防水剂B和养护温度对铁尾矿三免砖性能的影响

以某细粒低硅铁尾矿和无水泥固化剂为原料,制备免烧免蒸免水泥建材砖(简称"三免砖")。研究了防水剂B和养护温度对制品抗压强度、耐水性和抗冻性的影响及其机制。试验结果表明:随着防水剂B掺量的增加,制品的干抗压强度和24 h吸水率均下降,饱和抗压强度和软化系数均先升后降;随着初期养护温度的升高,制品的耐水性、抗冻性和各龄期的抗压强度都显著提高。采用XRD和FI-TR分析检测手段进行的机制研究表明:水化硅酸钙胶凝、钙矾石是三免砖的强度黏结相;防水剂B的掺入不会影响强度黏结相构成;提高初期养护温度和使用防水剂能抑制制品内部的碳化反应,并提高制品耐水性能。理论分析结果可以解释养护温度和防水剂B对制品性能的影响,为三免砖制备过程中高效防水剂的筛选及养护条件的优化提供了理论依据。

Effect of Waterproofing Agent B and Curing Temperature on Properties of the Burning-free,Autoclave Curing-free and Non-cement Building Bricks Made from Iron Tailings

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.