【作者】 王强；

【导师】 阎培渝；

【作者基本信息】 清华大学 ， 土木工程， 2010， 博士

【摘要】 钢渣是炼钢过程中产生的废渣,其排放量约为钢产量的15%。目前部分钢渣作为骨料或填料应用于混凝土、沥青路面和路基工程,但仍有大量的钢渣未能有效利用。将钢渣作为矿物掺合料用于混凝土配制是一个有效且高效的利用方式。我国的绝大部分钢渣为转炉钢渣,本文将研究转炉钢渣的胶凝性能及在水泥基复合胶凝材料水化硬化过程中的作用,主要研究内容和结论如下:（1）钢渣与水泥的水化过程相似,但钢渣的水化速率非常慢。提高钢渣的细度、提高钢渣水化环境的碱性和水化温度都能够激发钢渣早期的活性,相对而言,提高水化温度的效果最明显。（2）C₂S、C₃S和RO相是钢渣的主要矿物成分。磨细钢渣可以分为两个部分:胶凝组分(C₃S, C₂S, C₁₂A₇和Ca₂Al₂Si₃O₁₂)和惰性组分（RO相, C₂F和Fe₃O₄）。RO相在大粒径（> 60μm）颗粒中的含量大于在小粒径（< 6μm）颗粒中的含量,而胶凝组分在小粒径颗粒中的含量大于在大粒径颗粒中的含量。钢渣的水化产物主要为Ca（OH）₂和C-S-H凝胶;硬化浆体中还残存有未水化的C₂S和C₃S、RO相、C₂F和Fe₃O₄。尽管胶凝组分的水化对改善复合胶凝材料硬化浆体的孔结构有一定的贡献,但惰性组分并不能起到良好的填充作用,因而钢渣对于细化硬化浆体后期孔径的效果不如粉煤灰。（3）碱度决定了钢渣的主要矿物组成的种类,但不能反映这些矿物的相对含量。高碱度钢渣之间的活性差异不能用碱度来评价。本文提出了评价高碱度钢渣活性的方法,即钢渣活性系数（ HAI= （SiO₂+ Al₂O₃）/ （FeO+Fe₂O₃+MgO+MnO））,试验结果证明,用钢渣活性系数可以有效地评价高碱度钢渣的活性。（4）用钢渣替代部分水泥后,会使胶凝材料的水化诱导期延长,降低胶凝材料早期的水化速率。但由于钢渣水化的贡献以及钢渣和水泥水化的相互促进作用,7 d后,复合胶凝材料的水化速率高于纯水泥。本文定义了钢渣对水泥水化的促进因子,通过对该因子变化规律的研究可以得出结论:钢渣掺量越大,对水泥后期水化的促进作用越明显;龄期越长,对水泥水化的促进作用越明显。更多还原

【Abstract】 Steel slag is a by-product from the conversion of iron to steel, the amount of which emitted takes about fifteen percent of the steel production. At the moment, part of steel slag is being used as aggregates for concrete, asphaltic paving, and road bases. But most steel slag has not been efficiently used yet. Using steel slag as a supplementary cementitious material during the manufacture of concrete is an effective and a high efficient way for its utilization. Basic oxygen furnace steel slag is the most common steel slag in China. The aim of present research work is to investigate the cementitious properties of basic oxygen furnace steel slag and its role in the hydration and hardening process of cement-steel slag complex binder. The main content and results are listed as follows:（1） The hydration process of steel slag is very similar with that of cement, but its hydration rate is much low. Raising the fineness of particles, alkaline condition and elevated curing temperature can all promote the hydration of steel slag at early age, of which elevated curing temperature is the most effective to excite the activity of steel slag.（2） C₃S, C₂S and RO phase are the main minerals of steel slag. The steel slag can be divided into two parts: cementitious phases (C₃S, C₂S, C₁₂A₇ and Ca₂Al₂Si₃O₁₂) and inert phases （RO phase, C₂F and Fe₃O₄）. The proportion of RO phase in large particles （> 60μm） of steel slag is higher than that in small particles （< 6μm）. The proportion of cementitious phases in small particles is higher than that in large particles. Ca（OH）₂, C-S-H gel, unhydrated C₂S and C₃S, RO phase, C₂F, and Fe₃O₄ are the main hydration products of steel slag. Though the hydration of the cementitious phase of steel slag is beneficial for the improvement of pore structure of hardened paste, its inert phase can not act as microaggregates to densify the hardened paste. Thus, steel slag does not have the effect of improving the pore structure at later ages as fly ash.（3） The alkalinity of steel slag determines the type of major minerals but does not determine the content of minerals. The difference of activity among different types of high-alkalinity steel slag can not be further distinguished by alkalinity. The hydration activity index （HAI= （SiO₂+ Al₂O₃）/ （FeO+Fe₂O₃+MgO+MnO）） is defined to evaluate the hydration activity of steel slag, which is verified to be effective by the results of examples. The higher the hydration activity index, the higher the hydration activity of steel slag.（4） The dormant period of binder is prolonged and its hydration rate at early age is reduced by replacing cement by steel slag. The hydration rate of complex binder is higher than that of cement after 7 days, which is attributed to the hydration of steel slag at later age, as well as the mutual promotion of hydration between cement and steel slag. The promoting factor is defined to evaluate the increased degree of the hydration of cement by the promotion of steel slag. It can be concluded from the promoting factor that the promoting effect becomes more obvious with the adding amount of steel slag and the hydration age.更多还原