Dr. John Myers, associate professor of civil, architectural and
environmental engineering at Missouri University of Science and Technology, is
developing an environmentally friendly construction material with advantages
over traditional clay bricks and concrete masonry blocks.
The composite material is made primarily from ASTM class C fly ash, a
byproduct of coal-burning power plants, and wood fibers – two materials that
otherwise would be put in the nation’s landfills.
“In Missouri, a sizable portion of our power generation still comes from
coal,” Myers says. “What we’ve done is taken fly ash from the power industry
and wood fibers from unused timber products, such as upper tree limbs, and
we’ve developed a new, green construction material.”
The material is lighter, has more comparable durability and is less brittle
than clay bricks or concrete masonry blocks. The composite blocks also are fire
and impact/ballistic resistant, highly ductile, provide desirable insulation
properties and are less expensive to manufacture because they are made from
largely recycled waste materials.
Myers began refining the wood fiber and fly ash composite material concept
in 2003 in partnership with Robert Sinclair, president and CEO of Encore
Building Solutions Inc. in St. Louis. About that time, Sinclair launched Encore
with the idea to create a “green” building material that could be screwed
together, rather than set with mortar. Although they are not yet commercially
available for use in the construction industry, the EarthBlock and
BallisticBlock, made from the composite material developed by Myers and a
research team, are being marketed at encorebuildingsolutions.com.
Myers tested more than 40 variations before finding the optimum mix of
materials to create the blocks. He found a type of fly ash available in
Missouri that is high in calcium content works best when combined with oak or
pine fibers milled to about one-quarter to one-half inches. The fibers can come
from the discarded upper limbs of trees, or even recycled pallets.
Myers evaluated the durability of the blocks using specialized equipment in
the Butler-Carlton Civil Engineering Building at Missouri S&T that
simulates freeze/thaw cycles.
“We found that the freeze/thaw resistance of this material was superior to
that of conventional concrete,” Myers says.
A chemical additive also makes the blocks mold resistant.
Myers collaborated with Dr. Jason Baird, associate research professor of
rock, mineral and explosives research at Missouri S&T, to test the new
material at the university’s Experimental Mine. They found the material has
good energy dissipating qualities with improved blast resistance and reduced
fragmentation compared to conventional concrete. During an explosion, Myers
says it is the flying fragments, not the blast itself, that accounts for 80 to
90 percent of deaths.
A polyurea material, similar to that used to coat truck-bed liners, only
increases these characteristics when applied to the composite material.
Currently, Myers and Baird are working with the Air Force Research
Laboratory to conduct full-scale blast testing on the material. Myers and
Sinclair hope EarthBlocks and BallisticBlocks will be available commercially in
the very near future.