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California Aggregate Source Approval SOP

SOP Compliance Updated Jun 19, 2026 ยท Concrete Contractor

Why this matters

California concrete projects that touch public funds, schools, hospitals, or Caltrans right-of-way require aggregate from a Caltrans-approved source or an equivalent agency-approved source with documented test history. Pouring with unapproved aggregate exposes the contractor to rejection of the placement, removal-and-replace at contractor cost, DSA or OSHPD non-conformance reports, and on Caltrans work the cancellation of the bid item. The two failure modes that actually surface in the field are alkali-silica reactivity (ASR) from reactive chert, opaline, or strained quartz aggregates and contamination from organic fines or deleterious substances. Both are catchable at the source-approval stage; neither is curable once the slab is down. This SOP defines the steps to qualify a source before any concrete is batched.

Step 1: Confirm the agency requirement

Read the project specifications first. The relevant tiers are:

  • Caltrans Standard Specifications Section 90-1.02C "Aggregates" - requires aggregate from a Caltrans Authorized Material List source or compliance with Caltrans Test 554 (ASR) and Section 90 grading.
  • DSA (Division of the State Architect) - K-12 and community college work follows CBC Chapter 19 referencing ACI 318. Aggregate must meet ASTM C33.
  • OSHPD / HCAI - hospital work follows CBC Chapter 19A with stricter inspection of the mix design submittal package.
  • City / county public works - typically reference Caltrans Section 90 or the Greenbook (Standard Specifications for Public Works Construction).

If the project is private with no public funding, ASTM C33 compliance and the local building department's mix design submittal is the floor.

Step 2: Pull the source documentation

Request the following from the aggregate supplier in writing before the first ticket:

  • Caltrans source code and current Authorized Material List status (verify on the Caltrans Materials Engineering and Testing Services site, not on the supplier's letterhead alone).
  • ASTM C33 gradation reports for both coarse and fine aggregate, dated within 90 days.
  • ASR test results per ASTM C1260 (accelerated mortar bar) at 16 days. Expansion under 0.10 percent is non-reactive; 0.10 to 0.20 percent is potentially reactive and requires ASTM C1567 mitigation testing with the proposed SCM; over 0.20 percent is reactive and the source is rejected unless mitigation is proven.
  • Organic impurities per ASTM C40, deleterious substances per ASTM C33 Table 3, soundness per ASTM C88, and Los Angeles abrasion per ASTM C131.
  • Chloride content if the placement is reinforced and exposure category is C2 (ACI 318 Table 19.3.2.1).

Step 3: Validate ASR mitigation if required

If the source is potentially reactive, the mix design must include either Class F fly ash at 20 to 35 percent cement replacement, slag cement at 35 to 50 percent replacement, or lithium nitrate per ACI 221.1R. The mix design submittal must include ASTM C1567 results showing expansion under 0.10 percent at 16 days with the actual proposed SCM dosage. Do not accept a generic "fly ash mitigates ASR" statement; the test must be run on the proposed combination.

Step 4: Document the chain of custody

For each placement, the batch ticket must show the source code matching the approved submittal. If the supplier switches pits mid-project (common during pit reclamation cycles), the new source requires a fresh submittal package and approval before any concrete from that source is placed. This is the single most common cause of rejected pours on Caltrans work.

ASR damage shows up 5 to 15 years after placement as map cracking, gel exudation at cracks, and loss of strength. By the time it surfaces, the contractor's bond and warranty are usually expired but the design professional and the contractor remain exposed under the 10-year statute of repose in CCP 337.15. Source approval is the only practical control.

Step 5: File the approval package

Keep the approval package in the project file for the full retention window:

  • Caltrans projects: retain per Section 7-1.02K of the Standard Specifications.
  • DSA / OSHPD: retain per Title 24 record-retention requirements.
  • Private: retain through the statute of repose (CCP 337.15, 10 years from substantial completion).

Include the Caltrans AML printout, supplier mix design submittal with all referenced ASTM reports, the approved-by stamp from the engineer of record or the resident engineer, and every batch ticket cross-referenced to the placement log.

References

  • Caltrans Standard Specifications Section 90 "Concrete" (2024)
  • ASTM C33 / C33M-23 "Standard Specification for Concrete Aggregates"
  • ASTM C1260-23 "Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method)"
  • ASTM C1567-23 "Standard Test Method for Determining the Potential Alkali-Silica Reactivity of Combinations of Cementitious Materials and Aggregate"
  • ACI 318-19 "Building Code Requirements for Structural Concrete" Section 19.3
  • ACI 221.1R-98 "State-of-the-Art Report on Alkali-Aggregate Reactivity"
  • California Code of Civil Procedure Section 337.15 (10-year statute of repose)
  • California Building Code 2022 Chapter 19 and 19A

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