锈染骨料对湿筛与全级配大坝混凝土力学性能的影响对比

Influence of Rusty Aggregate on Mechanical Properties of Wet-screened and Fully-graded Dam Concretes

为分析锈染粗骨料对大坝混凝土力学性能的影响,对比测试不同骨料工况湿筛及全级配混凝土的抗压、劈拉及轴向拉伸性能。结果表明:锈染物附着在原岩表层,厚约3~5 mm,锈染骨料的强度略低于无锈染骨料,且压载过程中存在劈裂剥离现象;锈染物降低了混凝土的力学性能,锈染骨料混凝土的抗压、劈拉及轴拉强度降低率分别在5%、10%及13%以内,但随龄期的增长而减小;全级配混凝土劈拉强度、轴拉强度及极限拉伸值分别为湿筛混凝土的70%~79%、56%~62%及56%~63%;试件断面内部特大石及大石分布相对均匀、有被拔出或拉断的情况,锈染骨料切口可见锈染物。研究成果可为锈染骨料对混凝土的性能影响评价及在大坝中的合理应用提供技术支撑。

To investigate the influence of rusty aggregate on the mechanical properties of dam concrete,we conducted comparative test on the compressive strength,splitting tensile strength,as well as axial tensile performance of wet-screened and fully-graded concrete specimens with different aggregate conditions.Our findings unveiled that rust adhered to the surface of rock with a thickness of about 3-5 mm;the strength of rusty aggregate was slightly lower than that of conventional aggregate;splitting and peeling occurred in the loading process.Rust reduced the mechanical properties of concrete:the compressive strength,splitting tensile strength and axial tensile strength reduced by less than 5%,10%and 13%,respectively;but such reduction rate dropped with the increase of age.The splitting tensile strength,axial tensile strength and ultimate tensile value of fully-graded concrete were 70%-79%,56%-62%,and 56%-63%of those wet-screened concrete,respectively.In addition,we observed ultra-large and large aggregates distributed uniformly in the specimen and visible rust stains in the sections.The research findings offer technical support for the impact evaluation of rusty aggregates and their reasonable application in dams.