Asphalt testing instruments have different sampling methods and sample storage methods.

　　The sampling procedure using asphalt testing equipment differs between compacted and poured asphalt mixtures, as different sampling methods are required. Below, we’ll introduce these methods one by one:

　　1. Sampling during loading or unloading: When sampling during the loading or unloading process, collect at least three evenly spaced, regular-sized samples at specified intervals. After thoroughly mixing these samples, take a regular-sized sample as the test sample. Alternatively, the samples can be tested separately.

　　2. Sampling from the asphalt storage tank: The asphalt in the storage tank should be sampled only after it has been heated and melted, and then flows through pipelines or via an asphalt pump into the asphalt heating pot. For laboratory tests involving asphalt instruments, take at least three samples per batch, spaced apart. After thoroughly mixing these samples, collect 4.0 kg as the test sample; alternatively, the samples can be tested separately.

　　3. Solid Asphalt Sampling: When sampling from drums, bags, boxes, or loose whole blocks, the sample should be taken at least 5 cm below the surface and within 5 cm of the container’s side. If the asphalt can be crushed, use a clean tool to break it into pieces and then collect a sample from the middle portion. If the asphalt is soft and plastic, use a clean, heated tool to cut a sample from it.

　　4. Sampling at the inspection address: When the asphalt arrives at the inspection address and is unloaded, sampling should be carried out promptly. The samples taken shall consist of two portions: one portion for inspection testing, and the other portion retained for future reference.

　　Now that we know how to collect samples, how should we store them to avoid contamination?

　　1. With the exception of liquid asphalt and emulsified asphalt, all asphalt samples requiring heating must be stored in sealed metal containers with lids. It is strictly prohibited to store these samples in paper bags or plastic bags. Samples should be kept in a cool, clean place, taking care to avoid any contamination. After the sample containers have been properly covered, sealed, and thoroughly cleaned, identification markings—including the sample’s origin, type, sampling date, location, and sampler’s name—must be clearly marked on the container itself (not on the lid). This applies to the entire series of asphalt testing instruments.

　　2. In winter, proper antifreeze measures should be taken when handling emulsified asphalt samples.

　　3. With the exception of some specimens used for inspection, the remaining specimens should be carefully preserved for future reference.

　　4. When samples need to be heated for testing, take an adequate quantity at once to fill another sample container sufficient for the entire batch of experiments. Other samples should be sealed and stored properly, and repeated heating and sampling should be minimized as much as possible. For samples used in quality arbitration inspections, the number of times they can be reheated shall not exceed two.