Reducing Embodied Carbon with David Mar - COTE 3/8/2011

AIA COTE, San Francisco, CA March 8, 2011Reducing Embodied Carbon in the Built Environment

Resilience is SustainableThere Are No Bad Materials It’s the Cement

The Seismic Environment U.S. Geological Survey: 70% probability of a magnitude 6.7 or larger earthquake in the Bay Area in the next 30 yearsActive E.Q. Faults

Code Seismic Design Throw-away technology: Structure and Architecture absorbs energy through damage Large Inter-story Drifts: Result in architectural & structural damage High Accelerations: Result in content damage & loss of functionDeformed Section – Eccentric Braced Frame

Self-healing Structure • Immediate Occupancy - Green Tag - Minimal Repair Cost and Time • Self Centering Response - No Permanent Tilt - Tough & Damage Resistant • Small Interstory Drift - Protects Façade - Protects Gravity Frame

SF PUC Building Performance Goals High Performance Seismic Design • Immediate Occupancy Value Engineering Savings • $10 million Redesign in Concrete from Steel • After DD complete • Initiated by WebcorArchitect: KMD/Stevens

Steel to Concrete RedesignArchitect: KMD/Stevens Steel Scheme (155 Dampers)

Link Beam OptimizationTrade Partners: Herrick, Harris-Solinas

Link Beam Optimization

Rebar Savings conventional reinforcement post-tensioned reinforcementSave 50% steel

Structural Material MatrixArchitect: BNIM Architects

Structural Material OptionsArchitect: BNIM Architects

The Chartwell School

High Insulation & High Embodied Energy

Resource Efficient Framingconventional framing resource efficient framing Save 30% in lumber as compared to conventional framing Savings allowed FSC lumber

Conductivity Studies Thermal Bridging Framing StudyMechanical Engineer: Taylor Engineering

Low Cement ConcreteLimit cement contentSlag replaces cement (flyash does not)Pozzolanic concrete improves durabilityStrength does not equal to durabilityStronger aggregates need less cement

The Chartwell School Chapin Ready Mix LEED Platinum - Innovation Credit Orinda City Hall Cemex LEED Gold - Innovation CreditThe David Brower Center Hanson LEED Platinum – Innovation Credit San Francisco PUC Central Concrete Supply (in construction)

Fly Ash Fly ash is fine residue produced by the combustion of coal in power stations.

Granulated Blast-Furnace (GGBF) Slag Slag is a nonmetallic product developed simultaneously with iron in a blast-furnace.

Pozzolanic ConcretePORTLAND CEMENT AND CEMENTITIOUS POZZOLANS: CS + H = CSH + CH calcium water calcium calcium silicates silicate hydroxide hydrate (glue) (weak crystals) Pozzolans turn weak crystals into strong crystals NON-CEMENTITIOUS POZZOLANS: CH + S = CSH calcium silica (fly ash or slag) calcium hydroxide silicate (weak crystals) hydrate (glue)

Pozzolanic Concrete 1.15 4% 1.1 6ksi 1.05 50% Fly Ash-F 9%Unit Cost 1 5ksi 0.95 11% 15% 15% Fly Ash-F 0.9 4ksi 0.85 3ksi

Pozzolanic Concrete 1.2 1.15 Relative Cost 6 ksi 1.1 5 ksi 1.05 1 4 ksi 3 ksi 0.95 0.9 0.85 Fly Ash Content 0.8 15% 20% 25% 30% 35% 40% 45% 50% 55% 60%

Pounds per Cubic Yard0 100 200 300 400 500 600 421 lbs 105 lbs cement fly ash-F Pozzolanic Concrete 290 lbs 290 lbs cement fly ash-F 250 lbs 250 lbs 4ksi concrete fly ash -C cement 250 lbs 250 lbs cement slag 200 lbs 200 lbs cement slag 250 lbs 3ksi concrete 150 lbs cement slag

Pozzolanic Concrete

Durability Rapid Chloride Permeability Tests Per ASTM C 1202 at 56 Day Standard Cure 6,000 Charge Passed Chloride Ion Penetrability > 4,000 High 2,000 - 4,000 Moderate 1,000 - 2,000 Low 100 - 1,000 Very Low 5,000 < 100 NeglibilbeCharged Passed (Coulombs) 4,000 100% Cement 3,000 25% Fly Ash 100% Cement 100% Cement 2,000 100% Cement 25% Fly Ash 25% Fly Ash 1,000 25% Fly Ash EF V2 50% EF V2 50% EF V2 50% EF V2 50% EF V2 EF V2 EF V2 EF V2 70% 70% 70% 70% 0 450 550 650 750 Total Cementitious (Lbs)

Set Times

Pounds of CO 2 per Cubic Yard Concrete0 50 100 150 200 250 300 350 400 450100% Portland Cement50% Fly Ash Type F 18% reduction 50% Fly Ash Type C Carbon Dioxide Emission 42% reductionChartwell Mix: 55%70% Slag reduction

SF PUC BuildingArchitect: KMD/Stevens

Concrete Spec Collaboration Mix requirements: 1. Mat foundation: a. Compressive Strength: 8000 psi in 90 days. b. Maximum cement content per cubic yard: 200 lbs. c. CSM content: 70 percent of the total cementitious materials. 2. Core walls and columns: a. Compressive Strength: 8000 psi in 90 days. b. Maximum cement content per cubic yard: 225 lbs. c. CSM content: 70 percent of the total cementitious materials. 3. Post-tensioned concrete slabs and beams (compressive strength to be determined by maturity methods): a. Compressive Strength for stressing: 4500 psi in 3 days. b. Compressive Strength: 6000 psi at 56 days. c. Maximum cement content per cubic yard: 440 lbs. d. CSM content: 45 percent of the total cementitious materials. e. See paragraph 2.09 D in this SECTION for required reflective index.

Low Cement ConcreteArchitect: BNIM Architects

Low Cement Concrete 90 days 56 days 28 days 10 daysSupplier: Central Concrete

SF PUC BuildingKMD/Stevens Mat Slab •Strength 8ksi at 90 days •70% supp. cementitious material •Temp logging system •Maximum cement 200 lbs/yd •CO2 Footprint 335 lbs/yd Baseline •Cement 600 lbs/yd •CO2 footprint 760 lbs/yd •Delta = 425 lbs/yd

Low Cement Concrete Design Concrete Mix Optimization – Sustainability, Performance and Cost Elevated P.T. Slabs •Strength 4.5ksi at 3 days - constructability •Final strength 6ksi at 56 days - structure •45% supp. cementitious material •Minimum Reflective Index 0.7 - lighting •Maturity Testing - mix design •Maximum cement 440 lbs/yd •CO2 Footprint 562 lbs/yd Baseline •Cement 800 lbs/yd •CO2 footprint 944 lbs/yd •Delta CO2 = 382 lbs/ydArchitect: KMD / Stevens

Low Cement Concrete DesignTotal CO2 Savings:• 7,400,000 lbs CO2 reduction• Reduce C02 footprint by 50%

AIA COTE, San Francisco, CA March 8, 2011Reducing Embodied Carbon in the Built Environment

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Reducing Embodied Carbon with David Mar - COTE 3/8/2011

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Reducing Embodied Carbon with David Mar - COTE 3/8/2011 — Presentation Transcript