采用正交试验,研究了水胶比、硅灰掺量、矿粉掺量对C80高强泵送混凝土强度和可泵性的影响.结果表明,对于C80混凝土的28 d强度,各因素的影响大小顺序为:硅灰掺量>矿粉掺量>水胶比;对于可泵性,倒坍落度筒时间试验表明,矿粉掺量的影响非常显著,水胶比次之,硅灰掺量对倒坍落度筒时间影响不显著.在正交试验的基础上,得到了C80高强泵送混凝土的最优配合比:m(水泥):m(砂):m(石):m(硅粉):m(矿粉):m(减水剂):m(水)=450:739:1006:30:120:13.2:144.混凝土28 d抗压强度为96 MPa,达到C80混凝土的设计要求;混凝土初始坍落度在200~220 mm,2 h内坍落度损失小于20 mm,新拌混凝土倒坍落度筒时间低于10 s,粘度低,具有良好的可泵性.%The effects of water-cement ratio,silicon content and slag content on the strength and pump ability of C80 high-strength pumped concrete are studied by orthogonal test. The results of orthogonal test showed that the order of influencing factors of 28 days strength of C80 concrete was silica fume content>slag content>water cement ratio,for pump ability,the test of slumping time showed that the influence of slag dosage was very significant,the ratio of water-cement was the second,and the influence of silica fume content on the slumping time was non-significant. On the basis of orthogonal test,the optimum mix proportion of C80 high strength pumping concrete was obtained:m(cement):m(sand):m(stone):m(silica fume):m(mineral powder):m(water reducing):m(water)=450:739:1006:30:120:13.2:144. The test results show that the concrete strength is 96 MPa in 28 d,reaches the design requirements of C80 concrete. Concrete initial slump is between 200~220 mm,and the slump loss is within 20 mm in 2 h,fresh concrete collapsed to fall cone time less than 10 s,with low viscosity,good pump ability.
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