SBIR Phase I: Compacting Fly Ash to Make Bricks

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This Small Business Innovation Research (SBIR) Phase I project will develop a new method to make bricks using fly ash, which is a byproduct or waste material generated at coal-fired power plants. This new method for making bricks is simple and effective. It uses pressure instead of high temperature to make bricks, thereby reducing cost and conserving energy, at the same time recycling an otherwise wasted material. Preliminary research showed that strong bricks could be made this way, though the resistance of such bricks to freezing/thawing encountered in winter needs substantial improvement before such bricks can be used commercially. While current industry standards requires that bricks must pass at least 50 freezing/thawing cycles, the fly ash bricks produced at present can pass less than 10 cycles. This research explores several novel methods to improve the freezing/thawing property of such bricks, enabling them to meet standards and become commercially viable. The information generated will enhance current knowledge in the freezing/thawing effects on bricks, and in the understanding of crack formation during manufacturing of compacted products. The research enhances the state-of-the-art of a few technologies in making bricks. The broader impacts from this project could be significant. Much of the fly ash generated at coal-fired power plants is unused, ends up in landfills and slurry ponds. Using fly ash to make bricks not only produces a valuable commercial product but also reduces a major waste disposal problem for power plants. Furthermore, manufacturing ordinary clay bricks requires using high temperature (around 2,000 degrees F), which is energy-intensive and costly. In contrast, the fly ash bricks can be produced at room temperature, using only a fraction of the energy used in making clay bricks. The energy cost of making conventional clay bricks is very high, fly ash bricks are expected to cost much less than clay bricks to produce. As compared to conventional concrete bricks, which use cement, this new technology uses low-cost fly ash and hence costs less to produce.