摘要
为了探索煤气化渣作为掺和料的可行性,开展煤气化渣对水泥胶凝硬化产物强度的影响机理研究。通过对比分析煤气化渣、粉煤灰形成过程的差异,以扫描电镜、能谱仪、X射线衍射试验,研究煤气化渣、粉煤灰及两者水泥胶凝产物的微观结构与物相组成,并制备不同掺量的粉煤灰、煤气化渣的水泥胶砂试件,测试其不同龄期的力学强度。结果表明:粉煤灰和煤气化渣形成过程的不同导致两者微观形貌和物质构成存在较大差异,其烧失量由大到小排序为煤气化细渣、煤气化粗渣、粉煤灰,且细渣残碳含量远高于粗渣和粉煤灰。煤气化粗渣以层片状、块状结构居多,细渣多呈蜂窝形絮状体并夹杂少量的球状颗粒,粉煤灰多呈球状体,三者元素组成相似,均含有火山灰活性的铝硅酸盐矿物质。粗渣浆体中形成的钙矾石呈粗针棒状并交织成网,粉煤灰浆体中形成的钙矾石呈细针状并均布于C-S-H凝胶周围,细渣浆体中未发现明显的钙矾石相,粗渣消耗水泥水化产物Ca(OH)2的能力强于粉煤灰,细渣中活性矿物相被残碳包围,火山灰活性得不到发挥,残碳也影响水泥水化进程。掺粉煤灰、煤气化渣的水泥胶砂7 d强度均低于基准水泥胶砂,在28 d时,掺粉煤灰胶砂的抗压强度高于基准胶砂,掺粗渣胶砂则与基准胶砂持平,掺细渣胶砂远低于基准胶砂。粗渣可替代5%(质量分数,下同)的水泥作为胶凝材料使用,而细渣不宜直接用于水泥掺和料,研究结果可为煤气化渣综合开发利用提供重要参考。
In order to explore the feasibility of coal gasification slags as cement admixture,the strength mechanism of cement cementitious hardening products affected by coal gasification slags was studied.The differences of the formation processes between coal gasification slags or fly were analyzed by comparison with each other.The microstructure and phase composition of coal gasification slags,fly ash and their cement cementitious products were studied by scanning electron microscope,energy dispersive spectrometer and X-ray diffraction test.Cement mortar specimens with coal gasification slags or fly under different dosages were prepared respectively,and the mechanical strength values of cement mortars at different ages were tested.The results show that the distinct formation processes of fly ash and coal gasification slags lead to their great differences in micro-morphology and material compositions.Their ignition loss can be sorted from large to small as fine coal gasification slag,coarse coal gasification slag,fly ash,and the residual carbon content of fine slag is much higher than that of coarse slag and fly ash.Coal gasification coarse slag appears mainly in lamellar and massive structure.The fine slag possesses mostly honeycomb flocs with a small number of spherical particles.Fly ash presents mostly in spherical structures.There are similar in their elemental compositions,including aluminosilicate minerals with pozzolanic activity.The ettringite formed in the coarse slag slurry is thick needle-like and interwoven into reticular structure,while it is fine needle-like and well distributed around the C-S-H gel in fly ash slurry.No obvious ettringite phase is found in fine slag slurry.The amount of the Ca(OH)2 from cement hydration,consumed by the coarse slag is greater than that by fly ash.The active mineral phase in the fine slag is surrounded by residual carbon,so the pozzolanic activity cannot be released,and the residual carbon also affects the hydration process of cement.The 7 d strength of cement mortar mixed wi
作者
谢海巍
潘福元
刘尊青
李祖仲
刘溪溪
XIE Hai-wei;PAN Fu-yuan;LIU Zun-qing;LI Zu-zhong;LIU Xi-xi(School of Traffic&Transportation Engineering,Changsha University of Science&Technology,Changsha 410114,Hunan,China;School of Transportation and Logistics Engineering,XinjiangAgricultural University,Urumqi 830052,Xinjiang,China;School of Materials Science and Engineering,Chang’an University,Xi’an 710064,Shaanxi,China)
出处
《长安大学学报（自然科学版）》
CAS
CSCD
北大核心
2023年第2期26-34,共9页
Journal of Chang’an University(Natural Science Edition)
基金
新疆维吾尔自治区自然科学基金项目(2019D01A44)。
关键词
道路工程
胶凝机理
微观结构与物相组成
煤气化渣与粉煤灰
胶砂强度
road engineering
cementitious mechanism
microstructure and phase composition
coal gasification slag or fly
mortar strength
