This Small Business Innovation Research Phase I project aims to create next generation green cement, a much more sustainable alternative to Portland cement. Among several emerging green cements, magnesium cement is the most prominent and has many superior properties when compared to Portland cement. It does not need wet curing, has high fire resistance, low thermal conductivity, and good resistance to abrasion and chemicals. It also has high strength; 7,000-10,000 psi is not uncommon. However, the majority of commercial magnesium cement products experience strength loss when wet. Such strength reduction is a major obstacle to their widespread structural use. Furthermore, most magnesium oxides (the primary ingredient of magnesium cements) are produced from calcined magnesites. Magnesite deposits are not uncommon worldwide but larger deposits are all in foreign countries. Domestic magnesite deposits are not adequate for the economical production of magnesium cement and its products. Therefore, the intellectual merit proposed herein consists of 1) advancement of green cement technologies by developing production of a magnesium cement from low-cost minerals instead of magnesites and 2) optimization of the mineral composition to enhance strength and ductility, and to eliminate wet strength reduction of this new green cement. The broader impact/commercial potential of this project is in its sustainability and superior properties. Because of its mineral nature, magnesium cement is noncombustible, and has better fire, mold, and fungus resistance than Portland cement. Magnesium cement is also much "healthier" than existing competitive products made from wood, plastic, and gypsum that are susceptible to one or more of these negative effects. Although extensive durability data have yet to be obtained, preliminary studies have shown that magnesium cement materials are resistant to freeze/thaw cycles, dry/wet exposure, and alkali-silicate reaction. From a practical perspective, these green cements have workability similar to that of regular Portland concrete. They can be mixed, cast, and cured with common concrete equipment and practice. Therefore, the effort of switching from Portland cement to this green cement, either partially or completely, is expected to be minimal with a short learning curve. Potential applications include all markets currently served by Portland cement concrete. Immediate product niches served by this material could include interior wallboard, ceiling board, drop ceiling, tile backer, underlayment, floor substrate, exterior sheathing, fascia, trim, siding, roof substrate, exterior insulation and/or structural insulating panel construction, and pipes for water or sewerage storage and transportation.
