Sustainable High Performance Concrete Buildings

1
Sustainable High Performance Concrete Buildings

• Ed Alsamsam, PhD, PE, SE, LEED AP, Portland
  Cement Association
• Lionel Lemay, PE, SE, LEED AP, National Ready
  Mixed Concrete Association
• Martha Van Geem, PE, LEED AP, CTLGroup

2
Life Cycle Perspective
Material Acquisition Manufacturing Construction Op
eration Reuse/Recycling
3
LEED Categories
It evaluates environmental performance from a
whole building perspective over a buildings life
cycle, providing a definitive standard for what
constitutes a green building.
4
Life-Cycle of Building Materials
Embodied energy for materials acquisition,
manufacturing and construction accounts for lt 2
of total energy
Occupant energy-use accounts for 98 of
life-cycle energy
5
Minimum Energy Performance

• EA Prerequisite 2
• Minimum level of energy efficiency
• Comply with ASHRAE 90.1
• Prescriptive requirements or performance
  requirements
• Required prerequisite

6
Optimize Energy Performance

• EA Credit 1
• Option 1
• 110 points for 10.5 - 42 cost savings (3.5
  increments)
• Percent cost savings over baseline building
• ASHRAE 90.1 Performance Rating Method
• Option 2
• 4 points
• Comply with ASHRAE Guide for Small Office
  Buildings
• Option 3
• 1 point
• Comply of the Advanced Building Benchmark v 1.1

7
Optimize Energy Performance

• EA Credit 1
• All LEED projects are required to achieve two (2)
  Optimize Energy Performance points for projects
  registered after June 26, 2007
• 14 energy savings beyond code

8
Baseline Building ASHRAE 90.1

• Common, lightweight assemblies
• Roofs Insulation entirely above deck
• Above-grade walls Steel-framed
• Floors Steel-joist
• Window-to-wall ratio 0.40
• Roof reflectivity 0.30

9
Investigate Effects of Thermal Mass

• Increase thermal lag
• Off peak demand
• Lower energy costs
• Lower peak energy
• Smaller, more efficient HVAC equipment
• Reduce temperature swings
• Less heating and cooling energy required

10
Ten Simulated Scenarios

• DOE2.1E (visualDOE)
• Dynamic whole building energy simulation
• Six climate zones

11
(No Transcript)
12
Simulation Results

• Cold Climates
• Denver 21 savings
• Chicago 18 savings
• Qualify for 3 points (17.5 energy cost savings)
• Cool Climates
• Salem 23 savings
• Qualify for 4 points (21 energy cost savings)
• Mild Climates
• Memphis 16
• Qualify for 2 points (14.4 energy cost savings)

13
Brownfield Redevelopment

• SS Credit 3
• Rehabilitate documented contaminated sites
• Reduces pressure on undeveloped land
• Document contamination and remediate site
• Worth 1 point
• Solidification and stabilization with
  cementitious materials

14
Stormwater Management

• SS Credit 6.1
• Limit disruption and pollution of natural water
  flows by managing stormwater runoff
• 1 point
• Option 1 If existing imperviousness is less than
  50 then maintain existing discharge rate
• Option 2 If existing imperviousness is more than
  50 then decrease discharge rate by 25
• Promote natural infiltration
• Minimize impervious surfaces
• Green roofs
• Pervious pavements

15
Heat Island Effect (non-roof)

• SS Credit 7.1
• Reduce heat islands
• 1 point
• Option 1 Provide any combination of the
  following for 50 of the site hardscape
• Shade (w/in 5 years of occupancy)
• Paving materials with a Solar Reflectance Index
  (SRI) of at least 29
• Open grid paving system for 50 of parking area
• Option 2 Place a minimum of 50 of parking
  spaces under cover where roof has an SRI of at
  least 29

16
Heat Island Effect (roof)

• SS Credit 7.2
• Reduce heat islands
• 1 point
• Option 1 Using roofing materials having SRI
  equal to or greater than 78 for low sloped roof
  or 29 for steep sloped roof for a minimum of 75
  of the roof surface
• Option 2 Install a vegetated roof for at least
  50 of the roof area

17
Construction Waste Management

• MR Credit 2.1 and 2.2
• Divert construction, demolition, and land
  clearing waste from landfills
• 1 point for 50 diversion
• 2 points for 75 diversion
• Adopt construction waste management plan
• Recycle materials
• Recycle concrete
• Recycle aggregate
• Recycle wash water

18
Recycled Content

• MR Credit 4.1 and 4.2
• Increase demand for recycled products
• 1 point for 10 recycled content
• 2 points for 20 recycled content
• Use SCMs
• Fly Ash
• Slag
• Silica Fume
• Key to High Performance
• Improves durability
• Increases strength
• Improves constructability

19
Regional Materials

• MR Credit 5.1 and 5.2
• Increase demand for materials within region
• Based on value (cost) of materials
• 1 point for 10 manufactured regionally within a
  radius of 500 miles
• 2 points if 20 of regionally manufactured
  materials are also extracted, harvested, and
  recovered with 500 miles

20
Daylight and Views

• EQ Credit 8.1 and 8.2
• Provide occupant connection between indoor and
  outdoor spaces by introducing daylight
• 1 point for 75 of spaces
• 2 points for 90 of spaces
• Open floor plans
• Shallow floor plates
• Light colored surfaces

21
Innovation in Design

• Reduction of CO2 by 40
• Increase use of SCMs such as fly ash and slag

22
Innovation in Design

• Use exposed concrete surfaces to improve indoor
  air quality
• Reduces use of other finish materials

23
Concrete and Climate Change
24
How much CO2 embodied in concrete?

• Concrete uses 7 and 15 cement by weight
• Average quantity of cement is around 250 kg/m3
• 100 to 300 kg of CO2 embodied per cubic meter
• 33 to 57 of CO2 from calcination reabsorbed
  through carbonation over 100-year life

25
Energy of Production
Pentalla, Vesa, Concrete and Sustainable
Development, ACI Materials Journal,
September-October 1997, American Concrete
Institute, Farmington Hills, MI, 1997.
26
Concrete vs. Wood Frame

• Thermal mass systems save energy
• Lower CO2 emissions from building occupancy
• Research study compared energy performance of
  various concrete wall systems to wood and steel
• Concrete systems reduced energy by 17
• Stick-frame house must be 2x12 with R-38
  insulation to achieve same energy performance as
  insulated concrete wall comprised of 150 mm of
  concrete and two layers of 60 mm thick rigid
  insulation

Gajda, John, Energy Use of Single-Family Houses
With Various Exterior Walls, CD026, Portland
Cement Association, Skokie, IL, 2001, 49 pages.
27
Concrete Frame vs. Steel Frame

• Study compared the CO2 emissions of concrete and
  steel framed buildings
• Concrete frame produced 550 kg of CO2 per square
  meter of floor area
• Steel frame produced 620 kg of CO2 per square
  meter of floor area

Guggemos, A. A. and Horvath, A., Comparison of
Environmental Effects of Steel- and
Concrete-Framed Buildings, ASCE Journal of
Infrastructure Systems, June 2005, American
Society of Civil Engineers, Reston, VA, 2005.
28
What is the cement industry doing?

• 33 reduction in CO2 since 1972
• Additional 10 reduction by 2020 from 1990 levels
• Limestone additions
• Saves 11.8 Trillion Btus
• Eliminates 2.5 million tons of CO2
• Reduce waste by 60

29
What is concrete industry doing?

• Committed to continuous environmental improvement
• P2P Initiative (Prescriptive to Performance
  Specifications for Concrete)
• The P2P Initiative removes limits on materials
• Allows producers to meet performance requirements
• Minimize environmental impact

www.nrmca.org/P2P
30
Summary
31
Resources

• www.nrmca.org
• www.cement.org
• www.ctlgroup.com