New Caltrans RHMA policy:
RHMA is the pavement surface
course of choice when evaluating
alternatives for a project.
In July 2013, Caltrans
implemented the use of
Performance Graded Modified
(PG-M) asphalt binder with
minimum 10 percent CRM.
Public Resources Code 42703
requires Caltrans use crumb
rubber in asphalt paving
To meet this crumb rubber usage
goal Caltrans must continue to
seek new ways of using recycled
tires in California pavements..
Caltrans has recently changed its
mission statement to include
Caltrans goals include both
Sustainability and Stewardship.
It is time for an innovative
approach for drastically increasing
the amount of crumb rubber used
in California’s pavements to
support these environmental
The proposed increased use of
crumb rubber in pavements is not
based on the historical engineering
approach of using crumb rubber to
improve pavement performance, but
instead is based on creating an
asphalt binder which has less impacts
on the environment.
Caltrans proposal to increase the
use of crumb rubber in pavements
will be accomplished by a
dramatic change that will require
all asphalt binder used in
California be “Green” asphalt.
This “Green” asphalt proposal
would require the use of 5
percent crumb rubber in all
asphalt binder that is currently
classified as unmodified.
Implementation of Performance
Graded Asphalt with 5 percent
crumb rubber in place of
unmodified asphalt binders in
California would result in use of
8,300,000 to 10,000,000 tires in
asphalt pavement each year.
For Caltrans an additional
2,300,000 PTE’s could be used by
requiring Performance Graded
Asphalt with 5 percent crumb
With PG+5 and Asphalt Rubber
Binder (Wet Process) for RHMA,
Caltrans would be able to divert
Caltrans could increase PTEs used
in pavements by 51 percent which
is a dramatic increase in crumb
In March 2015 Caltrans met with
industry stakeholders to discuss
Caltrans PG+5 proposal and other
industry proposed alternatives.
March 2015 meeting alternatives:
1. Caltrans PG+5
2. Caltrans PG+5 with changes
3. Dry Process
4. Field blend
The alternatives will be evaluated in
Phase 1: Laboratory Testing
Phase 2: Field Construction
Phase 3: Environmental and Life Cycle
Phase 4: Specification
This effort will follow the the Rock
Products Committee process.
Draft Scoping document for
Increasing Crumb Rubber Usage
with Small Amounts of CRM in Hot
Secure needed research funding.
The total estimated research costs
for this project is $635,000.
Caltrans is partnering with
CalRecycle on funding the
research for this project.
Increasing Crumb Rubber Usage -
Small Amounts of CRM in Hot Mix
Asphalt scoping document
approved on October 09, 2015.
Next step is that the Asphalt Task
Group appoint Caltrans and Industry
Sub Task Group Co-Chairs.
Sub Task Group to evaluate the
alternatives in terms of the
4. Expected Performance
Lab Testing (December 2016)
Environmental and Life Cycle
Analysis (July 2017)
Pilot Projects (October 2017)
Specification (April 2018)