钢纤维长径比对C60混凝土抗裂性能及抗冻性能的影响
发布时间：2018-11-06 07:54
【摘要】：钢纤维高强混凝土已广泛应用于水利及土木工程领域,其耐久性直接关系到结构的使用性和安全性,所以钢纤维混凝土的耐久性研究早已受到了国内外研究界高度重视,但钢纤维长径比对其耐久性的影响研究较为不足,本文主要研究了钢纤维长径比对C60混凝土早期抗裂性能及抗冻性能的影响。本文研究的内容主要有以下两方面:(1)设计正交试验,综合分析水胶比、粉煤灰掺量和钢纤维体积率等因素对C60混凝土 28d的抗压强度、劈裂抗拉强度以及拉压比三种力学性能的影响,主要结论如下:①钢纤维对C60混凝土的抗压强度、劈裂抗拉强度和拉压比都有显著影响,尤其对后两者,但钢纤维掺量过多又会对这三种性能产生削弱影响;②确定C60钢纤维混凝土最佳配合方案为:水胶比取0.30,粉煤灰掺量取20%,钢纤维体积率取1.50%。(2)基于最佳配合比,研究钢纤维不同长径比对C60混凝土早期抗裂性能、冻融前后力学性能和抗冻性能的影响,主要结论如下:①钢纤维对C60混凝土早期裂缝有抑制作用,并且当钢纤维长径比为50时,C60混凝土早期塑性裂缝的面积和数量都被降到了最低,其阻裂效能等级达到一级;②C60钢纤维混凝土的抗压强度、劈裂抗拉强度和抗折强度,分别在钢纤维长径比为75、50和50时达到最大,综合考虑下长径比为50的钢纤维对其力学性能增强效果最好;③钢纤维长径比对混凝土基体抗压强度影响小于冻融次数对其影响;④当钢纤维长径比为50时,抗折和劈拉强度损失最小;长径比为75时,其损失次之;未掺入钢纤维和长径比为25时,其损失最大;⑤长径比为50和75的钢纤维,对C60混凝土抗冻性有明显的增强作用。本文探究了钢纤维长径比对C60混凝土力学性能和耐久性的影响,得出了抗裂性、抗冻性以及力学性能最好的C60钢纤维混凝土配合方案为:水胶比取0.30,粉煤灰掺量取20%,钢纤维体积率取1.50%,钢纤维长径比取50,并为建立钢纤维混凝土抗冻性指标提供了理论依据,也为试验研究钢纤维长径比对高强混凝土耐久性的影响提供了借鉴和方向。
[Abstract]:Steel fiber high strength concrete has been widely used in the field of water conservancy and civil engineering, and its durability is directly related to the use and safety of the structure. Therefore, the durability research of steel fiber reinforced concrete has been attached great importance to at home and abroad. However, the influence of the aspect ratio of steel fiber on the durability of C60 concrete is not enough. This paper mainly studies the influence of the ratio of length to diameter on the early crack resistance and freezing resistance of C60 concrete. The main contents of this paper are as follows: (1) the orthogonal test is designed to analyze the compressive strength of C60 concrete for 28 days, including the ratio of water to binder, the content of fly ash and the volume ratio of steel fiber. The main conclusions are as follows: (1) Steel fiber has a significant effect on the compressive strength, splitting tensile strength and tensile compression ratio of C60 concrete, especially on the latter two. However, too much steel fiber will weaken these three properties. 2. The optimum mix scheme of C60 steel fiber reinforced concrete is determined as follows: water / binder ratio 0.30, fly ash content 20 and steel fiber volume ratio 1.50. (2) based on the optimum mix ratio, The effects of different aspect ratio of steel fiber on early crack resistance, mechanical properties and frost resistance of C60 concrete before and after freezing and thawing are studied. The main conclusions are as follows: 1 Steel fiber can inhibit early crack of C60 concrete. When the ratio of steel fiber aspect to diameter is 50, the area and number of early plastic cracks of C60 concrete are reduced to the lowest, and the grade of crack resistance effectiveness reaches the first grade. The compressive strength, splitting tensile strength and flexural strength of 2C60 steel fiber concrete are maximum when the aspect ratio of steel fiber is 75 ~ 50 and 50, respectively. (3) the influence of the ratio of length to diameter of steel fiber on the compressive strength of concrete matrix is less than that of freeze-thaw ratio, 4 when the ratio of length to diameter of steel fiber is 50, the loss of flexural and split tensile strength is the least, and the loss is second when the ratio of length to diameter is 75. When the ratio of steel fiber to diameter is 25, the loss of steel fiber is the biggest, and the freezing resistance of C60 concrete is enhanced obviously when the ratio of length to diameter is 50 and 75. In this paper, the influence of the ratio of length to diameter of steel fiber on mechanical properties and durability of C60 concrete is studied. The best fit scheme of C60 steel fiber concrete with crack resistance, frost resistance and mechanical properties is obtained as follows: water / binder ratio is 0.30, fly ash content is 20 percent. The volume ratio of steel fiber is 1.50 and the ratio of length to diameter of steel fiber is 50. It provides a theoretical basis for the establishment of freezing resistance index of steel fiber concrete, and also provides a reference and direction for the experimental study on the influence of steel fiber length to diameter ratio on the durability of high strength concrete.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528
本文编号：2313637
[Abstract]:Steel fiber high strength concrete has been widely used in the field of water conservancy and civil engineering, and its durability is directly related to the use and safety of the structure. Therefore, the durability research of steel fiber reinforced concrete has been attached great importance to at home and abroad. However, the influence of the aspect ratio of steel fiber on the durability of C60 concrete is not enough. This paper mainly studies the influence of the ratio of length to diameter on the early crack resistance and freezing resistance of C60 concrete. The main contents of this paper are as follows: (1) the orthogonal test is designed to analyze the compressive strength of C60 concrete for 28 days, including the ratio of water to binder, the content of fly ash and the volume ratio of steel fiber. The main conclusions are as follows: (1) Steel fiber has a significant effect on the compressive strength, splitting tensile strength and tensile compression ratio of C60 concrete, especially on the latter two. However, too much steel fiber will weaken these three properties. 2. The optimum mix scheme of C60 steel fiber reinforced concrete is determined as follows: water / binder ratio 0.30, fly ash content 20 and steel fiber volume ratio 1.50. (2) based on the optimum mix ratio, The effects of different aspect ratio of steel fiber on early crack resistance, mechanical properties and frost resistance of C60 concrete before and after freezing and thawing are studied. The main conclusions are as follows: 1 Steel fiber can inhibit early crack of C60 concrete. When the ratio of steel fiber aspect to diameter is 50, the area and number of early plastic cracks of C60 concrete are reduced to the lowest, and the grade of crack resistance effectiveness reaches the first grade. The compressive strength, splitting tensile strength and flexural strength of 2C60 steel fiber concrete are maximum when the aspect ratio of steel fiber is 75 ~ 50 and 50, respectively. (3) the influence of the ratio of length to diameter of steel fiber on the compressive strength of concrete matrix is less than that of freeze-thaw ratio, 4 when the ratio of length to diameter of steel fiber is 50, the loss of flexural and split tensile strength is the least, and the loss is second when the ratio of length to diameter is 75. When the ratio of steel fiber to diameter is 25, the loss of steel fiber is the biggest, and the freezing resistance of C60 concrete is enhanced obviously when the ratio of length to diameter is 50 and 75. In this paper, the influence of the ratio of length to diameter of steel fiber on mechanical properties and durability of C60 concrete is studied. The best fit scheme of C60 steel fiber concrete with crack resistance, frost resistance and mechanical properties is obtained as follows: water / binder ratio is 0.30, fly ash content is 20 percent. The volume ratio of steel fiber is 1.50 and the ratio of length to diameter of steel fiber is 50. It provides a theoretical basis for the establishment of freezing resistance index of steel fiber concrete, and also provides a reference and direction for the experimental study on the influence of steel fiber length to diameter ratio on the durability of high strength concrete.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528
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