纳米Al_2O_3和MgO对超高性能混凝土耐磨性的影响及机理  

Effect of Nano Al_2O_3 and MgO on Abrasion Resistance and Mechanism of Ultra-high Performance Concrete

作　　者：李双欣[1] 高小建[2] LI Shuang-xin;GAO Xiao-jian(School of Civil Engineering,Harbin Institute of Technology,Harbin 150001,China;Key Laboratory for Structural Engineering Catastrophe and Control of the Ministry of Education,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]哈尔滨工业大学土木工程学院,哈尔滨150001 [2]哈尔滨工业大学结构工程灾变与控制教育部重点实验室,哈尔滨150001

出　　处：《表面技术》2018年第10期123-130,共8页Surface Technology

基　　金：黑龙江省博士后资助基金(LBH-Z14094)~~

摘　　要：目的基于材料制备角度,使用纳米材料提高超高性能混凝土(UHPC)强度,进而提高基体耐磨性。方法纳米Al_2O_3和Mg O分别以不同质量分数(0.05%、0.1%、0.15%、0.2%和1%)掺入UHPC,测试不同龄期力学强度及耐磨性,选取典型试件进行^(29)Si和^(27)Al的NMR和XRD分析,研究其内部结构特征,为分析纳米材料对UHPC强度及耐磨性的影响机理提供理论依据。结果掺入纳米Mg O的UHPC试件强度及耐磨性皆优于空白及纳米Al_2O_3试样,尤其是当掺量为0.35%(Mg-2)时,7 d抗压强度和抗折强度是空白样的1.11倍,磨损量减少了10%,但不同纳米Mg O对UHPC性能的影响程度略有不同。微观分析表明,纳米Mg O促进水泥水化进程,生成较其他试样更多的水化产物,因此UHPC内部结构较致密。但是纳米MgO又同时促进了水滑石的形成,随着纳米Mg O掺量的增多,水滑石的产量也随之增多,不利于结构致密化。结论纳米UHPC的耐磨性与抗压强度呈正比关系。纳米Mg O可促进水泥水化进程,使UHPC内部结构致密化,利于基体抗压强度和耐磨性的提高。但过量掺入导致水滑石在外部水化区域急剧形成,不利于机体性能的提高,掺入量为0.35%较为适合。The works aims to increase the strength of concrete to improve the abrasion resistance.In the perspective of material preparation in this work,nano materials are used to improve the strength of ultra-high performance concrete and then increase the abrasion resistance.Nano Al2O3 and MgO were added into UHPC in the weight percentages of cement(0.05%,0.1%,0.15%,0.2%and 1%)to test strength and abrasion resistance for different periods.Typical samples were selected to be analyzed for 29Si and 27Al by NMR and XRD and studied for internal structure to provide theoretical basis for effect mechanism of nano materials on UHPC strength and abrasion resistance.The UHPC mixed with nano MgO had higher strength and better abrasion resistance than plain samples and samples with nano Al2O3.When the admixture dosage reached 0.35%(Mg-2),compressive and flexural strength for 7 d was 1.1 times higher than that of plain samples and the wear reduced by 10%.However,different nano MgO influenced the properties of UHPC to the different extents.From the microstructural characterization,nano MgO increased the hydration process of cement,generated more hydration products and resulted in a denser microstructure.However,nano MgO enhanced the formation of hydrotalcite at the same time.As the amount of nano MgO increased,the production of hydrotalcite also increased,but decreased the structure compact.Abrasion resistance of nano UHPC is proportional to compressive strength.The addition of MgO promotes the hydration process,increases the compact of the microstructure of UHPC and then consequently increases the strength and abrasion resistance.However,over dosage can result in the formation of hydrotalcite in the outer hydration area,which is an adverse factor to increase the compressive strength and abrasion resistance.According to this work,the suitable addition is 0.35%.

关 键 词：超高性能混凝土 AL2O3 MGO 耐磨性 微观结构 水泥水化反应 水化硅酸钙凝胶 

分 类 号：TH117[机械工程—机械设计及理论]