摘要
超高性能混凝土(UHPC)是继高强度、高性能混凝土之后新近发展起来的一类新型混凝土材料。UHPC自身具备超高强度及高耐久性等优点,使其在高层、超高层建筑、大跨度空间结构与恶劣腐蚀环境下的重大土木工程中有广阔应用前景。本工作从材料制备角度,通过矿物掺合料改变UHPC基本配合比并且采用效率更高的微波养护方式对试件进行养护。通过一系列实验,观察矿渣的使用和微波养护对UHPC力学性能的影响,并通过微观表征分析研究其影响机理。制备了10%、25%、50%、70%和90%矿渣取代基本配合比中水泥部分用量试件,采用3 d延迟微波养护制度养护,测试3 d及28 d强度,随后选取性能典型试件进行29Si NMR、27Al NMR和XRD分析。实验发现标准养护下UHPC强度随着矿渣掺入而降低,但微波养护通过加速矿渣水化反应加强了混凝土力学强度发展进程。该加强效应对早期性能发展的影响更显著,且随着矿渣掺量增加而增强。微观表征分析首先确定了微波养护对试样水化的加速作用,并促进了晶体产物和短链C-S-H的形成,达到进一步克服矿渣对UHPC强度发展的延迟作用。
Ultra-high performance concrete( UHPC) is,after high strength concrete and high performance concrete,the newly developed concrete,which possesses high strength and high durability,ect. It has a significant application potential in the construction of high rise,super highrise buildings,large span structure and the civil projects under harsh corrosive environment. In the perspective of material preparation,ultra-high performance concrete( UHPC) was added with mineral admixture and was treated with microwave curing,more efficient curing method. The effect of mineral admixture and microwave curing method on the strength was studied,as well as the affecting mechanism through the microstructural characterization. The cement in UHPC has been partially replaced by blast furnace slag( BFS) in the weight percentages of 10%,30%,50%,70% and 90%. Three days delayed microwave curing regime was adapted. After the samples were tested for strength,some typical samples were selected to be examined with29 Si and27 Al NMR and XRD. It was found that,under the standard curing,the compressive strength reduced with the addition of BFS,but the microwave curing enhanced the development of strength through accelerating the hydration of BFS. The acceleration effects were more significant with the early age samples; moreover,it increased with the addition of BFS increasing. The microstructural characterization confirmed the acceleration of hydration by microwave curing,and showed that the formation of crystalline phases and C-SH with short chains were increased,which both help overcoming the retarded effects by the addition of BFS.
作者
高小建
李双欣
GAO Xiaojian;LI Shuangxin(School of Civil Engineering,Harbin Institute of Technology,Harbin 150001;The Key Laboratory of Structural Engineering Catastrophe and Control of the Ministry of Education,Harbin 150001)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第2期271-276,共6页
Materials Reports
基金
黑龙江省博士后资助基金(LBH-Z14094)~~
关键词
超高性能混凝土
矿物掺合料
微波养护
力学性能
微观机理
ultra-high performance concrete
mineral admixture
microwave curing
mechanical property
microstructure
