He came up with the concept for a better brick, one that would put to use fly ash, a waste product commonly issued from coal-power plants, and that would prove just as durable as regular clay bricks. Because they solidify under pressure instead of high heat, building his bricks would help save energy and would cost at least 20 percent less. In addition, their molded shape, which gives them a smoother and more uniform appearance, would help cut down on bricklaying time and work.
Having spent most of his professional career working with hydraulic presses, Liu jumped at the chance to try out his hydraulic rig when a power plant gave him some free fly ash to use in 1999. After mixing the powder with water and pounding it with 4,000 psi of pressure, he let the mixture set for two weeks and obtained blocks that were as strong as concrete. He found that their strength derived from the concrete's ability to stick together with cement, specifically the calcium oxide present within the material that would bind with surrounding elements when it reacted with water. The hard part for Liu was meeting federal safety standards, which took him another eight years and over $600,000 from the National Science Foundation (NSF) after his original discovery. In order to reach the goal of surviving 50 cycles of freezing and thawing (a test he initially failed when his bricks broke after eight), he incorporated an air-entrapment agent, a chemical often used to strengthen concrete bricks by preventing the infiltration of water into the material, into his mixture.
He hopes to license the bricks and start selling them next year, a step that may not prove popular with all potential clienteles. "The people who buy bricks will definitely be interested," says Pat Schaefer, a sales manager for Midwest Block & Brick. "But I don't see the brick companies liking it at all."
See also: ::Ask TreeHugger: Nearby Construction and Pollution, ::Sustainable Construction at Construmat: the R4House, ::BBC Enthuses about Hemp, Straw and Lime for Construction, ::TreeHugger Picks: Straw Bale Construction, ::Building Green: Energy Efficiency and Aesthetics From The Same Materials (Part 8), ::In praise of Brick Shithouses