混杂钢纤维聚合物改性水泥混凝土特殊铺装材料性能研究

发布时间：2018-07-04 23:09

本文选题：钢纤维混凝土 + 聚合物改性混凝土　；参考：《重庆交通大学》2017年硕士论文

【摘要】：聚合物改性混凝土与钢纤维混凝土是两种优异的路面材料,有很多优点,但也有不足。本文运用复合材料设计思想,将聚合物改性混凝土与钢纤维混凝土复合化,把聚合物改性混凝土良好的变形能力、抗渗性、耐磨抗滑性、低收缩性与钢纤维混凝土优异的抗弯拉、抗冲击、抗疲劳性集于一体,形成混杂钢纤维聚合物改性混凝土。利用扫描电镜从微观角度研究了聚合物改性机理,运用复合力学理论、纤维间距理论、裂纹尖端闭合力模型从理论角度分析了钢纤维阻裂机理;建立钢纤维阻裂有限元模型,从有限元模拟角度分析了钢纤维对裂纹尖端应力强度因子和最大拉应力影响。研究了混杂钢纤维聚合物改性混凝土在不同钢纤维掺量下多个方面的性能,并设置素混凝土、钢纤维混凝土、聚合物改性混凝土作为对照。这些性能包括:工作性、收缩性和抗压、抗折、断裂韧性与断裂能、抗冲击等基本力学性能以及抗高温、抗高温+水、抗硫酸盐、抗冻等耐久性能。本文主要研究结论如下:混杂钢纤维聚合物改性混凝土中聚合物网状薄膜、超短超细钢纤维与波纹型钢纤维一起组成多层次的阻裂网络,聚合物网状薄膜、超短超细钢纤维阻止或延缓混凝土内部微小裂缝的产生与扩展,波纹型钢纤维则进一步阻止宏观裂缝的发展,引起裂缝扩展的能量被大量消耗在克服这个多层次的阻裂网中。聚合物的加入能提高混凝土保水性,改善其工作性。聚合物与钢纤维能有效减小混凝土收缩,减小因收缩应力引起的混凝土内部损伤。当钢纤维掺量较低时,一般总体积掺量小于3%,钢纤维对混凝土抗压强度略有提高,而当钢纤维掺量较高,一般4%以上,抗压强度会略有降低。相对素混凝土,混杂钢纤维聚合物改性混凝土抗压峰值力略小,但其弹性模量更小,试件破坏时竖向位移更大,消耗压力机做功更多。钢纤维的加入能明显提高混凝土的抗折强度,提高幅度为22%~62%,且波纹型钢纤维对混凝土试件抗折强度贡献大于超短超细钢纤维。混杂钢纤维聚合物改性混凝土荷载-挠度曲线峰值过后,会出现明显的齿状形状,曲线上一个个较大的锯齿是一根根波纹型钢纤维被拔出,大锯齿上升段表示钢纤维被拔出的过程,下降段则为对应钢纤维被拔出后,承载力下降。混杂钢纤维聚合物改性混凝土具有优异的变形能力,极限拉应变是素混凝土的4-6倍。相对钢纤维混凝土,混杂钢纤维聚合物改性混凝土具有更大的断裂韧性与断裂能以及更好的延性,其中断裂韧性提高幅度为5.3%~33.8%,断裂能提高幅度为9.8%~107.2%。随钢纤维体积掺量提高,混杂钢纤维聚合物改性混凝土发生初裂、破坏对应冲击次数增多,混凝土冲击韧性增大,且破坏时主裂缝由一条变为多条。相对钢纤维混凝土,混杂钢纤维聚合物改性混凝土具有更好的抗高温、抗高温+水、抗硫酸盐、抗冻性能。混杂钢纤维聚合物混凝土60℃条件下抗折强度比常温下有所提高,提高幅度为0.88%~8.78%。混杂钢纤维聚合物混凝土在60℃水中下养护28天抗折强度较常温养护均有所下降,但下降幅度不大。
[Abstract]:Polymer modified concrete and steel fiber concrete are two excellent pavement materials, which have many advantages, but also have shortcomings. In this paper, the composite material design idea is used to combine polymer modified concrete with steel fiber concrete, and the good deformation ability, impermeability, wear-resisting and skid resistance, low shrinkage and steel fiber of the polymer modified concrete are made. It has excellent anti bending, impact resistance and fatigue resistance, forming a hybrid steel fiber polymer modified concrete. The mechanism of polymer modification is studied from the microscopic angle by scanning electron microscope. The theory of composite mechanics, the theory of fiber spacing and the closed force model of the crack tip are used to analyze the mechanism of the resistance to the steel fiber from the theoretical point of view. The effect of steel fiber on the stress intensity factor and maximum tensile stress at the crack tip is analyzed from the finite element simulation point of view. The properties of the mixed steel fiber polymer modified concrete in various aspects of the steel fiber are studied, and the concrete, steel fiber concrete and polymer modified concrete are set up. These properties include: working, contractility and compression, fracture resistance, fracture toughness and fracture energy, impact resistance and other basic mechanical properties as well as high temperature resistance, high temperature + water, sulfate resistance, frost resistance and other durability. The main conclusions are as follows: polymer mesh film, ultra short superfine steel fiber in hybrid steel fiber polymer modified concrete Together with corrugated steel fiber, a multilevel cracking network is formed. Polymer mesh film, ultra short superfine steel fiber prevents or delays the formation and expansion of small cracks in concrete. Corrugated steel fibers further prevent the development of macro cracks. The energy of crack expansion is consumed in overcoming this multilevel crack resistance network. The addition of polymer can improve the water retention of concrete and improve its working property. The polymer and steel fiber can effectively reduce the shrinkage of concrete and reduce the internal damage of concrete caused by the shrinkage stress. When the steel fiber content is low, the general volume content is less than 3%, and the steel fiber has a slight increase in the compressive strength of the coagulant soil, while the amount of steel fiber is added. Higher, more than 4%, the compressive strength will be slightly lower. Relative plain concrete, mixed steel fiber polymer modified concrete compression peak force is slightly smaller, but its modulus is smaller, the vertical displacement is greater when the specimen is damaged, and more work is done by the press. The addition of steel fiber can obviously improve the flexural strength of concrete, and the increase range is 22%~62%, The flexural strength of the corrugated steel fiber has a greater contribution to the flexural strength of the concrete specimen than the ultra short superfine steel fiber. After the peak of the load deflection curve of the hybrid steel fiber polymer modified concrete, there will be a distinct dentate shape. The larger sawtooth on the curve is pulled out of a root corrugated steel fiber, and the large serrated section indicates that the steel fiber is pulled out. When the corresponding steel fiber is pulled out, the bearing capacity is reduced. The hybrid steel fiber polymer modified concrete has excellent deformation ability, and the ultimate tensile strain is 4-6 times of that of the plain concrete. The composite steel fiber concrete has greater fracture toughness and fracture energy and better fracture energy. In the ductility, the increase of fracture toughness is 5.3%~33.8%, the increase of fracture energy is 9.8%~107.2%. with the increase of the volume of steel fiber, the initial cracking of the mixed steel fiber polymer modified concrete, the increase of the impact times, the increase of the impact toughness of the concrete, and the main crack from one to many. Mixed steel fiber polymer modified concrete has better resistance to high temperature, high temperature and water, sulphate resistance and frost resistance. The flexural strength of hybrid steel fiber polymer concrete at 60 C is higher than that at normal temperature. The increase is that the flexural strength of 0.88%~8.78%. hybrid steel fiber polymer coagulant soil is maintained at 60 degrees centigrade for 28 days and the flexural strength is more than normal. The maintenance has declined, but the decline is small.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

【参考文献】