solutions for the construction industry
Specifying Blended Cements
for Sustainable Healthcare Design
Photo courtesy Donley’s Inc.
Cementitious-based building materials and LEED
by Andrew Pinneke, PE, LEED AP
Hospitals, clinics, and other types of
medical facilities are striving to
create high-performance buildings
more conducive to healing, while also
reducing energy and water consumption to
minimize their environmental footprint.
As the demand for sustainable design and building practices
grows, concrete and cementitious-based building materials
are making a strong contribution to the construction of new
healthcare facilities. Concrete and blended cements can be
used to achieve credits under the U.S. Green Building Council
(USGBC) Leadership in Energy and Environmental Design
(LEED) program in uses ranging from stormwater
management to the improvement of indoor air quality (IAQ).
They do so while also offering possibilities for versatile design
innovations using shape, color, and texture.
With the longest life span of any building material, concrete
has all the advantages to respond to the challenges of
sustainable healthcare construction. A mixture of natural
substances, concrete is locally produced, entirely recyclable,
durable, and fire-resistant. It also provides good thermal mass
properties and acoustic insulation qualities.
Concrete’s thermal inertia properties enable it to absorb
heat during the day, store it, and give it back at night—this
makes for substantial heating and air-conditioning savings.
As it is a highly resistant and airtight material, concrete can
easily be used with other materials to provide optimal
insulation, while offering numerous solutions for limiting
greenhouse gas (GHG) emissions resulting from the
building’s daily use. In high-risk areas, concrete’s resistance
properties enable the design of buildings demonstrating
superior resiliency performance during natural disasters.
Blended cements (i.e. those under ASTM C595, Standard
Specification for Blended Hydraulic Cements, or ASTM C1157,
Standard Performance Specification for Hydraulic Cement)
contain supplementary cementitious materials (SCMs) as a
partial replacement for portland cement. This enhances the
material’s strength and versatility. The three most
commonly employed SCMs are:
• slag—a reclaimed by-product of the iron- and steelmaking process;
• fly ash—a coal-combustion by-product of power plants;
and
• silica fume—a by-product of silica metals and
ferrosilicon alloys.
Since they are recycled industrial materials, SCMs enable reuse
of by-products that would otherwise be landfilled. Moreover,
their use reduces the volume of portland cement required to
make concrete, decreasing the amount of energy associated
with cement production, lowering GHG emissions, and
reducing the virgin material required for making concrete.
How concrete contributes to LEED
Sustainable construction aims to identify building materials
and methods that are cleaner and more environmentally
responsible while ensuring the highest quality in terms of
aesthetics, durability, and strength.
There are several resources to help design professionals
tackle sustainability initiatives in the healthcare industry.
Though not a rating system, the first guide to enhancing
healthcare facilities was the Green Guide for Healthcare
(GGHC). Introduced in 2011, the most widely adopted
green building rating system in the United States is the
Figure 1 LEED 2009 for Healthcare
Sustainable Sites
Points
SS Credit 3
Brownfield Redevelopment
1
SS Credit 5.1
Site Development–Protect or Restore Habitat
1
SS Credit 5.2
Site Development–Maximize Open Space
1
SS Credit 6.1
Stormwater Design–Quality Control
1
SS Credit 6.2
Stormwater Design–Quantity Control
1
SS Credit 7.1
Heat Island Effect–Non-roof
1
SS Credit 7.2
Heat Island Effect–Roof
1
SS Credit 9.2
Connection to the Natural world–Direct Exterior Access for Patients
1
WE Credit 1
Water-efficient Landscaping
1
WE Credit 3
Water Use Reduction
1-3
Water Efficiency
Energy and Atmosphere
EA Prerequisite 2
Minimum Energy Performance
Required
EA Credit 1
Optimize Energy Performance
1-24
Materials and Resources
MR Credits 1.1, 1.2
Building Reuse–Maintain 55%, 75%, 95% of Existing Walls, Floors,
and Roof; 50% of Interior Non-structural Elements
1-4
MR Credit 2
Construction Waste Management–Divert 50 or 75%
1-2
MR Credit 3
Sustainably Sourced Materials and Products
1-4
MR Credit 6
Resource Use—Design for Flexibility
1
Indoor Environmental Quality
How concrete, cement,
and supplementary
cementitious materials
(SCMs) may contribute
to points under the U.S.
Green Building Council’s
(USGBC’s) LEED 2009 for
Healthcare program.
EQ Prerequisite 3
Hazardous Material Removal or Encapsulation (renovations only)
Required
EQ Credit 2
Acoustic Environment
1-2
EQ Credit 3.1
Construction IAQ Management Plan–During Construction
1
EQ Credit 4
Low-emitting Materials–Adhesives & Sealants or Paints & Coatings
1-4
Innovation in Design Process
ID Credit 1
Innovation in Design Process
1-4
ID Credit 2
LEED-accredited Professional
1
ID Credit 3
Integrated Project Planning and Design
1
Sustainable building materials and design options with low-carbon footprints
are helping minimize environmental impacts and achieve operational goals.
LEED for Healthcare (LEED-HC) rating system, which
provides sustainable construction standards for inpatient
and outpatient facilities and licensed long-term care
facilities. The rating system may also be used for medical
offices, assisted living facilities, and medical education and
research centers.
In comparison to LEED for New Construction (LEED-NC),
LEED for Healthcare modifies existing credits and features
new, healthcare-specific ones. In all, six prerequisites and 25
credits were modified, and three prerequisites and 15 credits
were added to the rating system. The minimum program
requirements for LEED-NC also apply to LEED-HC projects.
For structural elements and pavements, concrete containing
SCMs contributes to LEED credits in several categories.
(Figure 1, lists the specific names.)
Following the official launch of LEED-HC, projects meeting
certain criteria (i.e. hospitals, long-term care
facilities, and other buildings serving individuals
seeking medical treatment) must use the
healthcare program rather than LEED-NC.
Buildings with other medically related uses, such
as medical education and research centers, may
use LEED-HC at the project team’s discretion.
Many of the materials being used to build a new hospital at Gundersen
Lutheran Health System are being produced locally, including the concrete
containing slag cement and fly ash.
Photos courtesy GRT Admixtures
Sustainable Sites (SS)
In this category, concrete and blended cements
using SCMs contribute to points gained by:
• in-situ soil stabilization with soil cements in
brownfield redevelopment;
• reduced footprints and limited site disturbance
with above and below ground multi-story
concrete structures;
• pervious concrete and permeable grids for
stormwater management; and
• lighter-colored, high-albedo concrete pavements
in landscape and exterior systems or roof
systems with concrete tiles that reduce the urban
heat island effect.
Energy and Atmosphere (EA)
Buildings constructed using concrete possess thermal
mass, which helps moderate indoor temperature
extremes and reduce peak heating and cooling loads.
This improves energy performance in structures.
Light-colored concrete materials can be produced
using SCMs to reduce lighting energy costs.
Reflective surfaces help reduce the amount of
fixtures and lighting required. Additional benefits
with concrete envelope systems include:
• thermal mass and acoustical properties;
• pest resistance; and
• increased resistance to natural disasters, including
earthquakes, hurricanes, floods, and fire.
Gundersen Lutheran’s parking ramp was designed with many green qualities,
including concrete containing a silica fume-portland cement blend to achieve
a life expectancy of 100 years.
Materials and Resources (MR)
SCMs can extend a structure’s useful service life
The new North Tower
under construction at the
Moses H. Cone Memorial
Hospital specifies 40 percent
cementitious replacement
with slag cement to earn
points toward its Silver
certification under the LEEDHC program.
Photo courtesy Triad Business Journal
Slag Cement for Moses H. Cone
Slag cement is playing a key role in the construction of the
new $200-million, six-story North Tower at the Moses H.
Cone Memorial Hospital (Greensboro, North Carolina). The
largest construction project in the hospital’s 58-year history,
the tower takes advantage of natural light and passive
energy, features noise-reducing design, relies on locally
sourced building materials, and uses less energy and natural
resources in its construction and operation.
because they improve concrete durability. Well-constructed
concrete walls, floors, and roofing elements containing these
supplementary materials can be left in place when the
building is refurbished, its interior renovated, or its function
changed. The purpose of the reuse credit is to extend the life
of the existing building stock, conserving resources and
reducing waste and the environmental impact of new
construction.
Concrete-producers recycle returned concrete, aggregate,
and wash water during the construction process, which can
contribute to construction waste management credits.
Additionally, crushing and recycling of concrete waste
materials into clean fill or road base applications diverts
usable resources from landfills.
Recycled content credits are easily obtained with blended
cements and SCM use in concrete. Concretes containing
multiple SCMs can contribute to more LEED credits because
the percentage of virgin material replaced by recycled content
determines points. Moreover, SCMs extend concrete service
life through improved durability, further reducing impact on
landfills and lessening the economic burden of construction.
Cement manufacturers often replace fossil fuels with
recycled materials; many also include post-industrial recycled
content materials to replace conventional materials for
manufacturing portland cement. This may contribute to
achievement of this credit by reducing the demand for virgin
The approximately 6700-m2 (263,713-sf) expansion specified
40 percent cementitious replacement to target credits under
the U.S. Green Building Council’s (USGBC’s) Leadership in
Energy and Environmental Design for Healthcare (LEED-HC)
program. The project, targeting LEED Silver, uses a portlandslag cement blend to achieve greater strength potential and
long-term durability. By successfully combining these cements,
the hospital is aiming to reduce its building’s carbon footprint.
Completion is expected for June.
materials, materials sent to landfills, and energy required in
cement manufacture.
Indigenous resources used to manufacture cement and
concrete, including SCMs, are usually obtained or
regionally extracted within 800 km (500 mi) of the project
site, reducing the environmental impact of transportation.
Projects with large amounts of concrete can typically
achieve both regional materials credits.
Indoor Environmental Quality (EQ)
Concrete building materials contain low to negligible levels of
volatile organic compounds (VOCs) that degrade IAQ when
they off-gas from new products, such as interior finishes,
carpeting, and furniture. Additionally, VOCs combine with
other chemicals in the air to form ground-level ozone. As
concrete building materials serve as a structural and finish
material in wall and floor applications, they reduce the need for
applied finishes or flooring materials and contribute to a
healthier indoor environment.
Concrete-based building envelopes offer significant longterm economic advantages and provide quieter, more
comfortable, safer, and environmentally considerate structures.
Unbroken exterior envelopes offer air and moisture barriers,
preventing mold growth and providing fewer cold spots and
drafts offering thermal comfort to occupants. Thermal mass
affects temperature perceived by the occupants through
(Colorado) was the first hospital in the U.S. to
receive LEED-NC. With a LEED Silver rating,
the 18,580-m2 (200,000-sf) facility contains
many sustainable features, including a concrete
mix incorporating 25 percent fly ash to improve
durability, enhance performance, and obtain
LEED points for recycled content. The cast-inplace concrete structural system used for the
hospital building frame and floor systems was
selected based on functionality and
environmental impact considerations.
Concrete strengths included:
• 20,684-kPa (3000-psi) foundations;
• 27,579-kPa (4000-psi) columns;
• 34,474-kPa (5000-psi) floor slabs; and
• 41,369-kPa (6000-psi) concrete core and
shear walls.
The use of locally produced concrete
The Mayo Clinic’s new proton beam therapy center’s design includes concrete
eliminated the environmental impacts of
containing fly ash and slag cement to achieve strengths exceeding
transporting it from other regions and helped
62,053 kPa (9000 psi).
Photos courtesy GRT Admixtures
the design team achieve its performance, cost,
and sustainability goals. The project obtained
radiance rather than air temperature.
a total of 33 LEED points, including five points for a 35
Finally, concrete can help a structure admit more daylight
percent improvement in energy performance over
deeper into a building that can be used to facilitate daylighting American Society of Heating, Refrigerating, and Airconditioning Engineers (ASHRAE) 90.1, Energy Standard
strategies. Higher strength concretes can minimize beam
for Buildings Except Low-rise Residential Buildings.
depths and maximize daylight and views through windows.
The first hospital to receive LEED Platinum, Dell Children’s
An interior concrete core can be designed to accommodate
Medical Center of Central Texas, also relied on fly ash to
higher structural loads and shear forces, allowing fewer
achieve its performance and sustainability goals. As part of its
obstructions along the building perimeter. Post-tensioning
can be used to obtain longer spans, minimizing the number of LEED effort, the project team made the most of the
$200-million facility’s location on a brownfield site originally
columns obstructing views.
part of a former airport in Austin, Texas. Approximately
47,000 tons of runway materials were reused onsite, and the
Innovation and Design (ID)
building’s concrete mix incorporated 40 percent fly ash in
Concrete building materials containing SCMs provide
the 31,347 m3 (41,000 cy) used for the foundation and walls.
incentives going beyond LEED requirements and create
During construction, 92 percent (more than 32,000 tons) of
innovative strategies not specifically addressed in the rating
waste was recycled. Additionally, local building materials
system. Several potential credits have been identified that
were used on the structure’s exterior.
relate to exemplary performance of concrete building
On the same brownfield site is the adjacent Ronald
materials containing SCMs. Three examples are:
McDonald House of Austin, which provides nurturing
• decreased lifecycle environmental impact, due to concrete’s
programs and a supportive home-like environment for
low embodied energy and long life, durability, and low
families while children receive treatment in local medical
maintenance needs;
centers. Sustainable design elements that qualified the 2648• IAQ improvements thanks to eliminating the need to paint
m2 (28,500-sf) facility for LEED Platinum included:
or adhere finishes by choosing either architectural or
• building products selected for their contribution to a healthy
prefaced concrete building systems;
• high percentage of SCM use in comparison to the usual
indoor environment;
modest percentages of fly ash, slag cement, or silica fume.
• construction materials procured within an 800-km (500-mi)
radius of the site; and
Fly ash and LEED milestones
• use of concrete containing fly ash for structural
The $53-million Boulder Community Foothills Hospital
components.
With the longest life span of any building material, concrete has all the durability
advantages to respond to challenges of sustainable healthcare construction.
Park Nicollet
Methodist Hospital
relied on a silica
fume-portland
cement blend for the
concrete in the posttensioned decks of a
55,742-m2 (600,000-sf)
parking garage.
Ternary blends: the right prescription for Gundersen
Lutheran and Mayo Clinic
One of the largest healthcare construction projects in Wisconsin,
Gundersen Lutheran Health System’s campus renewal
initiative in La Crosse includes a new six-floor hospital
designed to meet LEED-HC standards. Many of the project’s
construction materials are being produced locally, including the
concrete supplied by La Crosse-based River City Ready Mix.
Work on the 37,161-m2 (400,000-sf) hospital began in
January 2011 and is scheduled to be completed late this year.
The 15,290 m3 (20,000 cy) of concrete placed for the slab,
walls, and other structural applications relied on a ternary
mix design of 20 percent slag cement, 15 percent fly ash, and
65 percent portland Type I/II. This enabled the material to
achieve specified strengths of 31,026 kPa (4500 psi) at 28 days.
About 120 km (75 mi) from La Crosse, the Mayo Clinic is
building a 10,220-m2 (110,000-sf), $188-million proton beam
therapy center in Rochester, Minnesota. The specialized cancer
treatment center’s design includes 14,847 m3 (19,419 cy) of
concrete containing a ternary mix of 33 percent Type I/II
portland cement, 33 percent fly ash, and 33 percent slag
cement to achieve a low heat of hydration and 28- and 56-day
strengths exceeding 62,053 kPa (9000 psi) for the multiple
mass concrete placements.
In March 2012, crews from Rochester-based Ready Mix
Concrete placed 1246 m3 (1630 cy) of concrete for more than
eight hours to complete a base slab 20 m wide by 57 m long
by 1.1 m deep (66 by 187 by 3 ½ ft). Two months later, this
was followed by the ‘big pour’—the largest in the history of
Rochester—that involved more than 500 truckloads of concrete.
Over the course of 28 hours, three pumps were used to place
4205 m3 (5500 cy) of concrete for the mass concrete foundation
walls, the thickest of which measured 6.6 m wide by 4.3 m high
(21 ft, 9 in. by 14 ft). The first treatment rooms are expected
to be open in the summer of 2015.
Green medical facilities going beyond hospital walls
While healthcare organizations are demanding sustainable
design and construction as a matter of course, green building
is no longer limited strictly to hospital projects. Sustainable
building materials and design options with low carbon
footprints are being prioritized to minimize environmental
impacts and safety concerns, as well as achieve operational
and wellness goals, throughout the medical campus,
including parking facilities, ramps and sidewalks, healing
gardens, and other specialized applications.
On Gundersen Lutherans’ campus, a new three-level
underground parking ramp was designed with many green
qualities, including concrete containing a silica fume-portland
cement blend to achieve a life expectancy of 100 years. Park
Certified LEED Silver,
the Cleveland
Clinic’s East 89th
Street Garage and
Service Center (also
pictured on cover
page) used more
than 76,450 m3
(almost 100,000 cy)
of concrete with
a mix containing
20 percent fly ash.
Photo courtesy Donley’s Inc.
Nicollet Methodist Hospital in Minneapolis also relied on a
silica fume-portland cement blend for the concrete in the
post-tensioned decks of its 55,742-m2 (600,000-sf) parking
garage, as well as for loading docks and sidewalks to ensure
a durable surface that can withstand snowplows and harsh
de-icing chemicals.
Slag cement is also increasingly being specified in
sustainable parking structures, such as the transit center
serving Tuality Hospital and Pacific University’s Health
Services campus in Hillsboro, Oregon. More than 4205 m3
(5500 cy) of concrete containing slag cement were used in the
columns around the perimeter, the post-tensioned cast-inplace concrete beams, and post-tensioned concrete elevated
decks in the parking facility.
Almost half of the concrete placed contained at least
40 percent slag cement, qualifying it for an ID point under
LEED-NC. The average slag content was 19 percent of all
cementitious materials used in the concrete, but cement
with as much as 93 percent slag cement content was used for
some mixes. Another sustainable benefit of using slag
cement in this project is the resulting lighter-colored, highperformance concrete mix absorbs less heat from solar
radiation and helps to lower the heat island effect. The
pervious concrete used also stores less heat due to its
relatively open pore structure.
Recognizing the unparalleled growth driven by construction
of its Heart and Vascular Institute, the Cleveland Clinic built
the largest and most sophisticated healthcare material-handling
and order fulfillment system in the United States. With a
concrete superstructure of more than 139,355 m2 (1.5 million
sf), the East 89th Street Garage and Service Center stands as
one of the largest concrete structures in Cleveland. Its
construction used almost 76,455 m3 (100,000 cy) of concrete
with a mix containing 20 percent fly ash.
To create the slab for the structure’s 96 by 168-m (315 by
550-ft) footprint, the first stage involved 415 truckloads of
concrete and four pump trucks, with crews from Donley’s
placing more than 3058 m3 (4000 cy) of concrete, covering
3066 m2 (33,000 sf). This was followed by three more large
placements—totaling 8180 m3 (10,700 cy) of concrete—to
complete the slab over the entire building area. Most of the
building products used in the $192-million LEED Silver
facility came from sources within 80 km (50 mi) of the site.
Almost 50 percent of the concrete placed in the transit center
serving Tuality Hospital and Pacific University’s Health Services
campus contained at least 40 percent slag cement, qualifying
it for a LEED Innovation in Design Process (ID) point.
The concrete used for deep foundation and structural support
elements, as well as the heavy concrete used for radiation
bunkers and X-ray rooms, also typically include high levels
of SCMs. A 34,474-kPa (5000-psi) self-consolidating concrete
(SCC) containing slag cement and fly ash was used in the
auger cast piles for the parking garage at the new Science +
Technology Park at Johns Hopkins in Baltimore. At Holy Cross
Hospital, one of the largest hospitals in Maryland, a proprietary
flow mix containing about 75 percent fly ash is being used in
sheeting and shoring applications to support a major campus
expansion program.
Conclusion
The healthcare industry is making great strides in
implementing sustainable design and construction practices for
creating healing environments as healthy as possible, and green
building certification has proven to be the best method
possible to achieve this goal. Concrete and cementitious-based
building materials offer extensive sustainable construction
benefits and can help achieve LEED for Healthcare
certification in many ways.
While the proper use of blended cements and
supplementary cementitious materials can be more complex,
the results achieved can provide higher-performance and
more environmentally-friendly concrete mixtures. Various
organizations, including the American Concrete Institute
(ACI) and the Slag Cement Association (SCA), offer
recommendations design professionals can consult on how
to specify such substitutions. Additionally, manufacturers
can provide technical assistance to help develop or modify
specifications; most can provide detailed test results, and
cs
additional support.
Additional Information
Author
Andrew Pinneke, PE, LEED AP, is a construction and building
system specialist at Lafarge. He serves as a consultant on a
wide range of sustainable construction issues and
coordinates the company’s sustainable construction efforts
throughout the United States. Pinneke previously worked as
a structural engineer for almost a decade. He sits on the
National Ready Mixed Concrete Association (NRMCA)
Sustainability Committee, the American Concrete Institute
(ACI) Building Information Modeling Committee 131, and the
ACI Foundation’s Strategic Development Council (SDC), as
well as participates in the American Society of Civil Engineers
(ASCE) and the U.S. Green Building Council (USGBC) local
and national chapters. Pinneke can be contacted via e-mail
at andrew.pinneke@lafarge-na.com.
responsible design and construction practices continues to grow,
these building materials continue to make a strong contribution to
the sustainable design and construction of high-performance
hospitals, clinics, and other medical facilities throughout the country.
Abstract
In pursuit of Leadership in Energy and Environmental Design
(LEED) ratings and making healing environments as healthy as
possible, healthcare organizations are increasingly relying on
concrete and cementitious-based building materials in the
construction of new facilities. As the demand for environmentally
Key Words
Division 03
Blended cement
Concrete
Fly ash
LEED-HC
MasterFormat No.
03 00 00–Concrete
UniFormat No.
A1010–Standard Foundations
A40–Slabs-on-grade
B10–Superstructure
B20–Exterior Vertical Enclosures
G20–Site Improvements
Silica fume
Slag cement
Supplementary cementitious materials
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