Truck Mix

The Concept :

CONVENTIONAL METHOD OF PRODUCTION OF CONCRETE :

Conventionally concrete is produced in a stationary plant located near the place of construction and is transported by means of special rotating trucks called Transit Mixers which keep the concrete alive during transport. However special chemicals are required to be added to the concrete in specific quantities which retard the setting of concrete and are therefore called retarders. The major raw materials required for making concrete are crushed aggregates both coarse & fine and are transported by huge dumpers from the quarry to the stationary plant and are kept in stock. They are re-handled several times before these are loaded by a front end loader into the bins of stationary plant. The stationary plant is a big equipment which has a huge capital cost. The stationary plant also needs around 40,000 sq.ft. of land and a team of expert operators and mechanics to operate & maintain the plant. It also needs a high capacity dedicated power source generally a Diesel Generator with a very high fuel consumption. The transit mixer trucks which carry the concrete are specially designed rotating drums mounted on commercial truck chassis. However the rotating drums are generally driven by a separate engine which is always working even during transportation of concrete.

Generally a small stationary plant of capacity 30 cubic meter per hr needs along with itself around 6 to 8 transit mixers, same no. of dumpers to carry raw material, one 125 Kva diesel Generator set, one front end loader, around one acre of land and several skilled workers , mechanics and drivers. If the capacity of the stationary plant is doubled, all other machinery increases in almost same proportion.

Also the concrete produced has a shelf life of around 4 hrs even after adding retarders. It has to be transported and placed at site within this period otherwise it is generally rejected by the buyer, which is a common thing to happen in traffic congested cities.

"TRUCKMIX" IS THEREFORE DESIGNED & DEVELOPED TO OVERCOME THE DRAWBACKS IN THE CURRENT SYSTEM.

WHAT IS "TRUCKMIX":

"TRUCKMIX" is "Concrete Production & Transportation Vehicle".

"TRUCKMIX" is one product which does the work of all the following machinery and produces better quality concrete:

• Dumper trucks which carry aggregates from the quarry to the stationary plant.
• Stationary plant which produces concrete.
• Huge captive power source ( diesel generator) to run stationary plant.
• Transit mixer trucks with rotating drums driven by separate engines.

How does it work ?

Transport Operation : CPTV carries four different types of aggregates, cement, fly ash, water and admixtures in separate compartments directly from the quarry to the place of construction.

Batching & mixing operation : After reaching site, with the help of electronic loadcells and sophisticated PLC system it batches all the raw materials on "gain in weight" Or "Positive weight basis" ( similar to a stationary plant) and mixes them in small batches in high speed horizontal pan mixer exactly similar to the Stationary plant. For this operation it does not require any other external power as it runs on the vehicle engine itself.

"TRUCKMIX-12.5" : This Model is suitable for mounting on TATA / ASHOK LEYLAND 2516 Chassis. It can carry and produce little more than 12.5 Tonnes (5 cubic meter) of concrete in each trip. When operated at site without transport, with continuous feeding it can give a production of 15 to 20 cubic meter of concrete per hour. Material is fed through belt conveyor.

Bigger models can be supplied with the introduction of 40/42 Tonnes capacity trucks.

INTRODUCTION TO "TRUCKMIX" SERIES :

Concrete is a construction material composed of cement as well as other cementitious materials such as fly ash, slag cement, aggregate comprising a coarse aggregate such as gravel, limestone, or granite along with a fine aggregate such as sand and chemical admixtures.

The word concrete comes from the Latin word concretus (meaning compact or condensed).

Concrete solidifies and hardens after mixing with water due to a chemical process known as hydration. Water reacts with cement, which helps in bonding the other ingredients of concrete together, eventually creating a stone-like material. The first major concrete users were the Egyptians in around 2500 BC and the Romans from 300 BC. The oldest known surviving concrete is to be found in the former Yugoslavia and is believed to have been laid in 5600 BC.

With the passage of time concrete has been increasingly used for the construction of pavements, pipe, architectural structures, foundations, motorways/roads, bridges/ overpasses, parking structures, brick/block walls, footings for gates, fences and poles and a numerous other purposes.

Presently, concrete is produced by batching the ingredients on weight basis and thereafter mixing the ingredients in a mixing plant installed at a particular location. The mixed ingredients are transported to the construction site in rotating concrete transit mixers mounted on commercial transport vehicles.

There are some mobile plants, which are trailer mounted and require a tractor truck to tow them from one place to another. Such are unable to transport the concrete (dry ingredients) along with the plant from one location to another as a regular mean of transportation . They also require an external source of power for operation of the plant as the required horsepower for operation of the plant is very high. This needs a dedicated external power source at each & every location power source at each & every location and needs to be plugged before starting the operation. The trailer mounted plants are thus very bulky and of very big size and have/trolley arrangement and are used only to carry the plant from one location to another.

Some vehicles are mounted with volumetric mixers but due to volumetric proportioning of limited ingredients and improper mixing, the volumetric type of mixers has limited applications.

Some mobile plants carry out weighing of ingredients in the mixer on loadcells. The biggest disadvantage of this is that for accurate batching the mixer has to be completely stopped. Which results in big loss of productive time in each cycle. Another disadvantage is that after the batching is over all the raw materials are in the mixer and the mixer has to be started with the load.

Therefore the mixer motor which has to be a high power motor, draws a heavy starting current in each & every mixing cycle. Which compels to have high connected load and huge requirement of power for comparatively smaller output. Which increases the capital & running cost. Also the next batch cannot be started unless and until the first batch is completely discharged from the mixer.

This increases the cycle time. However, the construction industry across the world utilizes the concrete, the ingredients of which are batched on a positive weight based batching system in a stationery plant. The concrete is produced by a forceful and homogeneous mixing of the various ingredients in various types of mixers like reversible drum, single/ twin shaft, planetary or Pan type mixers.

The conventional system of batching and mixing of the various ingredients of the concrete requires investment in dump trucks for transporting stones from stone quarry to a place near the site of construction. Again, a huge investment is required for installation of stationary plants for mixing all the ingredients of concrete except water.

Further, the vehicle and the mixer are operated by two separate engines which increase the use of fuel to run the engines and hence leading to an increase in the cost of the concrete.