To what accuracy must scales for gradation tests be calibrated?

For gradation tests, the scales must be calibrated to an accuracy of 0.2% of the weight tested. This level of precision is essential because gradation tests are critical for determining the particle size distribution of aggregates used in concrete and asphalt. Accurate weight measurements directly impact the test results, which in turn influence the quality and performance of construction materials.

The requirement for a 0.2% accuracy ensures that any variations in the weight of the samples are minimized, leading to more reliable and consistent gradation results. This level of accuracy also helps to conform to industry standards and specifications, which mandate precise measurements to ensure the integrity of the materials being tested. Therefore, calibrating the scales to this accuracy provides confidence in the testing processes and the materials used in construction projects.