Detection of size of manufactured sand particles based on digital image processing

Jianhong Yang,Si-jia Chen,Xiao-yu Huang,Wen Yu,Huai-ying Fang,Russell Goodall

doi:10.1371/journal.pone.0206135

Jianhong Yang, Si-jia Chen + Show 4 more

Open Access

https://doi.org/10.1371/journal.pone.0206135

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Abstract

The size distribution of manufactured sand particles has a significant influence on the quality of concrete. To overcome the shortcomings of the traditional vibration-sieving method, a manufactured sand casting/dispersing system was developed, based on the characteristics of the sand particle contours (as determined by backlit image acquisition) and an extraction mechanism. Algorithms for eliminating particles from the image that had be repeatedly captured, as well as for identifying incomplete particles at the boundaries of the image, granular contour segmentation, and the determination of an equivalent particle size, are studied. The hardware and software for the image-based detection device were developed. A particle size repeatability experiment was carried out on the single-grade sands, grading the size fractions of the manufactured sand over a range of 0.6–4.75 mm. A method of particle-size correction is proposed to compensate for the difference in the results obtained by the image-based method and those obtained by the sieving method. The experimental results show that the maximum repeatability error of single-grade fractions is 3.46% and the grading size fraction is 0.51%. After the correction of the image method, the error between the grading size fractions obtained by the two methods was reduced from 7.22%, 6.10% and 5% to 1.47%, 1.65%, and 3.23%, respectively. The accuracy of the particle-size detection can thus satisfy real-world measuring requirements.

Highlights

Differences in processing technology lead to fluctuations in the quality of manufactured sand
To ensure the quality of manufactured sand, there is a need for a means of monitoring the grain sizes in line with national standards (Test Methods of Aggregate for Highway Engineering (JTG E42-2005))[1]
The manufactured sand particle-size detection system was used for single-stage materials and to grade ingredients as a repeatability test

Summary

Introduction

Differences in processing technology lead to fluctuations in the quality of manufactured sand. To ensure the quality of manufactured sand, there is a need for a means of monitoring the grain sizes in line with national standards (Test Methods of Aggregate for Highway Engineering (JTG E42-2005))[1]. The vibrating-sieve method is a well-known method of determining the size of an aggregate, but the sieving process itself tends to destroy the gravel and affect the original grain size. The screening accuracy is affected by the grain shape, adversely affecting the accuracy of the test results.

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