METHOD OF SAMPLING
This method describes the procedure for sampling in-place granular subbase, granular shoulder and other similar non-proportioned aggregate products from the roadway. This sampling method is to be used only as a referee method in determining segregation.
A. Apparatus
1. Metal sampling template, approximately 10 in. (250 mm) wide, 14 in. (350 mm) long and 6 in. (150 mm) deep. A template identical to that specified in IM 322 is also acceptable.
2. Laboratory sampling scoop
3. Putty knife
4. Iowa DOT standard sample bags
B. Sampling Procedure
1. A minimum of three sampling locations shall be determined by the engineer and should always be obtained behind the laydown machine before the material is compacted. If the in-place aggregate does not appear to be uniform, the sample should be secured to represent a cross section of the roadway.
2. The template shall be placed on the surface and forced straight down through the material as far as possible.
3. All the material inside the template shall be scooped out and placed in the sample bag, making sure that all the material adhering to the scoop and the sides of the template is added to the sample.
C. Precautions
1. Care shall be taken to minimize segregation of the coarse and fine portions of the samples.
2. Care shall be taken to prevent contamination or loss of material during sampling.
3. Each sample shall be labeled and accompanied by a completed Form #193.