Answer to Question #309136 in Civil and Environmental Engineering for Oxian

Question

Discuss the change in volume of concrete at early ages

Answer 1

When the concrete is still plastic, change in volume occur. And after setting another type of volume change can occur. When cement is in plastic stage, it undergoes minor volume change of about 1%. It occurs as a result of evaporation from the cement paste or being used in chemical reaction of fresh concrete. As this occurs in plastic stage of concrete, this is termed as plastic shrinkage of concrete. It can lead to cracking which can be avoided by preventing water loss, using proper curing techniques.

Within the first 24 hours after pouring of concrete, volume fluctuations will occur, which are often overlooked during laboratory shrinkage tests. Unfortunately, these early-age volume shifts can be seen in various concrete structures such as pavements, buildings etc. and they can add to concrete shrinkage behavior as it ages. Drying shrinkage before the start of curing and autogenous volume shifts are two types of early volume changes. While early age volume changes are often ignored, studies shown that magnitudes of early age volume change of certain concrete that are equivalent to or greater than 28-days drying shrinkage measurement. in certain cases, expansion have been discovered.

When the concrete is still plastic, change in volume occur. And after setting another type of volume change can occur. When cement is in plastic stage, it undergoes minor volume change of about 1%. It occurs as a result of evaporation from the cement paste or being used in chemical reaction of fresh concrete. As this occurs in plastic stage of concrete, this is termed as plastic shrinkage of concrete. It can lead to cracking which can be avoided by preventing water loss, using proper curing techniques.

Within the first 24 hours after pouring of concrete, volume fluctuations will occur, which are often overlooked during laboratory shrinkage tests. Unfortunately, these early-age volume shifts can be seen in various concrete structures such as pavements, buildings etc. and they can add to concrete shrinkage behavior as it ages. Drying shrinkage before the start of curing and autogenous volume shifts are two types of early volume changes. While early age volume changes are often ignored, studies shown that magnitudes of early age volume change of certain concrete that are equivalent to or greater than 28-days drying shrinkage measurement. in certain cases, expansion have been discovered.