摘要
疏浚工程产生的大量淤泥含水率高且含有重金属等有害物质,对环境构成严重威胁。使用固化剂固化淤泥制备流态固化土是资源化利用淤泥的有效方法。目前常用的普通硅酸盐水泥(Ordinary Portland Cement,OPC)固化淤泥存在强度低、能耗高、碳排放高等问题,而矿渣硫铝酸盐水泥(Slag Calcium Sulfoaluminate Cement,G-CSA)是一种低碳高强的新型胶凝材料,在固化淤泥方面具有潜在的应用前景。采用G-CSA制备流态固化土并设置OPC流态固化土对照组,研究高贝利特硫铝酸盐水泥(High Belite Sulfoaluminate Cement,HB-CSA)熟料对G-CSA流态固化土力学性能的影响,并进行水化产物与孔结构表征,进而深入分析G-CSA的固化机理。结果表明,G-CSA流态固化土的强度随着HB-CSA熟料掺量的增加呈先增大后减小的趋势,在掺量为10%时G-CSA流态固化土力学性能达到最优,其28 d抗压强度和抗折强度分别为OPC流态固化土的2.35倍和2.06倍;G-CSA中的柱状AFt形成了骨架结构,C-S-H凝胶则将土颗粒粘结成一个整体,从而有效填充G-CSA流态固化土内部孔隙;适量的HB-CSA熟料能够减小G-CSA流态固化土的孔隙率,细化孔隙结构,进而提升其力学性能。
The large amount of sludge generated by dredging projects has high moisture content and heavy metals,posing a serious threat to the environment.The preparation of fluidized solidified soil by solidifying agents to solidify sludge is an effective method for resource utilization of sludge.The commonly used ordinary Portland cement(OPC)for solidification of sludge has problems such as low strength,high energy consumption,and high carbon emissions.However,slag calcium sulfoaluminate cement(G-CSA)is a new type of cementitious material with low carbon and high strength,which has potential application prospects in solidification of sludge.G-CSA was applied to prepare fluidized solidified soil and OPC fluidized solidified soil group was set.The effect of high belite sulfoaluminate cement(HB-CSA)clinker on the mechanical properties on G-CSA fluidized solidified soil was studied,and hydration products and pore structure were characterized to further analyze the solidification mechanism of G-CSA.The results show that the strength of G-CSA fluidized solidified soil increases first and then decreases with the increase of HBCSA clinker content.When the content is 10%,the mechanical properties of G-CSA fluidized solidified soil reach the optimal level,with its 28 d compressive strength and flexural strength being 2.35 and 2.06 times that of OPC fluidized solidified soil respectively;The columnar AFt in G-CSA forms a skeleton structure,while the C-S-H gel binds the soil particles into a whole,thus effectively filling the internal pores of G-CSA fluidized solidified soil;An appropriate amount of HB-CSA clinker can reduce the porosity of G-CSA fluidized solidified soil and refine the pore structure to improve its mechanical properties.
作者
孟宪鹍
张帅
许文若
皮振宇
李辉
徐名凤
周健
Meng Xiankun;Zhang Shuai;Xu Wenruo;Pi Zhenyu;Li Hui;Xu Mingfeng;Zhou Jian(Tianjin Luchi Engineering Consulting Co.,Ltd.,Tianjin 300060,China;Hebei University of Technology,Tianjin 300401,China)
出处
《市政技术》
2024年第2期14-20,121,共8页
Journal of Municipal Technology
基金
国家自然科学基金(52008151)。
关键词
矿渣硫铝酸盐水泥
流态固化土
力学性能
水化产物与孔结构
固化机理
slag calcium sulfoaluminate cement(G-CSA)
fluidized solidified soil
mechanical performance
hydration products and pore structure
solidification mechanism
