Potential for Manufacturing Unfired-Bricks Using Circulating Fluidized Bed Combustion Fly Ash

Abstract

The paper focuses on the manufacturing of the un-fired bricks using the circulating fluidized bed combustion fly ash by dry pressure molding method. The results show that: (1) The compressive strength of the brick reach the highest when it manufactured by cement 8 %, bottom ash 15 %, lime 12 %, gypsum 5 %, fly ash 60 % and water 15 %. The compressive strength can achieve 23.22 MPa. (2) NaCl, Na₂CO₃ and nuclei are better to improve the freeze-thaw resistance of the brick. (3) The drying shrinkage of the bricks added pp fiber can reach 0.69 mm/m which achieve the Chinese standard (JC239-2001). (4) The performance of the brick added the compound additive (NaCl 0.1 %, Na₂CO₃ 0.1 %, Nuclei 0.5 %, PP fiber 0.1 %) is much better than the brick adding single additives. The drying shrinkage is 0.65 mm/m and the compress strength of 7d, 28d and after freeze-thaw circles are 19.47, 27.22 and 21.96 Mpa, respectively.