不同因素对碱激发粉煤灰砂浆强度的影响及机理研究

Influences of Different Factors on Strength of Alkali-Activated Fly Ash Mortar and the Corresponding Mechanism Analysis

通过压汞试验探究了不同因素作用下碱激发粉煤灰砂浆内部的孔结构分布特征,并从孔结构特征角度出发对试件的力学性能进行解释.试验结果表明:随着养护龄期的增长,碱激发粉煤灰砂浆试件内部的孔隙率不断上升,但平均孔径(直径)不断下降,结构内部的孔结构分布由离散型的大孔结构逐步转变为分布更为均匀的小孔结构;养护温度和激发剂质量比均会对试件的强度和孔径分布产生影响,养护温度越高,粉煤灰水化越充分,结构内部孔径随着龄期的增长而逐渐减小,试件抗压强度越高;质量比对孔结构的影响最为复杂,随着质量比的变化,碱激发粉煤灰砂浆试件内部孔结构分布和强度均呈阶段性变化.

This paper investigates the pore structure characteristics of alkali-activated fly ash mortar affected by different factors via a mercury intrusion test,and explores the mechanical properties of specimens from the view of pore structure characteristics.Test results indicate that(1)with the growth of curing age,the porosity of alkali-activated fly ash mortar specimens increases,the average pore diameter decreases,and the distribution of internal pores changes from a discrete macroporous structure to a more uniform form;(2)both the curing temperature and the mass ratio of the excitant have an impact on the strength of specimens and the distribution of pore diameter,concretely,higher curing temperature may result in more fully hydration of fly ash,and the internal aperture of the structure may decrease with the growth of curing age,thus resulting in a higher compressive strength of the specimens;and(3)in the several above-mentioned factors,mass ratio has the most complex effect on pore structure,concretely,a continuous variation of mass ratio may result in a periodic change of pore structure distribution and compressive strength.