关键词: 鄂西赤铁矿尾矿, 免烧砖, 复合外加剂, 钙矾石

Abstract: In order to increase the strength of baking-free brick made from the hematite tailings of western Hubei province，under the condition of determining the optimum value of the early strength agent，carried out the optimum value test of complex adding early strength agent and water reducing agent，then obtain the optimum complex additive.Through studying the impact and hemechanism of action of the additive on the performance of baking-free brick，and analyzing the mechanism of action by SEM，the complex additive is benefit to accelerate the product of AFT and gelatum and is the key factor of increasing the compressive strength of baking-free brick.

Key words: Hematite tailings of western Hubei province, Baking-free brick, Complex additive, AFt