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³¤°²´óѧѧ±¨£¨×ÔÈ»¿Æѧ°æ£©[ISSN:1006-6977/CN:61-1281/TN]

Issue:

2018Äê04ÆÚ

Page:

56-63

Research Field:

ÇÅÁºÓëËíµÀ¹¤³Ì

Publishing date:

Info

Title:

Quantitative evaluation on aggregate uniformity of high performanceª¤concrete based on local density variance theory

Author(s):

YANG Jun;  ZHOU Jianª²ting;  CHEN Xiaoª²feng;  XIN Jingª²zhou;  CHENG Jun

(1. School of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, China; 2. School ofª¤Mathematics and Statistics, Chongqing Jiaotong University, Chongqing 400074, China;ª¤3. Department of Construction Engineering, Chongqing Real Estate College, Chongqing 401331, China)

Keywords:

bridge engineering;  uniformity quantitative evaluation;  local density variance;  HPC;  digital image processing

PACS:

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DOI:

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Abstract:

To solve the problem of scientific and highly efficient quantifying the aggregate uniformity of highª²performance concrete (HPC), a method based on density variance theory and computer digital image processing technology was proposed£¬and then the aggregate distribution of highª²performance concrete was quantified quantitative. The collected highª²resolution images were filtered and denoised. The aggregate shape was obtained using edge extraction, and the aggregate distribution image was obtained using corrosion, expansion, open and close operations. The calculation formula for local density variance was used to calculate the uniformity of the two randomly selected areas. The results show that the image denoising and the feature extraction methods for aggregate shapes can be realized by using MATLAB programming. In the image, the aggregate is thickened and blackened, the aggregate and the transition interface are sharpened, and the noise in the aggregate is removed, which can provide support for the analysis of uniformity. Based on the local density variance formula, three indices of the local density calculation for aggregate uniformity quantitative evaluation (i.e., ª«Uª«ª­1 and ª«Uª«ª­2, calculated at local side standard length ª«lª«ª­0, and ª«Uª«ª­3, calculated using the average over the entire local side length ª«lª«) can be used to quantify aggregate uniformity, which can avoid the influence of artificial or subjective factors. The variance of the uniformity ª«Uª«ª­1, ª«Uª«ª­2, and ª«Uª«ª­3 for two selected HPC testing zones is approximately 1% after rotating 0¡ã to 90¡ã to simulate different shooting angles. The volatility is small, which indicates high consistency in the three indicators. The variance of ª«Uª«ª­3 for selected area 1 and area 2 are 0.55% and 0.48%, respectively; the volatility is lower than that in ª«Uª«ª­1 and ª«Uª«ª­2. For more samples taken from different angles, the three uniformity indices tend to be stable, and the variance value is further reduced. The three indices of HPC aggregate uniformity can be evaluated separately or in combination. 2 tabs, 13 figs, 19 refs.

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Common functions

Last Update: 2018-08-03