Time of Setting of Hydraulic Cement by Vicat Needle ASTM C 191
Summary
TLDRThis video demonstrates how to determine the setting time of hydraulic cement using the Vicat apparatus. It explains the process of mixing cement with water and using both thick and thin needles to measure the cement's setting time. The initial setting time is recorded when the thin needle penetrates the paste up to 25 mm, while the final setting time is noted when the thick needle no longer penetrates the paste. This process helps identify how long the cement takes to hydrate and solidify properly.
Takeaways
- β²οΈ The video explains how to determine the setting time of hydraulic cement using the VCAT needle.
- π§ͺ Setting time refers to the duration it takes for cement to fully react or hydrate with water.
- π§ The required materials for this test include the VCAT apparatus, two needles (thick and thin), a mixer, a timer, 650 grams of cement, and a specified amount of water.
- π§ The water amount is determined by a normal consistency test, covered in a previous video.
- π Start the timer as soon as water is added to the cement in the mixing bowl.
- π Mix the cement paste thoroughly, as demonstrated in the normal consistency test.
- β³ After 30 minutes, use the thin needle on the VCAT apparatus to measure the penetration of the cement paste every 15 minutes.
- π When the penetration reaches 25 mm or less, it marks the initial setting time.
- π οΈ Switch to the thick needle to continue testing the cement paste until the needle no longer penetrates the paste, indicating the final setting time.
- β By following this process, you can determine both the initial and final setting times of hydraulic cement using the VCAT needle.
Q & A
What is the purpose of the VCAT needle test for hydraulic cement?
-The purpose of the VCAT needle test is to determine the setting time of hydraulic cement, which is the time needed for the cement to react or hydrate completely with water.
What materials and equipment are required to perform the VCAT needle test?
-The materials and equipment required include the VCAT apparatus, two needles (thick and thin), a mixer, a timer, 650 grams of cement, and a defined amount of water determined by the normal consistency test.
How is the amount of water needed for the test determined?
-The amount of water required is determined through a normal consistency test, which is covered in a previous video.
What is the first step in performing the VCAT needle test?
-The first step is to put the cement in the mixing bowl and add the defined amount of water. Then, start the timer at the exact moment the water is added to the cement.
How long should the cement paste be left after mixing?
-The cement paste should be left for 30 minutes after mixing before proceeding with the needle test.
How is the initial setting time of cement determined?
-The initial setting time is determined by placing the thin needle on the VCAT apparatus and repeating penetration tests every 15 minutes until a penetration depth of 25 millimeters or less is achieved.
How is the final setting time of cement determined?
-The final setting time is determined by placing the thick needle on the VCAT apparatus and repeating penetration tests every 15 minutes until the needle fails to penetrate the base surface.
What is the significance of the initial and final setting times in the VCAT needle test?
-The initial setting time represents the period during which the cement begins to hydrate and form a paste, while the final setting time indicates when the cement has fully set and can no longer be penetrated by the needle.
Why is it important to test the setting time of hydraulic cement?
-Testing the setting time of hydraulic cement is important to ensure it has adequate time to hydrate and develop strength before it is exposed to loads or other environmental conditions.
What is the time interval between each penetration test during the VCAT needle test?
-Penetration tests are performed every 15 minutes until the required setting time measurements are achieved.
Outlines
π Setting Time Test for Hydraulic Cement
This paragraph introduces the topic of determining the setting time of hydraulic cement using the VCAT needle apparatus. The setting time is the period during which cement fully reacts or hydrates with water. The equipment required for the test includes the VCAT apparatus, two types of needles (thick and thin), a mixer, a timer, 650 grams of cement, and a specific amount of water, as calculated from a prior normal consistency test. For more information on this consistency test, a reference video link is mentioned. The preparation steps begin with placing cement in a mixing bowl and adding water, ensuring that the timer starts simultaneously.
Mindmap
Keywords
π‘Hydraulic Cement
π‘Setting Time
π‘VCAT Needle Apparatus
π‘Initial Setting Time
π‘Final Setting Time
π‘Cement Paste
π‘Normal Consistency Test
π‘Penetration
π‘Mixing Time
π‘Hydration
Highlights
Introduction to setting time of hydraulic cement using VCAT needle.
Explanation of the reaction of cement with water to achieve complete hydration.
List of materials required: VCAT apparatus, two needles (thick and thin), mixer, timer, 650g of cement, and a pre-determined amount of water.
Water amount is determined by a normal consistency test, which was covered in a previous video.
Step 1: Put cement in the mixing bowl and add water.
Start the timer immediately after adding water to the cement.
Preparation of the cement paste following the same method as the normal consistency test.
Let the paste sit for 30 minutes.
Use the thin needle on the VCAT apparatus to measure initial setting time.
Adjust the needle until it contacts the base, then release it.
Penetration measurement is taken every 15 minutes until 25mm or less penetration is achieved.
The time between water contact and 25mm penetration marks the initial setting time.
Switch to the thick needle and adjust for final setting time measurement.
The time between water contact and when the thick needle fails to penetrate marks the final setting time.
Conclusion: Method to determine the initial and final setting times of cement using VCAT needle.
Transcripts
in this video we will cover setting time
of hydraulic cement by VCAT needle in
other words the time that cement me to
react or hydrate completely with water
in order to perform this test you need
the following the v-cut apparatus two
needles thick and thin one a mixer a
timer a 650 gram of cement and the
defined amount of water which has been
determined by the normal consistency
test which we had covered in a previous
video click here or on the link in the
description box to see the video first
put the cement in the mixing bowl then
add the water to the cement run your
timer at the exact time you have added
the water to the cement you need to
prepare the cement paste as we have done
in the normal consistency video leave
your paste for 30 minutes place the Hin
needle on the wicket apparatus set the
indicator on zero adjust the needle
until it become in contact with the base
surface release the needle the needle
will penetrate the waste repeat this
operation every 15 minute until a 25
millimeter or lists of penetration is
obtained the time between the initial
contact of cement and water and the
penetration of 25 millimeter is the
initial time of setting then place the
thick needle on the wicket aratus set
the indicator on 0 adjust the needle
until it become in contact with the base
surface release the needle the needle
will penetrate the waste repeat this
operation every 15 minute until the
needle failed to penetrate the base the
time between the initial contact of
cement and water and the fail of thick
needle to penetrate the waste is the
final time of sitting and by that we
were able to determine the setting time
of
like cement by wicked needle
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