Ensaio de massa especifica do cimento - NBR 16605

Summary

The video demonstrates a specific cement testing process following RBR 6605 standards. It details the steps, including the preparation of the cement mixture, temperature regulation through a water bath, and precise measurements of the liquid meniscus. The procedure aims to determine the cement's specific mass by calculating the difference in meniscus height before and after adding cement. The process also involves removing air bubbles from the mixture and repeating tests to ensure accuracy. The final result gives insights into the cement's density, which is crucial for its quality assessment.

Takeaways

• 😀 Ensure you have the correct container (referred to as 'leite') for the test according to RBR 6605 standards.
• 😀 Weigh the container before adding cement to accurately calculate the mass later in the procedure.
• 😀 Use a water bath (or 'van') to regulate the temperature of the sample for 30 minutes.
• 😀 After the water bath, measure the height of the liquid meniscus to begin the testing process.
• 😀 Add exactly 60 grams of cement to the container, using a funnel to prevent spillage and ensure accuracy.
• 😀 The liquid level should rise to between 18 and 24 cubic centimeters after adding the cement.
• 😀 Tilt the container at a 45-degree angle and gently tap it to remove any trapped air bubbles.
• 😀 Allow the mixture to settle for 20 minutes while keeping the container submerged in water.
• 😀 Measure the final height of the meniscus after the settling period to complete the test.
• 😀 Calculate the specific mass of the cement based on the difference in meniscus height and the mass of cement added.
• 😀 Repeat the procedure for verification and consistency, ensuring reliable results.

Q & A

What is the purpose of the cement density test described in the transcript?

The purpose of the test is to determine the density of cement by measuring the volume change when a known amount of cement is added to a liquid in a controlled environment.

What equipment is necessary for the test?

The test requires a container, a liquid (often referred to as 'leite' in the transcript), a funnel, a thermometer, a timer, a bath for temperature regulation, and a balance to measure the mass of cement.

What is the role of the liquid in this density test?

The liquid is used as a medium for the test. Its volume changes as cement is added, and by measuring this change, the density of the cement can be calculated.

Why is a bath used in this cement density test?

The bath is used to regulate the temperature, ensuring that the liquid's temperature remains consistent, which is important for accurate measurement and to avoid errors due to thermal expansion or contraction.

What is the significance of the meniscus measurement?

The meniscus measurement helps in determining the exact volume of the liquid before and after the cement is added. This volume difference is used in the calculation of cement density.

How is the cement added to the liquid in the test?

Cement is added using a funnel, and the amount added is carefully controlled to achieve a final liquid level between 18 and 24 cubic centimeters in the container.

What happens after the cement is added to the liquid?

The container is tilted at a 45-degree angle and gently tapped to remove any trapped air bubbles, ensuring an accurate measurement of the liquid's volume.

Why is it important to remove air bubbles during the test?

Air bubbles can distort the measurement of the liquid's volume, which would lead to an inaccurate calculation of the cement's density.

How is the final density of the cement calculated?

The density is calculated by comparing the mass of the cement added to the volume change of the liquid, which is determined by the difference in meniscus height before and after adding the cement.

What role do the temperature-regulated conditions play in the test?

Maintaining a stable temperature prevents changes in liquid volume due to temperature fluctuations, ensuring more accurate measurements for calculating the cement's density.