1. CONCRETE CHEMICALS & APPLICATIONS
Admixtures & construction chemicals are the chemicals added along with the ingredients of concrete or afterwards to get the required mix or strength & durability.

2. CONCRETE CHEMICALS & APPLICATIONS
Added along with the ingredients of concrete.
Added at the time of grinding cement in the cement factories.

3. CONCRETE CHEMICALS & APPLICATIONS
The effect of admixture depends on the
 Brand of cement.
 Grading of aggregates.
 Mix proportion.
Some important admixtures are discussed below:

4. PLASTICIZERS& SUPER PLASTICIZERS :
 In order to attain the high degree of workability these admixtures are used.
 Super plasticizers permit the water reduction up to 30% without reduction in workability.
 Used for production of flowing, self leveling , self compacting & production of high strength & high performance concrete.
 The quantity used are 0.1 to 0.4 % percentage weight of cement.
 The most common used plasticizers are calcium, Sodium & Ammonium lingnosulphates.

5. COMMONLY USED PLASTICIZERS

6. RETARDERS:
 Slows the process of hydration because of the concrete remains Plastic & Workable.
 If the concreting is done in hot weather, these retarders overcome the effect of high temperatures.
 Calcium sulphates, lignosulphonic acids & their salts.hydroxylates & their salts are most common retarders.
These admixtures which increase the compressive strength by 10 to 20 %

7. COMMONLY USED RETARDERS

8. ACCELERATORS:  Added to gain the earlier strength.
 Such situation may occur when
º Early removal of farm work is needed.
º Reduction in the period of curing time.
º Put the structure early to use.
º Accelerating setting time in cold weather.
 Calcium chlorides, Soluble carbonates, Silicates& some organic compounds are used as accelerators.
Very much used in underwater concreting.

9. COMMONLY USED ACCELERATORS

10. AIR-ENTRAINING ADMIXTURES:
 Concrete is made by using air entrained cement or addition of air-entraining agent.
 Produce large quantity of air bubbles and modify the concrete properties regarding workability, segregation, bleeding & finishing quality of concrete.
 Gains Resistance to frost action & permeability
Natural Wood resins, animal and vegetable fats, Water soluble soaps of resin acids etc.,

11. Commonly used air entraining admixtures

12. POZZOLANIC ADMIXTURES:
 Application of pozzolanic admixtures to the cement improves the quality of concrete such as
Lower the heat of hydration .
Increase the water tightness.
Reduce the alkali-aggregate reaction.
Resist the sulphate attack & improve the workability.
 Naturally available pozzolanic materials are clay, volcanic tuffs.
 Artificial pozzolanic materials are fly ash, steel slag, rice husk ash, marble powder, quartz & granite powder.

13. Commonly used air entraining admixtures

14. DAMP-PROOFING ADMIXTURES:
Advantages in reducing the permeability.
 These admixtures are available in powder or liquid form.
 It has the property of pore filling inside the concrete
 Silicates of soda,Aluminium & zinc sulphates, Aluminum & calcium chlorides are most common damp-proofing admixtures.

15. Commonly used air entraining damp-proof admixtures

16. CONSTRUCTION CHEMICALS
Chemicals which are used to enhance the performance.
Some common construction chemicals are,
Concrete curing compounds.
Polymer bonding agents.
Water proofing chemicals.

17. CONCRETE CURING COMPOUNDS:
In order to prevent the loss of water from the surface these curing compounds are used.
Synthetic resin,wax,chlorinated rubber are used as curing compounds
Resin and wax based compounds effectively seal the concrete from the surface evaporation.
Chlorinated rubber curing compounds forms a thin film on the surface of the concrete which protects drying and at the same time they fill the pores on the surface of the concrete.

18. POLYMER BONDING AGENTS:
By providing a bond coat between old concrete and new concrete.
Mixing of bonding agents with new concrete helps to provide a better bond.
Also increase the workability and reduce the shrinkage.
Roof bond ERB , Nit bond PVA are most common type of bonding agents
used for Concrete repair work such as ceiling of concrete roof, hydraulic structures, prefabricated members, pipes etc.,