Abstract: Burning-free，autoclave curing-free and non-cement building bricks(three-free for short) were prepared with the fine low-silica iron ore tailing and the self-made non-cement curing agent as the raw material.The effect of the content of waterproofing agent B and curing temperature on the properties of the products such as the compressive strength，water resistance，frost resistance and anti-carbonization，and also its mechanisms were studied.The results showed that with the dosage of waterproofing agent B increase，compressive strength and 24 h water absorption of products decreased while saturated compressive strength and softening coefficient are increased first and then decreased.With the increase of initial curing temperature，water resistance，frost resistance and compressive strength in every curing time are improved significantly.According to the mechanism analysis by XRD and FI-TR，the results show that hydrated calcium silicate gel and ettringite are strength binder phase of three-free bricks.Meanwhile，the addition of waterproofing agent B does not affect the composition of binding phase.The increase of initial curing temperature and the addition of waterproofing agent B can inhibit the carbonation reaction within products and improve water resistance.The results of theoretical analysis can explain the effect of curing temperature and waterproofing agent B on performance of the products.It provides theory basis for the high-effect waterproofing agent and the optimization of the curing conditions.

Key words: Fine low-silica iron ore tailing, “Three-free&rdquo, block, Waterproofing agent B, Curing temperature, Compressive strength, Water resistance