Acknowledgments 

This document was prepared by the U.S. Environmental Prote

in cooperation with the following agencies and associations: 

Department of Energy (DOE) 

Federal Highway Administration (FHWA)


The American Coal Ash Association (ACAA)


The Utility Solid Waste Activities Group (USWAG)

Glossary 

Alkali-Silicate Reactivity: The reaction between the alkalies (so

um) in Portland cement with certain siliceous rocks and minera

chert, strained quartz, and acidic volcanic glass, present in som

products of the reaction can cause abnormal expansion and cr

service. Class F fly ash is used in concrete to reduce the occu

reactivity. 

Attenuation: The reduction in mass or concentration of a comp

water over time or distance from the source of constituents of 

urally occurring physical, chemical, and biological processes, s

tion, dispersion, dilution, adsorption, and volatilization. 

Beneficial Uses: The use of byproducts in such a manner that 

beneficial function, while not adversely impacting human healt

ment. Beneficial uses of byproducts include construction appli

and concrete products, road bed, blasting grit, wall board, insu

rials), agricultural applications (e.g., as a substitute for lime) a

(e.g., absorbents, filter media, paints, plastics and metals man

ice control, waste stabilization). 

Borrow Pit: An area from which soil is excavated for use as a f

way application. 

Cement Clinker: The fused particles or pellets produced from t

ing zone (2200o F to 2700o F) of a rotary kiln in the cement ma

Raw materials (limestone, shale, iron ore, sand) are proportion

powder and blended before being processed through the rotar

Coal Combustion Products (CCPs): Residues from coal burning, 

ash, fly ash, boiler slag, and flu gas desulfurization materials (F

used beneficially. (The use of the term “coal combustion produ

ment does not change the legal definition of solid waste as de

U.S.C. 6903(27).)

Concrete: A construction material consisting primarily of aggre

cement, and water. Certain coal ashes can be used as a repla

of the Portland cement. 
Engineered Application: Use of a byproduct that has been specif

engineered (for example, a road design that incorporates approp

trol and provides adequate strength for the required use). 

Fill: Material such as dirt, gravel, or coal ash used to build up an 

Flowable Fill: A fill material that flows like a liquid, is self-levelin

paction or vibration to achieve maximum density, hardens to a p

strength, and is sometimes used as a controlled low-strength m

Flue Gas Desulfurization Materials (FGD): The materials created d

of removing gaseous sulfur dioxide from boiler exhaust gas. FGD 

are used as a replacement for gypsum in wallboard. 

Heat of Hydration: Heat evolved by chemical reactions with wate

the setting and hardening of Portland cement. 

Leachate: The liquid, including any suspended components in th

percolated through or drained from a pile or cell of solid materia

stream that issues from a pile or cell of solid materials and that 

dissolved solids, and decomposition products of the solids. 

Maximum Contaminant Level (MCL): The highest level of a contam

allowed in drinking water. 

Portland Cement: A hydraulic cement made by heating a mixture 

clay containing oxides of calcium, aluminum, iron, and silicon in 

ing the resulting clinker. 

Pozzolanic Properties: The phenomenon of strength developmen

lime and certain aluminosilicates react at ambient temperatures 

water. 

Sulfate Attack: Either a chemical or physical reaction (or both) b

usually in soil or ground water, and concrete and mortar. The ch

primarily with calcium aluminate hydrates in the cement-paste m

cause deterioration of the cement product. 
Using Coal Ash 

Highway Cons

A Guide to Benefits an
Use of Ash in 

Construction 

Through the 

❖	 In ancient times, the Ro

volcanic ash to concret

structures such as the 

and the Coliseum—bot

stand today. 

❖	 The first major use of c

crete in the United Stat

1942 to repair a tunnel 

Hoover Dam. 

❖	 One of the most impres

structures in the count

Horse Dam near Glacie

in Montana, was const

to 1952, with concrete 

coal fly ash. 
❖	 In Washington, DC

itan area subway s

the new Ronald Re

International Trade 

with concrete cont

❖	 Other significant s

coal fly ash in con

“Big Dig” in Boston 

and piers of Tampa 

Skyway Bridge. 
The U.S. Environmental Protection Agency (EPA) encour

coal combustion products (CCPs) in highway construct

as in concrete, road base, embankments, flowable fill, 

cial applications. The increased use of these materials, which w

discarded as waste, can reduce greenhouse gases in the atmos

energy consumption, and conserve natural resources. Some app

road embankments and other non-encapsulated (loose) uses, m

uation of local hydrogeological conditions to ensure protection o

the environment. 

To encourage the increased use of coal combustion products, EP

of Energy, and the Federal Highway Administration, along with t

Ash Association and the Utility Solid Waste Activities Group, are 

Coal Combustion Products Partnership (C2

P2). The purpose of C2P

beneficial uses of coal combustion products. This booklet is inte

and the public understand both the environmental benefits and p

of using coal combustion products in various applications. EPA a

Academy of Sciences are evaluating the use of coal combustion 

fill and will address this issue separately. 
Contents 

Background Basics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

What Are Coal Combustion Products?. . . . . . . . . . . . . . . . . . . . . 

How Are Coal Combustion Products Used? . . . . . . . . . . . . . . . . . 

How Are Coal Combustion Products Used in Highway Applicatio

What Are the Engineering Performance Standards for Using Coa

Construction? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Are There State Requirements for Using Coal Ash in Highway Co

Performance and Cost Benefits . . . . . . . . . . . . . . . . . . . . . . 

In Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

In Embankments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

In Flowable Fill. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

In Stabilized Base Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

In Asphalt Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

In Grouts for Pavement Subsealing . . . . . . . . . . . . . . . . . . . . . . . 

Environmental Benefits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Greenhouse Gas Emissions and Energy Reductions . . . . . . . . . . . 

Resource Conservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Solid Waste Reduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Environmental and Health Cautions Associated with Concr

(Encapsulated) Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Environmental and Health Cautions Associated with 


Unencapsulated Uses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Water Issues: Groundwater/Surface Water Health and Human In

Vegetation and Food Chain Issues . . . . . . . . . . . . . . . . . . . . . . . . 
Air Issues: Air Quality and Inhalation . . . . . . . . . . . . . . . . . . . . . . 

Occupational Issues: Inhalation and Skin Contact . . . . . . . . . . . . 

EPA’s Position on the Use of Coal Combustion Products . . . 

Regulatory Determinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Procurement Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Concrete Pavement:


Cold In-Place Recycling of Asphalt Pavement, Jackson County, M

Boston Central Artery/Tunnel Project, Massachusetts . . . . . . . . . 

Road Base: 

State Route 22 Project, Georgia . . . . . . . . . . . . . . . . . . . . . . . . . 

Embankments: 

Route 213/301 Overpass Project, Maryland . . . . . . . . . . . . . . . . 

Access Ramp Project, Delaware . . . . . . . . . . . . . . . . . . . . . . . . . 

Flowable Fill: 

McGee Creek Aqueduct Pipe Bedding Project, Oklahoma . . . . . . 

References and Other Sources. . . . . . . . . . . . . . . . . . . . . . . 

2 
Boiler/ 

Furnace

Background Basics 

What Are Coal Combustion Prod

When coal is burned in a power plant to generate el

behind residues that can be used as products or ra

marily in the construction industry. These materials 

combustion products, or CCPs. Power plants generate a variety of 

tom ash, fly ash, boiler slag, and flue gas 

desulfurization (FGD) materials. EPA and The concentrations 

occurring elements 

industry refer to the larger ash particles fly ashes are simila

that fall to the bottom of a furnace as found in naturally 

bottom ash, and ash that is carried 

upward by the hot combustion gases of the furnace as fly ash. Bo

instead of bottom ash when combustion occurs in a wet boiler, an

are produced from scrubbers used to remove sulfur from air emis

The concentrations of naturally occurring elements found in man

similar to those found in naturally occurring soil. A mineral analy

tion products from coal-fired power plants indicates that they ar

percent iron oxides, aluminum, and silica. They also contain oxid

naturally occurring elements found in coal, such as arsenic, bariu

chromium, copper, lead, mercury, selenium, and zinc. The exact 

tion of coal combustion products varies depending on the type o

extent to which the coal is prepared before it is burned, and the 

tions for combustion. 

Figure 1: Typical Steam Generating System 

Flue G

Coal 

FGD 

Precipitator 

or 

Baghouse 

Bottom Ash Fly Ash 

FGD Byproduc

Gypsum 

FGD Waste 

Treatment and Dewatering 

Air 

Heater 

Turbine 

Condenser 

Cooling 

Water 

SCR 

Note: SCR-Selective Catalytic 

Reduction DeNOx System FGD-Flue 

Gas Desulfurization System 
How Are Coal Combustion Produc

According to the American Coal Ash Association’s annual coal co

survey, almost 122 million tons of coal combustion residues were 

and more than 46 million tons were used as products in such ben

as concrete, roofing tiles and shingles, bricks and blocks for buildi

wallboard, and specialty uses such as filler in carpet and bowling 

shows the top uses of coal combustion products, and Figure 3 sh

of coal fly ash specifically for the reporting year 2003. These figur

number one use of coal combustion products collectively, and coa

ly, is in cement, concrete products, and grout. Figure 4 presents t

bustion product generation and use in 2003 by type of material. T

Figure 2: Top Uses of Coal Combustion Products, 2003 

Snow and Ice Control 

3,999,623 Tons 

3,956,973 Tons 

2,330,032 Tons 

1,661,388 Tons 

1,497,744 Tons 

788,184 Tons 

Other 2,042,037 Tons 

Aggregate 687,839 Tons 

Wallboard 

Waste Stabilization/ 

Solidification 

Cement/Raw 

Feed for Clinker 

M ining Applications* 

Road Base/Sub-base/ 

Pavement 

Blasting Grit/ 

Roofing Granules 

Soil Modification/Stabilization 773,076 Tons 

7,780,906 Tons 

* EPA and the National Academy of Sciences are evaluating the u

tion products as minefill and will address this issue separately. 

Source: American Coal Ash Association. 2004. 

4 
that for most coal combustion materials, the United States is ben

about a third of the material generated, with the exception of boil

shows a 95 percent usage rate. 

Coal combustion products have also been used as minefill materia

National Academy of Sciences are evaluating the use of these ma

Figure 3: Top Uses of Coal Fly Ash, 2003 

1

3,919,898 Tons 

3,024,930 Tons 

683,925 Tons 

515,552 Tons 

493,487 Tons 

Mineral Filler in Asphalt 52,60

Co

Structural Fill/ 

Waste Stabilization/ 

Solidification 

Cement/Raw 

Feed for Clinker 

Mining Applications* 

Soil Modification/Stabilization 

Road Base/Sub-base/Pavement 

Aggregate 137,171 Tons 

Flowable Fill 136,618 Tons 

Other 410,218 Tons 

Embankments


5,496,948 Tons


* EPA and the National Academy of Sciences are evaluating the u

tion products as minefill and will address this issue separately. 

Source: American Coal Ash Association. 2004. 
Use in Short Tons 

Figure 4: Coal Combustion Product Generation and Use (Sh

75,000,000 

60,000,000 

45,000,000 

30,000,000 

15,000,000 

0 

Total Production Total 

Fly Ash 

Bottom Fly Ash 

Boiler Slag 

FGD Material 

Other 

Source: American Coal Ash Association. 2004. 

How Are Coal Combustion Produ

Used in Highway Applications?


The two types of coal combustion products used most often in h

tion are fly ash and bottom ash. Fly ash can be used as a replac

cement in concrete and grout, as a fill material in embankments

highway subgrades and road base, and in flowable fill. Bottom a

aggregate in concrete and in cold mixed asphalt, and as a struct

embankments and cement stabilized bases for highway construc

presents details on coal combustion product use for the 2003 ye

applications shaded.


6 
Figure 5: Details of Coal Combustion Product Use (Short To

Highway Applications are shaded. 

Uses of CCPs Fly Ash Bottom Ash Boile

Concrete/concrete 

products/grout 

12,265,169 298,181 15

Structural fills/embankments 5,496,948 2,443,206 11

Cement/raw feed for cement 

clinker 

3,024,930 493,765 15

Road base/sub-base/pavement 493,487 1,138,101 29

Snow and ice control 1,928 683,556 102

Aggregate 137,171 512,769 31

Flowable Fill 136,618 20,327 

Mineral filler in asphalt 52,608 0 31

Wall board 0 0 

Waste stabilization/solidification 3,919,898 30,508 

Mining applications** 683,925 1,184,927 59

Blasting grit/roofing granules 0 42,604 1,45

Soil modification/stabilization 515,552 67,998 

Miscellaneous/other 408,290 1,331,331 2,

Total 27,136,524 8,247,273 1,75

Source: American Coal Ash Association. 2004. 

* Flue gas desulfurization materials include FGD gypsum, FGD material wet 

al dry scrubbers and FGD other. 

** EPA and the National Academy of Sciences are evaluating the use of coa

as minefill and will address this issue separately. 
What Are the Engineering Perfo

Standards for Using Coal Ash in 

Highway Construction? 

The American Society for Testing and Materials (ASTM) and the 

Association of State Highway and Transportation Officials (AASH

numerous standards that describe the proper use of bottom and 

neering activities. 

The standard for using fly ash in Portland cement concrete—the 

type of coal combustion product used in highway construction a

mon usage—is ASTM C 618, or the very similar AASHTO M 295

fly ash are defined in ASTM C618: Class F and Class C. These cl

related to the amount of free lime or calcium oxide in the ash an

coal. Both Class F and Class C fly ash have pozzolanic properties

they react with water and free lime (calcium oxide) to produce a 

pound. Class F fly ash typically contains from 2 to 6 percent calc

requires additional lime to obtain self-hardening properties. Clas

contains between 15 and 35 percent calcium oxide and does no

lime for self-hardening properties. 

8 
The Standard Guide for Design and Construction of Coal Ash Stru

E2277-03, addresses the second largest use of coal fly ash. This 

includes guidelines on using coal ash for structural fill application

ments and other uses), site characterization considerations such 

hydrologic investigations, laboratory test procedures, design con

methods, and construction considerations. This guide replaces A

For more information concerning the ASTM and AASHTO standa

coal ash use in highway construction see the Federal Highway A

June 2003 document, Fly Ash Facts for Highway Engineers. 

Are There State Requirements fo

Coal Ash in Highway Constructio

Many states have laws, regulations, policies, or guidance author

least limited use of coal combustion products in highway constr

instance, Wisconsin’s Department of Natural Resources has dev

self-implementing regulation (NR 538 

Wis. Adm. Code), which includes a 

five-category system to allow for beneficial use of industrial byproduct material, including coal ash.1 (See sidebar on 

page 10.) The Texas Natural Resource 

Conservation Commission issued guidance in 1995 that defined coal combustion products as “co-products” instead 

of waste when used in certain applications in accordance with industry standards. Many other state regulations 

adopt by reference the federal regulation, which exempts coal combustion 

products from classification as hazardous waste. For additional information on applicable regulations, contact 

your local and state authorities. 

States with CCP Law

Policies, or G

Alabama 

Alaska 

Arkansas 

California 

Connecticut 

Colorado 

Delaware 

Florida 

Georgia 

Illinois 

Iowa 

Kentucky 

Maine 

Maryland 

Massachusetts 

Michigan 

Missouri 

1 See <www.dnr.state.wi.us/org/aw/wm/solid/beneficial/index.html>. 
Wisconsin’s Beneficial Use of Indust

Byproducts Waste Management Pro

Wisconsin’s Beneficial Use of Industrial Byp

Program is a state-authorized voluntary e

program that encourages the beneficial u

boiler slag, paper mill sludge, foundry sand, and fo

alternatives to placing these materials in the state

landfills. For the reporting year 2000, the Wisconsi

of Natural Resources (WDNR) showed that particip

tors generated more than 1.4 million tons of coal a

slag and beneficially used more than 1.1 million to

cent). WDNR also estimated that, statewide (includ

not participating in the program), nearly 72 percen

and boiler slag generated in the state is beneficial

contrast, the American Coal Ash Association repor

29 percent of the coal ash generated nationally in 

eficially used. 

Wisconsin’s beneficial use program began in 1985 

state legislature gave WDNR authority to issue lan

tions for low-hazard wastes. In 1995, this authority 

ed to allow WDNR to develop a program and rule f

industrial byproducts. The result was enactment of 

538, “Beneficial Use of Industrial Byproducts.” The 

five different categories of industrial byproducts, 

the chemical characteristics of the materials, defin

end uses for each category, and provides 12 pre-ap

ficial uses for the materials. 

For small private projects (<5,000 cu. yds. of mater

tors may use their byproducts in a pre-approved b

without contacting WDNR. For large private or pub

generators must notify WDNR of the nature of the 

provide information about the material characteri

reserves the right to review any of these projects, 

process beyond notification is required. 

10 
To ensure success, WDNR used a technical advisory commit

help develop the program, including WDNR representative

all of the district offices, representatives from the generat

community, the Department of Transportation, Sierra Club 

other environmental groups, and a number of general cont

tors that perform aggregate construction work. Because m

the affected entities were part of the development process

program was not challenged in public hearings or in court. 

addition, the rule was coordinated with Department of 

Transportation requirements, and liability issues were addr

Another key to the success of the program is that it is larg

self-implementing. Generators can conduct their own mate

testing and can proceed without state approval for uses co

by the law. The self-implementing aspect of the program w

important to the generator groups on the committee; thes

groups were willing to balance the advantages of self-imp

tation with the disadvantages of recordkeeping and report

requirements included in the law. 

NR 538 became effective in June 1998. Its success can be m

ured by the high percentage of coal ash and slag use throu

the state, compared to the national average. In addition, n

environmental issues or problems have been associated w

implementation of the program. 
Performance and Cost Be

Using coal combustion products 

in highway construction yields Why Is Coal Fly 

a number of performance and The physical properties 

cost benefits, which can lead to environ- specifically, the unique 

mental benefits as well. Performance and particle size distrib

benefits can be realized from the use of good mineral filler in h

coal ash in concrete mixtures, embank- applications, improve t

ments, in flowable fill, as a stabilized able fill and grout, and 

ability of concrete. base course, in asphalt pavements, and 

in grouts for pavement subsealing. 

In Concrete 

Coal ash can be used to create superior products because of its 

tious properties. Mixing fly ash with Portland cement mixtures c

stronger and longer lasting roads and bridges than concrete mad

Portland cement as the binder (glue). The following are notable 

fits from using coal fly ash in concrete: 

Figure 6: Strength Gain of Fly Ash Concrete 

INCREASING TIME 

I 

N 

C 

R 

E 

A 

S 

I 

N 

G 

S 

T 

R 

E 

N 

G 

T 

H 

Fly A

Cem

❖ Improved workability of concrete due to the nature and shape 

❖ Reduced water demand 

❖ Reduced bleeding at the edges of pavement 

❖ Increased ultimate strength of the concrete 

❖ Reduced permeability to moisture, improving long-term durabil

12 
❖ Decreased heat of hydration during concrete curing


❖ Greater concrete resistance to various forms of deterioration


❖ Reduced concrete shrinkage


In Embankments 

Fly ash can be used as a borrow material for highway embankm

is compacted, a structural fill can be constructed that can suppo

performance benefits associated with this use include:


❖ Elimination of the need to purchase, permit, and operate a borr

❖ Placement over low-bearing-strength soils 

❖	 Ease of handling and compaction, which reduces


construction time and equipment costs


In Flowable Fill 

Flowable fill made with coal fly ash can be used in place of conven

materials and alleviates problems and restrictions generally associa

placement of those materials. Benefits include:


❖ Placement in any weather, including under freezing conditions


❖ 100 percent density with no compactive effort


❖ Ability to fill around and under structures inaccessible 


to conventional fill placement techniques


❖ Increased soil-bearing capacity


❖ Prevention of post-fill settlement problems


❖ Increased speed and ease of backfilling operations


❖ Decreased variability in the density of backfilled


materials


❖ Improved on-the-job safety and reduced labor and 


excavation costs


❖ Easy excavation later when properly designed

In Stabilized Base Course 

Fly ash and lime can be combined with aggregate to produce a qu

course. These road bases are referred to as pozzolanic-stabilized m

advantageous over other base materials because they provide: 

❖	 A strong durable mixture 

❖	 Reduced costs 

❖	 Autogenous healing 

❖	 Increased energy efficiency 

In Asphalt Pavements 

Fly ash also can be used as a mineral filler in


asphalt pavements. Mineral fillers increase the


stiffness of the asphalt mortar mix, improve


the rutting resistance of pavements, and


improve the durability of the mix. Other bene­


fits include:


❖	 Reduced potential for asphalt stripping 

❖	 Reduced cost compared to other 


mineral fillers


In Grouts for Pavement Subseal

Grouts for pavement subsealing are proportioned mixtures of fly as

materials used to fill voids under a pavement system without raisin

drilling and injecting grout under specified areas of the pavement. 

tions, the performance benefits include: 

❖	 Quick correction of concrete pavements 

❖	 Minimal traffic disturbance 

❖	 Development of high ultimate strength 

14 
In addition to these performance benefits, many coal combustio

costly to use than the materials they 

replace. At the same time, the durabili- The California Depa

Transportation requ

ty benefits from using coal ash con- concrete containing 

crete can reduce the cost of maintain- its roadways to imp

ing the nation’s road systems. This 

enhanced performance also provides additional environmental b

the need for new concrete to replace aging roads and bridges, t

reducing future energy consumption and greenhouse gas emissi

A New Era of Pavement Technolog

Over the past 15 years, the Federal Highway Administration (FHWA) 

state highway agencies, universities, and the pavement industry hav

dous advances in pavement technology. The FHWA’s Office of Pavem

has been focusing on combining recent technical advances to develo

ment systems that can last up to 50 years for roads—twice the lifetim

pavements. These long-life pavements will reduce the costs of maint

highway systems and also result in decreased material needs. Coal f

recycled materials are common components of these high-performa

cement pavements. 
Environmental Benefits 

The use of coal combustion products in highway constr

significant short- and long-term environmental benefits

using coal combustion products in lieu of other materi

Portland cement, reduces energy use and greenhouse gas emiss

serves natural resources. In addition, it prevents the disposal of 

resource, reducing the need for landfills and surface impoundme

inherent performance benefits of concrete made from coal ash a

additional environmental benefits. Highways and bridges made w

crete are more durable than those made without it and, therefor

be repaired and replaced as often. 

Greenhouse Gas Emissions and 

Reductions 

Producing cement involves many steps, including grinding and b

dients (such as limestone, shells or chalk, and shale, clay, sand, 

ing those ingredients to very high temperatures in a kiln, cooling 

ingredients with gypsum, then grinding down the mixture to form 

Figure 7: Generic Cement Production Process 

Water Slurry Grinding Blending Cooling 

Gypsum 

Mix 

Cement 

Clinker Kiln 

Emissions 

2500—3000°F 

Dry Raw Materials 

This energy-intensive process typically emits nearly one ton of g

for each ton of cement created and requires the equivalent of a 

16 
ton. Using fly ash—which would otherwise be disposed of—in concrete has 

the potential to significantly reduce the 

quantity of greenhouse gases emitted 

and the amount of fuel used. Typically, 

between 15 to 30 percent of Portland 

cement in concrete can be replaced 

with fly ash. 

The Federal Highway Administration 

reports that roads and bridges made 

with high-performance coal ash concrete can last years longer than those 

made with Portland cement as the only 

binding agent. Thus, using coal ash 

concrete reduces the need to produce 

new concrete, which consequently 

means further reductions in future 

What Are Gree

Emissio

The Earth’s atmospher

immense greenhouse, 

the sun to warm the p

habitable conditions. T

effect” occurs when so

absorbed by greenhou

atmosphere. Most gre

such as carbon dioxide

other trace gases like m

naturally. Human activ

this natural phenomen

fuels to power cars, ho

releases carbon dioxid

centrations of other g

the atmosphere. 

greenhouse gas emissions, energy use, and natural resources. F

coal combustion products are a locally available construction ma

less transportation costs and fuel usage 

for trucking the material to the construction site. 

In 2002, the American Coal Ash 

Association estimated that 12.6 million 

tons of fly ash were used as a substitute for Portland cement in the United 

States. The industry set a goal to 

increase its use to 20 million tons by 

2010. EPA estimates that this would 

reduce the future generation of greenhouse gasses by more than 6.5 million 

tons a year.2 

One ton of fly as

replacement for 

■	 Conserves enough 

hold about 1,200 p

the amount of sol

by one American o

■	 Reduces the equiv

months of an auto

dioxide emissions. 

■	 Saves enough ene

tricity to an averag

for 19 days. 

2 Estimated using EPA’s Waste Reduction Model, Solid Waste Managem

Greenhouse Gases, Second Edition, EPA 530-R-02-006, Office of Solid 
Resource Conservation 

Because coal ash can be used as a replacement for many mate

construction, its use reduces the need to quarry or excavate virg

therefore helps to reduce the environmental impacts associated with these 

activities. Reducing these operations 

helps prevent habitat destruction, protect scenic waterways, reduce water 

runoff and air emissions, and reduce 

energy use. In addition, each ton of 

coal ash used beneficially reduces the 

need for one ton of virgin resources. 

Examples of Virg

That Can Be Re

Coal A

Coal combustion produ

tuted for many virgin 

would otherwise have 

excavated, such as: 

■ Limestone and clay 

■ Gypsum to make w

■ Sand and gravel to 

■ Soil for road emba

18 
Solid Waste Reduction 

Although many U.S. industries are using coal combustion produc

States continues to dispose of more than 80 million tons of this 

and surface impoundments annually. 

Using coal ash as a substitute for 

cement in highway construction and 

other applications could reduce this 

waste. Typically, a ton of coal ash compacted to 70 pounds per cubic foot 

takes up approximately 28 cubic feet of 

landfill space. Every million tons of coal 

combustion products beneficially used 

instead of disposed of reduces the need for 656 acre-feet of lan

shows U.S. trends in the generation and use of coal combustion 

past several years. These data indicate that while the beneficial 

bustion products is increasing slowly, so has the generation of t

Figure 8. Production and Use of Coal Combustion Products

Thousand Tons 

Usage 

Percentage 24.9% 27.8% 29.0% 30.8% 29.1% 31.5% 

0 

20,000 

40,000 

60,000 

80,000 

100,000 

120,000 

140,000 

1996 1997 1998 1999 2000 2001 

Use 

Production 
Environmental and Healt

Cautions Associated with 

Concrete (Encapsulated) U

When coal ash is used in concrete for building road

constituents—such as heavy metals—are bound 

the matrix of the concrete and are very stable. Le

constituents for all practical purposes does not occur.3 

Occupational issues associated with coal


ash use in concrete include the handling of


dry coal ash prior to or during its inclusion in


a concrete mix or exposures during demoli­


tion of concrete structures. In these cases,


work inhalation and skin contact precautions


should be observed, as described on page


27 in the section called Occupational Issues:


Inhalation and Skin Contact.


3 U.S. Environmental Protection Agency. March 1999. 

20 
Environmental and Healt

Cautions Associated with 

Unencapsulated Uses 

Studies and research conducted or supported by Electric 

Research Institute (EPRI), government agencies, and un

that the beneficial uses of coal combustion products in 

tion have not been shown to present significant risks to human 

ronment. But, as with many other common substances, precaut

management practices should be applied when using coal ash in 

uses. Water and air are the two media most likely to be affected 

coal ash constituents. 

Ingestion, inhalation, and skin contact are the ways that humans 

things could be exposed to coal ash. Other issues that may nee

are leaching of elements such as mercury and metals into groun

nation of vegetation and the impact of other elements on the fo

borne dust. In most cases, however, the way that coal ash is us

requirements for that use, and the handling and management m

minimizes exposure to the ash. 

EPRI. May 1990, December 1990, February 1991, November 1993, 

1998, and 1998; Hassett, David J., et al 2001; Pflughoseft-Hassett, 

Environmental Protection Agency. August 9, 1993. 

4 
Mercury 

Although mercury in coal ash can potentially be released into the envi

leachate in water or as emissions to the ambient air, studies conducted 

of North Dakota Energy and Environmental Research Center and the U

Nevada, which tested bituminous, subbituminous, and lignite coals, ha

mercury releases from coal ash to the environment are negligible.5 Res

leachate tests showed that mercury was very stable in coal fly ash and 

1 percent of the initial mercury concentrations. Studies on the release 

coal ash to the ambient air show only minute losses to the environmen

EPA has proposed a new regulation, called the Clean Air Mercury Rule 

would require reductions in mercury emissions from coal-fired power p

posed regulation might affect the amount of mercury found in coal as

this regulation will increase mercury concentrations in coal ash or not 

time because this is the first time ever that EPA has regulated mercury 

power plants. EPA’s conclusions in this document are based on the regu

affecting power plants. EPA will reassess its position, if it appears that 

cant increase in the level of mercury in coal ash, when the CAMR is pro

Water Issues: Groundwater/Surf

Water Health and Human Ingest

Several studies6 over the past 10


years have shown that the use of


coal ash in highway construction


projects has resulted in little to no


impact on groundwater and


surface water quality, but some


precautions are necessary. 


Road Beds and Embankments: Coal ash used as a fill for road bed

ments, unlike that used in concrete, requires greater care to ens

The use of engineering standards and guidelines pertaining to co

ensure that the use of these materials will not negatively impac

5 Hassett, David J., et al. 1999. 6 EPRI. May 1990, December 1990, February 1991, November 1993, J

1998, 1998; Hassett, David J., et al 2001; Pflughoseft-Hassett, D.F., 

Environmental Protection Agency. August 9, 1993. 

22 
Environmental issues in these cases are largely determined by lo

such as groundwater depth and proximity to drinking water well

mentioned above show that while 

leaching of coal ash constituents is Precautionary 

possible from unencapsulated uses, Associated with U

CCP U

it does not occur in practice at high 

■ Assess hydrogeologic 

concentrations and has not been 

shown to migrate far from the site the site. 

when appropriate engineering prac- ■ Mitigate leaching thro

design practices and f

tices are followed. 

tion techniques. 

Despite the relative safety of using ■ Unencapsulated coal 

coal combustion products in unen- an assessment indicat

capsulated highway construction ground or surface wa

projects, some preventive and cau- particularly important 

tionary measures should be taken soils, shallow ground 

(See Town of Pines case study on imity to drinking wate

page 24): 

1) Conduct an evaluation of local groundwater conditions prior t

bustion products as a fill material. Numerous groundwater mo

such as EPA’s Industrial Waste Evaluation Model (IWEM), a g

and transport risk assessment model in EPA’s Guide for Indus

Management, and HYDRUS 2D.7 

2) Consult with your state regulatory agency for information on t

procedures, water quality standards, and other requirements. 

3) Once you determine that a site is appropriate for coal ash use

leaching of coal ash constituents by assuring adequate comp

to promote surface water runoff, and daily proof-rolling of the 

to impede infiltration. When construction is finished, a proper

cover will also help. Two helpful sources of construction infor

highway departments and the Federal Highway Administratio

document, Fly Ash Facts for Highway Engineers. 

IWEM model available at www.epa.gov/epaoswer/non-hw/industd/iw

2D model available at www.hydrus2d.com. 

7 
Case Study: Town of Pines, Indiana 

History 

The Town of Pines, Indiana, provides a cautionary 

waste disposal and the use of coal ash as general f

vulnerable areas. It is primarily a story about the g

contamination that arose because of poor early di

practices. It demonstrates several lessons on the n

coal combustion product construction practices an

terization when the material is not encapsulated—

assessing potential groundwater impacts. 

Background 

Pines is located about two miles south of Lake Mic

adjacent to Dunes National Lakeshore. The town’s 

water comes from shallow residential wells typica

ground water from 25 to 50 feet below ground lev

soils are sandy, unconsolidated, and highly acidic, 

organic content overlying a less permeable clay-ric

Since 1983, more than a million tons of coal ash an

rials have been disposed of at a local landfill or us

town as a fill material. The landfill was originally 

swampy area only 300 feet from the nearest drink

and has recently closed. The direction of groundwa

the east/northeast with a small northerly compone

ed the main portion of the Town of Pines. Coal ash 

used throughout the town to fill in low lying area

feet in some places—and to build roads that were 

uncovered and exposed to the elements. The shallo

Pines’s drinking water aquifer makes it susceptible 

nation of all types. 

In May 2000, the Indiana Department of Environm

Management (IDEM) began an investigation of the 

after a resident complained that it tasted foul. IDE

eral volatile organic compounds (VOCs) in the wat

24 
benzene. In January 2001, IDEM also found elevated levels 

methyl-tertiary-butyl-ether (MTBE). Both benzene and MTB

associated with gasoline and are not associated with the la

or coal ash. Later investigations discovered high levels of b

manganese, and molybdenum in the drinking water, which 

associated with coal ash. In short, the shallowness of the d

ing water wells, the porosity of the overlying sands, the lo

of the landfill, and the improper use of coal ash all contrib

to the contamination of the town’s drinking water. 

Lessons Learned 

Several important lessons can be learned from Pines: 

■	 Take care when using or disposing of any material in a h

ologically vulnerable area. 

■	 Before using coal ash as a fill material, conduct an asses

of its potential groundwater impacts. 

■	 Follow proper engineering requirements when using un

sulated coal ash. 

The environmental problems in the Town of Pines should n

courage the beneficial use of fly ash at other locations for 

road base, or embankments. But, these problems do highli

the need for properly assessing and addressing potential 

groundwater impacts. 
Vegetation and Food Chain Issu

EPA, in 2000, determined that the use of coal ash as a highway fi

as a substitute for lime in agricultural applications did not pose a 

addition, several EPRI (Electric Power Research Institute)studies8 h

the use of coal ash in unencapsulated highway construction proje

risk to roadside vegetation. Studies of road construction projects 

Arkansas, Georgia, Illinois, and Kansas indicate that while metal c

coal fly ash and bottom ash might ente

through absorption, the concentrations 

are found to be well below the toxic lim

In addition, studies examining the effec

fly ash constituents by animals have no

associated health problems.9 Some tes

elevated levels of some elements in bl

organs, while other tests found no con

These results indicate little potential fo

ments from highway construction projects to accumulate in soil 

concentration by food chain biomagnification (the process by wh

ing on affected plants can, in turn, accumulate the same constit

these constituents in their tissues). 

Air Issues: Air Quality and Inhal

Air inhalation of coal ash dust is primarily a worker safety issue. N

precautions should be taken to protect the public from dusting du

construction, when coal ash is first laid down. Dust is not an issue 

used in concrete or in a slurry form. 

Coal ash can become airborne during storage and


processing of ash, from traffic on roads, and


through wind erosion during ash placement. Like


other nuisance dust, however, specific controls


can address these exposure methods to prevent


air pollution and inhalation:


8 Electric Power Research Institute. June 1995. 9 Electric Power Research Institute. 1998. 

26 
❖	 High-calcium, self-hardening ash


should be stored dry in silos, while


low-calcium ash can be stockpiled


onsite if the ash is kept moist and


covered to prevent dusting and 


erosion.


❖	 Dry fly ash should be transported in


covered or pneumatic tanker trucks. 


❖	 Wind erosion of coal ash should be


mitigated in highway construction application by moistening th

the construction phase or by using the material in slurry form.


❖	 Coal ash used in road construction should be compacted and c

minimize dusting. 


Occupational Issues: 

Inhalation and Skin Contact 

Inhalation 

Workers involved with dry ash handling, concrete grinding, or


demolition activities can come in contact with fugitive dust con­


taining coal ash. Health risks associated with the inhalation of


these fugitive dusts in occupational settings can be limited by


following Occupational Safety and Health Administration (OSHA)


standards and practices. These standards and practices are


applicable whether or not coal ash is used in concrete. Workers


should request Material Safety Data Sheets (MSDS) from coal


combustion product suppliers when they are not sure of the


proper precautions. 


In addition, workers can minimize inhalation through a number


of actions:


❖	 Cleaning work areas regularly by wet sweeping or vacuuming. 

❖	 Wearing basic personal protection such as safety goggles with 

tect the eyes from dust.

❖	 Wearing a suitable particulate respirator (i.e., approved for part

National Institute for Occupational Safety and Health—NIOSH) 

late inhalation. 

❖	 Adding water to the ash to prevent fly ash from blowing during 

❖	 Using standard dust filters on vehicles and silos. 

❖	 Using mechanical ventilation or extraction in areas where dust 

the work environment. 

❖	 Using closed pumping systems for bulk deliveries. 

An EPRI study to determine potential health effects of workers in f

with coal fly ash concluded that routine operating activities did not 

exposures.10 In addition, occupational health records for these type

show a higher incidence of respiratory problems than those of pow

who do not work as closely with fly ash. In some occupational sett

Radioactivity and Radon 

Coal contains naturally occurring radioactive elements. After combu

ments and their decay products can remain in coal combustion ash. 

coal fly ash as a diffuse, naturally occurring radioactive material, wh

benign radioactive classification. 

Studies have shown that the level of radioactivity in coal combustio

about the same as the level found in surface rocks and soil.* A long

Valley Authority study of a 42-acre site that used more than 1 millio

fly ash in structural fill indicated that ambient radon levels measure

the fly ash fill were comparable to the levels 

measured in control areas without fly ash. 

Studies have also shown that radon releases from concrete blocks manufactured 

using coal fly ash are well below EPA’s 

radon action levels. ** 

*	 Electric Power Research Institute. 1998. 

** U.S. Environmental Protection Agency.


October 1998.


10 Electric Power Research Institute. 1998. 

28 
such as maintenance activities or in an accident, some power plan

exposed to higher concentrations of fly ash particles. In these case

problems related to either the presence of particles in the lungs or 

stances in the ash (e.g., metals or quartz) can occur from direct in

concentrations of coal fly ash.


Another study11 reviewed the toxicity and health hazards of coal fly 

coal mine dust, which is known to cause pneumoconiosis and emp

Researchers concluded that exposure to high concentrations of co

chronic bronchitis and air flow obstruction—typical of the common 

inhaling a variety of different types of dusts. However, the study fo

that coal fly ash can induce pneumoconiosis and emphysema. Exp

centrations of coal fly ash can be minimized or prevented by follow

presented earlier in this section and by observing OSHA requireme

sance dust.


Skin Contact 

Power plant workers and people involved in producing cement, con

based products can have skin contact with coal fly ash. In highway 

contact is likely limited to construction workers working with dry a

tion is finished, the road bed and a properly seeded soil cover will 

of skin contact. While most contact with coal ash can be controlle

dling and construction safety practices, if contact does occur, coal 

irritation or contact dermatitis.


Workers can minimize skin contact through a number of spe­


cific actions:


❖	 Wearing gloves or applying a barrier hand cream. 

❖	 Wearing loose, comfortable clothing that protects the


skin and washing work clothes regularly. 


❖	 Washing any exposed skin thoroughly with mild soap and


water prior to eating and at the end of work activities. 


Others exposed to coal ash should wash exposed skin with


mild soap and water and launder soiled clothing.


Borm, P.J.A., December 1997. 

11 
EPA’s Position on the Use 

Coal Combustion Product

EPA supports and encourages the beneficial use of coal com

in highway construction applications for several reasons. F

tion products are a significant component of the U.S. solid 

United States produced over 121 million tons of this material in 20

combustion products can be benefi­


cially used in highway applications


instead of being land disposed. This


beneficial use has many environ­


mental benefits, including reduced


energy consumption, greenhouse


gases, need for additional landfill


space, and raw material consump­


tion. Third, using coal combustion products in highway constructio

not result in environmental harm or human health problems if prop

practices are followed.


Regulatory Determinations 

EPA conducted two regulatory determinations on the manageme

combustion products, in 1993 and in 2000. As part of these reg

tions, EPA evaluated the following eight factors:


❖	 The source and volume of coal combustion products generated 

❖	 Current disposal practices. 

❖	 Potential danger, if any, to human health or the environment fro

coal combustion products.


❖	 Documented cases in which danger to human health or the en

been proved.


❖	 Alternatives to current disposal methods. 

❖	 The costs of such alternatives. 

❖	 The impact of those alternatives on the use of natural resource

30 
❖ The current and potential utilization of coal combustion product

In conducting these two regulatory determinations, EPA did not id

mental harm associated with the beneficial use of coal combustio

way construction applications and concluded in both determinatio

materials did not warrant regulation as a hazardous waste. The be

combustion products can include both encapsu­


lated and unencapsulated applications. EPA rec­


ognizes that unencapsulated uses of coal com­


bustion product require proper hydrogeologic


evaluation to ensure adequate groundwater 


protection.


The 2000 regulatory determination recommend­


ed a separate review addressing the use of coal


combustion wastes as fill for surface or under­


ground mines, which is currently underway.


Procurement Policy 

EPA also has provided guidelines to the federal government for p

and concrete products containing fly ash.12 In 1983, EPA promulg

eral procurement guideline that required agencies using federal 

a preference program favoring the purchase of cement and conc

ash. EPA also endorses the use of pozzolans, such as coal ash, a

method for stabilizing certain metal-bearing wastes. EPA publish

information pertaining to coal combustion products use in an en

sheet, Guideline for Purchasing Cement and Concrete Containing 

SW-91-086, January 1992).


In addition, Executive Order 12873, Federal Acquisition, Recyclin

Prevention, signed on October 20, 1993, directs federal agencie

mative procurement programs for environmentally preferable pro

requires EPA to issue guidance on principles that agencies shou

determinations for the preference and purchase of these produc

issued the Comprehensive Procurement Guideline, designating it

made with recovered materials, including coal fly ash. EPA also 

that flowable fill from the combustion of coal can be used as a r

12 U.S. Environmental Protection Agency. January 28, 1983. 
Case Studies 

The following case studies provide examples of how co

products have been used successfully in a variety of h

tion applications nationwide over the past few decade

Concrete Pavement: 

Cold In-Place Recycling of Asphalt Pavement, Jackson Cou

A Jackson County, Missouri innovative partnership rehabilitated 2

orating rural roads, resulting in an environmentally sound and supe

significant cost savings to the County. 

The “Jackson County Partnership” included the C

ment of Public Works, Lafarge-North America, K

Light and the University of Missouri-Kansas City 

nership developed a process in which the full de

base material were pulverized and mixed with f

These constituents were re-compacted to form 

cal sub-base and then covered with a new asph

In this project, an independent researcher and students from UMK

development of County specifications and evaluated the finished p

removal of the old asphalt and processing on site minimized the e

impact of the project including use of nearly 1,700 tons of Class C 

KCP&L and Lafarge-NA. The project to rehabilitate the road with f

one-third less than it would have to remove and replace the entire 

Bearing Ratio values, a measurement of strength, averaged 52 aft

of curing. This stronger road base permitted a thinner (less expen

asphalt to be applied as the final wear surface. 

On-site recycling of the old pulverized pavement with locally provi

reduced overall energy consumption, equipmen

and emission pollution, as well as truck traffic. 

eliminated landfill requirements, excavation, an

newly quarried rock and dredged sand. The par

strates not only the value of innovative coopera

zations, but also exemplifies the goals of the Co

Products Partnership. 

32 
Concrete Pavement: 

Boston Central Artery/Tunnel Project, Massachusetts 

Approximately 3.8 million yards of concrete con­


taining a 30 percent coal fly ash mix is being


used in the sprawling Boston Central Artery/


Tunnel project—one of the largest and most


technologically challenging highway projects in


the United States. Coal fly ash is being used as


part of the concrete design and specification


because of its resistence to alkali reactivity and


low heat of hydration. At the same time, the fly


ash used in place of cement will prevent approx­


imately 335,000 tons of greenhouse gases from
 Storrow Drive C

being released. 

The project has two major components: 

1.	 The replacement of a six-lane elevated highway with an eight- 

ground expressway directly beneath the existing road, culmina

bridge crossing of the Charles River (the Cable Stayed Bridge a

Drive Connector).


2.	 The extension of I-90 (the Massachusetts Turnpike) from its cu

south of downtown Boston through a tunnel beneath South Bo

Harbor to Logan Airport. The first link in this new connection—

Williams Tunnel under the harbor—was finished in December 

The concrete mixes u

were designed to mee

ifications. Using these 

for the elimination of c

which in turn helps th

schedule, saves on la

and allows for very lar

to 1,400 cubic yards i

Ted Williams Tunnel 
Road Base: 

State Route 22 Project, Georgia 

Post-construction environmental and performance testing determ

coal fly ash as a base course along part of Georgia State Route 

negligible environmental impacts and has shown sustainable hig

This test project was a joint venture of the Georgia Department 

(GDOT), Southern Company Services, and the Georgia Power Co

ing from the Electric Power Research Institute,


which promotes ash utilization in large volume


applications. The testing area was constructed


along a two-lane bypass section of Route 22,


near Crawfordville, Georgia, approximately 90


miles east of Atlanta. Both coarse and fine ash


were used to compare with the typical con­


struction materials replaced by fly ash. Site preparations began 

construction of the ash layers was completed in July 1985.


Class F fly ash supplied from Southern Electric System was used 

tions: 1) a lime-fly ash (LFA) stabilized sub-base, 2) a cement-st

(CFA) base course, and 3) a cement stabilized pond ash (CPA) b

of which were each placed in 1,000-foot-long test sections. 


Post-construction monitoring evaluated strength, road surface con

deflections, groundwater quality from four groundwater monitorin

ple leachate collection pipes, and environmental effects resulting 

ash. Results indicate that the performance of all test sections sur

control section and exceeded GDOT requirements. Environmental 

indicate that the environmental impact of the test sections has be

Embankments: 

Route 213/301 Overpass Project, Maryland 

Sixty thousand tons of Class F fly ash from the Baltimore Gas an

Delmarva Power plant were provided to the Maryland State High

Administration in 1993 and 1994 to create the highway embank

Route 213 overpass over Route 301 on Maryland’s eastern shor

34 
overpass was initiated in March 1999 by the Maryland Departm

Resources Power Plant Research Program to assess groundwate

and promote the beneficial use of coal combustion products gen

Maryland. Groundwater data collected during May, June, and Ju

that the leachate from the fly ash has had no discernable impac

ter quality at the site.


The site embankments were constructed using a base layer of s

placement of sandy clay berms to contain the sides of the fly as

and compaction of fly ash in 8-inch lifts. The fly ash was moiste

percent prior to compaction and covered with 2 feet of sandy cl

beneath the road were covered with a stone base and asphalt p

The groundwater study for this site involved using lysimeters, m

and soil moisture probes in and through the fly ash fill on the sh

213. Samples were collected to provide infor­


mation on the embankment material's physical


and chemical properties and were used to


assess the factors impacting the attenuation of


constituents. Pore and groundwater samples


collected at the site were analyzed for dissolved


trace elements, major cations and anions, and


alkalinity. Water quality results indicated elevat­


ed concentrations of several trace elements and


major ions in the fly ash pore water, indicating


that leachate is forming within the fly ash fill. The data also indic

these constituents are being attenuated in underlying soils and g

beneath the embankments. The water quality data indicate that 

for highway embankments can adequately protect groundwater 

Access Ramp Project, Delaware 

Nearly 10,000 tons of stockpiled fly ash from Delmarva Power and 

Edge Moor Station were used to construct the main access ramp

change to Interstate 495 near Wilmington, Delaware. This project 

during June 1987 and, during the two-year monitoring period that 

no significant environmental effects, but did show high performan
Environmental analysts studied the short-term effects of the pro

groundwater quality by evaluating four monitoring wells and fou

tion drains, and by collecting and analyzing runoff and leachate 

the ash fill area. In addition, monitoring of post-construction pe

that in-place soil had the same characteristics as a well-compa

Less than one-eighth of an inch of settlement was measured at 

tlement plate locations, indicating that the fly ash fill performed 

ventional materials. 

Flowable Fill: 

McGee Creek Aqueduct Pipe Bedding Project, Oklahoma 

Not only did the use of fly ash allow the entire McGee Creek Aq

Bedding project to proceed on a faster schedule, but it also resu

cent cost savings. The 1984 construction of this 16.6-mile aque

Oklahoma, by the U.S. Bureau of Land Reclamation reused 8,000 

This ash was used to make a flowable fly ash grout mix, which w

of compacted crushed stone for the pipe bedding. 

The pipeline contractor selected flowable fly ash grout for beddi

speed of bedding placement, reduce labor and equipment costs

more uniform bedding. The flowable grout mix contained 11 per

ash by weight, as well as sand, water, and R-7 chemical retarde

plied by Oklahoma Gas and Electric Company, had self-cementin

properties, and the chemical retarding agent was used to contro

characteristics. 

The performance of both the fly ash grout and a Portland cemen

also used on the project, was compared by visual inspection. Th

exhibited the least amount of segregation, bleeding, and shrinka

grout also set up in the trench faster than the cement grout, allo

lift to be placed sooner and the entire operation to proceed mor

conventional cement grout had been used. The material cost an

that the use of Class C fly ash and retarder in place of Portland c

the significant cost savings. In addition, the use of the fly ash gr

resulted in a reduced need for crushed stone. 

36 
References and Other So

American Coal Ash Association. 1998. Innovative Applications o

Products (CCPs). 

American Coal Ash Association. 2002. Annual Survey of Coal Co

Production and Use. 

American Coal Ash Association. 2003. Annual Survey of Coal Co

Production and Use. 

American Coal Ash Association. 2004. Annual Survey of Coal Co

Production and Use. 

ASTM C 618-03. (Also, AASHTO M 295). Standard Specification 

and Raw or Calcined Natural Pozzolan for Use as a Mineral Adm

ASTM E 2277-03. Standard Guide for Design and Construction o

Structural Fills. 

Borm, P.J.A. December 1997. Toxicity and Occupational Health 

Ash. A Review of Data and Comparison to Coal Mine Dust. Anna

Hygiene, Vol. 41, No. 6, 659–676. 

Department of Energy. July 1994. Barriers to the Increased Utiliz

Combustion/Desulfurization Byproducts by Governmental and Co

Office of Fossil Energy. 

Department of Energy/Energy Information Administration.1998. 

Energy Review, Appendix A. Washington DC. 

Electric Power Research Institute (EPRI). May 1990. Environmen

Assessment of Coal Ash Use Sites: Little Canada Structural Ash 

No. EN-6532. Palo Alto, CA. 

Electric Power Research Institute (EPRI). December 1990. Enviro

Performance Assessment of Coal Ash Use Sites: Waukegan Ash 

EPRI Report No. EN-6533. Palo Alto, CA. 
Electric Power Research Institute (EPRI). February 1991. Use of 

Highway Construction: Michigan Demonstration Project – Interim 

7175, Project 2422-7. 

Electric Power Research Institute (EPRI). August 1993. Fly Ash E

Fired Power Plants, EPRI TR-102576. 

Electric Power Research Institute (EPRI). November 1993. Enviro

Performance Assessments of Coal Ash Use Sites. EPRI Report N

Alto, CA. 

Electric Power Research Institute (EPRI). June 1995. Environmen

Assessment of Coal Combustion Byproduct Use Sites; Road Con

Applications, EPRI TR-105127. 

Electric Power Research Institute (EPRI). March 1998. High-Volu

Utilization Projects in the United States and Canada, EPRI CS-44

Project 2422-2. 

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and Potential Health Issues, EPRI Environmental Focus Issue Pap

Electric Power Research Institute (EPRI). 2002. Mercury Release 

Palo Alto, CA. 1005259. 

Energy Information Administration. 2000. Voluntary Reporting of 

2000, Report # DOE/EIA-0608. 

Federal Highway Administration (FHWA). June 2003. Fly Ash Fa

Engineers, FHWA-IF-03-019. 

Fly Ash Resource Center. Fly Ash Material Safety Data Sheet. 

www.geocities.com/capecanaveral/launchpad/2095/msds.html. 

Hassett, David J., Debra F. Pflughoeft-Hassett, Dennis L. Laudal, 

Pavlish. 1999. Mercury Release from Coal Combustion ByProduc

Environment. www.flyash.org/1999/ashpdf (then click on Hasset

Hassett, David J., Loreal V. Heebink. 2001. Release of Mercury V

Combustion Ash. From the 2001 International Ash Utilization Sym

October 22-24, 2001, Lexington, KY. 

38 
Heebink, Loreal V. and David J. Hassett. 2001. Coal Fly Ash Trac

in Soil Stabilization. From the 2001 Ash Utilization Symposium h

2001, Lexington, KY. 

Kalyoncu, Rustu S. 2000. U.S. Geological Survey Minerals Yearb

Combustion Products. 

Meij, Ruud and Henk te Winkel. 2001. Health Aspects of Coal Fl

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Pflughoseft-Hassett, D.F., D.J. Hassett, and B.A. Dockter. 1993. 

Ash Utilization and the Effects on Groundwater in North Dakota 

Uses/Concrete Applications. From Proceedings of the 10th Intern

Symposium held January 18-21, 1993, Orlando, FL,. EPRI TR-10

Vol. 1. 

Sutton, Michael E., Thomas E. Schmaltz, Cheri Miller, and Kathy 

Radon Emissions from a High Volume Coal Fly Ash Structural Fill 

2001 International Ash Utilization Symposium held October 22-2

Lexington, KY. 

U.S. Environmental Protection Agency. January 28, 1983. Guidel

Procurement of Products Containing Cement and Concrete, Fede

Notice. 48 FR 4230. 

U.S. Environmental Protection Agency. August 9, 1993. Notice o

Determination on Four Large-Volume Wastes from the Combusti

Electric Utility Power Plants, Federal Register Notice. 58 FR 424

U.S. Environmental Protection Agency. 1997. Annual Emissions a

Consumption for an “Average” Passenger Car. 

U.S. Environmental Protection Agency. October 1998. Suppleme

Congress on Remaining Wastes from Fossil Fuel Combustion—T

Background Document: Beneficial Use of Fossil Fuel Combustion 

Office of Solid Waste. 

U.S. Environmental Protection Agency. March 1999. Report to C

from the Combustion of Fossil Fuels—Volume II, EPA 530-S-99-

Waste. 
U.S. Environmental Protection Agency. 2000. Municipal Solid Wa

States: 2000 Facts and Figures. 

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Greenhouse Gases, A Life-Cycle Assessment of Emissions and S

Edition, EPA530-R-02-006. Office of Solid Waste. 

U.S. Environmental Protection Agency. February 2003. Guide for 

Management, EPA 530-R-03-001. Office of Solid Waste. 

40 
For More Information 

U.S. Environmental Protection Agency, Coal Combustion Product

www.epa.gov/c2p2/index.htm 

American Coal Ash Association


www.acaa-usa.org


Utility Solid Waste Activities Group


www.uswag.org


Federal Highway Administration, Pavement Technology


www.fhwa.dot.gov/pavement/


Department of Energy


www.doe.gov


The Fly Ash Resource Center


www.geocities.com/CapeCanaveral/Launchpad/2095/flyash.htm

Electric Power Research Institute (EPRI)


www.epri.com/destinations


U.S. Environmental Protection Agency, Comprehensive Procurem

Cement and Concrete Specifications 

www.epa.gov/cpg/products/cemspecs.htm 

University of New Hampshire, Recycled Materials Research Cen

www.rmrc.unh.edu/


EERC/University of North Dakota, Coal Ash Resource Center


www.eerc.und.nodak.edu/carrc/index.html


UWMilwaukee, Center for By-Products Utilization


ww.uwm.edu/Dept/CBU


Center for Applied Energy Research at the University of Kentuck

www.flyash.org


Ohio State University, Coal Combustion Product Extension Progra

ccpohio.eng.ohio-state.edu/ccpohio


West Virginia University, Combustion Byproduts Recycling Conso

wvri.nrcce.wvu.edu/programs/cbrc/index.cfm