Section 4123.  Modified Subbase Material

 

4123.01     DESCRIPTION.

Aggregate of the following Types:

·         Crushed stone,

·         Gravels for which 75% or more of the particles retained on the 3/8 inch sieve have at least one fractured face as defined in Materials I.M. 305,

·         Recycled pavements meeting Materials I.M. 210, or

·         Uniformly blended combinations of these materials with a maximum of 50% RAP.

·         Do not place RAP below high water table.

 

4123.02     GRADATION.

 

A.    Meet the requirements for Gradation No. 14 of the Aggregate Gradation Table, Article 4109.02.

 

B.    Process RAP to pass the 2 inch sieve.

 

C.    Uncrushed gravel and/or sand may be uniformly blended with crushed recycled pavement or crushed stone at a maximum rate of 50% to meet gradation requirements.

 

4123.03     QUALITY.

 

A.    The requirements of Table 4123.03-1 apply to virgin materials:

 

Table 4123.03-1: Aggregate Quality

Aggregate Quality

Maximum Percent Allowed

Test Method

Abrasion

50

AASHTO T 96

C Freeze

15

Iowa DOT Materials Laboratory Test Method No. 211, Method C

 

B.    The requirements of Table 4123.03-1 apply to recycled PCC when the aggregate source is unknown as outlined in Materials I.M. 210.