不同碱当量、粉煤灰和矿渣掺量对碱激发粉煤灰-矿渣地聚物力学性能及微观结构的影响  

Effect of Different Alkali Equivalent,Fly Ash and Slag Content on the Mechanical Properties and Microstructure of Alkali-activated Fly Ash-slag Geopolymer

作　　者：詹疆淮 李宏波[1] 傅博 拓明阳 ZHAN Jiang-huai;LI Hong-bo;FU Bo;TA Ming-yang(School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China;College of Civil Engineering, North Minzu University, Yinchuan 750021, China)

机构地区：[1]宁夏大学土木与水利工程学院,银川750021 [2]北方民族大学土木工程学院,银川750021

出　　处：《科学技术与工程》2021年第28期12218-12224,共7页Science Technology and Engineering

基　　金：国家自然科学基金(51668001);宁夏回族自治区自然科学基金(2020AAC03195,2019AAC03132)。

摘　　要：粉煤灰、矿渣复配组成碱激发复合水泥可以改善单一组分碱激发水泥的性能劣势。为了研究不同碱当量、不同粉煤灰和矿渣掺量对碱激发粉煤灰-矿渣砂浆力学性能、干燥收缩及微观结构特性的影响,采用抗压、抗折强度试验、吸水率试验、干燥收缩试验、微观扫描电子显微镜(scanning electron microscope,SEM)及傅里叶红外光谱(Fourier transform infrared spectrometer,FTIR)试验进行表征。结果表明:3、7、28 d龄期时,随着碱当量和矿渣掺量增加,粉煤灰-矿渣砂浆抗压、抗折强度呈逐渐增加趋势,吸水率和干燥收缩率呈逐渐下降趋势。其中龄期为28 d,碱当量为6%、矿渣掺量为100%时,碱激发粉煤灰-矿渣砂浆抗压强度达到峰值110.84 MPa,抗折强度达到峰值10.77 MPa,吸水率最小,为1.2%,与4%的粉煤灰-矿渣砂浆相比,碱当量为6%的砂浆干燥收缩率均减少10%以上。由微观分析知,粉煤灰-矿渣砂浆在碱激发作用下水化产物主要为铝硅酸盐凝胶和水化硅酸钙凝胶,粉煤灰掺量越大,凝胶结晶度越低。碱当量越大,体系水化产物数量越多,结构越密实。Alkali-activated composite cement composed of fly ash and slag can improve the performance disadvantage of single component Alkali-activated cement.In order to study the effects of different alkali equivalents,different fly ash and slag content on the mechanical properties,drying shrinkage and microstructure characteristics of alkali-activated fly ash-slag mortar,compressive strength,flexural strength test,water absorption test,drying shrinkage test,scanning electron microscope(SEM)and Fourier transform infrared spectrometer(FTIR)were used to characterize.The results show that at the age of 3 days,7 days and 28 days,with the increase of alkali equivalent and slag content,the compressive strength and flexural strength of fly ash slag mortar gradually increase,while the water absorption and drying shrinkage rate decrease gradually.When the age is 28 days,the alkali equivalent is 6%,and the slag content is 100%,the compressive strength of alkali activated fly ash slag mortar reaches the peak value of 110.84 MPa,the flexural strength reaches the peak value of 10.77 MPa,and the minimum water absorption rate is 1.2%,compared with the 4%fly ash slag mortar,the drying shrinkage of the mortar with alkali equivalent of 6%is reduced by more than 10%.According to the microscopic analysis,the hydration products of fly ash-slag mortar under the action of alkali are mainly aluminosilicate gel and hydrated calcium silicate gel.The greater the amount of fly ash,the lower the gel crystallinity.The greater the alkali equivalent,the greater the number of hydration products in the system and the denser the structure.

关 键 词：碱激发 粉煤灰-矿渣 强度 干燥收缩 微观结构 

分 类 号：TU528[建筑科学—建筑技术科学]