Asphalt mixture sampling is a key part of ensuring the quality of road construction, which involves extracting specimens from the construction site according to standard methods to make specimens that meet the experimental requirements. Laboratory testing of these specimens allows the material properties to be evaluated to ensure that it meets design specifications, thereby improving road durability and safety.
Asphalt mixture sampling method
Purpose and Scope of Application
The asphalt mixture sampling method is suitable for collecting hot mix asphalt mixture or room temperature asphalt mixture samples in mixing plants and road construction sites. These samples are used for quality inspection during construction or for the determination of the physical and mechanical properties of asphalt mixtures in the laboratory. Samples should be taken to ensure representativeness.
Instrumentation and material requirements
Tools – shovels, hand shovels, enamel trays or metal containers, plastic woven bags, etc.
Thermometer - a plug-in digital thermometer with a metal rod should be used, with a range of 0~300°C, a graduation value of 1°C, and a length of not less than 150mm.
Other materials – labels, solvents (e.g. kerosene), cotton yarn, etc.
Sampling method
Number of samples - the number of samples should be at least twice the amount used in the test, and the number of samples should be doubled for parallel tests.
Sampling process
Hot Mix Asphalt Mix – Sampling is taken from under the mixer discharge hopper in the mixing plant and is taken each time the material is discharged to ensure uniform mixing.
Loading of material trucks - After the truck is half-loaded, samples are taken from different heights and directions to ensure the representativeness of the sample.
Construction site sampling – sampling is taken on both sides of the paving width after paving and before rolling to ensure sample diversity.
Preservation and handling of specimens
The temperature should be measured immediately after sampling and packed into an insulated container at high temperatures. When storing, it should be protected from moisture and avoid being affected by the environment.
Labeling of the sample
The sample marking needs to record the basic information of sampling, including the name of the mixing plant, the type of mixture, the sampling time and the sampler.
Asphalt mixture specimen manufacturing method (compaction method)
Purpose and Scope of Application
This method is suitable for using the standard compaction method or the large compaction method to make asphalt mixture specimens for the laboratory to carry out physical and mechanical property tests. According to the nominal maximum particle size of the aggregate, the corresponding compaction method is selected.
Instrumentation and material requirements
Automatic Compaction Instrument - Includes standard compaction instrument and large compaction instrument, with automatic counting and control functions.
Asphalt mixture mixer - it needs to be able to ensure the mixing temperature and fully mix evenly, with a capacity of not less than 10L.
Mold test - the inner diameter of the standard compaction instrument is 101.6mm, and the height is 87mm.
The production process
Number of specimens - according to the particle size of the aggregate, select the appropriate number of specimens, at least 4 for the standard compaction method and at least 6 for the large compaction method.
Mixing and compaction - At the specified temperature, the mixture is mixed and then compacted by a compactor to form a standard specimen.
conclusion
Asphalt testing methods are essential to ensure quality management in highway construction. Through scientific sampling and specimen production methods, the physical and mechanical properties of asphalt mixture can be effectively evaluated, and reliable data support can be provided for road construction. The standardization and normalization of these detection methods help to improve the overall quality of asphalt mixtures and meet the needs of modern transportation infrastructure construction.
