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The Exploratory Advanced Research Program Fact Sheet 

Inorganic Polymers: 

Novel Ordinary Portland Cement-Free Binders 

for Transportation Infrastructure 

Exploratory Advanced Research . . . Next Generation Transportation Solutions 

Researchers are studying how building 

materials can be made in a way that is 

less energy intensive and can result in cost 

savings. 

One such building material is concrete, 

which is used to make sidewalks and roads, 

among other structures. Concrete consists 

of cement, water, sand, and stones that are 

mixed together. When cement is mixed 

with water, it acts like a binder—or glue—to 

hold together all the sand and stones that 

make up concrete. However, producing 

ordinary portland cement, the type of 

cement most often used, can be energy 

intensive because cement manufacturing 

requires high heat. This is because the 

limestone used to make cement releases 

carbon dioxide when heated, while the 

kilns where cement production occurs burn 

fossil fuels for heat. 

To address this concern, researchers at the 

University of California, Los Angeles 

(UCLA) have developed “cement-free” 

inorganic polymer binders (IPBs) for 

producing concrete. They studied how IPBs 

made from fy ash, an industrial byproduct 

that comes from coal-fred power plants, 

can completely replace the portland 

cement binders currently used to make 

concrete. With research partners at the 

University of California at Santa Barbara, 

University of Texas at Austin, and Boral 

Materials, along with support from the U.S. 

Department of Transportation’s 

Exploratory Advanced Research (EAR) 

Program, the researchers defned fy ash’s 

characteristics at the atomic level so that 

they could understand how those 

characteristics infuenced binder behavior 

during concrete production. 

How to Produce a Cement-Free Binder 

Fly ash is an attractive supplement and 

alternative to cement as a binder for several 

reasons. Fly ash’s chemical composition 

enables it to undergo desirable chemical 

reactions, producing an end product that 

performs similarly to traditional cement 

binders. Fly ash is also available on a large 

scale—often ending up in landflls—thereby 

ofering a benefcial use for a material that 

would otherwise simply be disposed. 

To produce an IPB, or cement-free binder, the 

researchers mixed a solid aluminosilicate 

precursor—fy ash—with a solution that 

prompts alkaline activation. Alkaline activation 

is a chemical process, during which the fy ash 

dissolves in the solution to form a product 

with binding properties similar to those of 

cement. Although the development of these 

cement-free binders made from fy ash is still 

maturing, the goal is to use these binders to 

produce building materials that are strong, 

durable, and suitable for construction. 

However, the researchers sought to go beyond 

the successful production of an IPB using fy 

ash. They wanted to gain new insights into 

how fy ash reacts with certain chemical 

solutions so that they can better understand 

how those reactions afect binder 

performance and production. The researchers 

wanted to know how to control the speed of 

reactions, which would help in making real-world 

production more feasible. The researchers also 

looked at temperature settings during the 

production process. The proper curing of IPBs 

requires high temperatures, but the 

researchers wanted to explore facilitating 

reactions at typical temperatures versus high 

temperatures because real-world applications 

call for simpler production conditions. 

By studying the fundamental variables that 

afected the formation of an IPB and 

examining how diferent chemical solutions 

could afect fy ash’s reactivity, the researchers 

established foundational tools and 

methodologies that the construction industry 

can apply as it pursues ways to integrate 

industrial byproducts into the manufacturing 

of building materials. 

How Atomic Changes Can Make 

a Big Diference 

Establishing how fy ash might react when 

introduced into certain chemical solutions 

required the researchers to develop a 
Inorganic Polymers: 

Novel Ordinary Portland Cement-Free Binders 

for Transportation Infrastructure 

molecular design strategy 

through the exploration of 

three themes. The frst 

theme was determination of 

the desired characteristics of 

fy ash to produce cementfree binders. This also 

involved matching the 

aluminosilicate precursor—in 

this case, fy ash—with the 

activation solution. Gaining 

such insights necessitated 

analysis of the compositional 

and physical parameters of 

fy ash using various analytical methods to see 

how variations in those parameters may 

infuence reactions and the composition of the 

fnal product. 

The second theme was establishment of the 

molecular processes and products that result 

when cement-free binders react under typical 

conditions. The researchers examined this 

aspect by using solid- and liquid-phase nuclear 

magnetic resonance, vertical scanning 

interferometry, and molecular simulations to 

analyze materials at the atomic scale. These 

tools helped the researchers examine how fy 

ash-based substances dissolve, what kind of 

chemical species form in the solutions, and the 

composition of the inorganic polymer hydrates. 

Both the frst and second themes served to 

develop a foundational understanding of the 

composition and reactivity of cement-free 

binders from their chemical structure to 

reaction evolution. 

The third theme was exploration of how binders 

made from inorganic polymers evolve 

throughout a reaction. Researchers developed a 

sophisticated computational algorithm that can 

serve as a calculator for reactions. Using an 

embedded material properties database, the 

platform allowed construction technologists to 

input the solid and liquid compositions of the 

precursors. Outputs then provided calculated 

estimates of how a cement-free binder may 

perform across a range of chemical 

compositions. 

Photo credit: © Henry Samueli 

School of Engineering and 

Applied Science, University of 

California, Los Angeles. 

A three-dimensional image 

acquired using vertical 

scanning interferometry that 

shows a cluster of fy ash 

particles. The color gradient 

from blue to red indicates the 

height relative to the adjacent 

surface (low to high). 

Photo credit, page 1: © The 

American Ceramic Society, 

courtesy of Wiley’s Journal of 

American Ceramic Society. 

A gray-scale image of 

numerous fy ash particles 

embedded in a resin that was 

imaged using backscattered 

electrons using a scanning 

electron microscope. 

Publication No. 

FHWA-HRT-18-029 

HRTM-30/04-19(WEB)E 

 

EXPLORATORY ADVANCED RESEARCH 

What Is the Exploratory 

Advanced Research Program? 

The EAR Program addresses the need 

for longer term, higher risk research 

with the potential for transformative 

improvements to transportation systems. 

The EAR Program seeks to leverage 

advances in science and engineering 

that could lead to breakthroughs for 

critical, current, and emerging issues 

in highway transportation by experts 

from diferent disciplines who have 

the talent and interest in researching 

solutions and might not do so without 

EAR Program funding. 

To learn more about the EAR Program, 

visit https://highways.dot.gov/research/ 

exploratory-advanced-research. The 

website features information on research 

solicitations, updates on ongoing 

research, links to published materials, 

summaries of past EAR Program events, 

and details on upcoming events. 

By exploring these three themes, the 

researchers aimed to advance the 

understanding of cement-free binders, 

improve the ability to controllably manufacture 

such materials, and ascertain how these 

cement-free binders may perform in practical 

highway construction applications. 

Learn More 

For more information about this EAR 

Program project, contact Jack Youtchef, 

FHWA Ofce of Infrastructure Research 

and Development, at 202-493-3090 

(email: jack.youtchef@dot.gov).