Material characterization for RC beam-column joints with and without steel fibers

This research hypothesized that incorporating 0.7% hooked-end steel fibers significantly enhances concrete's mechanical behavior, particularly improving ductility and flexural performance for seismic-resistant structures. The study aimed to demonstrate that steel fibers can effectively complement conventional transverse reinforcement in beam-column joints.
Experimental results strongly support these propositions. Fiber-reinforced concrete exhibited superior toughness and deformation capacity in both flexural and compression tests. BSFR specimens showed load-deflection curves with substantially larger area under the curve, indicating higher energy absorption compared to plain concrete (PB). Similarly, CSF cylinders displayed more ductile stress-strain response with greater post-peak deformation capacity. Tensile tests on rebars (Bar numbers 3, 4, and 6) confirmed expected mechanical properties, providing reliable data for numerical modeling.
Notable findings include maintained workability (slump 16-18 cm despite fiber addition), substantially improved post-cracking behavior, and reduced brittleness. Comprehensive material characterization ensures full reproducibility. Complete stress-strain and load-deflection curves with mean values and standard deviations facilitate robust statistical analysis.
This multifaceted dataset validates numerical models of FRC elements, enables optimized mixture design for seismic applications, and allows direct performance comparison between plain and fiber-reinforced concrete under monotonic loading.
Methodology utilized certified universal testing machines (Instron, Tinius Olsen) with precision data acquisition (National Instruments). Instrumentation included LVDTs and extensometers for accurate displacement and strain measurement. All procedures adhered to ASTM and NMX-ONNCCE standards.
Data Repository Structure
1. Beam Data and Photos: Flexural test results for fiber-reinforced and plain concrete beams, including Excel sheets with processed data, load-deflection curves, and failure mode photographs showing fiber bridging effects.
2. Aggregate Characterization and Slump Tests: Detailed coarse/fine aggregate properties (gradation, density, absorption) and slump test results for both concrete types in compiled Excel sheets.
3. Cylinder Data and Photos: Uniaxial compression test results categorized into fiber-reinforced, plain concrete, and comparative datasets. Includes stress-strain curves, mechanical properties, and failure mode photographs.
4. Steel Rebar Data and Photos: Tensile test results for Bar numbers 3, 4, and 6, featuring stress-strain curves, mechanical properties, and photographic documentation of specimens.

本研究提出假设：掺入0.7%的弯钩型钢纤维（hooked-end steel fibers）可显著改善混凝土的力学性能，尤其可提升抗震结构所需的延性与抗弯性能。本研究旨在证明，钢纤维可有效弥补梁柱节点（beam-column joints）中传统横向配筋（transverse reinforcement）的不足。
实验结果有力验证了上述假设。纤维增强混凝土（Fiber-Reinforced Concrete, FRC）在抗弯与抗压试验中均表现出更优异的韧性与变形能力。相较于素混凝土（Plain Concrete, PB）试件，BSFR试件的荷载-位移曲线下面积显著更大，表明其能量吸收能力更强。同理，钢纤维混凝土（CSF）圆柱体试件的应力-应变响应更具延性，峰后变形能力也更出色。对3号、4号及6号钢筋（rebars）开展的拉伸试验证实了其预期力学性能，为数值建模提供了可靠数据。
本研究的重要发现包括：即便掺入纤维，混凝土仍可保持良好的工作性（坍落度为16~18 cm）；开裂后性能大幅改善；脆性显著降低。本研究开展了全面的材料表征，确保实验可完全复现。完整的应力-应变曲线与荷载-位移曲线（含平均值与标准差）可为稳健的统计分析提供支撑。
本多维度数据集可验证纤维增强混凝土构件的数值模型，可为抗震应用中的混凝土配合比优化设计提供依据，同时可实现单调荷载下素混凝土与纤维增强混凝土的直接性能对比。
本研究采用经认证的万能试验机（universal testing machines，包括Instron、Tinius Olsen）与高精度数据采集系统（National Instruments）。测试仪器包括线性可变差动变压器（Linear Variable Differential Transformer, LVDTs）与引伸计，用于精准测量位移与应变。所有实验流程均符合ASTM与NMX-ONNCCE标准。
数据仓库结构
1. 梁构件数据与照片：涵盖纤维增强混凝土与素混凝土梁的抗弯试验结果，包含存储处理后数据的Excel表格、荷载-位移曲线，以及展现纤维桥接效应的破坏模式实拍照片。
2. 集料表征与坍落度试验：收录两种混凝土的粗细集料详细性能参数（级配、密度、吸水率）与坍落度试验结果，全部整理为汇总的Excel表格。
3. 圆柱体试件数据与照片：包含按纤维增强混凝土、素混凝土及对比数据集分类的单轴抗压试验结果，涵盖应力-应变曲线、力学性能参数与破坏模式实拍照片。
4. 钢筋数据与照片：收录3号、4号及6号钢筋的拉伸试验结果，包含应力-应变曲线、力学性能参数，以及试件的影像记录资料。