摘要
采用水泥、矿渣粉、粉煤灰和减水剂对磷石膏进行改性。最终得到的磷石膏基复合胶凝材料的强度为原状磷石膏的2倍,软化系数从0.5提高至0.8。磷石膏基复合胶凝材料的比强度和孔隙率之间存在明显的线性关系,随着孔隙率的减小比强度增加。通过扫描电镜(SEM)对磷石膏基复合胶凝材料微观形貌的演变过程进行表征,发现随着矿渣粉、水泥、粉煤灰和减水剂的掺加,基体由疏松转变为致密;主要的水化产物二水石膏从针状转变为棒状或片状,并且出现了水化硅酸钙(C-S-H)凝胶,其填充于体系内部的孔隙并将二水石膏连成整体。利用X射线衍射(XRD)分析和傅里叶变换红外吸收光谱(FT-IR)测试对水化产物的微观结构进行研究。结果表明,复合体系中的主要产物为二水石膏,但是由于可用水量的减少,体系中仍剩余少量磷石膏未水化。
Phosphogypsum was modified with cement,slag powder,fly ash and water reducer.The strength of the final phosphogypsum based composite cementitious material was twice that of undisturbed phosphogypsum,and the softening coefficient was increased from 0.5 to 0.8.There was an obvious linear relationship between the specific strength and porosity of phosphogypsum based composite cementitious materials.When the porosity was decreased,the specific strength was increased.The microstructure evolution of phosphogypsum based composite cementitious material was characterized by scanning electron microscope(SEM).It was found that with the addition of slag powder,cement,fly ash and water reducer,the matrix changed from loose to dense;The main hydration product dihydrate gypsum changed from needle to rod or sheet,and hydrated calcium silicate(C-S-H)gel appeareds,which filled the pores in the system and connects dihydrate gypsum as a whole.The microstructure of hydration products was studied by X-ray diffraction(XRD)analysis and fourier transform infrared absorption spectroscopy(FT-IR).The results showed that the main product in the composite system was dihydrate gypsum,but due to the reduction of available water,a small amount of phosphogypsum remained in the system without hydration.
作者
张太玥
谢凡
郭君渊
ZHANG Taiyue;XIE Fan;GUO Junyuan(Architectural Engineering Institute,Jiangsu College of Engineering and Technology,Nantong 226000,China;Shanghai Modern Architectural Design Group Engineering Construction Consulting Co.,Ltd;Key Lab of Advanced Civil Engineering Materials(Tongji University),Ministry of Education)
出处
《无机盐工业》
CAS
CSCD
北大核心
2022年第9期136-142,共7页
Inorganic Chemicals Industry
基金
南通市科技计划项目(JC2021172)
江苏省高等学校自然科学面上项目(18KJD580001)
江苏省高校“青蓝工程”资助。
关键词
磷石膏
复合胶凝材料
孔隙率
微观结构
水化机理
phosphogypsum
composite cementitious materials
porosity
micro structure
hydration mechanism
