Section 4125. Aggregate for Bituminous Sealcoat

 

4125.01 DESCRIPTION.

Crushed stone, gravel, or sand.

         Must be washed.

         Crushed aggregate is required for primary and interstate roadways and may be specified for other projects.

         Produce crushed gravel as a separate operation by crushing the gravel particles retained on a screen at least 1/4 inch (6 mm) larger than the aggregate size specified.

 

4125.02 GRADATION.

Meet aggregate gradation requirements for the gradation number specified in Table 4125.02-1. Unless specified otherwise, use the 1/2 inch (12.5 mm) sieve size.

 

Table 4125.02-1: Aggregate Gradation Requirements (Bituminous Sealcoat)

Size

Gradation No.

1/2 inch (12.5 mm) Crushed Gravel or Stone

19

Screened Gravel

20

3/8 inch (9.5 mm) Crushed Gravel or Stone

21(a)

Sand Cover Aggregate

1(b)

(a) 1/2 inch (12.5 mm) size may be used when 3/8 inch (9.5 mm) size is specified except for Primary Road applications.

(b) For a crushed stone product allow up to 4% passing the #200 (75 μm) sieve.

 

4125.03 QUALITY.

         Free from objectionable clay coatings that prevent emulsions from fully coating the aggregate when determined using Materials I.M. 349.

         Type 4 or better frictional classification as shown in Materials I.M. T203.

         For cover aggregate for bituminous sealcoat, meet the requirements of Table 4125.03-1:

 

4125.03-1: Aggregate Quality (Bituminous Sealcoat)

Aggregate Quality

Maximum Percent Allowed

Test Method

Abrasion

40

AASHTO T 96

C Freeze

10

Office of Materials Test Method No. Iowa 211, Method C

Shale (+ No. 4 (4.75 mm) sieve)

5.0

Materials I.M. 372

Shale (+ No. 16 (1.18 mm) sieve)

(Sand cover aggregate)

2.0

Materials I.M. 344