Evaluation of aggregate gradation in lightweight concrete via image processing

Barbosa, Fernando Policarpo; Farage, Michèle Cristina Resende; Beaucour, Anne-Lise; Ortola, Sophie

doi:10.1016/j.conbuildmat.2011.08.081

Cited by 20 publications

(13 citation statements)

References 11 publications

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“…Eurolightcon [5] emphasizes the importance of homogeneity among the constituents of lightweight concrete. During the mixing of LWC, due to the low density of the aggregates used and the longer mixing times [6], the LWC is susceptible to the segregation of the aggregates as a result of the differences between the densities of their components. In fact, during the vibration of the concrete, lightweight aggregates tend to float.…”

Section: Introductionmentioning

confidence: 99%

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Numerical model for describing the segregation phenomenon in lightweight concrete using density sections

Tenza-Abril¹,

Villacampa²,

Baeza-Brotons³

et al. 2017

Int. J. CMEM

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In this work, numerical models were obtained for describing the segregation phenomenon in lightweight aggregate concrete. To that end, a numerical methodology based on the generation of geometric models of finite elements has been applied, selecting those that describe better this phenomenon. The use of lightweight aggregate concretes (LWC) allows greater design flexibility and substantial cost savings. It is also well known that it contributes to a positive impact on the energy consumption of a building due to the high-thermal resistance values. However, lightweight concretes are susceptible to present aggregate segregation due to density differences between its components during concrete vibration. Segregation in concrete may strongly affect the concrete global properties. This fact justifies the needs for the identification and quantification of this phenomenon, in order to estimate the concrete segregation experimentally, a LWC was mixed in laboratory conditions. Controlled segregation was caused applying different times of internal vibration in a cylinder specimen. The specimens were horizontally sectioned in order to obtain the density in each section because the segregation index can be estimated obtaining a relation by comparing the densities of the upper and lower parts. Firstly, ANOVA test was performed to determine the statistical significance (p<0.05) of the differences in the density of the different sections, differences in the aggregate type and differences in the time of concrete vibration. Results show that there is a significant difference of each section and there is no significant difference of each lightweight aggregate used to mix the concrete in spite of their different density. In order to model the segregation in the LWC, at first, linear models were considered and rejected because for not explaining the phenomenon. However, the application of numerical models shows good results to describe the phenomenon of segregation in LWC.

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Section: Introductionmentioning

confidence: 99%

“…To quantify the phenomenon of segregation, Ke and Beaucour propose several methods to determine segregation index [6]. In one of the methods to determine segregation index, the densities obtained from the upper and lower slices of a cylinder can be used.…”

Section: Introductionmentioning

confidence: 99%

Numerical model for describing the segregation phenomenon in lightweight concrete using density sections

Tenza-Abril¹,

Villacampa²,

Baeza-Brotons³

et al. 2017

Int. J. CMEM

View full text Add to dashboard Cite

show abstract

“…The ability of fresh concrete to remain uniform during consolidation is a critical issue in the mixture design [9]. During the mixing of lightweight aggregate concrete (LWAC), due to the low density of the aggregates used and the longer mixing times [10], LWAC is susceptible to segregation of the aggregates as a result of the differences between the densities of their components [11]. In fact, during the vibration of the concrete, lightweight aggregates tend to float.…”

Section: Introductionmentioning

confidence: 99%

Image analysis applications for the study of segregation in lightweight concretes

Solak¹,

Tenza-Abril²,

Baeza-Brotons³

2017

Int. J. CMEM

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The use of lightweight concrete allows great flexibility and cost savings when it is used in building construction having a positive impact on the energy consumption of buildings due to its good thermal characteristics. However, it is also known that the differences between the densities of the materials used to produce these concretes make it highly susceptible to the segregation phenomenon. The main objective of the present work is to present a method to quantify this phenomenon using techniques of image analysis. In this work, a lightweight concrete produced was molded in cylindrical molds using different times of internal vibration and causing different degrees of segregation. The samples were cured, vertically saw-cut in two pieces (halves) and the sections were photographed. Subsequently, the halves were saw-cut horizontally in four equal parts and posteriorly their densities were determined experimentally. The densities obtained were used to calculate the segregation index of each sample (experimental method). Furthermore, the photographed sections were processed using image analysis software in order to determine the volumetric proportions of aggregates in each sample (noise reduction, threshold adjustment, binarization and fill holes). The processed images were used to calculate the densities and segregation index of the lightweight concrete produced through image analysis. In addition, using the photographed sections, a vertical density profile was programmed to analyze the distribution of the lightweight concrete components (mortar and aggregate). Finally, the results obtained experimentally and through image analysis were compared. This study demonstrates that the image analysis allows a deeper knowledge of the behavior of segregated concrete

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“…These processes are both time and man-power consuming. Recently, image processing (IP) techniques have been applied to estimate the geometrical properties of aggregates in asphalt mixtures and Portland cement concrete by applying computer software processes to images of sectional cuts to calculate the sizes, areas, perimeters and gradation of aggregate particles when the materials [3][4][5][6][7][8][9][10][11][12][13][14][15]. Some of key articles are summarized as follows.…”

Section: Introductionmentioning

confidence: 99%

“…[5] used concrete section images to find thresholds and make binary images. Then they calculated the gradation by IP and used the diameter to separate the size distribution, and then compared the results between the image and manual results.…”

Section: Introductionmentioning

confidence: 99%

Development of a Size-Based Multiple Erosion Technique to Estimate the Aggregate Gradation in an Asphalt Mixture

Saensomboon¹,

Sangpetngam²

2017

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Abstract. Image processing (IP) techniques have recently been applied in the field of asphalt materials to help identify aggregate particles and measure their geometrical information based on sectional images of the material. This study examined IP techniques to improve the accuracy of analyzing the size distribution of aggregates in an asphalt mixture, and proposed two new methods: seven-layer overlaying (SLO) and size-based multiple erosion (SBME) to solve the problem of identifying connected aggregate particles that often occurs in typical IP applications. The proposed methods were tested for their effectiveness with a typical IP method using a referenced sectional image of asphalt mixture. Both the proposed methods successfully improved the accuracy of detection (number and size distribution) of aggregate particles, but the SBME approach was superior over the SLO method.

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Evaluation of aggregate gradation in lightweight concrete via image processing

Cited by 20 publications

References 11 publications

Numerical model for describing the segregation phenomenon in lightweight concrete using density sections

Numerical model for describing the segregation phenomenon in lightweight concrete using density sections

Image analysis applications for the study of segregation in lightweight concretes

Development of a Size-Based Multiple Erosion Technique to Estimate the Aggregate Gradation in an Asphalt Mixture

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