【作者】 张洋；

【导师】 王瑞燕；

【作者基本信息】 重庆交通大学 ， 材料与化工硕士（专业学位）， 2023， 硕士

【摘要】 高强高性能已经成为现代混凝土发展的方向,传统配合比设计方法偏向于经验化。为使混凝土结构更加密实,提高混凝土空隙的利用率、减小了胶凝材料用量,同时提升混凝土基体的强度,本文基于粒子干涉理论对高强混凝土的集料级配进行研究,在此基础上用拨开系数、水胶比对配合比进行优化。同时为了改善高强混凝土(High Strength Concrete,HSC)的脆性,掺入钢纤维制备了钢纤维高强混凝土(Steel Fiber Reinforced High Strength Concrete,SFRHSC),钢纤维高强混凝土以其优异的性能,已经广泛应用在各项工程中。但实际上,使用钢纤维成本较高,材料利用率低,在搅拌成型过程中容易结团,不利于混凝土的工作性,使钢纤维高强混凝土在成型或施工又面临一些技术困难。层布式钢纤维混凝土(Layered Steel Fiber Reinforced Concrete,LSFRC)和复合式钢纤维混凝土(Composite Steel Fiber Reinforced Concrete,CSFRC)的出现为解决以上问题提供了新的思路。本文从钢纤维的层布梯度分布方式、体积掺量、种类等角度,分析层布梯度分布钢纤维高强混凝土的弯曲韧性,与掺入式钢纤维混凝土和复合式钢纤维混凝土进行对比,主要内容如下:(1)基于粒子干涉理论,对间断级配和连续级配最大粒径分别为19、9.5和4.75mm的配比进行流动性及立方体抗压强度试验,研究集料级配对高强混凝土流动性和抗压强度的影响。并探究水胶比和拨开系数对混凝土的影响。(2)通过对高强混凝土进行升温养护,设置温度梯度为20、40和60℃,保持养护湿度95%以上,分析养护温度对混凝土抗压强度的影响。测试各个养护温度后的1、3、7和14d干燥收缩,探究各养护温度对级配理论高强混凝土体积变形的影响。(3)通过掺入微细钢纤维体积率为0、0.5、1.0、1.5和2.0%,研究微细钢纤维体积掺量对掺入式高强混凝土流动性、抗压强度和弯曲韧性的影响。(4)通过控制层布钢纤维总体积掺量为1%和2%,分析层布梯度、层布梯度掺量对LSFRC弯曲韧性的影响。采用微细钢纤维(WX12)、剪切型钢纤维(JQ)和三种不同长径比的端钩钢纤维(DG25、DG35和DG60),分析层布梯度分布钢纤维种类对LSFRC土弯曲韧性的影响。(5)通过控制复合方式的钢纤维总体积率为0.5%,对比分析两种复合式钢纤维混凝土与掺入式钢纤维混凝土弯曲韧性,分析CSFRC的优缺点。(6)将层布梯度分布与掺入组合式钢纤维混凝土组合,钢纤维体积率为1和2%,分析这种组合方式对高强混凝土弯曲韧性的影响。更多还原

【Abstract】 High strength and high performance have become the development direction of modern concrete,and traditional mix design methods tend to be empirical.In order to make the concrete structure more dense,improve the utilization rate of concrete voidage,reduce the amount of cementing material,and improve the strength of concrete matrix,this thesis studies the aggregate gradation of high-strength concrete based on the particle interference theory.On this basis,it optimizes the mix ratio with the allocation coefficient and water-cement ratio.In order to improve the brittleness of High Strength Concrete(HSC),Steel Fiber Reinforced High Strength Concrete(SFRHSC)was prepared by adding steel fiber reinforced high strength concrete(SFRHSC).Steel fiber high strength concrete has been widely used in various projects because of its excellent performance.But in fact,the use of steel fiber cost is high,the material utilization rate is low,in the process of mixing forming easy clumping,is not conducive to the work of concrete,so that steel fiber high strength concrete in the forming or construction and face some technical difficulties.Layered Steel Fiber Reinforced Concrete(LSFRC)and Composite Steel Fiber Reinforced Concrete(Composite Steel Fiber Reinforced Concrete),The emergence of CSFRC provides a new way to solve the above problems.In this thesis,the bending toughness of steel fiber high-strength concrete with gradient distribution of steel fiber is analyzed from the Angle of layered gradient distribution,volume content and type of steel fiber concrete,and the comparison is made with the mixed fiber concrete steel fiber concrete and composite steel fiber concrete.The main contents are as follows:(1)Based on particle interference theory,flow and cube compressive strength tests were conducted on the proportions of discontinuous and continuous gradations with maximum particle sizes of 19,9.5 and 4.75 mm,respectively,to study the influence of aggregate gradation on the flow and compressive strength of high-strength concrete.The influence of water-binder ratio and stripping coefficient on concrete is also explored.(2)The effect of curing temperature on compressive strength of concrete was analyzed by setting temperature gradient of 20,40 and 60℃ and maintaining curing humidity above 95%.The drying shrinkage at 1,3,7 and 14 days after each curing temperature was tested,and the influence of each curing temperature on the volume deformation of graded high-strength concrete was explored.(3)The effect of the volume fraction of fine steel fibers on the fluidity,compressive strength and bending toughness of the mixed high-strength concrete was studied by adding the volume fraction of fine steel fibers at 0,0.5,1.0,1.5 and 2.0%.(4)The influence of laminate gradient and laminate gradient content on the bending toughness of LSFRC was analyzed by controlling the total volume and content of laminate steel fiber as 1% and 2%.The effects of layered gradient distribution on bending toughness of LSFRC were analyzed by microsteel fiber(WX12),shear steel fiber(JQ)and end-hook steel fiber(DG25,DG35 and DG60)with different length-diameter ratios.(5)By controlling the total volume rate of steel fiber composite way is 0.5%,the bending toughness of two kinds of composite steel fiber concrete and mixed steel fiber concrete is compared and analyzed,and the advantages and disadvantages of composite steel fiber concrete are analyzed.(6)The effect of layered gradient distribution on flexural toughness of high-strength concrete is analyzed by combining composite steel fiber concrete with steel fiber volume ratio of 1 and 2%.更多还原