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R.c.c design criteria...

on November 30, 2018

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What is a quantity of cement and sand for a 748 sq.ft area roof cc???

Answered Thu One has to know (Neglecting quantity of reinforcement for normal work ) the mix proportion of ingredients in concrete, and or quantity of cement (kg) per cubic metre, type of cement (as specific gravity of cement is different for OPC, PPC and PSC) thickness of slab (to find the volume) and the expected wastage while handling (lead and lift, type of transportation from mixing to placement) In general for 748 Sq. Ft area of slab, considering with 300 kg/cu.m of cement, then for 1 inch thick slab, it requires and average of 11 bags of cement. If it is 4 inch thick, it will be 44 bags, and if 5 inch thick, it will be 55 bags. (without considering wastage and without deduction for reinforcement) Regarding sand, assuming twice the weight of cement, then it requires 44x2x50 to 55x2x50 kg, i.e., 4400 kg to 5500 kg of dry sand. When computed volumetrically, assuming density as 1500 kg/cu.m, requires around 2.93 cu.m to 3...

What is plasticity of cement and concrete ????

First of all I would like to tell you there is always some properties of any materials or mixtures which are neglected at the long run or does not have any significance after a specific period. I think while referring plasticity of cement and concrete you are trying to know Plasticity of cement paste ( cement water mix) and Plasticity of fresh concrete mix (cement, fine aggregate, coarse aggregate and water). These properties are our concern only when the cement paste and concrete are in semi solid state ( when they are not in hardened state). For Cement Paste plasticity is required to mould the paste into desired shape. We call it consistency of cement when it is not too hardened nor too flowable ( flowable means fluid state which allows it to flow under gravity because of low viscosity). This consistency property helps us to make a workable ( workability is the property by virtue of which a paste has greater degree of ease to work with). Hence this consistency incorporates plasti...

What is segregation and bleeding in concrete ?????

Segregation of concrete:- Segregation can be defined as the separation of the constituent materials of concrete. A good concrete is one in which all the ingredients are properly distributed to make a homogeneous mixture. There are considerable differences in the sizes and specific gravities of the constituent ingredients of concrete. Therefore, it is natural that the materials show a tendency to fall apart. The conditions favorable for segregation are: Badly proportioned mix where sufficient matrix is not there to bind and contain the aggregates Insufficiently mixed concrete with excess water content Dropping of concrete from heights as in the case of placing concrete in column concreting When concrete is discharged from a badly designed mixer, or from a mixer with worn out blades Conveyance of concrete by conveyor belts, wheel barrow, long distance haul by dumper, long lift by skip and hoist are the other situations promoting segrega...

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R.c.c design criteria...

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