Changes to Section 26-Aggregate Bases in Caltrans 2010 Standard Specifications

In the new 2010 standard specifications there has been a change to Section 26-Aggregate Bases.  The most exciting of which is that there is no longer a provision that only 50% of the aggregate base can be made from recycled materials.  It is now allowed to have any combination of broken stone, crushed gravel, natural rough surfaced gravel, sand, and/or processed reclaimed asphalt concrete, PCC, LCB, or CTB.

The other big change is that the Class 3 Aggregate Base is no longer specified in the special provisions on a job by job basis.  The specification is now present in the Standard Specifications.  It reads as follows:


26-1.02C  Class 3 Aggregate Base

When tested under California Test 202, aggregate must comply with the grading requirements for the sieve sizes shown in the following table:

Aggregate Grading
Sieve sizes	Percentage passing
	1-1/2 inch maximum		3/4 inch maximum
	Operating range	Contract compliance	Operating range	Contract compliance
2"	100	100	--	--
1-1/2"	90–100	87–100	--	--
1"	--	--	100	100
3/4"	50–90	45–95	90–100	87–100
No. 4	25–60	20–65	40–70	35–75
No. 30	10–35	6–39	12–40	7–45
No. 200	3–15	0–19	3–15	0–19

Aggregate must comply with the quality requirements shown in the following table:

Aggregate Quality
Property	California Test	Operating range	Contract compliance
Resistance (R-value) (min)	301	--	50
Sand equivalent (min)	217	21	18

The Caltrans 2010 standard specifications can be found in pdf form at http://www.dot.ca.gov/hq/esc/oe/standards.php and are now for sale in book form on the Caltrans website here.


*Sorry about the tables looking weird...the platform I'm using doesn't seem to like them and gives me some funky formats...