AASHTO R 66:16(2020) Standard Practice for Sampling Asphalt Materials.
Note 2—An alternate to completely filling a container with emulsified asphalt is to fill the container until a small amount of space remains. Squeeze the container to cause the contents to fill to the top. Place the cap and securely tighten it. The space remaining will aid in mixing the sample prior to testing.
6.5. Transferring samples from one container to another shall be avoided. if possible.
6.6. Immediately after filling, sealing, and cleaning, properly identify the sample containers with a suitable marker. Write on the container itself, not on the lid. Labels or tags also may be used for identification if they can be securely fastened to the container in such a manner as to ensure that they vill not be lost in transit. Labels or tags shall not be attached to containers by using the lids to secure them. All identification materials shall maintain their integrity at temperatures up to 200°C
6.6.1. Label information shall include at a minimum: material type, source, and sample date.
8.2.1. Samples of liquid asphalt materials and materials liquefied by heating may be taken by the “dip method” using a clean wide-mouth plastic jar or friction-top can in a suitable holder. A clean container must be used to take each sample. and the material sampled shall then be transferred to another new and clean container for retaining or testing the sample.
8.2.2. A detachable or permanent sampling pipe fitting, similar in design to the one shown in Figure 4. may be inserted in the discharge line. This outlet assembly is to be inserted into the discharge line between the unloading pipe and hose as close to the end as is practical. The sample shall be taken after one third and not more than two thirds of the load has been removed. Before the sample is taken, 4 L (1 gal) shall be drawn from this sampling valve and discarded. The sample shall be taken slowly.
8.2.3. If the distributor is not equipped with a sampling valve, a sample may be obtained from a nozzle on the spray bar.
Note 3 Take care when sampling from a distributor to ensure the bar and nozzle are flushed prior to sampling to avoid contamination.AASHTO R 66 pdf download.