冻融条件下BFRP筋混杂纤维再生混凝土粘结性能研究
发布时间：2018-08-17 18:16
【摘要】：纤维增强复合材料作为一种新型复合材料应用于混凝土结构中,主要通过两种形式:一种是利用纤维材料耐腐蚀、轻质高强的特性,经过加工制作成纤维筋代替钢筋,从而解决钢筋长期使用锈蚀所造成的耐久性及安全性问题;另一种是利用纤维短切纱良好的力学性能,掺入混凝土基体中对结构起到增韧阻裂的效果。随着社会的发展,环境问题得到重视,废弃混凝土作为再生骨料用于再生混凝土结构中,有效解决了废弃混凝土对环境的污染以及对天然石料的开采,但是由于再生骨料各项性能低于普通骨料,导致再生混凝土的力学性能比普通混凝土略低。故利用纤维材料良好的性能,与再生混凝土相结合,可将两者优点充分发挥,起到互补作用。对于纤维再生混凝土的研究,国内仍处于起步阶段,大部分集中对再生混凝土的力学性能研究,在其抗冻性能方面的研究仍不成熟。本文为研究冻融循环条件下玄武岩-聚丙烯混杂纤维再生混凝土与BFRP筋的粘结性能,通过中心拉拔试验研究不同冻融循环次数、单掺纤维不同体积掺量、混掺纤维不同体积掺量三种因素对BFRP筋与混杂纤维再生混凝土粘结性能的影响及粘结-滑移本构关系模型。主要研究工作如下:(1)通过立方体抗压强度试验、劈裂抗拉强度试验、轴心抗压强度试验及静力受压弹性模量试验对冻融循环条件下混杂纤维再生混凝土力学性能进行研究,结果表明:单一掺入纤维的再生混凝土除劈拉强度得到提高,其他三种力学性能均有所降低;而混杂纤维再生混凝土各项力学性能指标均得到提高,但是也有一定范围,掺量过多会减弱混杂纤维对混凝土性能的改善,其中掺入玄武岩纤维体积掺量0.3%时,对混杂纤维再生混凝土起到最优效果,经过冻融循环后的混杂纤维再生混凝土力学性能得到提高。(2)通过中心拉拔试验,主要研究不同冻融循环次数、单掺和混掺纤维掺量三种因素对BFRP筋与再生混凝土基体之间粘结性能的影响,并得到粘结-滑移曲线。结果表明:单掺纤维时BFRP筋与再生混凝土粘结应力有所降低,但是改善了粘结性能的延性,玄武岩纤维掺量单掺0.3%时效果最优;混掺纤维提高了BFRP筋与再生混凝土粘结性能和混凝土延性,但是有一定范围,纤维掺量过多减弱对粘结强度的改善;经过冻融循环后的纤维再生混凝土与BFRP筋粘结强度均得到提高。(3)结合国内外相关的粘结-滑移本构关系模型与试验所得粘结-滑移曲线,通过试验所得数据建立四段式冻融条件下BFRP筋与混杂纤维再生混凝土粘结-滑移本构关系模型,并与试验值进行比较,拟合效果较好。
[Abstract]:As a new type of composite material, fiber reinforced composites are mainly used in concrete structures in two forms: one is to use the characteristics of corrosion resistance, light weight and high strength of fiber materials to produce fiber tendons instead of steel bars. In order to solve the durability and safety problems caused by the long-term use of steel bar corrosion, the other is to use the good mechanical properties of fiber shearing yarn, and the effect of toughening and cracking resistance to the structure can be achieved by adding it into the concrete matrix. With the development of society, environmental problems have been paid attention to. Waste concrete is used as recycled aggregate in recycled concrete structure, which effectively solves the pollution of waste concrete to the environment and the exploitation of natural stone. However, the properties of recycled aggregate are lower than that of ordinary aggregate, which leads to the mechanical properties of recycled concrete being slightly lower than that of ordinary concrete. Therefore, combining the good properties of fiber materials with recycled concrete can give full play to the advantages of the two materials and play a complementary role. The research of fiber recycled concrete is still in the initial stage in China. Most of the researches focus on the mechanical properties of recycled concrete, and the research on its frost resistance is still immature. In order to study the bond behavior between basalt polypropylene hybrid fiber recycled concrete and BFRP tendons under freeze-thaw cycle conditions, the central drawing tests were carried out to study the different freeze-thaw cycles and the volume content of single fiber. The effect of three factors with different volume content of mixed fiber on the bond properties of BFRP tendons and hybrid fiber recycled concrete and the bond-slip constitutive relation model. The main research works are as follows: (1) the mechanical properties of hybrid regenerated concrete under freeze-thaw cycle are studied by cube compressive strength test, splitting tensile strength test, axial compressive strength test and static compressive elastic modulus test. The results show that the tensile strength of recycled concrete with single fiber is increased, and the other three mechanical properties are decreased, while the mechanical properties of recycled concrete with hybrid fiber are all improved, but there is also a certain range. When the volume of basalt fiber is 0.3, the reclaimed concrete with hybrid fiber has the best effect, too much admixture will weaken the improvement of concrete performance of hybrid fiber, and when the volume of basalt fiber is 0.3, the reclaimed concrete with hybrid fiber will have the best effect. After freeze-thaw cycle, the mechanical properties of hybrid fiber recycled concrete are improved. (2) through central drawing test, the different freeze-thaw cycles are studied. The effect of single and mixed fiber content on the bond behavior between BFRP bars and recycled concrete matrix was investigated and the bond-slip curve was obtained. The results show that the bond stress between BFRP tendons and recycled concrete decreases, but the ductility of bond properties is improved. The bond properties and ductility of recycled concrete and BFRP tendons were improved by blending fiber, but the bond strength was improved by excessive fiber addition. After freeze-thaw cycle, the bond strength between regenerated fiber reinforced concrete and BFRP tendons has been improved. (3) the bond-slip constitutive relationship model and the bond-slip curve obtained from the experiment are combined with the domestic and foreign models. The bond-slip constitutive relation model of BFRP bar and hybrid fiber recycled concrete under four stage freeze-thaw condition was established and compared with the experimental data.
【学位授予单位】：辽宁工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528
[Abstract]:As a new type of composite material, fiber reinforced composites are mainly used in concrete structures in two forms: one is to use the characteristics of corrosion resistance, light weight and high strength of fiber materials to produce fiber tendons instead of steel bars. In order to solve the durability and safety problems caused by the long-term use of steel bar corrosion, the other is to use the good mechanical properties of fiber shearing yarn, and the effect of toughening and cracking resistance to the structure can be achieved by adding it into the concrete matrix. With the development of society, environmental problems have been paid attention to. Waste concrete is used as recycled aggregate in recycled concrete structure, which effectively solves the pollution of waste concrete to the environment and the exploitation of natural stone. However, the properties of recycled aggregate are lower than that of ordinary aggregate, which leads to the mechanical properties of recycled concrete being slightly lower than that of ordinary concrete. Therefore, combining the good properties of fiber materials with recycled concrete can give full play to the advantages of the two materials and play a complementary role. The research of fiber recycled concrete is still in the initial stage in China. Most of the researches focus on the mechanical properties of recycled concrete, and the research on its frost resistance is still immature. In order to study the bond behavior between basalt polypropylene hybrid fiber recycled concrete and BFRP tendons under freeze-thaw cycle conditions, the central drawing tests were carried out to study the different freeze-thaw cycles and the volume content of single fiber. The effect of three factors with different volume content of mixed fiber on the bond properties of BFRP tendons and hybrid fiber recycled concrete and the bond-slip constitutive relation model. The main research works are as follows: (1) the mechanical properties of hybrid regenerated concrete under freeze-thaw cycle are studied by cube compressive strength test, splitting tensile strength test, axial compressive strength test and static compressive elastic modulus test. The results show that the tensile strength of recycled concrete with single fiber is increased, and the other three mechanical properties are decreased, while the mechanical properties of recycled concrete with hybrid fiber are all improved, but there is also a certain range. When the volume of basalt fiber is 0.3, the reclaimed concrete with hybrid fiber has the best effect, too much admixture will weaken the improvement of concrete performance of hybrid fiber, and when the volume of basalt fiber is 0.3, the reclaimed concrete with hybrid fiber will have the best effect. After freeze-thaw cycle, the mechanical properties of hybrid fiber recycled concrete are improved. (2) through central drawing test, the different freeze-thaw cycles are studied. The effect of single and mixed fiber content on the bond behavior between BFRP bars and recycled concrete matrix was investigated and the bond-slip curve was obtained. The results show that the bond stress between BFRP tendons and recycled concrete decreases, but the ductility of bond properties is improved. The bond properties and ductility of recycled concrete and BFRP tendons were improved by blending fiber, but the bond strength was improved by excessive fiber addition. After freeze-thaw cycle, the bond strength between regenerated fiber reinforced concrete and BFRP tendons has been improved. (3) the bond-slip constitutive relationship model and the bond-slip curve obtained from the experiment are combined with the domestic and foreign models. The bond-slip constitutive relation model of BFRP bar and hybrid fiber recycled concrete under four stage freeze-thaw condition was established and compared with the experimental data.
【学位授予单位】：辽宁工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528
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