R.C.C (Reinforced Cement Concrete

Reinforced cement concrete 

IS code for R.C.C  

Poison ratio 

Creep 

What is R.C.C 

In RCC, the concrete which is made up of cement, coarse gravel and water is reinforced with the help of steel or iron bars.

 R.c.c code 

IS 456-2000

IS 3370-2009 

IRC 6-2010 

PERMISSIBLE LIMITS OF IMPURITIES OF WATER 

IMPURITIES                  PERMISSIBLE LIMIT 

ORGANIC                      200mg/l 

INORGANIC                  3000mg/l 

CHLORIDES                  2000 mg/l

SULPHATE                     400 mg/l 

SUSPENDED SOLID      2000 mg/ l 

Tensile strength of concrete 

Ftc= 0.7√fck 

Modulus of elasticity 

Ec = 5000√fck  

Poisson`s ratio 

Varies from 0.1 to 0.3 for concerete 

It can be taken as 0.2 for all design calculation purpose 

Creep 

It depend upon the following factors 

1- Stress level 

2- Age at loading 

3- Duration of loading 

Age at loading                     Creep Coefficient 

7 days                                     2.2 

28 days                                   1.6

1 year                                     1.1 

Shrinkage of concrete 

Concerete shows shrinkage due to loss of moisture by evaporation. Shrinkage also cause strain in concerete. 

Is 456 recommends a value of 0.003 mm/m 

Frezing and Thawing 

If frezing and thawing condition exists, then durability of concrete should be enhanced by adding suitable air entraining admixture 

IS 456-2000 recommends the percentage of entrained air for nominal maximum size of aggregate as follows 

Nominal maximum              Entrained air %

 size of aggregate 

7 days                                    2.2 

28 days                                  1.6 

1 year                                    1.1  

 The various grades of concrete as per their use are listed below 

1. For RCC work - not lower than M20 
2. For post tensioning works - M35 and above 
3.   For Pretensioned prestressed concrete- M40 and above। 

Lower than M20 may be used for plain concerete works, lean concerete, simple foundation, masonry walls and other simple construction works.  

Note the maximum cement content used for rcc construction is 450 kg/m3 as per IS 456-2000 

Design Mix Concerete 

IS 10262: 2009 is the code for concerete mix design which gives recommendations for design of concrete mixes . Following information/ data is required for the design of a Concerete mix. 

(1) Grade of concrete 

(2) Standard deviation 

(3) Type of cement 

(5) maximum water cement ratio by weight

(6) Type of aggregate 

(7) Size of aggregate 

(8) Minimum cement content 

(9) Degree of workability and exposure condition

(10) Type of admixture to be used

Workability Requirement for different condition

Placing Condition	Degree	Slump
Binding Concerete , very low,shallow section,  pavement  using  pavers		determine by the            compaction                factor 0.75-0.80
light reinforced beams,।                   Slabs,walls, columns floors, Lining of canal, strip footing  Mass concereting	Low	25-75
Heavily reinforced slabs, beams,                            Walls, columns pumped concrete	medium	50-100
Trench fill , in situ piling	High	100-150