1350.04.01.01.02 – This…

1350.04.01.01.02 – This section is extremely prescriptive. There is no need to specify the use of a Type A or D water reducer. Plant-added superplasticizers should be at the concrete producer’s / Contractor’s option in a performance specification. The specification also states that the standard concrete set is within 3 hours, which is not correct… the concrete industry would have to add an accelerator in many cases to achieve a 3-hour initial set time.

1350.04.02.01.01 – I am struggling with this list of a – f. Items a and E relate to different concrete production and placement location methods. Item b is a placement and consolidation method for ready mixed concrete. Items C and D overlap since different “sources of materials” includes different sources of admixtures. Item F is not defined in the standard at all.

1350.04.02.01.01 – The concrete delivery ticket cannot contain two mix design numbers, and the concrete industry does not utilize mix codes assigned by third parties.

1350.04.02.01.05 – What exactly is required to comply with “Documentation for aggregates used in concrete demonstrating compliance with the requirements of OPSS 1002”. Shouldn’t confirmation that the aggregates are on the DSM list be sufficient since conformance testing has already been reviewed by the MTO? We would also note that the admixture industry will not supply compatibility certification letters for products from other suppliers. We would request that item d be deleted.

1350.05.03 – During recent industry consultations, the MTO indicated that they would be identifying applications that are not impacted by scaling that can utilize more than 25% slag or 10% fly ash but we do not see that included in the specification. We would suggest that the SCM replacement levels be completely removed for items such as: structural elements below the frost line, mass concrete elements, caissons, bridge piers that are not within 10 metres of a second road (bridges over waterways).

1350.05.03 – Delete “For tremie concrete, the minimum cementing material content shall be 415 kg per cubic metre of concrete”. This is a prescriptive requirement not a performance requirement. We would welcome the opportunity to identify the performance requirements for tremie concrete placements at the committee level but at a minimum Tremie concrete should have a specification requirement that is not based on cement content.

1350.05.04.01 – The cement and concrete industries at the national level have moved to support Type II and Type III Environmental Product Declarations (EPDs) in 2023. The Federal Treasury Board has implemented a performance based system for Greenhouse Gas Reductions (GHG) for all federally funded projects with at least 100 m³ of ready mixed concrete. We have highlighted these initiatives at past ORBA Structures Committee meeting but we see no proposed changes from the prescriptive systems the MTO has followed in the past. We would request that a standalone meeting be scheduled to address these critical sustainability issues.

1350.05.04.01 – Self Consolidating Concrete was a new ready mixed concrete product in the Ontario marketplace about 25 years ago. SCC is no longer “new” and its utilization shouldn’t be subject to a project specific request on every project. The standard needs to leave the choice of the use of this product to the contractor.

1350.05.04.02 & 1350.05.04.03 – OPSS 1350 PROV remains the only standard in Ontario that doesn’t utilize the CSA A23.1/.2 Exposure Class requirements. This standard also sets concrete performance requirements that are less stringent that the minimum performance requirements of the CSA A23.1/.2 standard in contradiction to the bridge code (S-6) and the Ontario Building Code. This standard also ignores the CSA A23.1/.2 requirements for a maximum W/CM ratio and prescriptively specifies concrete slump in contradiction to the CSA Standard. We would ask that the MTO ensure conformance with the CSA A23.1/.2 standard and ensure adherence to S-6 minimum requirements. We request a follow-up meeting with the Chief Engineer regarding the potential impacts on public safety associated with setting concrete performance requirements that are less stringent than those specified in the Ontario Building Code since these lesser requirements migrate their way into commercial and municipal projects.

1350.05.04.03 – Slump requirements of Table 1 do not conform with the slump requirements of CSA A23.1 – clause 4.3.2.3.2. Update to match the CSA standard (a tighter slump tolerance does not result in better concrete). As outlined previously, concrete slump is to be selected by the Counteractor based on their method of concrete placement and construction methods. The Contractor should indicate on the Mix Design submission their target slump and the acceptance tolerance of CSA A23.1/.2 clause 4.3.2.3.2 should then define jobsite acceptance or rejection. Additionally, the concrete industry adds superplastiziers primarily at the concrete plant. The specification should not require jobsite additions of these products unless the Contractor/Concrete Producer feel this is more appropriate.

1350.06.02 – The ready mixed concrete industry and the contractors have been requesting the expanded use of the mobile concrete mixers, not their elimination. Why are these mixers not acceptable when the Contractor and the Concrete Producer are proposing their use and are willing to certify that they will provide concrete that meets all MTO performance requirements?

1350.07.04.03 – Many concrete producers no longer utilize a “automated printing device” (aka Dot Matrix Printer) and have moved to electronic delivery tickets that are produced when the concrete load is batched at the plant. Approximately 50% of the concrete trucks in the province now have “electronic tablets” for the recording of jobsite additions and times, so the requirement for “in writing” cannot be met since the data is in electronic form. 

1350.07.05.07 – The Within-Batch Uniformity requirements of Table 2 do not conform to CSA A23.1 – Table 13. Please update Table 2 to conform to the requirements of CSA A23.1/.2.

1350.08.01.01 – Update to read “The individual test results shall be provided to the Contractor and Concrete Producer as they become available”. CSA A23.1/.2 requires the Owner to provide concrete test results to the Concrete Producer within 5 business days of the test report being issued.