Pekerjaan Struktur Beton Bertulang // Quality Control Pekejaan Beton part1

Summary

This training video covers the essential procedures for quality control in concrete work on construction projects. It includes steps for casting preparation, such as ensuring the right concrete mixture, reinforcement installation, and proper formwork. The video also delves into the concrete casting process, emphasizing sample testing, the number of required samples, and key tests at various stages (4th, 14th, 21st, and 28th day). Additional topics include concrete maintenance, filling out casting forms, and ensuring proper equipment and materials are available. The video is a comprehensive guide to concrete quality control for construction professionals.

Takeaways

• 😀 Ensure the composition of the concrete mixture is accurate, whether using concrete from a batch plant or a site mix.
• 😀 Always conduct sample tests for concrete to guarantee the mixture meets the required design specifications.
• 😀 For concrete from a batch plant, the quality is generally guaranteed, while with site-mixed concrete, extra caution is necessary.
• 😀 Pay attention to the cleanliness of the reinforcement materials and ensure proper installation of wire and bonding.
• 😀 Check that the thickness of the decking concrete meets the required standards, such as a minimum of 50mm for soil contact or 30mm for non-soil contact.
• 😀 Ensure formwork is securely installed and capable of withstanding the weight of wet concrete to prevent structural issues.
• 😀 Thoroughly clean the casting area, removing debris like wire pieces, plastic, leaves, and wood, to ensure clean and quality concrete casting.
• 😀 In the casting process, ensure the availability of concrete, either from a batch plant or site mix, and have necessary materials and tools ready.
• 😀 Maintain proper sampling procedures as per standards (e.g., SNI 03 28 47 of 2002), ensuring that a minimum of five test objects per concrete type are made.
• 😀 Sampling frequency should follow regulations, with tests at 4, 14, 21, and 28 days, and additional testing may be needed if the planned quality is not met.

Q & A

What is the first step in the preparation process for concrete casting?

The first step is to ensure the composition of the concrete mixture. If concrete is from a batching plant, confirm the mix design from the supplier and test samples. For site-mixed concrete, ensure the mix design is correct and perform sample tests.

What is the difference between using concrete from a batching plant (Bejingplan) and site-mixed concrete?

The main difference is that concrete from a batching plant guarantees quality, and any issues related to quality can be claimed from the supplier. With site-mixed concrete, the responsibility for quality control lies with the user, making it riskier if the design is not followed precisely.

Why is it important to ensure the thickness of decking concrete?

The thickness of decking concrete must be ensured because it serves as a protective cover for the reinforcement. Concrete covers that are in contact with soil or water should have a minimum thickness of 50 mm, while other surfaces like beams not in direct contact with water or soil need 30 mm.

What should be done to ensure formwork is properly set before concrete casting?

Ensure that the formwork is installed firmly and supported as necessary. This prevents the formwork from collapsing or shifting during the casting, which could lead to uneven concrete placement and structural risks.

What must be done regarding cleanliness before starting the concrete casting?

Before casting, the area must be thoroughly cleaned. This includes removing wire pieces with magnets, cleaning up plastic waste and leaves, and spraying dust and wood pieces with a compressor to ensure no contaminants affect the concrete.

What is the minimum number of test objects required for concrete testing?

The minimum number of test objects required for concrete testing is five. This applies to each concrete quality used in one project and ensures an accurate representation of the concrete’s quality.

What factors determine the number of concrete samples to be tested?

The number of concrete samples to be tested depends on the casting size. For instance, one pair of test objects is required for each casting of 120 cubic meters of concrete or 500 m² of concrete floor or walls. The larger the casting, the more samples are needed.

When should concrete testing be conducted during the curing process?

Concrete testing should be done on the 4th, 14th, 21st, and 28th days of curing. If the planned concrete quality is not met by the 28th day, further testing may be necessary to assess the mix’s performance.

What is the role of the concrete technician during sampling?

The concrete technician plays a critical role in ensuring that sampling is done correctly. They oversee the collection of samples and ensure that the proper procedures are followed, with a representative from the owner or a third-party observer also present to verify the process.

How are concrete samples randomized if the required number is not met?

If the required number of test objects is not met due to sampling conditions, randomization is applied. This involves using the same volume interval of the test and ensuring that at least five samples are gathered for testing.