Que4.1. Explain the colorful way in the manufacturing of concrete.
Answer The colorful stages in the manufacture of concrete are as follows 1. Batching of Concrete Batching is the process of measuring concrete blend constituents by either mass or volume and introducing them into the mixer. To produce concrete of invariant quality, the constituents must be measured directly for each batch.
The two styles of batching are as follows Volume Batching Volume batching isn’t a good system because of the inaccuracies it introduces in the dimension of grainy accoutrements .
Loose beach in a wettish condition occupies further volume than dry compacted beach due to the miracle of bulking. Hence, the effect of bulking must be considered while measuring beach.
Despite downsides, for less importantnon-engineered small workshop, this system is espoused because of its ease in operation. still, it is unscientific and hence not recommended for important workshop.
ii. Weigh Batching Weigh batching is the correct system of measuring the accoutrements that are used to make concrete. Use of weigh batching system facilitates delicacy, inflexibility, and simplicity. c. For large workshop, a weigh batching factory is used.
2. Mixing The mixing should insure that the mass becomes homogeneous, livery in colour and thickness. styles of Mixing Hand mixing. ii. Machine mixing.
3. Transporting It’s the process of transferring of concrete from the mixing factory to the construction point. It can be done by following accoutrements Mortar Pan Concrete is carried in small amounts.
ii. Barrows and strollers Short flat hauls on all types of onsite concrete construction.
iii. Cranes and Pails Used for work above ground position, pails use with cranes, cableways, and copters.
4. contraction of Concrete contraction of concrete is process espoused for expelling the entangled air from the concrete.
ii. In the process of mixing, transporting and placing of concrete air is probably to get entangled in the concrete.
iii. It has been set up from the experimental studies that 1 air in the concrete roughly reduces the strength by 6.
5. Curing It’s the process in which the concrete is defended from loss of humidity and kept within a reasonable temperature range.
ii. The result of this process is increased strength and dropped permeability.
iii. Curing is also a crucial player in mollifying cracks in the concrete, which oppressively impacts continuity.
6. Finishing i. The finish can be rigorously functional or ornamental.
ii. Finishing makes concrete seductive and serviceable.
iii. The final texture, hardness, and common pattern on crossbeams, bottoms, sidewalks, quadrangles, and driveways depend on the concrete’s end use.
Que4.2. Explain the mixing and transporting operations of concrete in a work point.
Answer styles of Mixing Concrete is mixed either by hand mixing or by machine mixing, grounded on the volume of concrete needed.
1. Hand Mixing Mixing by hand is employed only for specific cases where quality isn’t of important significance, either because of the insignificant nature of the work or because the volume of concrete needed is less.
ii. Hand mixing generally doesn’t produce invariant concrete and hence should not be typically used, unless it’s for veritably small domestic workshop.
2. Mechanical Mixing Mechanical mixers can be divided into two main types batch mixer and nonstop mixers.
ii. Batch mixers produce concrete batch by batch, one batch at a time. The operation is intermittent. The raw material is loaded at one end and the concrete is discharged at the other end. This constitutes a cycle of operation which is repeated until enough volume of concrete is produced.
iii. nonstop mixers produce concrete at a specified rate. The raw accoutrements are continuously entered at one end and mixed concrete exits from the delivery end.
Transportation of Concrete The following styles are used for transporting concrete
- Direct Discharge into Forms by Short Cataracts Short cataracts in asemi-circular shape strengthened at intervals are simple and provident to use.
- ii. Free fall of concrete from a height of further than 2 m must be avoided.
2. Barrows Manual barrows of roughly 80 kg capacity can be used for long vertical distances.
ii. For major workshop, power barrows of 800 kg capacity, up to 300 m hauls are used.
3. Dumpers and exchanges
i. These are used for vertical long hauls.
ii. Because of jarring, especially if the terrain is rough, the concrete during conveyance has the threat of isolation.
4. Elevating Towers and Hoist Inmulti-storied structures, elevating halls are used for lifting concrete pails. The lifted concrete is also distributed by either cataracts or barrows. This type of transportation can be used where high lifts are needed.
5. Monorail System
i. In coverts and in levee spots, a single track is laid to carry a rail power cart which moves at a speed of 80 m/min.
ii. This type of transportation can be used for covering long distances. 6. Cranes and Cableways
i. When concreting is to be done in a large design covering mountains and denes, cranes and cableways are used to give three- dimensional transport enabling both vertical and perpendicular movement.
ii. Depending on the point condition, the type of crane can be chosen. It may be a derrick, straggler, or wheel mounted.
7. Belt Conveyor i. It can be used when hauling concrete over long distances.
ii. It isn’t veritably important recommended because of its vulnerability to isolation.
iii. The original setting- up cost is also high. Discharge can be as high as 115 m3/h. 8. Concrete Pail and Skip The capacity of the skip varies from about0.2 m3 to 10 m3.
Que4.3. What are the preventives to be taken while transporting concrete? What are the advantages and disadvantages of concrete pump?
Answer preventives in Transporting of Concrete Following preventives should be used during transporting of concrete
1. While water is added to cement, the procedure of hydration thresholds and with the passage of time, so concrete should be transported as fast as possible to the formwork within the original setting time of cement.
2. The procedure of mixing, transporting, placing and compacting concrete should not take further than 90 twinkles in any case.
3. No water shall be lost from the blend during transportation.
4. The concrete combine should be defended from drying in hot rainfall and from rain during transport from the place of mixing to the position of placing.
5. isolation of concrete should be avoided under all circumstances.
6. The concrete shall be kept agitated in truck mixer in order to avoid it from getting stiff if further time is likely to be spent during transportation. Advantages of Concrete Pump
1. Concrete pumping is a briskly and lightly system to complete a design.
2. Concrete pumping reduces labour costs.
3. It reduces point traffic as there are less construction workers.
4. It provides a steady work pace, adding productivity.
5. It’s effective and provident for colorful sized systems, including domestic and marketable.
6. Several pumps can pour contemporaneously for larger systems.
Disadvantages of Concrete Pump
1. Possibility of a concrete pump breaking down.
2. threat of injury to construction workers and damage to property.
3. During busy ages it isn’t always easy to find a concrete pump that is available.