摘要
为探讨粉煤灰基地聚物砂浆力学性能和微观孔结构的影响因素,利用正交设计和单一变量法研究了养护温度、高温养护时长、水相含量z、水玻璃模数n、胶砂比J和溶胶比R对砂浆强度的影响,获得了其数学关系模型。同时,借助压汞法分析了微观孔结构和砂浆宏观力学性能的关系。结果表明:提高养护温度可以显著地增加砂浆的抗压强度,并且最佳温度为70~80℃;高温持续养护4 d可以获得砂浆抗压强度和抗弯强度的最大值,养护24 h可分别获得最大抗压强度和抗弯强度的91.9%和71.3%。砂浆强度的敏感性因素从大到小依次为水相含量z、水玻璃模数n、胶砂比J、溶胶比R;砂浆强度随着水相含量z的增大而急剧降低,两者几乎呈线性关系;砂浆的抗压强度和抗弯强度随着水玻璃模数n的增加先增大后减小,满足二次函数关系;胶砂比和溶胶比对砂浆的强度影响较小。孔隙率越小,砂浆强度越高;孔隙率对强度的影响要明显大于孔径分布;在孔隙率相近时,胶凝孔隙(≤10 nm)和过渡孔隙(10~100 nm)的体积百分数越大,砂浆强度越高。
In order to investigate the influence factors of the mechanical properties and the microscopic pore structure of fly ash based geopolymer mortar, the curing temperature, high temperature curing time, water phase content z, water glass modulus n, solution/cement ratio R and the cement/sand ratio J were studied by orthogonal design and single variable method, respectively. And its mathematical model was proposed. The relationship between microscopic pore characteristics and mechanical properties of mortar was analyzed by mercury intrusion porosimetry(MIP).The results showed that increasing the curing temperature can significantly increase the compressive strength of the mortar, and the optimum temperature is 70~80 ℃. The maximum compressive strength and flexural strength of mortar can be obtained by continuous curing at high temperature for 4 d, while 91.9% of the maximum compressive strength and 71.3% of the maximum flexural strength can be obtained respectively by curing for 24 h. The sensitivity factors from large to small on mechanical properties of mortar as follows as water phase content, water glass modulus,the cement/sand ratio and the solution/cement ratio. The strength of mortar decreases sharply with the increase of water content z, and the two have almost linear relationship. The compressive strength and flexural strength of the mortar first increase and then decrease with the increase of the modulus n of the water glass, satisfying the quadratic curve relationship. The effect of cement/sand ratio and solution/cement ratio on the strength of mortar can be ignored. When the porosity is similar, the larger the volume ratio of the gel aperture(≤10 nm) and the transition aperture(10~100 nm), the higher the strength of the mortar. However, the effect of porosity on the strength is significantly greater than the influence of pore size distribution.
作者
杨世玉
赵人达
靳贺松
李福海
胡丁涵
YANG Shiyu;ZHAO Renda;JIN Hesong;LI Fuhai;HU Dinghan(School of Civil Eng.,Southwest Jiaotong Univ.,Chengdu 610031,China)
出处
《工程科学与技术》
EI
CAS
CSCD
北大核心
2020年第6期162-169,共8页
Advanced Engineering Sciences
基金
国家自然科学基金项目(51778531)
四川省科技计划项目(2019YJ0219)
四川省科技厅项目(2020ZYD011)。
关键词
粉煤灰
地质聚合物
抗压强度
压汞法
正交试验
fly ash
geopolymer
compressive strength
mercury intrusion porosimetry
orthogonal test
