Question

What is autogenous shrinkage?

(a) It is not a result of any change in the concrete production process. Rather, it is a result of certain environmental conditions which frequently occur in the Central Missouri area

(b) It is defined as the contracting of a hardened concrete mixture due to the loss of capillary water. This shrinkage causes an increase in tensile

(c) It is an important phenomenon in young concrete. At low w/c ratios, less than about 0.42, all the water is rapidly drawn into the hydration process and the demand for more water creates very fine capillaries

(d) It occurs when the concrete is exposed to air containing carbon dioxide

This question was addressed to me in final exam.

My enquiry is from Types of Shrinkage in chapter Elasticity, Creep and Shrinkage of Concrete Technology

Answer 1

Correct option is (c) It is an important phenomenon in young concrete. At low w/c ratios, less than about 0.42, all the water is rapidly drawn into the hydration process and the demand for more water creates very fine capillaries

The explanation: It is an important phenomenon in young concrete. At low w/c ratios, less than about 0.42, all the water is rapidly drawn into the hydration process and the demand for more water creates very fine capillaries.