清水自密实二衬混凝土材料设计

Design and Study on Mechanical Property of Fair-faced Self-compacting Second Lining Concrete

采用体积分析法设计应用于隧道二衬的清水自密实混凝土,以C30混凝土强度为评价指标对其材料组成进行了优化:当10~20mm和5~10mm两档粒径的粗集料混合比例为7∶3时,抗压强度最高;当粗集料体积率超过0.35时,混凝土密实效果下降,强度下降;当砂体积率为0.44时混凝土强度达到最大值;矿物掺合料总体掺量在45%,其中矿粉(GGBS)掺量为25%,粉煤灰掺量为20%时强度达到最大值;设计的混凝土强度达到C30标准并具备良好的自密实性能与清水效果。

Through volume analysis method,the fair-faced self-compacting second lining concrete was designed and applied in the second lining.The composition of concrete was optimized by taking concrete strength as the index.When the mixture ratio of coarse aggregate of 10~20 mm and 5~10 mm is 7∶3,its compression strength is best.When volume ratio of coarse aggregate exceeds 0.35,the compaction effect and compression strength begin to decrease.With its sand volume ratio reaching 0.44,its compression strength reaches a maximum.While the total mineral admixture is 45%,of which the granulated blast furnace slag(GGBS)is 25%and the fly ash 20%,compression strength is the best.The concrete designed is up to C30 standard and have good self-compacting effect and appearance.