4133.01 DESCRIPTION.
Crushed stone or natural sand and gravel.

4133.02 GRADATION.
Meet the requirements for Gradation No. 32 of the Aggregate Gradation Table, Article 4109.02, except when used as backfill under flowable mortar or as floodable backfill.

4133.03 QUALITY.
For crushed stone, meet the following requirements:

TABLE 4133.03
Coarse Aggregate Quality	Maximum Percent Allowed	Test Method
Abrasion	55	AASHTO T 96
C Freeze	20	Iowa DOT Materials Laboratory
Total of Abrasion & C Freeze	65	---
Clay Lumps and Friable Particles	4	Materials I.M. 368

4133.04 BACKFILL UNDER FLOWABLE MORTAR.
Use one of the following:

A. Natural sand complying with the requirements for Gradation No.1 of the Aggregate Gradation Table, Article 4109.02, with a maximum of 4% passing the No. 200 (75 μm) sieve.

B. Material complying with the requirements for Gradation No. 12 of the Aggregate Gradation Table, Article 4109.02.

C. Material complying with Article 4133.05.

4133.05 FLOODABLE BACKFILL.