Why are various type of admixtures used in concrete - major reason or advantage?

Tese are different types of Admixtures,which are used in concrete,some water reducing,accelerators.retarders,high-performance water reducers plus retarders,

as per your requirements.

To maintain the required quality of work performance and quality of concrete for which purpose will be used. 

1 various ype of admixtures used in civil construction

because sum admixtures increese the setting time sum will change the property like plasticity.porosity etc

for various reason what couid adjust with purpose or the usage of concret  like control time and hardner moisture resistance 

to provide required slump and without increase the W/C rate in order to not reduce compresive strength. 

To increase setting time of concrete, increasing compressive strenght etc

concrete admixtures used for set retarding to slow down the chemical process of setting. they also reduce high temperatures.

Air entrainment admixture used to prevent segregation and bleeding of concrete.

Water reducing admixture which is used to obtain more slump at lower water cement ratio.

Accelerating admixtures to increase the strength of the concrete and decrease the setting time

Shrinkage reducing admixtures which are added during early mixing of concrete to prevent long term shrinkage

Superplasticizers which are used to obtain flow and very high slumop where consolidation and vibrations are not possible

Réponse: l'avantage des adjuvats dans les béton est pour amééliorer la qualité de béton vis -à- vis à la résistance et la consitance pour pouvoir mettre ce dernier en place .

• To reduce the cost of concrete construction
• To achieve the certain properties in concrete more effectively than by other means
• To maintain the quality of concrete during stages of mixing, transporting, placing and curing in adverse weather condition
• To overcome certain emergencies during concreting operations

Nowadays there are many admixtures available in the market. Depending upon the requirement they can be used to increase workability (Plasticisers), Curring agents, Rapid hardening agents, Anti-Abrasion agents, Air Entrant agents etc.

The main purpose could be:

1. Slump 2. High strength 3. Salt Water 4. Rapid Hardening 5. Chemical resistance etc.