Exploratory Advanced Research . . . Next Generation Transportation Solutions

mixed results. Fly ash, an abundant byproduct 

of coal-fired power generation, offers the opportunity to reduce greenhouse gas emissions 

when it is substituted for portland cement in 

concrete. Fly ash improves the resistance of 

concrete to alkali–silica reaction (ASR), a major 

contributor to structural deterioration, and 

increases concrete’s durability. Although the 

compressive strength of high volume fly ash 

concrete can develop to exceed that of regular 

concrete, high volume substitution of some fly 

ashes delays the initial setting time and reduces 

the early age strength that is critical to meeting 

construction schedules and preventing drying 

shrinkage cracking. In this project, DRMC, a new 

performance-based materials approach to delaying and reducing cracking associated with 

mechanical and environmental loading, will be 

applied to concrete made with fly ash and recycled concrete aggregates. DRMC uses microfibers to delay the formation and propagation 

of microcracks and uses macrofibers to prevent 

further widening and spreading of macrocracks. 

The DRMC method has been demonstrated 

in a hybrid fiber-reinforced concrete (HyFRC) 

composite to promote superior crack resistance. The HyFRC mixture contains low volume 

fractions of polyvinyl alcohol microfibers and 

steel macrofibers. As described by Terry Arnold 

at FHWA, “It is hoped that this radical approach 

will reduce cracking, limit the entrance of water 

and corrosive pollutants, and slow and eventually starve destructive reactions by confining 

the products of ASR and corrosive processes. 

The DRMC approach is extraordinary in its 

apparent ability to reduce cracking regardless 

of its cause—whether that is shrinkage, mechanical distress, or expansive deterioration. This 

project will attempt to extend that benefit 

to concrete that utilizes recycled concrete as 

aggregate and high volume fly ash to replace 

50 percent of portland cement.” 

Phase I of the project began with evaluation 

of how well DRMC delays the initiation of ASR 

and corrosion damage in steel-reinforced HyFRC 

and control specimens under accelerated corThe Exploratory Advanced Research Program Fact Sheet

The Need to “Green” Concrete

Portland cement concrete is the world’s predominant building material. Its durability, formability, and relatively low cost keep it in high 

demand worldwide, despite its deleterious effects. 

Concrete production is a major source of carbon 

dioxide and consumes vast amounts of energy, 

water, and other natural resources. End-of-life 

disposal of obsolete and failing concrete structures is costly and wasteful. Researchers have 

been working for several decades to reduce the 

environmental impact of concrete by incorporating waste materials, particularly recycled concrete and fly ash, in its formulation. In this EAR 

Program project, a promising approach may be 

key to widespread use of these materials to build 

longer lasting concrete structures that are safer 

for the environment. 

Reducing Use of Portland Cement

Efforts to reduce the carbon footprint of concrete through novel concrete mixtures have had 

Slowing the deterioration of highway 

infrastructure, reducing carbon emissions, conserving resources, repurposing 

industrial waste—this Exploratory Advanced Research (EAR) Program project is 

pursuing multiple benefits through a 

unique experimental approach: Deterioration Reduction through Micro and 

Macro Crack Control (DRMC). The project, 

“Service Life Enhancement and Reduction 

in Carbon Footprint of Highway Structures” at the University of California, 

Berkeley, was funded by the Federal 

Highway Administration (FHWA) in 2010. 

Paving the Way for Greener Highways

Extending Concrete’s Service Life Through Multiscale Crack Control 
rosion testing and cyclic 

loading. Phase II is subjecting the high volume fly ash/

recycled concrete mixtures 

to similar evaluations. Additional tests with pre-cracked 

specimens will be conducted 

to isolate the separate effects of crack resistance and 

high volume fly ash on ASR. 

A unique feature of the study 

will be its use of motionless 

x-ray laminography, a nondestructive testing technique 

that enables researchers to 

characterize cracking around 

the steel reinforcement undergoing corrosion. 

Although HyFRC demonstrates increased 

cracking resistance in portland cement concrete 

mixtures, it is not known how concrete containing 

less portland cement will respond to the multiscale fiber reinforcement. High rates of portland 

cement substitution by fly ash may result in 

decreased pH levels, which compromise the protective passive film on steel reinforcement. The 

critical question is whether the material’s crack 

resistance will suffice to prevent steel corrosion 

in the absence of the protective film.

Sustainable, Next-Generation 

Infrastructure

“Achieving crack-resistance in concrete that uses 

less portland cement would open the door to 

greater use of sustainable materials in building 

and rehabilitating our highways and bridges and 

sharply reduce the environmental impact of these 

structures,” says Arnold. “If this project succeeds, 

there will be many potential benefits—extended 

service life, reduced carbon emissions, conservation of finite resources, and productive use of 

material headed for the landfill.” 

Learn More

For more information on this project, contact 

Terry Arnold, FHWA Office of Infrastructure 

Research and Development, at 202-493-3305 

(email: terry.arnold@dot.gov). 

Publication No. 

FHWA-HRT-13-079

HRTM-30/09-13(1M)E

Paving the Way for Greener Highways 

Extending Concrete’s Service Life Through Multiscale Crack Control 

Photo credit, page 1: 

© 2013 Claudia Ostertag. 

The photo shows ASR 

damage in a bridgesupporting column.

What Is the Exploratory 

Advanced Research Program?

FHWA’s Exploratory Advanced Research 

(EAR) Program focuses on long-term, 

high-risk research with a high payoff 

potential. The program addresses underlying gaps faced by applied highway 

research programs, anticipates emerging 

issues with national implications, and 

reflects broad transportation industry 

goals and objectives. 

To learn more about the EAR Program, visit the Exploratory Advanced Research Web site at www.fhwa.dot.gov/

advancedresearch. The site features information on research solicitations, updates 

on ongoing research, links to published 

materials, summaries of past EAR Program events, and details on upcoming 

events. For additional information, contact 

David Kuehn at FHWA, 202-493-3414 

(email: david.kuehn@dot.gov), or Terry 

Halkyard at FHWA, 202-493-3467 (email: 

terry.halkyard@dot.gov). 

Two concrete samples 

using equivalently reactive 

aggregate. Left, ASRdamaged concrete with 

cracks marked; right, 

crack-resistant HyFRC 

for concrete strength 

and stiffness retention.