蒸养钢渣/镍渣-水泥基复合胶凝材料的水化机理与长期性能

Ground steel slag and ferronickel slag both possess low reaction activity and their application in cementitious material will face the risk of long-term volume stability problem. Under the background of construction industrialization, the basic research for application of steam cured steel/ferronickel slag-cement based materials will definitely provide a new way in reasonable utilization of steel slag and ferronickel slag. This project will firstly investigate the reaction mechanism of steel and ferronickel slag in steel/ferronickel slag- gypsum - Ca(OH)2 system under steam curing in order to simulate the reaction in cement paste. The influence of the factors, including water binder ratio, mineral admixtures, steam curing regime and curing time, on the hydration process, mechanical property, shrinkage and resistance to sulfate attack of steel /ferronickel slag-cement based material under steam curing will be studied experimentally. Consequently, the quantitative relationship between the composition, structure and macro-performance will be established. The interaction between various compositions in the system and their impact on the hydration process and long-term performance will be revealed. In particular, the role of MgO, Fe2O3 in steel / ferronickel slag during the steam curing process and the service period, respectively, will be uncovered. The leaching behavior of Cr ion in ferronickel-cement based cementitious system will be tested in order to ensure the safe application of ferronickel slag. The results of this research are expected to provide scientific understanding for the application of steel /ferronickel slag in precast concrete.

磨细钢渣、镍渣用于水泥基材料中均具有活性低及安定性不良的风险。结合我国的建筑工业化，开展蒸养条件下钢渣/镍渣-水泥基材料的应用基础研究，将为科学地利用钢渣和镍渣提供新的途径。本项目以蒸养条件下钢渣/镍渣-石膏-Ca(OH)2体系为出发点，探寻钢渣/镍渣在模拟水泥浆体碱性环境下的反应机制；系统研究水灰比、矿物掺合料、蒸养制度及养护龄期对蒸养条件下钢渣/镍渣-水泥基材料的水化过程与机理、力学性能，以及收缩变形、抗硫酸盐侵蚀等长期耐久性的影响规律，建立组成、结构和宏观性能之间的定量关系，揭示体系中各组分之间的相互作用及其对水化过程和长期性能的影响规律，重点探明钢渣/镍渣中的MgO、Fe2O3在蒸养阶段以及材料在服役过程中的长期反应机制；研究蒸养条件下镍渣-水泥体系中Cr离子的溶出规律，确保镍渣在水泥基材料中使用的安全性。本研究成果将为钢渣/镍渣在预制混凝土中的应用提供科学的依据。

磨细钢渣、镍渣用于水泥基材料中均具有活性低及安定性不良的风险，针对上述问题，本项目首先从镍渣、钢渣的来源、冶炼工艺、粒径等角度出发，探明了镍渣、钢渣的组成，特别是镍渣中MgO、Fe2O3的存在形式，然后采用石膏、氢氧化钙等作为激发剂，模拟水泥碱性环境中研究了镍渣在水泥中的反应机制；然后采用多种测试手段研究了水化环境（碱激发、水泥环境、蒸汽养护、标准养护）、矿物掺合料（矿渣、偏高领土）及养护龄期等条件下钢渣/镍渣复合胶凝材料的水化过程与机理、力学性能、以及收缩变形、抗硫酸盐侵蚀等长期耐久性能，建立了钢渣/镍渣组成、结构和宏观性能之间的关系。同时，采用碱溶出方法探明了镍渣中的活性矿物和重金属Cr离子的溶出规律，并提出了镍渣活性的评价方法；最后，创新性地将干法化学刻蚀技术引入到钢渣粉的预处理过程中，并系统研究了干法化学刻蚀钢渣粉的工艺、机理和改性后钢渣复合胶凝的水化硬化特征，为解决钢渣的安定性不良和早期活性低等问题提供了新的出路。