Coarse aggregate equivalent particle size grading method based on three-dimensional image

Abstract

The invention provides a coarse aggregate equivalent granularity grading method based on a three-dimensional image. The method comprises the following steps of obtaining coarse aggregate pictures through a CCD (Charge Coupled Device) camera, and carrying out a series of image processing operations (such as image filtering, image binarization, image filling, contour extraction and the like) on the coarse aggregate pictures to obtain coordinate points and thickness information of an outer contour of a particle; calculating equivalent granularity and various grain shape parameters (such as needle piece degree, flatness, three angles and sphericity degree) of the coarse aggregate according to the obtained thickness information and the outer contour coordinate points, and comparing by a characterization method of the thickness of the coarse aggregate; a new equivalent particle size characterization method being provided for coarse aggregates of different shapes, the difference error between an image method and a screening method being further corrected, and accurate grading being achieved. According to the coarse aggregate equivalent particle size grading method based on the three-dimensional image, accurate measurement of the coarse aggregate equivalent particle size is achieved, and grading precision of coarse aggregate particles is improved.

Description

technical field [0001] The invention relates to the field of engineering machinery, in particular to a method for grading equivalent particle sizes of coarse aggregate based on three-dimensional images. Background technique [0002] Grading refers to the proportion relationship between aggregate size particles. If the grading is appropriate, the amount of mortar filling the aggregate voids can be reduced, the amount of water per unit volume and gel material consumption can be reduced accordingly, and the production cost of concrete can be reduced. To measure bone Material grading must know the equivalent particle size of each aggregate particle. [0003] At present, vibrating sieving method and image method are often used to measure the equivalent particle size of coarse aggregate particles. The vibration sieving method measures the equivalent particle size of coarse aggregate particles. The measurement process is to pour the coarse aggregate into the square hole sieve, and...

AI Technical Summary

Problems solved by technology

[0004] The flatness of the coarse aggregate is manually measured with a vernier caliper. According to the national standard, the highest value of the particles when lying flat is taken as the particle thickness to calculate the flatness. The measurement efficiency of this method is low, and the measurement results are easily affected by human factors. Impact

[0005] The vibratory sieving method can only measure the gradation of coarse aggregate, but cannot measure the morphological parameters of coarse aggregate

And the sieving method is limited by the number of sieve layers because the division of the particle size segment is limited, so the measurement of the particle size distribution is slightly rough, which affects the accuracy of the measurement results to a certain extent. In addition, due to the severe vibration during the sieving process, Some particle types may be highly susceptible to breakage, affecting their particle size distribution

However, the characterization of the coarse aggregate particle size in the image method is mainly based on the contour information of the particles (mainly the front projection contour), so there are some differences with the measurement results of the sieving method in actual operation (the particles will constantly change their positions and directions during the vibration process). error

In addition, in the actual measurement process, a single characterization method is usually used to characterize the equivalent particle size of the particles. Through experiments, it is found that the measurement result of the maximum inscribed circle diameter of the contour is smaller than that of the sieving method, and the maximum inscribed circle diameter of the convex hull is smaller than that of the sieving method. The measurement result of the method is smaller than that of the sieving method, and the measurement accuracy of the other two characterization methods is lower, resulting in a large error in the grading results

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