Do anybody have an idea what is bar bending schedule?why waterproofing is required after compaction?

Question

i want to know what are the honeycomb structures that are formed in the concrete even after compaction so that we have to use waterproofing?

Answer 1

Bar bending schedule is the schedule for those people working on site to set up the concrete beams, columns etc etc

they have to bend and shape the required numbers of required sized steel bars, to set up the Beams, columns, slabs etc etc before pouring concrete.

Answer 2

must be weak mixture or temprature diff.

Answer 3

water proofing the wind this natural come

Answer 4

in concrete construction that too reinforced one,,,,,,,,,,

the reinforcing bars are bended to various shapes for industrial purposes >>>>>>>>> this is bar bending

and now the second part after the solid particles are closely packed in a mixture or mortar the spaces are covered wid them and waterproofing is done ..........coz.....honey comb in concrete due to high water-cement ratio and production of concrete may not as per concrete mix design. Due to these reasons capilary pores are develolped in the new concrete. Hence water proofing is required after made of poor concrete ...............

Answer 5

Bar bending schedule is a work out which indicates the exact requirement of steel in a reinforced cement concrete structure, it also indicate the type, quality, size of bars to be used and also standard diameter at which it can be bent to maintain the strength, and elasticity.

Actually W.P. is not required after the compaction but a layer of 1: 4 of cement and aggregate to avoid the exposure of coarse aggregate and prevent it from corrosion and erosion

Answer 6

1. Bar bending is a schedule should be prepared as per structural drawings. It  indicate that what type of diameter of steel reinforcement to be used, how many numbers of bars is to be used and what will be the length of dia. of bar to be used. Bar bending schedule gives us total quantity of steel reinforcement to be used in the building and also for preparation of estimate and also checking the steel during construction process.

2. Water proofing is required after compaction because there may be honey comb in concrete due to high water-cement ratio, production of concrete may not as per concrete mix design.  Due to these reasons capilary pores are develolped  in  the new concrete. Hence water proofing is required after made of poor concrete and also it does not give proper strength as per structural design and concrete mix design nor the durability of the structura.

Answer 7

To strenghen parts of conrete in tension, bar bending schedule is essential.After placing bars, concreting is done with immediately covering it wet gunny bags to protect it from direct sunlight which produces honey combing.Water proofing can be one of the alternative of curing of fresh concrete till it hardens upto 28 days.

Answer 8

I agree with most of the above \but... waterproofing is not only necessary for honeycomb concrete but even if the concrete is so dense that no honeycomb is there you still have to waterproof because the ground water always contains sulphate and chlorine salts that are very aggressive to the concrete so we need to prevent them from attacking the concrete and hence the steel reinforcement from rusting

Answer 9

bar schedules are drawing and calculations for the bending of bars pre casting of concrete for reinforced foundations

waterproofing is required because you want the foundations to remain dry and solid i.e. if they get wet and dry , wet and dry the water molecules leave voids within the foundation and over time these voids grow in size eventually becoming cracks in the road (the dripping tap syndrom)

Answer 10

The inner structure is purely clean and after compaction waterproofing is must.

Answer 11

Bar bending schedule or bar scheme diagram is the detailed representation of bend and cut bars upon the designers discretion. This will aide as in determining the materials quantity, strength and for economic and practical purposes as well. Structural members such as beams,girders,columns,footings,piles,wal... are usually done with bar bend schedule as a guide in positioning them upon casting in place. Some examples are the proper bending of ties and stirrups, bending of hooks, point where the top and bottom bars terminate, bend for anchorages, bend for development, bend for splicing if necessary, U straps, bend of bars in slabs, and bend for longitudinal position of re bars. Remember that a thorough structural analysis must be done before making a bar bend schedule for safety purposes.

Honeycomb are voids left in concrete owing to failure of the mortar to fill effectively the spaces among coarse aggregate particles. These are caused by the used of dry mix that was not properly consolidated. This is because cement, water, aggregates, and admixtures were not properly poured upon casting. I dont exactly know if waterproofing has something to do with honeycomb but I think with some reasons. Usual practice is by using vibrators,admixtures and proper design mix to prevent such defects in concrete.

Waterproofing of concrete is a way to help reduce water seepage by the use of (but not limited to) crystalline concrete waterproofing.This method uses a catalytic reaction to seal the pores, capillaries and shrinkage cracks that occur naturally in concrete. Crystalline waterproofing penetrates into the concrete.It consists of a dry powder compound of Portland cement, very fine treated silica sand, and proprietary chemicals. Combining the product with water and applying it to the surface of concrete results in a catalytic reaction that forms non-soluble crystalline fibers within the pores and capillary tracts of concrete. This seals the concrete against moisture penetration. Water penetration through basement and crawl space foundation walls is usually caused by condensation or exterior water source, from inadequate grading, rainwater collection, or poor footing drains. The source of condensation or exterior water must be corrected prior to application of crystalline concrete waterproofing.

Answer 12

In R.C.C. structures steel reinforcement are being used.The reinforcement should be bent to different angles as per the designers drawings and schedules.This schedule will be given by the designer/ structural engineer.

since concrete is porous it needs waterproofing to make it water tight and impermeable

Honeycombness is formed due to improper water cement ratio,improper compaction or vibrating

Answer 13

1) Bar bending schedule is a chart prepared by the engineer to detail the reinforcement. It consists of dia. of steel, its position,total length,total nos. and its shape with a neat sketch.

2) The reason of honey comb in this case not due to less compaction. The mix you are using contain course aggregate more than required. Check the aggregate cement ratio.