Sustain Contruction New

SUSTAINABLE CONSTRUCTION

with Coal Combustion

Products

A Primer for Architects Produced by the American Coal Ash Association Educational Foundation www.acaa-usa.org

Building a Sustainable Future Our built environment has implications for

Coal combustion products (CCPs), often

the sustainable use of natural resources,

referred to as “coal ash” are materials

energy consumption and carbon emissions. Over half of the world’s population now lives in urban areas, and

produced when coal is burned to generate electricity. Each year in the U.S., coal-fueled power plants produce over 110 million tons of CCPs. About 40% of CCPs are recycled

by 2050 over two-thirds of the global

annually into concrete and a variety of green

population will be urban. Sustainable

building products.

building practices are vital for protecting the

Products made with CCPs in place of mined

natural environment while supporting livable

or manufactured materials perform better,

cities and long-term economic viability.

cost less, and decrease environmental impacts. Concrete made with coal fly ash

Substituting recycled industrial materials

is stronger and more durable than concrete

for conventional products in construction

made with cement alone. And the

results in tremendous environmental and

environmental benefits of CCP recycling are

economic benefits including improved

huge: for every ton of coal fly ash used as

technical performance and longevity; decreased water, energy and land use;

a replacement for portland cement, approximately one ton of greenhouse gas emissions are prevented. Annually, this

reduced emissions; and lower construction

reduces carbon emissions by 13 million

costs. One such recycling success story

tons–equivalent to taking 2.5 million cars

is coal combustion products.

off the road.

Fly Ash - Improving Strength Fly ash is a powdery material that is captured by emissions control equipment before it can “fly” up the power plant stack. Mostly comprised of silica, alumina and calcium compounds, fly ash has mechanical and chemical properties that make it a valuable ingredient in concrete, providing long-term structural strength. Fly ash concrete is less permeable and more resistant to acid, sulfates and other destructive chemical reactions than concrete made with cement alone. Fly ash lowers the heat of hydration, improves workability, and reduces shrinkage and cracking. More than half of the concrete produced in the U.S. contains fly ash, used for roads, bridges, buildings and concrete blocks. Builders routinely specify 40 percent fly ash in concrete mixes, but 70 percent or more in high volume

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applications has been used where structural stability is paramount.

Synthetic Gypsum - from Floor to Ceilings

Boiler Slag Lasting Durability

Power plants equipped with flue gas desulphurization (FGD) emissions controls, also known as scrubbers, create byproducts that include synthetic gypsum. Although this material is not technically “ash� it is classified as a coal combustion product.

Scrubbers utilize high-calcium sorbents, such as lime or limestone, to absorb sulfur and other elements from the flue gases.

Synthetic gypsum is used in nearly 30 percent of wallboard manufactured in the U.S. The use of synthetic gypsum avoids the mining of virgin gypsum, yielding water, energy and emissions reductions. Synthetic gypsum has also been used for cement production, self-leveling flooring applications and as an agricultural amendment to treat poor soil conditions, improving crop yields.

Boiler slag is molten ash collected at the base of older boilers that is quenched with water and shatters into black, angular pieces having a smooth, glassy appearance.

Boiler slag is typically used for roofing granules, asphalt coatings and blasting grit.

Bottom Ash - Filling Many Needs Bottom ash is a heavier, granular material that is collected from the bottom of coal-fueled boilers. Bottom ash is often used as an aggregate to replace sand and gravel, and as an ingredient in masonry products including concrete blocks. Bottom ash has also been identified as an excellent growing medium for green roofs, providing water retention benefits.

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Reaching New Heights with CCPs

One World Trade Center

Wilshire Grand Center

Burj Khalifa Tower

At 1,776 feet high, One World Trade

The foundation for the 73-story Wilshire

The tallest man-made structure in the

Center in New York City is one of the

Grand tower in Los Angeles was

world, Burj Khalifa towers 2,722 feet

greenest super-tall buildings in the U.S.

specifically designed to absorb ground

above Dubai, UAE. To achieve the

movement during earthquakes and enable

structural strength needed to withstand

the building to withstand severe

high winds and support the building’s

windstorms. The tower’s foundation is a

massive weight, the tower was designed

concrete slab utilizing high quality fly ash

with a “Y” shaped buttressed core

as a 25% substitution for portland cement

constructed with high performance fly ash

to improve structural strength and

concrete. The concrete mix was designed

concrete saved about 6000 tons of carbon

durability. The foundation for the Wilshire

to provide low permeability and high

dioxide emissions, 8 million kWh of

Grand set a world record for the largest

durability. Two of the largest concrete

energy and 30,000 gallons of fresh water.

continuous concrete pour of 21,200 cubic

pumps in the world delivered the

The high-strength fly ash concrete

yards. Fly ash was essential to the

concrete mix to heights over 2000 feet.

enabled the design to use smaller

project’s success because it mitigates

Over 330,000 cubic yards of concrete was

structural supports in columns and

the heat of cement hydration in such a

used in the construction of Burj Khalifa.

walls, yielding more livable floor area.

large-scale pour.

The design had unique durability and sustainability requirements, including using high-strength “green concrete” utilizing fly ash and slag. The concrete mix tripled the compressive strength of conventional concrete, up to 14,000 psi (pounds per square inch). The green

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Beauty in Sustainable Design with CCPs Oakland Cathedral To create lightness and space, the Cathedral of Christ the Light in Oakland, California used architecturally-exposed reinforced concrete made with fly ash.

A main design objective of the cathedral was to have the smallest environmental footprint possible, so the use of recycled fly ash achieved both strength and sustainability objectives.

Shri Swaminarayan Mandir (12) by 4nitsirk/CC 4.0

BAPS Temple The BAPS Hindu Temple in Chicago was built with

Aqua Tower The design inspiration for the

high volume (65%) fly ash concrete for the reinforced foundation, beams and shear walls to achieve a 1,000 year service life.

82-story Aqua Tower in Chicago was eroded rocks found around the Great Lakes. The wave-like balconies were created by unevenly pouring different mixtures of concrete, with the gray concrete containing more fly ash while the lighter concrete contains more portland cement.

Arizona Residence This residence designed by Arizona architect Michael Frerking was

Milwaukee Art Museum

constructed using “poured earth”

The Milwaukee Art Museum was constructed with

made with 67 percent fly ash to

high volume fly ash to achieve a variety of important

substantially reduce the building’s

design objectives. To create the unique sculptural

carbon footprint and minimize

Quadracci Pavillion, concrete was poured into

energy use.

one-of-a-kind wooden forms.

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Programs Supporting CCPs Wall-Form Products Most of these products have hollow interiors and are stacked or set in place and can be filled with high volume fly ash steel-reinforced concrete.

Fly ash and bottom ash are also used extensively in grouts and masonry products, including concrete veneer stone, available in a wide range of color options.

Flooring Applications Many builders are using CCP- based floor underlayments in construction, to address a variety of flooring situations and challenges. Self-leveling underlayments may be placed to aid in preparation of the floor prior to installation of the finished floor systems. Over-layments are sometimes specified to correct defective flooring issues prior to installation of carpeting, tile, wood or other surfaces. These applications also can provide sound insulating features. For examples of these applications see www.maxxon.com/go_green. Fly ash and synthetic gypsum are used widely in commercial applications, and can be used in single-family and multi-family homes to support LEED or Green Globes’ points for indoor environmental quality, low emitting materials, recycled content, regional materials and innovation in design.

Masonry Products

Masonry Products Fly ash and bottom ash are used extensively in grouts and masonry products, including concrete veneer stone, available in a wide range of color options.

Site Preparation CCPs have many uses when preparing a project site for development. Fly ash can be used to stabilize and solidify soils at Brownfield sites or in construction areas. If rains have made work areas difficult to access by vehicular traffic, self-cementing fly ash or fly ash combined with portland cement, cement kiln dust or lime kiln dust can dry up these areas quickly and economically. Blending self-cementing fly ash with existing soils allows for the stabilization of roads and parking areas prior to paving. When embankments or structural fills are needed, fly ash, bottom ash and boiler slag can be combined with earthen materials to meet engineering specifications for compaction,

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Ceiling Tiles & Pan Products

Ceiling tiles and

with fly ash and

can be textured

compressive strength, grain size distribution and other

with a wide rang

geo-technical considerations.

different archite

in Sustainable Architecture’

nel

Green Roofs Diagram courtesy U.S. EPA

Typically, green roofs are part of a normal roof system which involves green space on top of a building. Green roofs are usually modular in design allowing plants to be planted in movable sections or containers.

A waterproof barrier separates the green roof from the structural roof.

The units containing plants have a drainage system, filter cloth and lightweight growing media to allow the plants to establish their roots.

Green roofs can provide a wide range of benefits including aesthetic appeal, energy conservation, noise reduction, preventing water runoff, and improved air quality. Green roofs typically require less maintenance and are longer lasting than conventional roofs, and help reduce carbon emissions. Because of its lightweight, granular characteristics, bottom ash is an ideal material for part of the growing media. For more information: www.greenroofs.com and www.greenroofs.org

Carpet Backing Backing comprised of recycled materials can take years of abuse without sacrificing performance. The inherent “ball-bearing” effect resulting from the spherical nature of the glass particles of fly ash contribute to better packing factors in various polymer systems. For carpet backing systems, this translates to improved flammability ratings, better tuft binds, and improved dimensional stability. As a bonus to the performance characteristics fly ash imparts to these engineered systems, carpet backings qualify or LEED Materials and Resources credits for recycled content, and under NSF/ANSI 140 standards for sustainability.

Composites Fly ash also serves as filler in wood

Geotechnical Geotechnical applications include soil stabilization, road base,

products, countertops, plastic

engineered structural fill, and embankments. The use of CCPs in

products, paints, and metal castings.

controlled low-strength materials (CLSM), sometimes called flowable fills, provides economic alternatives to many backfill situations. When utility trenches are constructed at a job site, often the dirt or

d wall products made

earthen materials excavated are removed immediately. This

d synthetic gypsum

necessitates importing fill materials once the trench work is complete.

d and pigmented

Rapid setting flowable fills made with fly ash, bottom ash and cement

ge of colors for

ectural features.

(if needed) can be used to efficiently close the exposed work areas allowing the surface to be finished rapidly.

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Certifying the Safety and Benefits of CCPs

LEED V4

LEED Platinum Bardessono hotel

LEED Platinum home in Mill Valley, California.

Image credit: Mariko Reed Photography

Leadership in Energy and Environmental

toward certification in the categories of

gypsum products also earn credits.

Design (LEED) is a green building

Sustainable Sites, Water Efficiency, Energy

Innovative design strategies can garner

certification program developed by the

and Atmosphere, Materials and Resources,

additional credits, including reducing

U.S. Green Building Council that recognizes

Regional Priority, Innovation, and Indoor

carbon emissions through the use of high

best-in-class building strategies and

Environmental Quality.

volume fly ash concrete, fly ash bricks

practices. LEED v4 is the newest

and other recycled products made with

version of this global benchmark for

Concrete containing at least 25% fly ash is

CCPs. Using CCPs in pervious pavements,

high-performance green buildings. To

considered by LEED as an environmentally

which reduces the rate and quantity of

receive LEED certification, a building must

preferable product, earning credits in the

storm water runoff, can contribute to

attain a specific number of credits, with

Materials and Resources category.

earning LEED credits in the categories

Silver, Gold and Platinum levels

Materials that limit the extraction of raw

of Sustainable Sites, Water Efficiency,

r epresenting advanced certification. Using

materials such as synthetic gypsum

and Materials and Resources.

CCPs in construction can earn credits

wallboard as a replacement for mined

Please visit www.usgbc.org/v4

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Environmental Product

Greenprint: Denver, Colorado Declarations

Demonstrating Safety

An Environmental Product Declaration

The U.S. Environmental Protection Agency

(EPD) is an independently verified

(EPA) has conducted a thorough scientific

and registered document quantifying

evaluation of the safety of using fly ash in

the full life-cycle environmental performance of a product, evaluated in accordance with ISO standards.

EPDs are based on product

concrete and synthetic (FGD) gypsum in wallboard, finding that releases of constituents of potential concern are comparable to or lower than those from analogous products made without CCPs,

category rules (PCR) that define

or are at or below relevant health-based

the requirements for EPDs of a

benchmarks. In its 2014 published beneficial

certain category. CCP products that

use evaluation report, EPA concluded that

have EPDs include fly ash bricks

these uses “contribute significant

and carbon-neutral “green cement”

environmental and economic benefits” and

made with 95% fly ash. EPDs allow consumers to compare the environmental performance of products made with CCPs to analogous non-CCP products.

that “the Agency believes that these beneficial uses provide significant opportunities to advance Sustainable Materials Management.” See: http://www. epa.gov/waste/conserve/imr/ccps/pdfs/ ccr_bu_eval.pdf

Green Globes

The Reagan Building in Washington D.C., headquarters for EPA, was constructed with fly ash concrete.

The Green Globes building rating and

in building construction can help score

certification program was developed

points related to site development,

by the Green Building Initiative and is

materials and resources, energy

accredited by the American National

consumption, water use, emissions,

Standards Institute (ANSI). Green

and indoor environments.

Globes evaluates the environmen-

Green Globes provides early feedback

tal friendliness and sustainability

in the construction process, before

of building projects. As with LEED,

critical final decisions are made.

Green Globes promotes green building

Independent, third-party assessors

practices that yield energy efficiency,

are used in the rating. Green Globes

emissions reductions, water savings,

has been recommended by the U.S.

use of recycled and reclaimed materi-

General Services Administration (GSA)

als, healthier indoor environments, and

as one of two certifications (with LEED

reduced ecological footprint. Green

being the other) for evaluating the

Globes assesses building environmen-

performance of federal government

tal impacts on a 1,000-point scale in

agency buildings Please visit

seven categories. Utilization of CCPs

www.greenglobes.com

Perot Museum in Dallas holds the highest Green Globes certification

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The Future of CCPs in Sustainable Construction Coal combustion products are projected to continue to play a major

tons in 2033 and production of synthetic gypsum is projected to

role in sustainable construction over the next 20 years. Utilization

grow from 35.2 million tons in 2013 to 38.8 million tons in 2033, as

of coal combustion products in major markets has grown by an

shown in the chart below.

average of 4.7 percent a year since 1974, increasing to over 51 mil-

Ash beneficiation and other emerging technologies are

lion tons recycled during 2013. CCP utilization has increased during

expanding the use of CCPs into new markets and products,

three of the last five recessions since 1974 as markets have taken

ensuring dependable, high quality CCPs will be available well

advantage of the lower cost of CCPs compared with alternative

into the future. Producers and marketers are working together to

materials. The figure below shows the production and utilization of

ensure CCPs will continue to comply with applicable construction

CCPs since 1990.

standards and specifications.

Despite retirements of coal-fueled power plants over the last few

As sustainable construction becomes more important, more and

years, coal is expected to remain a primary energy source in the

more architects, construction firms and consumers have come to

U.S. for decades to come, according to the U.S. Energy Informa-

recognize the environmental, economic and sustainability benefits

tion Administration (EIA). Coal will account for the largest share of

that CCPs deliver. Science and practical experience has trans-

electric generation through 2040. As a result, fly ash production

formed the perception of fly ash and other CCPs from waste to

is forecast to grow from 53.5 million tons in 2013 to 54.9 million

valuable product.

Change to Utilization of CCPs 60 55 50

Fluidized Bed Combustion

Short Tons (Millions)

45

Flue Gas Desulfurization

40

Boiler Slag

35

Bottom Ash

30

Fly Ash

25 20 15 10 5

Data Years

10

20 05

20 02

19 99

19 96

19 93

19 90

19 87

19 84

19 81

19 78

19 78

19 75

19 72

19 69

19 66

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Sustainable Building Resources The American Coal Ash Association (ACAA)

Green Globes is an online green building

LEED green building certification program,

advances the management and use of coal

rating and certification tool licensed for use

administered by the U.S. Green Building

combustion products in ways that are

in the U.S. by the Green Building Initiative.

Council (USGBC), is the premier bench-

environmentally responsible, technically

The Green Globes New Construction as-

mark recognizing best-in-class sustainable

sound, commercially competitive, and

sessment can be used for a wide range of

building strategies and practices. To receive

more supportive of a sustainable global

commercial, institutional and multi-residen-

LEED certification, building projects satisfy

environment. www.acaa-usa.org

tial building types to advance sustainability

prerequisites and earn points to achieve

and environmental goals. Visit: www.

different levels of certification.

greenglobes.com or www.thegbi.org

Visit: www.usgbc.org/leed

several standards, including ASTM C618,

Specific guidance on the use of high

The National Association of Home Builders

ACI 232.2 and ACI 232.3. Marketers of fly

volume fly ash can be found in a book

(NAHB) ToolBase is the housing industry’s

ash will commit to the quality specified as

by V.M. Malhotra and P.K. Mehta,

best resource for technical information on

they supply fly ash to ready mix producers,

High-Performance, High-Volume Fly Ash

building products, materials and new tech-

who in turn ensure the concrete will meet

Concrete, 3rd Ed. This book contains

nologies. ToolBase Resources combines

the designer’s needs through their own

mix designs, recommendations,

product descriptions, design & construc-

quality program. Visit: www.astm.org/Stan-

precautions and examples of high volume

tion guides, best practices, performance

dards/C618.htm and www.concrete.org

fly ash concrete placement and

reports, case studies, and other resources

for more information on the standards.

applications.

in a way that builders and remodelers will

The BEES: Building for Environmental and

The Industrial Resources Council (IRC)

Economic Sustainability Software devel-

Is a collaboration of non-profit industry

The National Ready Mix Concrete

oped by NIST brings to your fingertips a

associations working together to promote

Association (NRMCA) has guidance

powerful technique for selecting cost-ef-

the appropriate use of industrial materials,

documents available that define the quality

fective, environmentally preferable building

including coal combustion products. Visit:

requirements for all concrete mix designs,

products. Visit: www.nist.gov/el/econom-

www.industrialresourcescouncil.org

including those using fly ash or slag. Visit:

The quality and characteristics of fly ash as a component of concrete are defined in

find useful. Visit: www.toolbase.org

ics/BEESSoftware.cfm

www.nrmca.org The International EPD® System library

Best Practices Guide for High-Volume Fly

contains environmental product declara-

Oikos is an online directory for green

Ash Concretes: Assuring Properties and

tions (EPD) listed by product category and

building products. Please visit:

Performance is published by the National

country. Information on creating and using

www.oikos.com

Institute of Standards and Technology

EPDs and product category rules (PCR) is

(NIST). The best practices guide considers

available at: www.envirodec.com

Sustainable Sources is an online source for

all aspects of high volume fly ash (HVFA)

green building information, including fly ash

concrete production from materials char-

concrete related information. Visit: www.

acterization through curing to long-term

sustainablesources.com

performance. NIST Technical Note 1812 is available at http://concrete.nist.gov/~bentz/ NIST.TN.1812.pdf

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Coal Combustion Products Build Sustainable...

Residences

Masonry Products

Office Buildings

Government Structures

Skyscrapers University Facilities

ervious and P Asphaltic Pavements

Bridges

Churches and Temples

Concrete Floors

Composite Products

Airports

Green Roofs

Dams and Reservoirs

Stone Veneers

Stadiums and Arenas

Plastic and Mineral Fillers

Outdoor Sports Complexes

Wallboard Panel Products

Tilt-up Buildings

Museums

Tunnels and Roadways Monuments

andscaping Applications L ...and much more.

American Coal Ash Association Educational Foundation 38800 Country Club Drive,Farmington Hills, MI 48331 720.870.7897 info@acaa-usa.org All of the images contained in this document are of buildings constructed using coal combustion products.

Printed on recycled paper.

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