高温碳化养护和钢渣预碳化对钢渣水泥基胶凝材料性能的影响

发布时间：2018-04-05 16:05

本文选题：钢渣　切入点：高温养护　出处：《北京化工大学》2015年硕士论文

【摘要】：钢渣是炼钢工业中产生的最主要的固体废弃物之一,随着全球的钢产量的逐年递增,随之产生的钢渣量也越来越多,而中国的粗钢产量在2014年超过了世界钢产量的一半,达到8.2亿t,而作为副产物的钢渣的产量也超过了1亿t。因其化学和矿物组成与水泥熟料的成分类似,故将钢渣作为水泥掺合料成为钢渣综合利用的主要途径之一。本文主要研究了高温和碳化养护对钢渣水泥基胶凝材料性能的影响；以及预碳化钢渣制备钢渣水泥基胶凝材料性能。尤其对不同的养护方式下钢渣胶凝材料的浆体结构和水化产物,以及预碳化后钢渣微粉的矿物组成的变化以及掺预碳化钢渣后胶凝材料早期强度和安定性的改善情况做了详尽的研究和分析。为提高掺钢渣胶凝材料的早期强度和改善安定性提供理论支持。本实验主要使用新余热闷钢渣,分析了高温、碳化和标准养护对钢渣胶凝材料性能的影响,结果表明,通过高温碳化养护的方式,激发钢渣活性,使大掺量钢渣胶凝材料早期和后期的强度均大幅增加,达到了P42.5水泥强度等级,高温养护只能提高胶凝材料的早期强度,由于早期过快的水化速率使得在硬化的浆体中引入大孔从而形成较多微观裂缝,且早期高温养护会阻碍水泥基材料的后期水化,所以其后期强度低于标准养护。研究结果表明,高温碳化养护后的钢渣水泥基材料表面生成了一层致密的CaCO3外壳,能提高胶凝材料的强度,并有效防止水泥基材料发生溶解侵析,提高胶凝材料的耐久性。高温碳化养护生成的CaCO3的颗粒粒径为1～8μm,在胶凝材料中能起到微集料作用,为C3S的水化起到了晶核的作用,从而加速C3S的水化速度。细小的CaCO3颗粒为Ca(OH)2提供了大量的晶核,使得Ca(OH)2生成的更加分散,不再生长成特定晶格取向的片层状大颗粒,具有较好的力学性能。同时研究了对钢渣微粉进行预碳化处理后替代30%水泥熟料,制备钢渣水泥基胶凝材料。结果表明：预碳化钢渣微粉后,钢渣粉中的游离氧化钙(f-CaO)以及其他钙盐如具有胶凝活性的C3S,C2S等均会被碳化生成CaCO3,且碳化后钢渣中RO相的衍射峰几乎消失,说明预碳化对改善胶凝材料安定性有一定的积极作用。使用TG-DTA和SEM-EDS以及水化放热曲线分析掺预碳化钢渣胶凝材料的水化产物的水化速率和水化程度,根据TG-DTA曲线的计算结果,浆体水化3d时,预碳化试样的化学结合水量为21.65%,标准试样为9.84%,即预碳化钢渣胶凝材料试样3d的水化程度是标准试样的2.2倍,预碳化钢渣胶凝材料28d的净浆试样总的化学结合水量为28.41%,标准试样为24.04%,增长率为18.18%。说明预碳化可以有效提高胶凝材料早期水化速率和后期的水化程度。分析预碳化的净浆试样28d的SEM-EDS图谱,发现其结构密实,且主要水化产物—水化硅酸钙已长成块状整体,在裂缝处放大,发现在水化硅酸钙的连接处有棒状连接物,经能谱分析为Ca(OH)2。而未碳化的Ca(OH)2结构呈片层状。说明经碳化后的掺钢渣胶凝材料中的Ca(OH)2不再朝特定晶格取向生长,而是生长方向多元化,能更好的与水化硅酸钙形成整体,增加材料的密实度。
[Abstract]:Steel slag is one of the main solid waste generated in the steel manufacturing industry, with the world's steel output has been increasing year by year, the amount of slag produced more and more, and the crude steel production in 2014 China more than half of the world's steel output, up to 820 million T, and as a byproduct of the production of steel slag is more than 100 million T. because of its chemical and mineral composition of cement clinker and similar components, so the steel slag as cement admixture has become one of the main ways of comprehensive utilization of steel slag. This paper mainly studies the influence of high temperature and carbonation of steel slag cementitious materials can be prepared; and pre carbonization steel slag cementitious properties of steel slag materials. Especially paste structure and hydration products of steel slag cementitious materials under different curing methods, and the change of composition after pre carbonization of slag powder and mixed with mineral pre carbonated steel slag cementitious materials after early Do a detailed analysis of the improvement of strength and stability. To provide theoretical support to improve the early strength and improve the stability of steel slag cementitious materials. This experiment used Xinyu heat-stuffing slag at high temperature was analyzed, and the effect of the curing carbonization, steel slag cementitious materials. The results showed that through high temperature carbonization curing way, stimulate the activity of steel slag, the early and late steel slag cementitious material strength were greatly increased, reached the P42.5 cement strength grade, high temperature curing can improve the early strength of cementitious materials, due to early hydration rate makes the big hole introduced in the hardened paste in order to form more micro cracks, late hydration and early stage curing will hinder the cement based material, so its late strength is lower than the standard curing. The results show that the steel slag cement curing after high temperature carbonization The material formed on the surface of the CaCO3 shell of a dense layer, can increase the strength of the cement, and effectively prevent the occurrence of dissolved leaching of cement-based materials, improve the durability of cementitious materials. High temperature curing of the generated CaCO3 particle size of 1~8 m, the micro aggregate effect can play in cementitious materials in the nucleus role for the hydration of C3S, so as to accelerate the hydration speed of C3S. The fine CaCO3 particles of Ca (OH) 2 provides a large amount of crystal nucleus, the Ca (OH) 2 generation is more dispersed, not large particles grow into specific regeneration lamellar crystal orientation, has good mechanical properties. At the same time on the pre carbonization process of steel slag powder instead of 30% cement clinker, preparation of steel slag cementitious materials. The results showed that the pre carbonization of steel slag powder, slag powder of free calcium oxide (f-CaO) and other calcium salts such as cementitious activity. C3S, C2S etc. will Carbonization of CaCO3 generation, and the diffraction peak of RO phase after carbonization in the slag almost disappeared, indicating pre carbonization to improve a certain positive role in cementitious materials. The stability analysis of hydration products with pre carbonation of steel slag cementitious materials using TG-DTA and SEM-EDS as well as the hydration exothermic curve of hydration rate and hydration degree according to the calculation results, TG-DTA curve, 3D water slurry, chemical pre carbonization samples with water was 21.65%, the standard sample is 9.84%, the hydration degree of pre carbonization steel slag cementitious material 3D specimen is 2.2 times the standard sample, pre carbonation of steel slag cementitious materials 28d paste sample total chemical the water was 28.41%, the standard sample is 24.04%, the growth rate of 18.18%. shows that the pre carbonization can effectively improve the degree of hydration of cementitious material hydration rate and later. SEM-EDS analysis paste sample 28d pre carbonization, the dense solid structure, And the main hydration product of calcium silicate hydrate has grown into a whole block, magnified in the cracks, found at the connection of calcium silicate in water rod connected by energy spectrum analysis, Ca (OH) 2. and Ca (OH) 2 carbide structure is layered by adding slag after carbonization. The cementitious material of Ca (OH) 2 is no longer in a particular lattice orientation growth, but the growth direction of diversification, the better is formed integrally with the hydrated calcium silicate, increase the density of the material.

【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ172.44

【参考文献】