He Zhi-Hai, Du Shi-Gui, Chen Deng
College of Civil Engineering, Shaoxing University, Shaoxing 312000, China.
College of Civil Engineering, Shaoxing University, Shaoxing 312000, China.
J Hazard Mater. 2018 Jul 5;353:35-43. doi: 10.1016/j.jhazmat.2018.03.063. Epub 2018 Apr 3.
Lithium slag (LS) is discharged as a byproduct in the process of the lithium carbonate, and it is very urgent to explore an efficient way to recycle LS in order to protect the environments and save resources. Many available supplementary cementitious materials for partial replacement of cement and/or silica fume (SF) can be used to prepare ultra high performance concrete (UHPC). The effect of LS to replace SF partially by weight used as a supplementary cementitious material (0%, 5%, 10% and 15% of binder) on the compressive strengths and microstructure evolution of UHPC has experimentally been studied by multi-techniques including mercury intrusion porosimetry, scanning electron microscope and nanoindentation technique. The results show that the use of LS degrades the microstructure of UHPC at early ages, and however, the use of LS with the appropriate content improves microstructure of UHPC at later ages. The hydration products of UHPC are mainly dominated by ultra-high density calcium-silicate-hydrate (UHD C-S-H) and interfacial transition zone (ITZ) in UHPC has similar compact microstructure with the matrix. The use of LS improves the hydration degree of UHPC and increases the elastic modulus of ITZ in UHPC. LS is a promising substitute for SF for preparation UHPC.
锂渣（LS）是碳酸锂生产过程中排放的副产品，为保护环境和节约资源，探索锂渣的高效回收利用途径迫在眉睫。许多可用的辅助胶凝材料可部分替代水泥和/或硅灰（SF）来制备超高性能混凝土（UHPC）。通过压汞法、扫描电子显微镜和纳米压痕技术等多种技术，实验研究了锂渣按重量部分替代硅灰用作辅助胶凝材料（占胶凝材料的0%、5%、10%和15%）对超高性能混凝土抗压强度和微观结构演变的影响。结果表明，锂渣的使用在早期会使超高性能混凝土的微观结构劣化，然而，适当含量的锂渣在后期会改善超高性能混凝土的微观结构。超高性能混凝土的水化产物主要由超高密度硅酸钙水化物（UHD C-S-H）主导，超高性能混凝土中的界面过渡区（ITZ）具有与基体相似的致密微观结构。锂渣的使用提高了超高性能混凝土的水化程度，并增加了超高性能混凝土中界面过渡区的弹性模量。锂渣是制备超高性能混凝土中硅灰的一种有前景的替代品。
