all materials used in the production of R.M.C. They should test for size, shape, cleanliness, density, and moisture content. Sieve analysis on all aggregates and sands performed regularly to ensure particle size distribution. During the transportation of RMC from plant to site, The drum should agitate to  avoid  the setting of concrete. Depends upon the lead distance, if the time elapsed between plant and site more, than some admixtures should add in concrete to increase the setting time. The labor used at the site and with a truck should be skilled. Concreting is an intermittent process, so as there should be the availability of concrete without break.

17. APPLICATIONS Ready mix concrete can be used for a vast array of applications including: C ivil engineering projects R oad developments Foundations Bridges Walls F loors & bases Driveways F ootpaths. Any type of construction that requires a durable material can benefit from the strength and convenience of ready mix concrete.

18. 18 Ready Mix Concrete (RMC) allows speedy construction through programmed delivery at site, mechanized operation with consequent economy. RMC reduces the labor cost and site supervising cost. RMC comes with consistency in quality through accurate & computerized control of sand aggregates and water as per mix designs. Production of RMC helps in minimizing cement wastage due to bulk handling. Production of RMC is relatively pollution free. Environment-friendly. Reduced project time resulting in savings in all aspects. Proper control and economy in use of raw material resulting in saving of natural resources. Better quality concrete is produced as it is made from consistent methods and in advanced equipment. No need to store construction materials at the site. No delays in completing major projects like constructing dams, roads, bridges, tunnels, etc. Safe work practices - No disruption in the project schedules. Advantages of Ready-Mix Concrete

19. 19 Disa dvantages of Ready-Mix Concrete Requires huge initial investment. Not suitable for small projects (less quantity of concrete is required). Need an effective transportation system from the batching plant to the job site. Labor should be ready at the site to cast the concrete in position without any delay to avoid slumps in the mixture. Concrete has limited time and should be used within 210 minutes of batching the plant. Traffic jam or breakdown of the vehicle can create a problem. It will generate additional road traffic. Generally, Ready Mix Trucks are large in size and may cover lot of area in the road blocking other traffic.

20. TRANSPORTATION   Ready Mixed Concrete shall be transported from the mixer to the point of placing as rapidly as possible and practicable by methods that will maintain the workability and will prevent segregation loss of any constituents or ingress of water or foreign matter. The concrete shall be delivered at the site of work and discharge shall be completed with-in Two hours of adding mixing water to the dry mix of cement and aggregate. Before the delivery of concrete produced in Ready Mixed Plant/ captive Batching Plant it is the responsibility of the producer to ensure that each truck mixer is inspected to confirm its compliance with the requirements.

21. MIXING PROCESS

22. 22 TRANSIT MIXED CONCRETE In  transit mix concrete , all of the raw ingredients are loaded directly into the truck mixer. No plant mixer is involved. Some or all of the mixing water is usually introduced at the plant. The mixer drum is rotated at charging speed during loading. 1. In Transit Mixing, the dry materials are proportioned at the RMC plant, the water being added & the mixing done in route to the job in a truck mixer, which essentially consists of a mixer drum mounted on a conventional chassis. 2. Power for rotating the drum is obtained either from the truck engine or from an independent petrol engine. 3. The truck mixer is provided with a water supply tank with equipment for measuring the quality of water entering the drum, & a revolution counter indicating the extent of mixing. 4. As soon as the mixer drum is charged with its complete batch of materials from the batching plant, the truck proceeds to the concrete pouring point, the mixing operation taking place in route, the water level and the mixing controls being operated by the driver; where the length of the haul is long, delivery of freshly mixed concrete is assured by starting the mixing operation towards the end of the haul. 5. On arrival at the worksite, the concrete is discharged over detachable chutes into receptacles or directly on to the forms.

23. PARTS OF TRANSIT MIXER DRUM AND BLADES:- The mixing drum is made of high abrasion resistant steel and blades of high abrasion resistant alloy steel to mix any type of ready mix concrete and to discharge it smoothly. HOPPERS:- Wide mouth hopper specially designed to receive sticky ready mix concrete in large quantities with ease. HOPPER STEPS AND HANDRAIL:- Layout of hopper steps and handrails are made user friendly for standing at ease for cleaning purpose ensuring better safety. Side steps made from rust proof steel are attached as a standard equipment with stripes for anti slip and fender for easy movement. SCOOP:- Scoop is made from Abrasion resistant steel for durability and weight reduction Instead of traditional MS thick plates with liners.

24. 24 CENTRAL MIX CONCRETE In central mixing, both the operations of proportioning & mixing are carried out at a batching plant & deliver the mixed concrete to the site in an agitator truck, which keeps the mix concrete in correct form. In case of centrally mixed type, the drum carrying the concrete revolves slowly so as to prevent the mixed concrete from “segregation” & prevent its stiffening due to initial set. • Central mixing is resorted to when there is likely to be a considerable period lag between the time of mixing and the time of placing. With agitation a maximum of one and half hours between mixing & placing can be allowed. Another important consideration in favour of central mixing method is the fact that more concrete can be transported in a single trip when the truck-mixer is used as an agitator. The effect of this is to reduce the transportation charges, all other factors being equal.

25. 25 SHRINK MIX CONCRETE Shrink mix concrete  is partially mixed in a central mixer and then charged into a truck mixer, where the mixing is completed. The truck mixer is turned at high speed while charging the concrete. Mixing can be completed at the plant or at the job site. The number of revolutions needed to complete the mixing of shrink mix concrete in the truck mixer varies depending on the size of the central mixer vessel and the duration of mixing or co-mingling of all of the ingredients (often less than 90 seconds), but generally about 30 turns of the mixer truck drum produces mix uniformity throughout the load.

26. MARKET SURVEY Source https://dir.indiamart.com/impcat/ready-mixed-concrete.html https://dir.indiamart.com/search.mp?ss=ready+mix+concrete+in+noida&src=as-context%3Akwd%3Dreadymixconcretein%3Apos%3D10%3Acat%3D53%3Amcat%3D36131&prdsrc=1&mcatid=36131&catid=53&cq=noida&cq_src=city-mcat https://dir.indiamart.com/delhi/ready-mixed-concrete.html

27. 27 COMPANY GRADE PRICE A1 Ready Mic Concrete ( Chappraula , Delhi) M35 ₹3300 per cubic meter Garg Redimix Pvt Ltd. (Delhi) M7.5 – M50 ₹4000 per cubic meter Gupta Trading Co. (Delhi) As per requirement ₹6100 per cubic meter Nutech Concrete (Delhi) M35 ₹4400 per cubic meter Shree Building Solutions Private Ltd. (Goa) As per requirement ₹ 5200 per cubic meter Gahlawat Cement Agency (Delhi) M30 ₹ 4700 per cubic meter Build Makaan (Delhi) As per requirement ₹ 4600 per cubic meter M/S. Shiv Traders (Sector 22, Noida) As per requirement ₹4000 per cubic meter Shri Krishna Contraction Company And Earth Movers (Noida) M20 ₹ 4600 per cubic meter Shripati Infraprojects Pvt. Ltd. (Noida) M10 – M50 ₹4000 per cubic meter KR Kannappa Chettiar (Chennai) M20, M25, M30 ₹ 4600 per cubic meter Kishan Trading Co. (Ahmedabad) M10, M20, M25, M30 ₹4550 per cubic meter B-Easy Solutions India Private Limited (Bengaluru) As per requirement ₹4100 per cubic meter Kashyap Incorporation (Jalandhar) M20, M25, M30, M35, M40 ₹3500 per cubic meter

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