Cutting Paragraphs and Important Table of IS CODE 456 : 2000 (PART I)

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IS 456:2000

•  Some Important Cement types and its Code :

• Silica fume is usually used in proportion of 5 to 10 percentage of the cement content of mix.
• Meta-kaoline having fineness between 700 to 900 m²/kg may be used as a pozzolanic material in concrete.
• Aggregate should be comply with IS code 383 : Specification for the fine and coarse aggregate.
• Sulphate as a SO3 content in other (other than described in IS 383) types of aggregate should not be grater then 0.5 % and should not absorb more than 10% of thier own mass of water.

• Size of aggregate according to clause no 5.3.3;

• Water used in maxing and curing shall be clean and ....

Table 1

• For Admixures;

• Reinforcement shall be .....

• Storage of the materials shall be as described in IS 4082.

*****************************CONCRETE*******************************

Table 2

Grade of the concrete after 4th amendment 2013; (updated)

Properties of concrete

VERY IMPORTANT TABLE ALL THE TIME

(For Workability of concrete; in other word criteria for the slump according to placing conditions of concrete in various section, element or works etc.)

in short;

Slump test

Workability             slump value         

very low                   < 25 mm  (Then do COMPACTION FACTOR TEST)

low                              25 to 75 mm (Mass Concreting)

  

medium                       50 to 100 mm 

                                    75 to 100 mm (When needle vibrator used)

high                             100 to 150 mm

     

very high                  > 150 mm (Then do FLOW TEST)

Compaction Factor test;

Workability                       compaction factor value ( always less then 1)

very low                                                0.7 to 0.8 

low                                                        0.8 to 0.85

medium                                                0.85 to 0.95

 

high                                                more then 0.95

Durability of Concrete:

•            Durability of concrete is one that performs satisfactorily in the working environment during its anticipated exposure conditions during service.The materials and mix proportions specified and used should be such as to maintain its integrity and, its integrity and, if applicable, to protect embedded metal from corrosion.
•           one of the main characteristics influencing the durability of concrete is its permeability to ingress of water, oxygen, carbon dioxide, sulphate and other potential deleterious substances. Impermeability is governed by the constituents and workmanship used in making the concrete. With normal weight aggregates a suitably low permeability is achieved by having an adequate cement content. Sufficiently low free water/cement ratio, by ensuring complete compaction of the concrete, and by adequate curing.
• The factor influencing durability include:

          a) the environment;

          b) the cover to embedded steel;

         c) the type and quality of constituent material;

         d) the cement content and water/cement ratio of concrete;

         e) workmanship, to obtain full compaction and efficient curing; and 

         f) the shape and size of the member.

Requirement for durability 

Exposure Conditions:

Table 3

in short ;

Mild               =>          Protect against weather condition.

Moderate      =>          Contd. under water

Severe           =>          Alternate Wet and Dry condition  (Coastal environment)

Very Severe  =>          Sea water spray

Extreme        =>          Tidal zone ( Chemical attack)

NOMINAL COVER TO REINFORCEMENT ;

(also give some nominal cover to reinforcement in PART- I of basic civil engineer question of this blog.....) which are;

Slab  =  20 mm

Beam  =  25 mm

Column  =  40 mm

Footing =  50 mm

Raft Foundation (Bottom And Earth Side)  =  75  mm

Raft Foundation (Top) =  50 mm

Staircase  =  15 mm

Water Retaining Structure  =  20 mm/ 30 mm

Shear wall  =  25 mm

Retaining wall  =  20 mm ( 25 mm on earth )

Strap Beam = 50 mm

Grade Beam =  20 mm

Flat Slab  =  20 mm

Cover according to exposure condition of the environment;

• Minimum nominal cover according to exposure condition,

 

                  Mild                       25 mm

                 Moderate               30 mm

                 Severe                   45 mm

                Very Severe           50 mm

               Extreme                  75 mm

   Nominal cover according to period of fire resistance;

Nominal cover (For the purpose of protection against spalling)

For Beam = 40 mm;

For Slab = 35 mm.

Contd in PART-II.........