METHOD OF SAMPLING

COMPACTED ASPHALT MIXTURES

 

SCOPE

 

This IM provides the procedures used for sampling compacted asphalt mixtures.

 

REFERENCED DOCUMENTS

 

IM 204, Inspection of Construction Project Sampling & Testing

 

APPARATUS

 

         Core drill suitable for cutting a sample from the mat

 

         Core tongs if a core drill is used to cut the sample

 

         Hammer

 

         Steel plate 4 in. (100 mm) wide, 4 in. (100 mm) long, 1/8 in. (3.175 mm) thick and curved to fit firmly around the core being taken. A piece of core bit will serve this purpose.

 

         Wedge A small cold chisel makes a suitable wedge.

 

PROCEDURE

 

1.    Unless otherwise specified, sampling frequency shall comply with IM 204 and sample sites shall be randomly located by the Engineer.

 

NOTE: Exercise care during sampling, handling, transporting and testing to minimize possibility of damaging the specimens.

 

2.    Drill completely through the layer being sampled.

 

NOTE: If samples are to be cut from compacted mixtures that are still warm, it may be necessary to subject the sample site to artificial cooling equivalent to surface contact with ice for approximately 20 minutes.

 

3.    Use the curved steel plate for protection of sample. Then place the wedge behind the plate and strike it with a sharp blow from the hammer. This will snap the sample loose.

 

4. If a layer being sampled adheres to a lower layer such that it is necessary to remove two or more layers during the sampling process, cool the composite sample and remove the extraneous material before testing by sawing or other suitable methods.

 

5. All samples shall be carefully inspected for damage before testing. Samples that are damaged shall be replaced by additional samples obtained as outlined above.

 

  1. Mark the core for later identification.

 

DOCUMENTATION

 

Assign a number to each core and record the core number, date sampled, station, and transverse position on the appropriate form.