10/4/17 - Last week, Caltrans’ Chief of Construction Rachel Falsetti issued a directive to contractors on the option to use returned plastic concrete.  Construction Procedure Directive #17-6, Contractor Option to Use Returned Plastic Concrete, advises contractors that Section 90-9 of the 2015 Revised Standard Specifications allows use of up to 15% returned plastic concrete with fresh concrete.  Sidewalks, driveways, and drainpipe cover are among eligible applications.  The specification was developed by a team of CalCIMA Technical Committee operators working with Caltrans’ Rock Products Committee.  Among the findings of the work group were that for every yard of concrete reused there is a 15.3% reduction in carbon footprint and 16.2% percent reduction in embodied energy.

ASTM C1798-16 & ASTM C94-17a - Specification for Returned Fresh Concrete for use in a new batch of Ready-mixed Concrete.  "Fresh concrete not yet discharged from a ready-mixed concrete transportation unit when it is returned to the manufacturer."
* Returned concrete is of adequate quality to be reused.
* Does not grant permission for use.  Purchaser shall be notified of use (in C94).
* Does not apply to less than 1000 lbs (0.25 Cyds).

ASTM C1602 - Using recycle water into fresh concrete.