Fabrication of Baking-Free Bricks Using Gold Tailings and Cemented Materials with Low Alkalinity

The purpose of this paper was using gold mine tailings and cemented materials with low alkalinity to fabricate baking-free bricks.The obtained baking-free brick samples were evaluated by unconfined compressive strength(UCS),water absorption percentage,freezing-thawing cycle,and drying-wetting cycle.The microstructures of the baking-free brick samples were analyzed using X-ray diffraction(XRD)and scanning electron microscope(SEM)techniques.The baking-free brick specimens cured for 28 days with the addition of 10%mixing water consumption and 1:6 cement/tailing ratio tended to obtain favorable comprehensive properties such as a high compressive strength of 15.15 MPa,a low water absorption percentage of 11.8%,excellent freezing-thawing resistance with a 8.9%UCS loss rate after 15 freezing-thawing cycles and good drying-wetting resistance with a 11%UCS loss rate after 10 drying-wetting cycles.The XRD and SEM test results verified that different kinds of hydrate products including C-S-H and C-S-A-H gels,and ettringite were produced during hydration process,which were responsible for good physical,mechanical properties,and durability of the obtained baking-free bricks.Therefore,the experimental results showed that it was practical and reasonable to utilize the homemade cementitious materials in our laboratory to stabilize the gold tailings for production of baking-free bricks,which still met the requirements of major regional construction standards in some countries.