HOW IT’S MADE
Fiber reinforced polymer (FRP) is making its presence known as a compelling, rust-free alternative to the traditional steel rebar used in concrete reinforcement applications. Basalt Rebar is a derivative from the most abundant rock on earth: basalt. Thousands of fibers are compressed, and wound spirally into a structural reinforcement rod.
Deep within the planet, massive plates have been churning for billions of years, creating minerals which we commonly call rocks. Once the boiling pot beneath our feet launches these materials upward, the cooling begins. Then curious humans seek innovative ways to use them to our advantage. One such rock is basalt.
Since basalt fiber rebar is corrosion and rust-resistant, it was originally viewed as an ideal material for use in marine construction and on overpasses and bridges which were often exposed to salt.
THE TENSILE STRENGTH OF STEEL, YET 75% LIGHTER
Once trucks leave the quarries carrying tons of the all-natural volcanic rock, they deliver their cargo to the factory. There, the basalt is crushed and loaded into a stone melting furnace where it’s melted at temperatures of 1,400 Celcius for six hours. The molten rock is further processed by being drawn through platinum bushings – or tiny nozzles. Finally, the basalt exits this part of the assembly as continuous fibers – with diameters of anywhere from 9 to 13 microns – and wound on large drums. As the fibers are drawn from the bushings, they are stretched taut, decreasing their diameter up to 90 percent.
Thousands of these continuous strands are compressed until they form a cylinder-type shape. During this process, they are coated with epoxy, which acts like adhesive to give the basalt rebar an enhanced bonding surface. Before the final setting, a Dacron strand is wrapped tightly around the fiber rebar. This winding also creates some abnormalities in the fiber rebar to ensure it will bind with concrete. Also in this phase, a coating of quartz sand is applied to the bundle. The final result is a basalt fiber rebar that is double the tensile strength of steel and is 75 percent lighter.
Taking a microscopic look at the differences between the dark colored continuous basalt fibers which stem from volcanic rock, basalt shares some commonalities with others found among quarry minerals. One huge difference is that white silica fiberglass is man-made.
Even the American Concrete Institute (ACI) has acknowledged that fiber reinforced polymers (FRP) may be implemented in concrete reinforcements. Their June 2016 AC-454 report states that basalt fiber and the unique corrosion resistant (E-CR) manmade fiberglass are compatible in the production of FRP concrete reinforcements.
Thus, the brown basalt fiber reinforced polymer (BFRP) and the white fiberglass rebar (GFRP) are the only two “glass state” structural components that bear its stamp of approval for use in concrete reinforcement.
GREEN-FRIENDLY, A SMALLER CARBON FOOTPRINT
As basalt is a single element, no other properties or compounds are required for its conversion to fiber. As a result, the quarry process to collect basalt rock requires less of a carbon footprint in comparision to white silica based E-CR fiberglass, which involves mining dozens of materials.
BLOCKS HARMFUL UV RAYS
Because of its natural opaque composition, basalt can deflect the harmful ultraviolet rays of the sun. Manmade white fiberglass, however, requires that it must be shielded from the sun or it will deteriorate.
Boron, a potentially toxic trace mineral, is present in white fiberglass. However, at the base fiber level, basalt is non-toxic and naturally boron-free.
With its durability, strength and longevity, basalt has no true rival; it will no doubt be the last rock standing.