2. Portland Low Carbon Concrete Initiative Presentation to Austin JSC — original pdf

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CITY OF PORTLAND LOW CARBON CONCRETE INITIATIVE City of Austin Joint Sustainability Commission December 18th, 2024 Cary Watters Sustainable Procurement Program Manager Agenda • Origin of the initiative • Initiative development • Pilot projects • Embodied carbon threshold • Exemptions • Misconceptions • Lessons learned • Open discussion 2 Origin of the initiative 2016 Sustainable Supply Chain Analysis 3 Timeline of City and State Partnership to Advancement of Low Carbon Concrete City of Portland Concrete EPD Requirements for City Projects City of Portland Buy Clean policy developed Advisory committee Data collection Pilot projects Concrete Embodied Carbon (GWP) Threshold Requirements 2016 2017 2018 2019 2020 2021 2022 2023 State of Oregon Concrete EPD Incentive Program Buy Clean legislation introduced, did not pass Buy Clean legislation introduced again, did not pass Buy Clean Oregon Passes (DOT only) State of Oregon 4 Steps in the initiative: Convened a committee of stakeholders. 1. 2. 3. 4. 5. Established a product-specific EPD requirement for concrete mixes used on City projects Established a baseline average EPD for Portland area for Portland cement concrete Conducted pilot tests of lower-embodied carbon concrete mixes Established requirements for GWP thresholds for concrete mixes 5 Step 1: Low Carbon Concrete Committee Representing Stakeholder Type City of Portland – Sustainable Procurement Program City Bureau/Committee Convener City of Portland – Water Bureau City of Portland – Bureau of Transportation City of Portland – Bureau of Environmental Services - Materials Testing Lab Oregon Department of Environmental Quality 4 Portland area ready-mix suppliers 3 structural and materials engineers 3 contractors – residential, commercial, infrastructure Architect City Bureau City Bureau City Bureau Engineers Contractor Designer Subject Matter Expert – Low Carbon Concrete Concrete Producers 6 Step 2: City of Portland Low Carbon Concrete Procurement Policy for EPDs 7 Step 2: City of Portland Low Carbon Concrete Procurement Policy for EPDs • EPDs are submitted as part of the specifications submittal for a concrete mix • Our staff reviews EPD for: • Is the EPD current (not expired) • Is the EPD 3rd-party verified • Rare issues concrete EPD • One Bureau submitted the EPD for the cement, but not the ready-mix 8 Step 3: Determine a baseline • GWP range of the 1100 published EPDs in Portland region (2019) • 17 plants, 4 producers • Portland skewed higher than PNW average 9 EPD Mobile Mix Concrete in Portland • Link to EPD for Mobile Mix Concrete • Establishes a baseline: the average environmental impact of ready-mix concrete produced and delivered by four mobile mix companies servicing the Portland, Oregon metro area. 10 Added GWP to Approved Concrete Mix Designs List 11 Step 4: Pilot Projects • Evaluated effects on project schedule, cost, & finishing in the field Traffic signal pole footing Driveways Pavement and ADA ramps Stormwater + Playground 12 Results of Pilot Studies • Set up time is longer in cold temperatures • Early strength is reduced in cold temperatures, but final 28-day compression strength meets design PSI • Minor difference in float feel, no difference in look • Utilities are still detectable below, regardless of slag content • Maturity Testing Sensors (right) are helpful to assess early strength • In the pilot projects, the embodied carbon of the low-carbon mixes ranged from 23-50% GWP savings vs. the 100% cement mixes Read the case study reports here 13 Step 5: Concrete Embodied Carbon Threshold • Applies to City-owned or solicited construction projects • Compliances pathways: 1. Concrete Embodied Carbon Thresholds – Per Mix (table 1 right) 2. Concrete Embodied Carbon Thresholds – Project Average (using an equation) visit this link for the full requirements 14 GWP Savings of Concrete Embodied Carbon Thresholds City of Portland Concrete Embodied Carbon Threshold Compared to NRMCA Pacific Northwest (PNW) Average per strength class Strength PSI @ 28 days 2,500 3,000 4,000 5,000 6,000 8,000 3000LW 4000LW 5000LW 2022 PNW Average GWP 180.02 199.84 241.95 295.20 311.94 372.65 396.24 439.72 483.36 City of Portland GWP limits (per cubic yard) 2023 GWP Threshold vs. 2021 EPD Mobile Mix GWP Savings 180 200 242 295 312 373 396 440 483 - 40% 36% 32% - - - - - 15 Exemptions • Not required for mix volumes of < 50yd3 over the entire project. • EPDs for concrete mixes supplied by a mobile mix concrete producer may be a “Portland Metro Area Industry Average EPD for Mobile Mixers” in lieu of a product-specific EPD so long as their firm is listed on the EPD as a participating producer (and other conditions). • Listed companies: Jake’s Mobile Mix, Portland Water Bureau, Volume Concrete, and Tualatin Valley Short Load Concrete • A prime contractor may seek a temporary exemption to the GWP threshold if the applicable concrete producer can demonstrate that supply chain constraints outside the producer’s control mean that producing a compliant mix for the application is temporarily not possible. visit this link for the full requirements 16 Misconceptions 1. 2. 3. 4. “Is the City is mandating a concrete mix that substitutes a large part of the cement for furnace slag?” “We are worried it will take a long time for low carbon concrete to obtain the required strength.” “Doesn’t low carbon concrete take longer to set up?” – “Will the cost of the low carbon concrete be higher?” 17 Local Cost Impacts • Meeting City of Portland GWP threshold requirement is easy to achieve with advance procurement notice and causes a cost premium of 0-5%. • 20-40% GWP reduction is currently at a ~10%+ cost premium. • Cost premium attributed to materials costs vs. EPD development among large producers. 18 Considerations for concrete GWP reductions • Is your project overengineered? Review your specifications • Do all poured concrete areas need early strength? Foundation and slab-on grade pours are best opportunities for type 1L concrete. Review your construction sequencing • Need a new mix? Let the mix company work for you. Call your suppliers at least 30 days in advance. • How far are mixes being trucked? Long trucking distances can affect GWP, but typically not as much as cement content and composition. 19 Lessons Learned and Recommendations for step 6 onward 1. Adopt GWP Thresholds per Committee Recommendations & Establish Updating Protocols/Procedures 2. Work with Inter-Bureau Team on Implementation of Thresholds a. EPDs b. Usage Reports c. Develop recommendations on how to update standard specifications to more performance-based specifications. Key areas for the Team to address: • Remove any w/cm ratio specs2 • Check for/remove any minimum cement content requirements • Check for/update any SCM limits • Ensure Type 1L and common SCMs are not outright prohibited on any applications • Require early consultation with concrete suppliers in the project prior to submitting mix designs, etc. d. Develop standard specifications for engineering/architect professional services on CM/GC projects to consult with concrete supplier in the design phase of the project e. Develop template “instructions to bidders” for construction services projects using concrete that direct bidders to consult with their concrete supplier regarding using low-carbon mixes for the specific project when developing their bids. 3. Revisit Inspection Practices by City Inspectors 4. Develop Outreach Materials 5. Seek Reinforcing Collaborations 6. Revisit How to Shift to Low-Carbon Concrete Among Mobile-Mix Producers 7. Support New Material/Market Development with More Pilot Tests As Needed 20 Cary Watters Sustainable Procurement Program Manager cary.watters@portlandoregon.gov VISIT US ONLINE portland.gov/bps The City of Portland is committed to providing meaningful access. To request translation, interpretation, modifications, accommodations, or other auxiliary aids or services, contact 311, Relay: 711. Traducción e Interpretación | Biên Dịch và Thông Dịch | अनुवादन तथा व्याख्या | 口笔译服务 | Устный и письменный перевод | Turjumaad iyo Fasiraad | Письмовий і усний переклад | Traducere și interpretariat | Chiaku me Awewen Kapas | 翻訳または通訳 | ການແປພາສາ ຫຼ ອະທິ ບາຍ | ﺔﯾﮭﻔﺷﻟا | Portland.gov/bps/accommodation ﺔﯾرﯾرﺣﺗﻟا ﺔﻣﺟرﺗﻟا ື ການ وأ