Analysis of self-compacting concrete workability based on twin-shaft mixing images

DING Zhongcong; AN Xuehui

doi:10.16511/j.cnki.qhdxxb.2018.25.043

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Journal of Tsinghua University(Science and Technology) ›› 2018, Vol. 58 ›› Issue (11) : 979-985. DOI: 10.16511/j.cnki.qhdxxb.2018.25.043

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Analysis of self-compacting concrete workability based on twin-shaft mixing images

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Abstract

The movement of self-compacting concrete (SCC) during mixing reflects its workability. Therefore, the SCC workability can be quantified by analyzing mixing images. In this study, eight concrete specimens with different workabilities were produced in a twin-shaft mixer. A smart phone was used to record all the mixing processes. Afterwards, images of interest and regions of interest (ROI) were selected from the image sequences for quantitative comparisons. The image of interest was the moment when a blade arm formed a 45° angle with the shaft before the mixer stopped. The SCC contour within the ROI was used as an indicator to indicate the SCC workability. The Y coordinate of the point with an X coordinate of 300 pixels (Y₃₀₀) was used to describe the SCC contour and to estimate SF. The results show that Y₃₀₀ is directly related to SF with a small relative error. This method can be used in a real-time monitoring system to estimate the SCC workability during mixing.

Key words

self-compacting concrete / workability / twin-shaft mixer / visual features

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DING Zhongcong, AN Xuehui. Analysis of self-compacting concrete workability based on twin-shaft mixing images[J]. Journal of Tsinghua University(Science and Technology). 2018, 58(11): 979-985 https://doi.org/10.16511/j.cnki.qhdxxb.2018.25.043

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