Section 4132.  Special Backfill Material

4132.01     DESCRIPTION.

· Crushed stone, crushed PCC, crushed composite pavement, or reclaimed HMA,

· Mixtures of gravel, sand, and soil, or

· Uniformly blended combinations of the above.

· Do not place Reclaimed HMA below high water table.

4132.02     GRADATION.

Meet the gradations of Tables 4132.02-1 and 4132.02-2:

Table 4132.02-1: Gradation Requirements for Special Backfill Material
Material	Gradation (Aggregate Gradation Table, Article 4109.02)
Crushed Stone Crushed PCC Crushed Composite Pavement	No. 30
Gravel or Gravel Blends with Crushed Stone, PCC or Composite	No. 31

Table 4132.02-2: Gradation Requirements for Reclaimed HMA Used for Special Backfill Material
Material	Gradation
Reclaimed HMA	Nominal top size of 2 inches

4132.03     QUALITY.

For gravel mixture, comply with the following:

A.    Plasticity Index.

Not to exceed 10%. Test according to Iowa DOT Materials Laboratory Test Method No. 109.

B.    Carbon Content.

Not to exceed 1.0%. Test according to Iowa DOT Materials Laboratory Test Method No. 111.