摘要
【目的】混凝土常规力学性能试验方法并不适用于堆石混凝土,而缩尺试验能否应用于堆石混凝土仍有待验证。目前,无损检测方法已广泛应用于混凝土强度测定,但其在大尺寸堆石混凝土中的适用性还有待研究。【方法】为此,将大尺寸堆石混凝土试验仓作为研究对象,采用回弹法和超声回弹综合法对不同龄期、不同测距下的试验仓进行现场无损检测,并计算其抗压强度。【结果】结果显示:使用回弹法得到的强度推定值相对集中,试验仓90 d龄期的整体强度虽达到设计强度,但与其他研究的试验结果相比较小;将90 d龄期的检测结果代入全国统一测区混凝土抗压强度换算公式后,计算的强度变异系数最高达到48.22%,离散程度大;测距超过2 400 mm后,堆石混凝土C15试验仓3个龄期的波形平缓且波速分布范围较大,波速范围为994~4 391 m/s;C15试验仓在180 d时3 820 m/s以上的声速占比较大,为65.12%;使用超声回弹综合法得到的强度结果在60~180 d龄期内随龄期的增长而逐渐增大。【结论】结果表明:回弹法并不适用于堆石混凝土的强度推定;全国统一测区混凝土抗压强度换算公式并不适用于堆石混凝土,超声回弹综合法需要建立专用的堆石类堆石混凝土抗压强度换算公式,且当测距超过2 400 mm时不建议使用超声回弹综合法;可为无损检测方法在堆石混凝土中的应用提供参考,以避免不必要的检测。
[Objective]The conventional mechanical property test method for concrete do not apply to rock-filled concrete,and it remains to be verified whether the shrinkage test can apply to rock-filled concrete. At present, non-destructive testing method have been widely used for concrete strength determination, but their applicability to large-size rock-filled concrete remains to be investigated. [Methods]The large-size rock-filled concrete test silo was taken as the object of study, and the combined rebound and ultrasonic rebound method were used to carry out on-site non-destructive testing of the test silos at different ages and measur-ing distances and to calculate their compressive strengths. [Results]The test result show that the strength presumptions obtained using the rebound method are relatively concentrated, and the overall strength of the test silo at the age of 90 d reaches the design strength. But, it is small compared with the result of other studies and tests. After the test result of 90 d age substitute into the conversion formula of concrete compressive strength in the national unified test area, the maximum coefficient of variation of strength calculated reaches 48. 22%, with a high degree of dispersion. After the range exceeds 2 400 mm, the waveforms of the three ages of the rock-filled concrete C15 test silo are gentle, and the wave velocity is a wide range of distribution, ranging from 994 m/ s to 4 391 m/ s. the sound velocity above 3. 82 km/ s in the C15-test silo at 180 d accounts for a large proportion, 65. 12%. the strength result obtained by using the ultrasonic rebound synthesis method continue to increase with the 60~180 days age period. [Conclusion]The result show: The rebound method is not suitable for the strength determination of rock-filled concrete;The conversion formula for the compressive strength of concrete in the nationally harmonized survey area does not apply to rock-filled concrete, the ultrasonic rebound synthesis method should establish a specially rock-filled concrete curve fo
作者
张书倩
唐晓玲
李友彬
杨韬
ZHANG Shuqian;TANG Xiaoling;LI Youbin;YANG Tao(College of Civil Engineering,Guizhou University,Guiyang550025,Guizhou,China)
出处
《水利水电技术（中英文）》
北大核心
2024年第5期181-190,共10页
Water Resources and Hydropower Engineering
基金
国家自然科学基金项目(52069004)
贵州省科学技术基金项目(黔科合基础-ZK[2021]一般293)
黔东南水投科研(JHNJSK-JSFW(XNSY)-2022)。
关键词
堆石混凝土
无损检测
回弹法
超声回弹综合法
强度
rock-filled concrete
nondestructive testing
rebound method
ultrasonic rebound synthesis method
strength
