What are the initial and final setting times of cement what is their importance?

Initial setting time duration is required to delay the process of hydration or hardening. Final setting time is the time when the paste completely loses its plasticity. It is the time taken for the cement paste or cement concrete to harden sufficiently and attain the shape of the mould in which it is cast.

What are the initial and final setting times of cement?

Initial Setting Time of Cement = 7:45 am – 7:00 am = 45 min. Final setting Time of Cement = 12:00 pm – 7:00 am = 5 hr = 300 min.

What should be the initial & final setting time of cement for hot & cold climate?

A period of 30 minutes is the minimum initial setting time, specified by ISI for ordinary and rapid hardening Portland cements and 60 minutes for low heat cement.

How initial setting time of cement is determined?

The time period elapsed between the moment water is added to the cement and the time, the needle fails to penetrate the mould of 5mm when measured from the bottom of the mould, is the initial setting time of cement.

What is the main reason affecting the final setting time and hardening of Portland cement?

Factors that affect initial and final setting time of cement:- The fineness of cement, the presence of salts in sand, atmospheric conditions. For example, cement requires a temperature of 27°c to complete Hydration, during winters the climate is low which stops the hydration and takes a longer time to set harden.

What is meant by final setting time of cement?

The final setting time is the time elapsed between the moment the water is added to the cement, and the time when the paste has completely lost its plasticity and has attained sufficient firmness to resist certain definite pressure.

What is the setting time of cement?

Setting time is the time required for stiffening of cement paste to a defined consistency. Indirectly related to the initial chemical reaction of cement with water to form aluminum-silicate compound. Initial setting time is the time when the paste starts losing its plasticity.

How long does it take for cement paste to set?

Well, After mixing cement with water, it takes time to place the cement paste in position, initial setting time possess a primary role in strength & it is mandated that cement paste or concrete is placed in position before it crosses initial setting time. i.e.,30mins.

What does final set mean in cement?

Final set. Occurs when the cement has hardened to the point at which it can sustain some load. These particular times are just arbitrary points used to characterize cement, they do not have any fundamental chemical significance. They describe the setting of the cement and are not tied to the setting time of concrete.

What is crystallization stage of cement setting?

Crystallization Stage – It is the final stage of the cement setting; the cement particles hydrate totally and turn as the stable element form. The initial and final setting time of the cement can be determined by the method mentioned in IS code 4031 part 5 by the Vicat Apparatus ( IS code 5513 )