纤维矿渣微粉混凝土高温性能试验研究
[Abstract]:Through the mechanical properties tests of 1232 concrete specimens with fiber slag powder at room temperature, high temperature and high temperature, combined with microscopic test and mechanism analysis, the temperature, the content of slag powder and the content of polypropylene fiber were discussed. The effects of volume ratio of steel fiber and strength grade of concrete on the mechanical properties of fiber slag micro-powder concrete are studied. The main contents and conclusions are as follows: 1. The mechanical properties of fiber slag micro-powder concrete at room temperature were studied. The results show that the compressive strength, splitting tensile strength and deformation, flexural strength and deformation of fiber slag micro-powder concrete can be improved by slag micro-powder and steel fiber, and polypropylene fiber can improve the compressive strength of fiber slag micro-powder concrete. The elastic modulus and split tensile deformation are improved in varying degrees, and with the increase of concrete strength grade, splitting tensile strength and deformation, flexural strength and deformation of fiber slag micro-powder concrete are improved in varying degrees. Based on the statistical analysis of the test results, the compressive strength and splitting tensile strength of concrete with fine powder of slag, polypropylene fiber and volume ratio of steel fiber at room temperature were established. Models for calculating flexural strength and modulus of elasticity. 2. SEM analysis and mechanism analysis of fiber slag micro-powder concrete after high temperature were carried out. The results show that temperature, slag micro-powder, polypropylene fiber, steel fiber and concrete strength grade have different effects on the burning loss rate of fiber slag micro-powder concrete. With the increase of temperature, the internal moisture of fiber slag micro-powder concrete gradually evaporates and decomposes, and the morphology of cement hydrates such as C-S-H gel, ettringite AFt crystal and calcium hydroxide Ca (OH) 2 crystal in the transition zone between cement paste and aggregate and cement paste is obtained. The state and quantity as well as the pore and fracture have changed in different degrees. The process of high temperature burst and microstructure damage at high temperature is related to the water decomposition and vaporization and migration process. The mechanical properties of fiber slag fine powder concrete after high temperature and high temperature were studied. The results show that the compressive strength ratio, splitting tensile strength ratio, flexural strength ratio and elastic modulus ratio of fiber slag micro-powder concrete are decreased by high temperature. The change of slag powder and polypropylene fiber content has little effect on high temperature compressive strength ratio, splitting tensile strength ratio, flexural strength ratio and elastic modulus ratio of fiber slag micro powder concrete. The ratio of high temperature compressive strength, split tensile strength and flexural strength of fiber slag micro-powder concrete has been improved to some extent, and the ratio of splitting tensile strength and flexural strength has been greatly improved. The calculation models of high temperature compressive strength, splitting tensile strength, flexural strength and elastic modulus of fiber slag micro-powder concrete are established by comparing and analyzing the experimental results of high temperature and normal temperature. 4. The deformation properties of fiber slag micro-powder concrete at high temperature were tested. The compression resistance of fiber slag micro-powder concrete was analyzed systematically by temperature, slag powder content, polypropylene fiber content, volume ratio of steel fiber and strength grade of concrete. Under the influence of splitting and bending deformation, the stress-strain curve equation of fiber slag micro-powder concrete under high temperature compression was established considering the influence of temperature, slag powder content, polypropylene fiber content and volume ratio of steel fiber.
【学位授予单位】:郑州大学
【学位级别】:博士
【学位授予年份】:2013
【分类号】:TU528
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