摘要
为研究初始裂缝尺寸及材料组成特性等因素对混凝土断裂韧度的影响,通过混凝土切口梁三点弯曲试验,探讨了相对切口深度、粗骨料最大粒径及分布和水灰比等因素改变时混凝土断裂韧度的变化规律。结果表明:相对切口深度对混凝土断裂韧度有一定影响,不同相对切口深度下,混凝土缺口敏感性不同;随着粗骨料最大粒径增加,混凝土断裂韧度呈增大趋势,断面二值图和粗骨料水平投影面积率可有效反映粗骨料对混凝土断裂韧度的影响;随着水灰比减小,混凝土断裂韧度逐渐增加;混凝土断裂韧度与切口梁试件裂缝前端阻裂带的"强弱"有关。在分析试验结果的基础上,建立了多因素影响下混凝土断裂韧度的计算模式,在混凝土配合比已知的情况下,该模式可用于分析诸因素对混凝土断裂韧度的影响并预测混凝土断裂韧度。
In this paper, the effects of the initial crack size and mix proportions of concrete upon fracture toughness of concrete （Kic） were studied. Through the three-point bending test on the specimens of con-crete, the effects of influencing factors including notch depth （ao/h）, maximum particle diameter and distri-bution of coarse aggregate （dmax） and water-cement ratio （W/C） upon Kic were studied. The results show that ao/h has some effect on Kic. The notch sensitivities of concrete are different at different ao/h. Kic tends to increase as dmax increases. The binary image of cross section and the horizontal projection area ratio （D） reflect the effect of coarse aggregate on Kic effectively. Kic increases as W/C decreases. Kic is related to the magnitude of cracking resistance capacity of the band for cracking resistance at crack tip field. Based on the test results, the calculation model under the influencing factor is established for calculating Kic, and this calculation model can be used to analyze the effect of influencing factor upon Kic and predict Kic when mix proportions of concrete are known.
出处
《水利学报》
EI
CSCD
北大核心
2013年第5期601-607,共7页
Journal of Hydraulic Engineering
基金
国家自然科学基金资助项目(51209103)
黄河水利科学研究院基本科研业务费专项(HKY-JBYW-2013-2)
关键词
相对切口深度
粗骨料
水灰比
混凝土
断裂韧度
relative notch depth
coarse aggregate
water-cement ratio
concrete
fracture toughness
