Question

10) LIST AT LEAST 3 CONCRETE ADMIXTURES THAT HAVE BEEN DEVELOPED IN THIS CENTURY (2000-2020), AND EXPLAIN:

a) Use or Application

b) Typical Dosage

c) Advantages

d) Disadvantages

type please

Answer 1

Three Concrete admixtures of this century:

a) Corrosion inhibiting admixtures

Applications: RCC, PCC, high steel beams, doubly reinforced sections.

dosage : 5 litre/m3

advantages : provides resistance to steel against corrosion

increase durability

disadvantages: makes the concrete very low permeable and hence shrinkage cracks are often seen.

b) Polymer dispersion admixtures

applications: structures in chemical prone areas

structural elements at freezing point abd sudden temparature change.

dosage : 0.3 to 0.5 percent by weight of concrete

advantages : Makes concrete chemical resistant

makes the effect of temperature change fatigue very low.

Disadvantages: Lower flexural and tensile strength

c) viscosity modifying admixtures

applications : In alteration of setting time of concrete, concrete mixing techniques, precast concrete members

dosage : 0.08 to 0.3 percent by weight

advantages: It reduces the segregation of concrete

Gives advantage of controlling the setting time

disadvantages:

decreases the lifespan if concrete

Reduces the compressive strength