多种钢纤维对超高性能混凝土力学性能影响的比较研究
发布时间：2019-03-21 08:09
【摘要】：摘要：本学位论文主要进行了多种异形钢纤维对超高性能混凝土(UHPC)力学性能影响的试验研究。 文章测定了2种不同水胶比(0.18、0.26)、6种不同抗拉强度及形状的钢纤维掺入的混凝土试件,经标准养护28d后的基本力学性能(立方体抗压强度、轴心抗压强度、劈裂抗拉强度、静力受压弹性模量)及断裂能,研究不同种类的钢纤维对其力学性能的影响。 基本力学性能试验结果表明：(1)总体而言钢纤维的掺入对0.26水胶比HPC及0.18水胶比UHPC的抗压强度略有提升。波纹形钢纤维对0.18水胶比UHPC抗压强度有相对显著的提高,而端钩形钢纤维则对0.26水胶比HPC抗压强度有所提高。(2)钢纤维的掺入对HPC及UHPC劈裂抗拉强度的提升主要与钢纤维自身抗拉强度及钢纤维的长径比呈正相关。表面附着橡胶的高强度环保波纹形钢纤维对HPC韧性改善效果在试验所用6种钢纤维中最为突出。(3)抗拉强度590MPa、长径比相对较低的两种钢纤维对混凝土的各项力学性能并无明显提升,甚至出现了UHPC抗压强度降低的现象,表明该类型的钢纤维不宜用于超高性能混凝土 断裂能试验结果表明：(1)环保波纹形钢纤维对HPC及UHPC断裂能提升最明显,在其外部附着橡胶的辅助作用下,能够阻止或减缓混凝土裂纹的产生。(2)自身抗拉强度为2000MPa的钢纤维在拔出时变形的程度不大,拥有更多弯曲形态的波纹形钢纤维会比端钩形钢纤维更好地发挥其在裂缝间的桥接作用。(3)同种强度的普通端钩形钢纤维与波纹形钢纤维在UHPC中所测得的断裂能值差别不大,但在HPC中端钩形钢纤维明显比波纹形钢纤维更好地提升了混凝土的断裂能。(4)低长径比的鞍山波纹形钢纤维与螺纹形钢纤维对UHPC断裂能的提升效果不明显的情况,与其钢材强度偏低存在主要联系,且这两种钢纤维的脆性较大,在UHPC中的掺入属于增加了界面薄弱层。 上述试验结果表明,钢纤维在高性能混凝土与超高性能混凝土中起到的作用与其自身抗拉强度、长径比、形状均有联系,且本文试验中所用各钢纤维对不同混凝土力学性能的影响规律不同,需综合考虑钢纤维的各项因素与混凝土自身强度的相匹配性。综合基本力学性能与断裂能的试验情况,可知抗拉强度为590MPa的波纹形与螺纹形钢纤维总体不适用于UHPC,而高抗拉强度的环保波纹形钢纤维与长径比较大的端钩形钢纤维对HPC的力学性能改善效果最为明显。
[Abstract]:Abstract: this thesis mainly deals with the effects of various special-shaped steel fibers on the mechanical properties of ultra-high performance concrete (UHPC). In this paper, the basic mechanical properties (cube compressive strength, axial compressive strength) of two concrete specimens with different water binder ratios (0.18,0.26), six kinds of steel fibers with different tensile strength and shape after standard curing for 28 days were measured. Splitting tensile strength, elastic modulus of static compression) and fracture energy were used to study the effects of different kinds of steel fibers on their mechanical properties. The experimental results of basic mechanical properties show that: (1) the compressive strength of 0.26 water-binder ratio and 0.18-water-adhesive ratio UHPC is slightly increased by the addition of the total steel fiber to 0.26 water-binder ratio HPC and 0.18-water-adhesive ratio UHPC. The compressive strength of corrugated steel fiber is higher than that of UHPC. (2) the increase of splitting tensile strength of HPC and UHPC is positively correlated with the tensile strength of steel fiber itself and the ratio of length to diameter of steel fiber. (2) the increase of tensile strength of HPC and UHPC with the addition of steel fiber is positively correlated with the tensile strength of steel fiber itself and the ratio of length to diameter of steel fiber. The compressive strength of end hook steel fiber is higher than that of HPC. The high strength and environmental protection corrugated steel fiber attached to the surface of rubber has the most outstanding effect on the toughness improvement of HPC. (3) the tensile strength of 590MPa is the most prominent among the 6 kinds of steel fibers used in the test. The two kinds of steel fibers with relatively low aspect ratio have no obvious improvement on the mechanical properties of the concrete, and even have the phenomenon of the decrease of the compressive strength of UHPC. It is shown that this type of steel fiber is not suitable for testing the fracture energy of ultra-high performance concrete. The results show that: (1) the environmental protection corrugated steel fiber enhances the fracture energy of HPC and UHPC most obviously, under the auxiliary effect of the rubber attached to the outer part of the steel fiber. It can prevent or slow down the formation of concrete cracks. (2) the steel fiber with its own tensile strength of 2000MPa does not deform greatly when it is pulled out. Corrugated steel fibers with more bending shape will play a better role in bridging between cracks than end hook steel fibers. (3) the fracture of common end hook steel fibers with same strength and corrugated steel fibers measured in UHPC is better than that of end hook steel fibers. (3) the fracture of common end hook steel fibers with the same strength and that of corrugated steel fibers is better than that of end hook steel fibers. There's not much difference in the value of crack energy, However, in HPC, the fracture energy of concrete is obviously improved by end hook steel fiber compared with corrugated steel fiber. (4) the effect of Anshan corrugated steel fiber with low aspect ratio on UHPC fracture energy is not obvious. It is mainly related to the low strength of the steel, and the brittleness of the two kinds of steel fibers is greater, and the addition of UHPC into the steel fiber is an increase of the interface weak layer. The results show that the effect of steel fiber on high-performance concrete and ultra-high performance concrete is related to its own tensile strength, length-diameter ratio and shape, and that the steel fiber plays an important role in high-performance concrete and ultra-high performance concrete. The influence of the steel fiber on the mechanical properties of the concrete is different in this paper. It is necessary to consider the matching between the steel fiber and the strength of the concrete. Based on the experimental results of basic mechanical properties and fracture energy, it is known that the corrugated and threaded steel fibers with tensile strength of 590MPa are not suitable for UHPC, in general. But the environmental protection corrugated steel fiber with high tensile strength and the end hook steel fiber with larger length and diameter have the most obvious effect on improving the mechanical properties of HPC.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528.572
本文编号：2444750
[Abstract]:Abstract: this thesis mainly deals with the effects of various special-shaped steel fibers on the mechanical properties of ultra-high performance concrete (UHPC). In this paper, the basic mechanical properties (cube compressive strength, axial compressive strength) of two concrete specimens with different water binder ratios (0.18,0.26), six kinds of steel fibers with different tensile strength and shape after standard curing for 28 days were measured. Splitting tensile strength, elastic modulus of static compression) and fracture energy were used to study the effects of different kinds of steel fibers on their mechanical properties. The experimental results of basic mechanical properties show that: (1) the compressive strength of 0.26 water-binder ratio and 0.18-water-adhesive ratio UHPC is slightly increased by the addition of the total steel fiber to 0.26 water-binder ratio HPC and 0.18-water-adhesive ratio UHPC. The compressive strength of corrugated steel fiber is higher than that of UHPC. (2) the increase of splitting tensile strength of HPC and UHPC is positively correlated with the tensile strength of steel fiber itself and the ratio of length to diameter of steel fiber. (2) the increase of tensile strength of HPC and UHPC with the addition of steel fiber is positively correlated with the tensile strength of steel fiber itself and the ratio of length to diameter of steel fiber. The compressive strength of end hook steel fiber is higher than that of HPC. The high strength and environmental protection corrugated steel fiber attached to the surface of rubber has the most outstanding effect on the toughness improvement of HPC. (3) the tensile strength of 590MPa is the most prominent among the 6 kinds of steel fibers used in the test. The two kinds of steel fibers with relatively low aspect ratio have no obvious improvement on the mechanical properties of the concrete, and even have the phenomenon of the decrease of the compressive strength of UHPC. It is shown that this type of steel fiber is not suitable for testing the fracture energy of ultra-high performance concrete. The results show that: (1) the environmental protection corrugated steel fiber enhances the fracture energy of HPC and UHPC most obviously, under the auxiliary effect of the rubber attached to the outer part of the steel fiber. It can prevent or slow down the formation of concrete cracks. (2) the steel fiber with its own tensile strength of 2000MPa does not deform greatly when it is pulled out. Corrugated steel fibers with more bending shape will play a better role in bridging between cracks than end hook steel fibers. (3) the fracture of common end hook steel fibers with same strength and corrugated steel fibers measured in UHPC is better than that of end hook steel fibers. (3) the fracture of common end hook steel fibers with the same strength and that of corrugated steel fibers is better than that of end hook steel fibers. There's not much difference in the value of crack energy, However, in HPC, the fracture energy of concrete is obviously improved by end hook steel fiber compared with corrugated steel fiber. (4) the effect of Anshan corrugated steel fiber with low aspect ratio on UHPC fracture energy is not obvious. It is mainly related to the low strength of the steel, and the brittleness of the two kinds of steel fibers is greater, and the addition of UHPC into the steel fiber is an increase of the interface weak layer. The results show that the effect of steel fiber on high-performance concrete and ultra-high performance concrete is related to its own tensile strength, length-diameter ratio and shape, and that the steel fiber plays an important role in high-performance concrete and ultra-high performance concrete. The influence of the steel fiber on the mechanical properties of the concrete is different in this paper. It is necessary to consider the matching between the steel fiber and the strength of the concrete. Based on the experimental results of basic mechanical properties and fracture energy, it is known that the corrugated and threaded steel fibers with tensile strength of 590MPa are not suitable for UHPC, in general. But the environmental protection corrugated steel fiber with high tensile strength and the end hook steel fiber with larger length and diameter have the most obvious effect on improving the mechanical properties of HPC.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528.572
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