基于分形理论的冻融荷载耦合作用下纤维混凝土的抗压强度  

Investigation on compressive strength of fiber reinforced concrete subjected to the coupling effects of freeze-thaw cycling and loading utilizing fractal theory

作　　者：孙杰[1] 申紫豪 廖海峰 SUN Jie;SHEN Zihao;LIAO Haifeng(School of Urban Construction,Wuhan University and Technology,Wuhan 430065,China;Central&Southern China Municipal Engineering Design and Research Institute CO.,LTD.,Wuhan 430074,China)

机构地区：[1]武汉科技大学城市建设学院,武汉430065 [2]中国市政工程中南设计研究总院有限公司,武汉430074

出　　处：《复合材料学报》2024年第11期6101-6110,共10页Acta Materiae Compositae Sinica

基　　金：西南交通大学道路工程四川省重点实验室开放课题;湖北省住房和城乡建设厅(Zy2022o014)。

摘　　要：为了研究持续荷载与冻融循环耦合作用下纤维混凝土的抗压性能与分形维数值之间的关系,开展了不同压应力水平(0、0.3、0.5)作用下的纤维混凝土冻融循环试验。对冻融前后纤维混凝土裂缝进行分形特征研究,并基于分形理论研究了不同耦合作用下试件的抗压强度变化规律,建立了裂缝分形维数与抗压强度的演化方程。结果表明:随着冻融循环次数的增加,试件抗压强度逐渐减小。当冻融循环次数增加到160次,不同耦合应力水平下试件抗压强度损失率差异显著,其中在耦合应力水平为0.3时损失率最小为21.59%,耦合应力水平为0.5时损失率最大为33.58%。裂缝的分形维数与耦合作用有明显的线性关系,能够定量反映纤维混凝土的劣化规律,裂缝分形维数的数值越大,纤维混凝土冻融损伤越大,抗压强度越低。This study explores the correlation between the compressive attributes of the fiber reinforced concrete and the fractal dimension value under the combined influence of continuous loading and freeze-thaw cycling.Freeze-thaw cycling tests were conducted on the fiber reinforced concrete with varying compressive stress levels(0,0.3,0.5).The fractal characteristics of the concrete cracks pre and post freeze-thaw were examined,and the alteration in the compressive strength of the samples under different coupling effects was analyzed using the fractal theory.An evolution equation was established between the fractal dimension of the cracks and the compressive strength.Findings indicate that as the number of freeze-thaw cycles increases,the compressive strength of the sample progressively decreases.When the number of freeze-thaw cycles increases to 160,the loss rates in the compressive strength of the specimens under different coupling stresses exhibit the significant differences,the smallest loss rate of 21.59%is observed at a coupling stress of 0.3,while the maximum of 33.58%is noted at a coupling stress of 0.5.A clear linear relationship is found between the fractal dimension of the cracks and the coupling effect,quantitatively reflecting the deterioration pattern of the fiber reinforced concrete.A larger fractal dimension value of the cracks indicates greater freeze-thaw damage to the fiber reinforced concrete and a lower compressive strength.

关 键 词：纤维混凝土 冻融循环 分形维数 损伤变量 抗压强度 

分 类 号：TU528[建筑科学—建筑技术科学] TB332[一般工业技术—材料科学与工程]