Henry Liu (civil engineer)
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Henry Liu is a retired American civil engineer and the president of Freight Pipeline Company (FPC). During Liu's earlier career he was a professor of civil engineering and the director of Capsule Pipeline Research Center, a state/industry university cooperative research center at University of Missouri–Columbia. After retirement, Liu founded FPC, the company which developed fly ash brick, a new type of building brick made from a waste by-product of coal power plants.[1]
Liu had spent most of his working career compressing industrial freight using hydraulic presses. In 1999, he was given some fly ash by a client, and decided to compress it "just to see what would come out." Liu mixed the fly ash with water and applied 4,000 psi (28 MPa) of pressure. After two weeks, he found that the mixture had set into blocks with the strength of concrete. Owing to the high concentration of calcium oxide in fly ash, the bricks can be described as "self-cementing".
Liu took another eight years and a National Science Foundation grant of $600,000 to perfect the manufacturing technique.[2] After much experimentation, he discovered that by adding an air entrainment agent, which generates microscopic bubbles in the hardened brick that better accommodate the expansion of freezing water, he was able to produce a brick which could withstand over 100 freeze-thaw cycles, thereby comfortably meeting US federal safety standards.
Since the manufacturing method uses a waste by-product rather than clay, and solidification takes place under pressure rather than heat, it has several important environmental benefits. It saves energy, reduces mercury pollution, alleviates the need for landfill disposal of fly ash, and costs 20% less than traditional methods.
[edit] References
- ^ Popular Science Magazine, INVENTION AWARDS : A Green Brick, May 2007
- ^ National Science Foundation, Press Release 07-058, "Follow the 'Green' Brick Road?", May 22, 2007
