STUDY ON THE COMPRESSIVE CONSTITUTIVE MODEL OF CONCRETE CONFINED BY HIGH-STRENGTH STAINLESS STEEL WIRE MESHES/ECC
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摘要: 为将新型复合材料“高强不锈钢绞线网/ECC约束素混凝土”用于实际工程结构,基于高强不锈钢绞线网/ECC约束高强混凝土(简称HSME约束高强混凝土)复合材料轴心受压试验结果,分析ECC强度、核心混凝土强度以及横向钢绞线体积配网率等对其受压性能的影响规律。试验结果表明:HSME能够有效约束核心混凝土轴心受压,破坏模式具有明显的延性性能,根据试验数据绘出HSME约束高强混凝土复合材料受压应力-应变曲线,可以分为三个阶段:弹性阶段、弹塑性阶段和下降段。根据各阶段曲线的数学特征,建立HSME约束高强混凝土复合材料受压本构关系的全过程模型表达式。引入ECC特征值和横向钢绞线特征值,对本构模型的各参数进行分析,提出HSME约束高强混凝土复合材料的开裂压应变、峰值应力、峰值压应变和极限压应变等参数的表达式。将各参数代入所建立的受压本构关系绘出其应力-应变曲线,模型结果与试验所得应力-应变曲线吻合良好,开裂压应变与极限压应变的计算值与试验值对比范围分别为0.949~1.068和0.938~1.039。表明所提出的受压本构模型能够较好地反映HSME约束高强混凝土复合材料的应力-应变关系。
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关键词:
- 高强不锈钢绞线网/ECC /
- 受压本构模型 /
- 理论分析 /
- 约束混凝土 /
- 应力-应变关系
Abstract: To investigate the application of the novel composite material 'high-strength stainless steel wire mesh/ECC confined concrete' in engineering practice, based on the axial compression test results of high-strength stainless steel wire mesh/ECC confined high strength concrete (referred to as HSME confined high strength concrete) components, the effects of ECC's strength, strength of core concrete and transverse steel strand reinforcement ratio on the compressive performance are investigated and analyzed. The test results indicate that the HSME can effectively constrain the core concrete, and the specimens exhibit ductile failure pattern. The compressive stress-strain curves of the HSME confined high strength concrete are obtained based on the test results, which include three stages: elastic stage, elastoplastic stage and descending stage. According to the mathematical characteristics of the stress-strain curve at each stage, the constitutive model of HSME confined high strength concrete under the whole loading process is established. The ECC characteristic value and the transverse steel strand characteristic value are introduced to analyze various parameters of the proposed constitutive model. Then, the formulas of cracking strain under compression, peak stress, strain at the peak stress and the ultimate compressive strain, et al, are proposed. The stress-strain curves are obtained by substituting parameters into the proposed compressive constitutive relationship, which are in good agreement with the stress-strain curves obtained from the test results. The ratios of calculated value to the test value for the cracking strain under compression and the ultimate compressive strain are within 0.949-1.068 and 0.938-1.039, respectively. It demonstrates that the proposed compression constitutive model could accurately describe the stress-strain relationship of the HSME confined high strength concrete. -
表 1 试件设计
Table 1. Design of specimens
分组 编号 混凝土强度等级 ECC水胶比 s/mm ρw/(%) CA CA1 C55 0.25 50 0.18 CA2 C55 0.28 50 0.18 CA3 C55 0.25 (增稠剂) 50 0.18 CB CB1 C60 0.25 70 0.13 CB2 C60 0.25 50 0.18 CB3 C60 0.25 30 0.30 CC CC2 C65 0.25 50 0.18 CC3 C70 0.25 50 0.18 注: s 为横向钢绞线间距;ρw为横向钢绞线体积配箍率。 表 2 主要试验结果
Table 2. Main test results
编号 fco/
MPafm,t/
MPaσcr/
MPafecc/
MPaσcr/
feccεeco σs/
MPaσs/
feccεecu CA1 36.2 3.98 13.73 41.87 0.33 0.0032 30.13 0.72 0.0051 CA2 36.2 3.04 14.05 40.41 0.35 0.0030 31.31 0.77 0.0048 CA3 36.2 4.34 14.95 42.95 0.35 0.0031 29.89 0.70 0.0055 CB1 38.4 3.59 13.84 42.01 0.33 0.0030 32.22 0.77 0.0048 CB2 38.4 3.63 11.90 42.23 0.28 0.0031 32.52 0.77 0.0048 CB3 38.4 3.65 13.82 42.14 0.33 0.0032 32.37 0.77 0.0061 CC2 42.6 3.72 15.55 50.09 0.31 0.0032 37.52 0.75 0.0046 CC3 47.9 3.70 19.54 53.70 0.36 0.0030 41.81 0.78 0.0044 注:fco为核心混凝土轴心抗压强度;fm,t为ECC抗拉强度平均值;σcr为HSME约束高强混凝土复合材料的开裂应力;fecc为HSME约束高强混凝土复合材料的峰值应力(即抗压强度);εeco为HSME约束高强混凝土复合材料的峰值压应变;σs为HSME约束高强混凝土复合材料横向钢绞线拉断时的应力;εecu为横向钢绞线拉断时对应的应变(定义为极限压应变)。 表 3 开裂压应变与极限压应变计算值与试验值对比
Table 3. Comparison of calculated value and test value of cracking strain under compression and ultimate compressive strain
编号 λe/(%) λw/(%) εecr/(%) 比值 εecu/(%) 比值 试验值 计算值 试验值 计算值 CA1 1.4 1.6 0.0513 0.0527 1.030 0.51 0.53 1.039 CA2 1.1 1.6 0.0538 0.0527 0.981 0.48 0.49 1.021 CA3 1.6 1.6 0.0540 0.0531 0.983 0.55 0.55 1.000 CB1 1.2 1.1 0.0508 0.0553 1.088 0.48 0.45 0.938 CB2 1.2 1.5 0.0511 0.0553 1.082 0.48 0.49 1.029 CB3 1.2 2.5 0.0570 0.0553 0.970 0.61 0.60 0.984 CC2 1.1 1.4 0.0601 0.0601 1.002 0.46 0.47 1.022 CC3 1.0 1.2 0.0694 0.0661 0.957 0.44 0.43 0.977 注:λe为约束层ECC特征值;λw为横向钢绞线特征值;比值为计算值/试验值。 -
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