Depending on the project scale, concrete can be ordered from a ready-mix supplier or produced on-site (site mix). If batching plants are far from the construction site, mixing concrete locally may be more practical — its working time is only about two hours, and long delivery can affect quality.

Ideally, you can rent a semi-automatic mixer with a pump and trained workers to ensure consistency and reliable strength.

Regardless of how the concrete is produced, testing is essential. The most common method is the slump test, which checks the mix’s workability. Additionally, test samples must be cast into standard molds — in Indonesia, cylindrical specimens are used — and tested after 28 days in an independent laboratory with calibrated equipment.

Several labs in Denpasar and South Kuta offer such testing services. You can find contact information QR codes in the photo gallery
Keep all testing reports until the construction is completed, or even longer. These documents may help resolve disputes or identify problems that arise later. Together with design documentation, they can determine whether errors were caused by the architect or the construction team.

For faster on-site evaluation of completed structures, ultrasonic scanning and Schmidt hammer testing can be used. While these methods are not legally binding, they provide a good indication of actual concrete quality.

Note that in Bali, laboratories generally cannot properly test cylindrical cores. They use the same press as for small cube samples, without proper calibration or conversion. The result is a simple report with raw numbers, without any formal statement of concrete quality.