引水隧道混凝土衬砌中粉煤灰含量对抗压强度的影响

Influence of fly ash content on compressive strength of concrete lining of headrace tunnel

水工工程大量使用粉煤灰取代水泥,使用粉煤灰配制混凝土的性能严重影响施工效果,因此研究引水隧道混凝土衬砌中粉煤灰含量对抗压强度的影响有重要意义。本研究通过调整粉煤灰含量,分别制备了15%、25%与35%等3种粉煤灰含量的混凝土试件,并改变养护温度,调整粉煤灰细度,分别验证这些影响因素下掺合粉煤灰混凝土的抗压强度。考虑到引水隧道衬砌所处的实际环境,还研究了自然环境对于粉煤灰混凝土抗压强度的影响。研究结果表明:含量为25%的粉煤灰具有更加良好的抗压强度,同时将温度控制在22℃时,选择45 mm的方孔筛且筛余量为25%的粉煤灰细度,更能提升混凝土的抗压强度;粉煤灰会与酸性物质发生反应,所以粉煤灰掺量过多会降低混凝土的抗压强度。

Fly ash is widely used in hydraulic engineering to replace cement,and the performance of concrete prepared with fly ash seriously affects the construction effect.Therefore,it is important to study the influence of fly ash content on compressive strength in concrete lining of headrace tunnel.In this study,by adjusting the fly ash content,concrete specimens with 15%,25%and 35%fly ash content were prepared,respectively,and the compressive strength of concrete mixed with fly ash under these influencing factors was verified by changing the curing temperature and adjusting the fineness of fly ash.Considering the actual environment of headrace tunnel lining,the influence of natural environment on the compressive strength of fly ash concrete was also studied.The research results showed that the fly ash with a content of 25%had better compressive strength,at the same time,when the temperature was controlled at 22℃,45 mm square hole sieve with 25%fineness of fly ash was selected,it could well improve the compressive strength of concrete.Fly ash could react with acidic substances,therefore excessive amount of fly ash could reduce the compressive strength of concrete.