LUNAR CONCRETE SIDEWALK
A DURABLE ALTERNATIVE TO IMPORTED CEMENT
In March 2015, PISCES in collaboration with the Hawaiʻi County Dept. of Research and Development, the University of Hawaiʻi at Mānoa, NASA and Kodiak FRP Rebar installed a ‘lunar sidewalk’ in downtown Hilo on Hawaiʻi Island using basalt-based construction materials. The sidewalk consisted of three slabs of experimental concrete, each with unique binding agents as part of a trial process to see which held up best over time. These included a fly-ash basalt paver, a baked basalt paver, and a fly-ash binder reinforced with Kodiak FRP basalt rebar.
After a one-year assessment, PISCES found the flly-ash basalt paver exceeded the durability of traditional cement. The baked basalt pavers showed less durability, but were redesigned following the trial and used in PISCES’ VT/VL Landing Pad construction project where they outperformed residential concrete.
The lunar sidewalk experiment had two significant benefits for Hawaiʻi and space exploration endeavors: 1) learning to use volcanic basalt fines (a waste product of local quarries) as an alternative building material while reducing environmental and economic costs of importing concrete; and 2) learning to utilize native resources on other planets or celestial bodies for construction while sparing the costly expense of transporting them from Earth.
By using locally sourced basalt fines, PISCES hopes to reduce the environmental impacts associated with cement production. It is estimated that 5 to 7% of global CO2 emissions are a result of cement production. In addition, Hawaiʻi pays a premium for cement, importing more than 300,000 metric tons annually. This represents a large economic, environmental and social toll to the state.