Plasticizer charts - Admixtures used in RCC

Admixtures	Functions	Typical compounds	Application	Disadvantages
Accelerating admixtures or accelerators	More rapid gain of strength or higher early strength. More rapid setting.	Calcium chloride Calcium formate Triethanolamine  (TEA) Soluble inorganic salts Sodium nitrite Sodium sulphate Sodium aluminate Sodium silicate	1. Normal rate of strength development at low temperature. 2. To counter retarding effects 3. Shorter stripping times. 4. Plugging of pressure leaks. 5. Sprayed concreting.	1. Possible cracking due to heat evolution. 2. Possibility of corrosion of embedded effects reinforcement.
Retarding admixtures or retarders	Delayed setting	Soluble carbohydrate derivatives: starch Hydroxylated carboxylic acids, Inorganic retarders Sugars	1. Maintain workability at high temperatures. 2. Reduce rate of heat evolution. 3. Extend placing times, e.g., ready-mixed concrete. 4. Prevent cold joint formation.	May promote bleeding.
Water-reducing accelerators	Increased workability with faster gain of strength.	Mixtures of calcium chloride and lignosulfonate.	Water reducer with faster strength development.	Risk of corrosion.
Water-reducing retarders	Increased workability and delayed setting	Mixtures of sugars or hydroxylated carboxylic acids and lignosulfonate.	Water reducer, with slower loss of workability.
Air-entraining agents	Entrainment of air into concrete.	Aluminum powders, Natural wood resins, fats, lignosulfonates, alkyl sulfates, sodium salts of petroleum, sulfonic acids.	Enhanced durability to frost without increasing cement content, improvement in workability, lowered permeability and cellular concrete.	Careful control of air content, water-cement ratio, temperature, type and grading of aggregate and mixing time is necessary.
Damp-proofing or water-proofing agents	1. Water-repellent, i.e. prevention of water from entering cap 2. Reduced water permeability of concrete.	Potash soaps, calcium-stearate, aluminium-stearate, butylstearate, petroleum	1. Reduced permeability. 2. Enhanced durability. 3. Increased freeze-thaw resistance. 4. Reduced drying shrinkage. 5. Reduced surface staining. 6. Water tightness of structures without using every low water-cement ratio.	1. Not efficient under high hydrostatic pressure. 2. Requires low water-cement ratio and full compaction.
Plasticizers (water reducers)-8 to 15 percent water reduction	Higher flowability	Hydroxylated carboxylic acid derivatives Calcium and sodium lignosulfonates.	1. Higher workability with strength unchanged. 2. Higher strength with workability unchanged. 3. Less cement for same strength and workability.	Certain special types of cements like sulphate resistant cement (low C3A content) and expansive cement do not perform well.
Superplasticizers (Super-water reducers) – 15 to 30 per cent water reduction	Greatly enhanced workability.	Sulfonated Melamine formaldehyde resin, sulfonated naphthalene-formaldehyde resin, Mixtures of saccharates and acid amides.	1. Water reducer, but over a wider range. 2. Facilitate production of flowing or self-leveling concrete	1. Tendency to segregate. 2. Flowability is not long lasting. 3. During hot weather the workability retention period decreases fast.