普通混凝土生产工艺制备非预混UHPC的实践与验证

Practice and verification of preparing non premixed UHPC by ordinary concrete production process

提出了适用于工业化大规模生产UHPC的“非预混料、常规搅拌设备拌制技术”,即不预混UHPC粉料,对常规混凝土搅拌站进行微调整,采用普通混凝土上料和搅拌工艺生产UHPC。对普通混凝土搅拌站改造主要是因为料仓不足,新增加硅灰、粉煤灰微珠和钢纤维3种上料设备,以满足UHPC的生产条件。以德余高速乌江特大桥项目UHPC桥面板大规模生产为依托,采用该技术,对粗骨料UHPC的施工配合比(其中粗骨料掺量719 kg/m^(3),钢纤维体积掺量2%,具有较高的力学性能)进行生产,共计1 600余m^(3)。工程实践表明,实测留样强度数据符合正态分布,混凝土质量波动性较小,强度检验评定满足要求。该技术使UHPC的生产方式可以脱离预混料制备这一环节,明显简化了UHPC的生产流程,拓展了UHPC的制备途径。

It proposes a“non premix,conventional mixing equipment mixing technology”that is suitable for large-scale industrial production of UHPC,namely,no premix of UHPC powder,micro adjustment of conventional concrete mixing plant,and production of UHPC by using ordinary concrete loading and mixing process.The transformation of ordinary concrete mixing plant is mainly because the silo is not enough to add three kinds of feeding equipment,namely silica fume,fly ash bead and steel fiber,to meet the production conditions of UHPC.Relying on the large-scale production of UHPC bridge deck of Deyu Expressway Wujiang Super Large Bridge Project,this technology was used to produce UHPC with coarse aggregate(including 719 kg/m^(3)of coarse aggregate and 2% of steel fiber by volume,which have high mechanical properties),totaling more than 1 600 m^(3).The engineering practice shows that the measured strength data of reserved samples conform to normal distribution,the fluctuation of concrete quality is small,and the strength inspection and evaluation meet the requirements.This technology enables the production of UHPC to be separated from the link of premix preparation,significantly simplifies the production process of UHPC,and expands the preparation path of UHPC.