粉煤灰对砂浆性能的影响

Study of Influence of Fly Ash on the Properties of Mortar

以粉煤灰取代部分水泥,研究其掺量对砂浆收缩率、失水率和力学性能的影响,并利用X射线荧光光谱分析仪(XRF)和扫描电子显微镜(SEM)对粉煤灰的化学成分和微观形貌进行分析。实验结果表明:掺量在10%～60%,砂浆的收缩率与粉煤灰掺量成反比关系,而失水率与粉煤灰掺量成正比关系;砂浆试块抗压、抗折强度随粉煤灰掺量的增大先增大后减小,在掺量30%左右,其强度达到最大值;粉煤灰对砂浆的前期强度影响不大,而对后期强度增长非常大。因此,在砂浆中加入适量的粉煤灰,可以在满足砂浆力学性能的前提下,抑制砂浆的收缩变形。

Fly ash is used as a partial replacement for cement.The authors studied the effect of percentage of fly ash replacement on shrinkage rate,water loss rate and mechanical properties of mortat.The chemical composition and microscopic structure of fly ash were tested by X ray fluorescence spectrum analyzer（XRF） and scanning electron microscope（SEM）.The result shows that for the 10~60% fly ash replacement,as more fly ash is added,the general shrinkage of mortar decreases and water loss rate increases.The compressive strength and flexural strength increases first and then decreases,and reaches the highest value for around 30% replacement.Fly ash has little effect on early strength gain of mortar,but plays an important role in later strength gain.Therefore,given the appropriate percentage of fly ash replacement,the performance of the mortar can be improved and the shrinkage deformation of the mortar can be prevented.