滨海高热环境下160 MPa级UHPC的制备与应用研究

Study on preparation and application of 160 MPa UHPC in coastal high heat environment

基于广东省滨海湾大桥制备了滨海高热环境下应用的160 MPa级超高性能混凝土(UHPC),对其轴心抗拉性能与微观结构开展研究,并进行钢桥面铺装应用。结果表明:CM_(2)型掺合料可明显增大UHPC的流动度、减小水胶比,出机扩展度达到自密实状态,32℃条件下UHPC拌合物2 h扩展度基本无损失;90℃蒸汽养护后UHPC抗压强度达180 MPa,轴拉性能弹性段抗拉强度为9.6MPa,极限抗拉强度11.4 MPa,极限拉伸应变为0.35%,极限、弹性段抗拉强度比为1.9,具有明显的应变硬化特征。采用改进的生产线与专业化的施工设备可实现160 MPa级UHPC规模化制备与施工应用。

In order to prepare 160 MPa ultra-high-performance concrete that meets the application of high heat environment,UHPC with different components were prepared according to the requirements of Binhaiwan Bridge in Guangdong Province,and the tensile performance and microstructure of UHPC shaft with optimal ratio were studied,and the preferred ratio group was used for steel bridge deck paving.The results show that the CM_(2)admixtures can significantly improve UHPC fluidity,reduce the water-to-adhesive ratio,and reach the self-compacting state of the machine expansion,the 2 h expansion of UHPC mixtures in 32℃ environment is basically no loss,and the working performance is adapted to the pouring requirements of high heat environment.The compressive strength of UHPC cube after steam curing at 90℃reaches 180 MPa,the tensile strength of the elastic section of the shaft tensile performance is 9.6 MPa,the ultimate tensile strength is 11.4 MPa,the ultimate tensile strain is 0.35%,and the ratio between ultimate tensile strength and the tensile strength of the elastic section is 1.9,which has obvious strain hardening characteristics.The improved production line and professional construction equipment can realize the large-scale preparation and construction application of 160 MPa-class UHPC.