Investigation of the relationship between ultrasonic pulse velocity and strength development of slag concrete and its application to in-place strength evaluation

• Main Authors: Chin-Chang Lin, 林晉章
• Other Authors: 林宜清
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/93110885223171945078

碩士 === 國立中興大學 === 土木工程學系所 === 99 === 　The purpose of this thesis is to discuss the relationship between the wave velocity and the compressive strength of slag concrete. We establish the relationship between conductivity coefficient and the saturation degree of concrete, and further the relationship can be used to modify the wave velocity of in-place measurement by the difference of saturation degree. The specimens used in the studies are made of slag concrete with 30% replacement. The specimens has a constant volume ratio of fine aggregate to total aggregate. Ten concrete mixture proportions are used in the study and they include two cement paste volume ratios (Vpaste) of 36% and 42%, and five water-cement ratios of 0.3, 0.4, 0.5, 0.6, and 0.7. The specimens are used to establish the relationship between the wave velocity and the compressive strength. In addition, we also establish the relationship between conductivity coefficient and the saturation degree of concrete. Eventually, these two established relationship curves can be used to estimate in-place concrete strength. 　Experimental results show that concrete strength estimated by the measured wave velocity has an error of 30% without considering the effect of moisture content. We measure the in-place concrete conductivity coefficient and the related saturation degree to modify the wave velocity, effectively improving the accuracy of estimated compressive strength. Prove it possible to estimate in-place concrete strength by wave velocity modified by moisture content.