Table of Contents
- 1 Does the setting time vary with grade of cement?
- 2 What is the importance of knowing the initial and final setting time of cement?
- 3 What is the difference between initial and final setting time of cement?
- 4 How does fineness affect the time of setting?
- 5 How will you distinguish initial setting time from final setting time?
Does the setting time vary with grade of cement?
Normally the initial setting time for 43 or 53 grade of OPC or PPC is 30 minutes and final setting time is 10 Hours.
What are the factors that affect setting time?
The major factors affecting the time of setting are cement composition, water-cementitious material ratio (w/cm), temperature, and admixtures. When cement hydrates faster, the time of setting is reduced. Increases in the w/cm result in increased time of setting.
What is the importance of knowing the initial and final setting time of cement?
Initial setting time test is important for transportation, placing and compaction of cement concrete. 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.
How do you increase the initial setting time of concrete?
These admixtures are Accelerators and Retarders. Accelerators have been designed to significantly boost the early setting times and increase the early age strengths of concrete. Setting times of non accelerated concrete are significantly slower as temperatures get colder.
What is the difference between initial and final setting time of cement?
The initial time refers to the time that cement turns into paste by mixing with water and begins to lose its plasticity. And the time that cement completely loses its plasticity by mixing with water and begins to have a certain structural strength is known as the final setting time.
How much is the initial setting time of concrete?
The time available for mixing the cement and placing it in position is an Initial setting time of cement. If delayed further, cement loses its strength. For Ordinary Portland Cement, The initial Setting Time is 30 minutes.
How does fineness affect the time of setting?
The finer the cement particles are, the larger the total surface area is and the bigger the area contacting with water is. Thus, the hydration will be quick, the setting and hardening will be accelerated correspondingly, and the early strength will be high.
Can initial setting time of cement be increased or decreased?
Setting of Cement decreases by adding calcium chloride because it acts as a accelerator which increase the reaction process.
How will you distinguish initial setting time from final setting time?
What is meant by initial setting time?
Initial setting time of cement is defined as the time elapsed between the moments when water is added to the cement to the time when the cement paste starts losing its plasticity.