Aggregate Prequalification Program


The Aggregate Prequalification Program (APP) has been developed to provide contractors the ability to submit aggregate for quality assurance testing by Caltrans before the award of construction contracts. It is intended to reduce costs, delays, and additional liquidated damage payments to Caltrans associated with prequalification testing during the construction phase and allows Caltrans to achieve the goal of developing additional project delivery efficiencies as specified in SB 1.

The program is managed by Caltrans, Division of Engineering Service (DES), Materials Engineering and Testing Services (METS), Office of Central Laboratories (OCL), and the Aggregate Materials Testing Branch (AMTB).

Program Requirements

Requests for aggregate to be verified under the APP are addressed in the order in which a complete submittal has been received. The general process is identified below:

  1. Aggregate suppliers should e-mail the Aggregate Prequalification Request Form to the APP Administrator (
  2. A sampling date will be scheduled and a certified inspector from Caltrans will be present for sampling.
  3. Quality Control and Quality Assurance testing will be performed concurrently.
  4. Aggregate supplier must submit Quality Control test results onto the Data Interchange for Materials Engineering (DIME) database and e-mail the test reports to APP Administrator (
  5. After Quality Control and Quality Assurance testing are completed and test results are processed, the APP administrator will e-mail the supplier an acceptance notification valid for up to one year or a rejection notification.
  6. If accepted, the material will be placed on the Aggregate Prequalification Program List.

For full details and procedures on the submittal process, refer to the Authorization Criteria (PDF).

The Department retains the right to inspect, sample, and test aggregate source materials for additional verification at any time.

If you have any questions regarding the APP, please contact the APP Administrator at


  • Why is there a witness required to observe the APP sampling?

    We require both the sampler and witness to be Caltrans IA certified for CT 125. This ensures that both the QC (Vendor) and QA (Caltrans) labs receive a proper split sample, and that the two programs remain independent. The Department's witness observes the sampling, takes custody of the QA split-sample, and delivers the sample to the QA lab. The Vendor is responsible for delivering the QC sample to the QC lab.

  • How long does the approval process take?

    While it can vary depending on time of year, region, and project workloads. Although the approval process can take up to 2 months, it usually takes approximately six weeks to complete. Making sure that you properly fill out and submit all paperwork and test reports in a timely manner will help minimize the turnaround time and prevent delays to your submittal.

  • Where can I find the requirements for material acceptance?

    Currently, the APP prequalifies aggregates for use based on the values given in Section 90 of the Caltrans Standard Specifications. The acceptable ranges of values are given in section 90-1.02C.

  • How can I gain access to DIME?

    If you do not have a DIME account, you can find more information about the registration process on the DIME Website or by visiting the Caltrans DIME YouTube Channel.

  • Who can I contact if I have any questions about the APP?

    If you have any further questions about the APP or policies, or if you would like to give feedback on the program, you may email us at