纤维特征参数对HES-HDC单轴拉伸性能的影响及拉伸韧性评价方法
Effect of Fiber Characteristics Parameters on Uniaxial Tensile Properties of HES-HDC and Evaluation Method of Tensile Toughness
杨家盛 1邓明科 1张晴晴 1邓友生 2张阳玺 1范洪侃3
作者信息
- 1. 西安建筑科技大学 土木工程学院,陕西 西安 710055
- 2. 西安科技大学 建筑与土木工程学院,陕西 西安 710054
- 3. 西安五和建筑科技研究院有限公司,陕西 西安 710055
- 折叠
摘要
为探究高早强高延性混凝土(HES-HDC)在不同PE纤维直径与体积率下的单轴拉伸力学性能,设计了17组薄板试件进行单轴拉伸试验,研究PE纤维直径(22 μm和25 μm)及体积率(1.00%、1.25%和1.50%)对不同龄期(2 h、24 h、7 d、28 d和56 d)HES-HDC应力-应变曲线、拉伸强度和应变的影响;根据试验结果提出了HDC拉伸韧性评价方法.结果表明:在拉伸荷载作用下,HES-HDC应力-应变曲线展示出应变强化特性,破坏过程呈多裂缝开展;2 h龄期时,HES-HDC拉伸强度与应变达到3.29 MPa和0.88%以上;28 d时,HES-HDC拉伸应变可保持在1.28%以上;当纤维体积率为1.00%时,小直径纤维对试件拉伸应变有利,而大直径纤维对试件拉伸强度有利;综合大直径纤维试件拉伸强度与应变,纤维最佳体积率为1.25%.提出的拉伸韧性评价方法可评价HDC薄板受拉全过程的韧性.随龄期的增长,HES-HDC拉伸韧性指数降低,而拉伸强度系数提高;小直径纤维试件的拉伸韧性高于大直径纤维试件;纤维体积率为1.25%时试件拉伸韧性最大.
Abstract
To investigate the uniaxial tensile mechanical properties of high-early-strength high ductility concrete(HES-HDC)at different PE fiber diameters and volume fractions,17 groups of thin-plate specimens were designed and loaded under uniaxial tensile tests.The effects of PE fiber diameters(22 μm and 25 μm)and fiber volume fractions(1.00%,1.25%,and 1.50%)on stress-strain curve,tensile strength,and strain of HES-HDC specimens at different curing ages(2 h,24 h,7 d,28 d and 56 d)were investigated.A tensile toughness evaluation method suitable for the characteristics of HDC was proposed based on the test results.The results show that the HES-HDC stress-strain curve exhibits strain-hardening characteristics under uniaxial tensile loading,and the failure process is carried out with multiple cracks.The tensile strength and strain of HES-HDC at 2 h reach over 3.29 MPa and 0.88%,respectively,and the tensile strain at 28 d could remain more than 1.28%.When the fiber volume fraction is 1.00%,small-diameter fiber is beneficial to the tensile strain of specimens,while large-diameter fiber is beneficial to the tensile strength of specimens.Considering the tensile strength and strain of specimens with large-diameter fiber,the optimal fiber volume fraction is 1.25%.The proposed tensile toughness evaluation method can evaluate the tensile toughness of HDC during its whole loading process.In addition,the tensile toughness index of HES-HDC decreased with the increase of curing age,while the tensile strength coefficient increased.The tensile toughness of specimens with small-diameter fiber is higher than that of specimens with large-diameter fiber.The tensile toughness of specimens is the highest when the fiber volume fraction is 1.25%.
关键词
高早强高延性混凝土/纤维直径/纤维体积率/单轴拉伸/抗拉强度/拉伸韧性Key words
high-early-strength high ductility concrete/fiber diameter/fiber volume fraction/uniaxial tension/tensile strength/tensile toughness引用本文复制引用
基金项目
国家自然科学基金资助项目(51878545)
西安市重大科技创新计划项目(20191522415KYPT015JC017)
出版年
2024
国家科技期刊平台
NSTL
万方数据