Codes and regulation · October 23, 2026

Ontario seeks comment on four proposed aggregate specification updates

By Workvado / Litequo LLC · Published October 27, 2026 · Updated October 27, 2026

The Ministry of Transportation opened a 21-day consultation on changes to four OPSS aggregate standards, including concrete, asphalt, miscellaneous and base or backfill materials; the proposals are not yet in force.

Ontario’s Ministry of Transportation posted a proposal on October 23 to update four Ontario Provincial Standard Specifications for aggregates: OPSS 1002 for concrete, OPSS 1003 for hot-mix asphalt, OPSS 1004 for miscellaneous aggregates and OPSS 1010 for base, subbase, select subgrade and backfill materials. The Technical Consultation Portal opened a 21-day comment period running through November 13, 2026. The ministry’s proposal summary says the revisions are intended to clarify material requirements, align specifications with test methods and practices, and improve contract administration. The notice is explicitly at proposal stage. It is a consultation on draft changes, not a final standard or a new rule that contractors should treat as already effective. Its significance is that aggregate suppliers, testing laboratories, designers and contractors have a short window to review how the proposed wording could affect qualification, sampling, acceptance and records.

The four specifications cover materials used at different points in infrastructure work. MTO’s published 2025 version of OPSS 1004, for example, applies to aggregates used as clear stone, granular sheeting, gabion stone, mortar sand, rip-rap, rock protection, truck-arrester-bed aggregate and winter sand. OPSS 1002 covers concrete aggregates; OPSS 1003 applies to hot-mix asphalt; OPSS 1010 addresses base, subbase, select subgrade and backfill. These are not interchangeable product categories. A proposed change to concrete-aggregate acceptance may matter to a concrete producer or testing team, while a revision to winter sand administration can affect a different procurement and application cycle. The public notice groups them in one consultation, but each proposal should be assessed against the material and contract types a business actually supplies or builds.

For OPSS 1002, the notice describes two proposed changes: revised insoluble-residue requirements under test LS-613 for aggregates used in concrete pavement and exposed concrete bridge-deck driving surfaces, and permission to use mathematically combined gradations for acceptance. If adopted, the wording could affect how a producer demonstrates conformance and how a contract administrator reviews a combined aggregate blend. It would not eliminate the need to meet the stated performance or quality requirements; the draft’s exact language and any transition terms would control. Contractors should avoid trying to infer test thresholds or acceptable blends from the summary alone. Ready-mix producers, aggregate suppliers, pavement contractors and testing laboratories would need to read the proposed clauses, identify whether they use those aggregate applications and consider whether existing mix designs or QA procedures would have to change.

For OPSS 1003, MTO proposes changes to LS-613 and LS-609 requirements for Designated Sources for Materials aggregates, with the stated aim of improving acceptance requirements. The portal summary does not spell out the revised thresholds, sampling frequency or documentation changes. That leaves technical detail to the proposal documents and the eventual standard if adopted. Asphalt contractors and aggregate suppliers could use the consultation to identify whether the proposed changes clarify acceptance decisions or create a new testing burden. A useful comment would identify the affected clause, explain the current operational issue and provide supporting test or production evidence, while distinguishing a technical concern from a preference for a particular source. Vague objections are less likely to help the ministry improve the specification than a specific example tied to a material, test method and contract administration outcome.

The OPSS 1004 proposal includes several distinct items: adding CASL qualification as a prerequisite to waive certain quality-assurance physical-property tests for gabion stone, rip-rap and rock-protection materials; revising the 19-millimetre sieve gradation requirement for 19-millimetre clear stone; and updating winter-sand gradation requirements and administration. These changes touch both material characteristics and the process for acceptance or testing. The 2025 published specification already separates product uses such as clear stone, gabion stone, rip-rap and winter sand; the consultation is proposing changes to selected portions, not wholesale replacement of every aggregate provision. Producers and contractors in these segments may want to check how qualification and test-waiver rules would work with their current sources, and whether sieve and gradation requirements are clear enough to support consistent purchasing and acceptance.

For OPSS 1010, the proposal would add definitions and administrative requirements for loose reinforcing materials and introduce an acceptance limit for mica content. The portal summary does not state the proposed mica threshold or describe how sampling and testing would be conducted. Because OPSS 1010 governs materials used in base, subbase, select subgrade and backfill applications, suppliers and earthworks contractors may need to assess whether the new terminology captures products they currently sell or place. They can also consider whether the proposed acceptance approach is workable at stockpile, delivery and placement stages. The consultation is an opportunity to raise implementation questions—such as test method, sample representativeness, lot definition or responsibility for failed tests—before text is finalized. These are questions for the draft clauses and ministry, not assumptions about what the final rule will require.

The Ministry’s broader Ontario Provincial Standards information provides an important implementation caveat: use of the standards is not mandatory for every owner, and each infrastructure owner determines which versions to use and when to implement or cancel them. For MTO construction contracts, the standards referenced in the tender documents govern the work. A municipality or other owner may use a different version or include local amendments. Therefore, even if the ministry finalizes these revisions, contractors will need to check the contract’s incorporated specification and applicable addenda before changing a mix design, source approval or testing plan. A proposal posted to the MTO portal does not automatically amend every municipal project or retroactively change a signed contract. Teams should track the consultation outcome and then confirm the effective version adopted by the relevant owner.

The consultation closes at 11:59 p.m. on November 13, 2026. A supplier, contractor, consultant or testing organization that depends on affected aggregate specifications can review the proposal and submit comments through the Technical Consultation Portal under notice 000-0320. The most useful internal review is to map each proposed change to a product, test procedure, quality record and client specification, then identify the practical effect if the language is adopted. The portal does not promise that every comment will be incorporated, and no final implementation date is given in the proposal notice. For contractors, the immediate action is to keep current project requirements in view, participate in the consultation if the proposed wording affects their work, and avoid treating draft text as a binding requirement until MTO and the relevant owner publish or adopt a final version.

Proposal posted

October 23, 2026

Specifications under consultation

OPSS 1002, OPSS 1003, OPSS 1004 and OPSS 1010

Comment period

October 23–November 13, 2026 (21 days)

Consultation notice

MTO TCP 000-0320; proposal stage

Sources

1. Proposed Updates to Aggregate Material Specifications (OPSS 1002, OPSS 1003, OPSS 1004, and OPSS 1010), TCP 000-0320, Ontario Ministry of Transportation, read October 27, 2026
2. Ontario Provincial Standards, Ontario Ministry of Transportation, read October 27, 2026
3. OPSS.PROV 1004, Material Specification for Aggregates – Miscellaneous, April 2025, Ontario Ministry of Transportation, read October 27, 2026