LAB IN YOUR GRASP - KARAKTERISASI MATERIAL BETON : 17 PENGUJIAN KUAT TEKAN BETON

Summary

This video outlines the process of concrete compressive strength testing, a key method to assess concrete’s ability to withstand axial loads. The process involves measuring the concrete's diameter and height, calculating its volume and weight, and ensuring the pressure surface is smooth. A capping method using sulfur is applied to improve test accuracy. The concrete is then placed under a compressive strength machine, which applies pressure until failure, allowing for the calculation of the compressive strength. This procedure follows standards like SNI 1974 and STMJ 39, ensuring reliable results for structural design.

Takeaways

• 😀 Concrete compressive strength testing is essential to determine the capacity of concrete to withstand axial compressive loads.
• 😀 Compressive strength is a fundamental characteristic of concrete, affecting the design of concrete structures.
• 😀 The standard test object for concrete compressive strength has a cylindrical shape, typically 15 cm in diameter and 30 cm in height, or 10 cm in diameter and 20 cm in height.
• 😀 Concrete compressive strength testing is carried out based on the SNI 1974 in 2011 or STMJ 39 in 20 standards.
• 😀 Testing can be performed at various ages, generally 13, 7, 14, 21, 28, and 56 days.
• 😀 The first stage of testing involves measuring the diameter and height of the concrete sample to calculate its volume.
• 😀 A caliper or ruler can be used to measure the concrete's diameter and height, and multiple measurements are taken for accuracy.
• 😀 The concrete's volume weight is measured using a digital scale, and the volume weight is calculated based on the test object’s weight and volume.
• 😀 To ensure accurate results, the concrete pressure surface must be smooth, which may involve cutting or applying caving using sulfur.
• 😀 After caving, the concrete is placed on the compressive strength machine and subjected to pressure at a speed of 0.5 to 300 MPa per second.
• 😀 The compressive strength is calculated based on the maximum load achieved during the test, with cracks and the failure point also being noted.

Q & A

What is the primary objective of concrete compressive strength testing?

The primary objective of concrete compressive strength testing is to determine the capacity of concrete to withstand axial compressive loads. It is a fundamental characteristic of concrete, as most concrete structure designs rely on its compressive strength.

Which standards guide the concrete compressive strength testing process?

Concrete compressive strength testing is carried out based on SNI 1974 in 2011 or STMJ 39 in 20.

What are the typical dimensions of the cylindrical test object used in concrete compressive strength testing?

The cylindrical test object typically has a diameter of 15 cm and a height of 30 cm. Alternatively, a cylinder with a diameter of 10 cm and a height of 20 cm can also be used.

At what ages is concrete compressive strength generally tested?

Concrete compressive strength is generally tested at the ages of 7, 14, 21, 28, and 56 days.

How is the average diameter of the concrete test object measured?

The average diameter of the concrete test object is measured by drawing a straight line across the circle, dividing it into two to find the midpoint, and then drawing a perpendicular line at the midpoint. This is repeated at several angles to get an accurate measurement.

Why is it necessary to calculate the volume weight of the concrete during the test?

Calculating the volume weight of the concrete helps in determining the density of the test object, which is necessary for further calculations of compressive strength.

What is the role of sulfur capping in concrete compressive strength testing?

Sulfur capping is used to ensure that the pressure surface of the concrete test object is smooth and uniform. The capping process involves using heated liquid sulfur to form a cap that helps achieve consistent results during testing.

How is the compressive strength of concrete calculated after the test?

The compressive strength of concrete is calculated by dividing the maximum load reached during the test by the cross-sectional area of the concrete cylinder.

What is the speed at which the concrete is pressed during the compressive strength test?

During the compressive strength test, the concrete is pressed at a speed of 0.5 to 3.0 MPa per second.

What should be observed during the concrete compression test?

During the concrete compression test, the maximum load reached should be noted, and attention should be given to any cracks that occur. The typical cracks that may appear during the test are also significant indicators.