Fractal Research on Cracks of Reinforced Concrete Beams with Different Aggregates Sizes

2011 ◽  
Vol 250-253 ◽  
pp. 1818-1822 ◽  
Author(s):  
Hong Quan Sun ◽  
Jun Ding ◽  
Jian Guo ◽  
Dong Liang Fu
Keyword(s):  
Fractal Dimension ◽  
Reinforced Concrete ◽  
Theoretical Basis ◽  
Concrete Beams ◽  
Fractal Theory ◽  
Aggregate Size ◽  
Fractal Dimensions ◽  
Reinforced Concrete Beams ◽  
Crack Evolution ◽  
Fractal Characteristics

Under the concentrated loads, the crack evolutions of reinforced concrete experimental beams (RCEB) with three different aggregate sizes are studied. Using fractal theory, the generation, development and distribution of the cracks on the RCEB are analyzed. The results show that the cracks on the RCEB have fractal characteristics obviously. By studying the fractal dimension of the cracks, the aggregate sizes have significant effect to the cracks on the RCEB. The relationships of the fractal dimensions of the crack evolution in loading processing and loads meet the power function laws. The researching results of this paper provide a new theoretical basis for selecting the appropriate aggregate size to improve the strength of reinforced concrete beams.

Research on Influences of the Coarse Aggregate Size on the Cracks of the Reinforced Beam

2012 ◽  
Vol 503-504 ◽  
pp. 832-836
Author(s):  
Hong Quan Sun ◽  
Jun Ding
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Fractal Theory ◽  
Aggregate Size ◽  
Reinforced Concrete Beams ◽  
Static Loads ◽  
Reinforced Beams ◽  
Maximum Crack

This paper gives the influences of the coarse aggregate size on the cracks of the beam with different aggregate sizes under static loads. The coarse aggregate sizes are ranked into three classes: small size (4.75mm ~ 19mm), big size (19mm ~ 37.5mm) and mixed size (4.75mm ~ 37.5mm). The developments of cracks of three reinforced concrete beams with the different of coarse aggregate sizes under the static loads are researched. The results show that under the action of the same loads, The reinforced concrete beams with the big aggregate size and mixed aggregate size have almost the same maximum crack width, while the maximum crack width of the beam with small aggregate size is less than formers. Using fractal theory, the fractal dimension of the cracks is studied. The result shows that the aggregate sizes have significant effect to the cracks on the reinforced beams.

scholarly journals Development of Back-calculation Model for Aggregate Gradation Determination Using Fractal Theory

2018 ◽  
Vol 159 ◽  
pp. 01006
Author(s):  
Bagus Hario Setiadji ◽  
Supriyono ◽  
Djoko Purwanto
Keyword(s):  
Fractal Dimension ◽  
Fractal Theory ◽  
Asphalt Mixture ◽  
Fractal Dimensions ◽  
Calculation Model ◽  
Careful Consideration ◽  
Upper And Lower Bounds ◽  
Aggregate Gradation ◽  
Fractal Characteristic ◽  
Fractal Characteristics

Several studies have shown that fractal theory can be used to analyze the morphology of aggregate materials in designing the gradation. However, the question arises whether a fractal dimension can actually represent a single aggregate gradation. This study, which is a part of a grand research to determine aggregate gradation based on known asphalt mixture specifications, is performed to clarify the aforementioned question. To do so, two steps of methodology were proposed in this study, that is, step 1 is to determine the fractal characteristics using 3 aggregate gradations (i.e. gradations near upper and lower bounds, and middle gradation); and step 2 is to back-calculate aggregate gradation based on fractal characteristics obtained using 2 scenarios, one-and multi-fractal dimension scenarios. The results of this study indicate that the multi-fractal dimension scenario provides a better prediction of aggregate gradation due to the ability of this scenario to better represent the shape of the original aggregate gradation. However, careful consideration must be observed when using more than two fractal dimensions in predicting aggregate gradation as it will increase the difficulty in developing the fractal characteristic equations.

Application of Fractal Theory in Aggregate Gradation Research

2012 ◽  
Vol 204-208 ◽  
pp. 1923-1928
Author(s):  
Bo Tan ◽  
Rui Hua Yang ◽  
Yan Ting Lai
Keyword(s):  
Fractal Dimension ◽  
Fractal Theory ◽  
Asphalt Mixture ◽  
Fractal Dimensions ◽  
Aggregate Gradation ◽  
Structure Characteristics ◽  
Aggregate Distribution ◽  
Dimension Formula ◽  
Mass Fractal ◽  
Fractal Characteristics

The paper presents the fractal dimension formula of distribution of asphalt mixture aggregate diameter by the deducing mass fractal characteristics function. Taking AC-20 and SMA-20 as examples, selected 6 groups of representative grading curves within the grading envelope proposed by the present specification, and calculated their fractal dimensions. The asphalt mixture gradation has fractal dimension D (D∈(1,3)), and the fractal of continuous gradation is single while the fractal of gap-gradation shows multi-fractal with 4.75 as the dividing point. Fractal dimension of aggregate gradation of asphalt mixture reflect the structure characteristics of aggregate distribution, that is, finer is aggregate, bigger is the fractal dimension.

The Influence of the Coarse Aggregate Size on Mechanical Properties of Reinforced Concrete Beams

2012 ◽  
Vol 184-185 ◽  
pp. 696-700
Author(s):  
Hong Quan Sun ◽  
Jun Ding
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Aggregate Size ◽  
Plane Section ◽  
Reinforced Concrete Beams ◽  
Static Loads ◽  
Small Aggregate ◽  
Normal Section

This paper gives the influence of the coarse aggregate size on the mechanical properties of the beam with different coarse aggregate sizes under static loads. In the research, three reinforced concrete beams with three different coarse aggregate sizes separately are tested. The stains and the deflections of the beams under the static loads are measured. The results show that under the action of the same loads, the maximum strains of the reinforced concrete beams with the big and the small aggregate size separately are larger than that of the beam with mixed aggregate size, and the deflection of the beam with the big aggregate size is larger than that of the beam with small aggregate size. In the loading process, the changes of the normal section strain of the reinforced concrete beams are satisfied the assumption of the plane section.

scholarly journals Fractal Characterization of Non-Uniform Corrosion of Steel Bars in Concrete Beams after Accelerated depassivation and Seven-Year Natural Corrosion

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3919 ◽  
Author(s):  
Haoyu Jiang ◽  
Nanguo Jin ◽  
Hailong Ye ◽  
Ye Tian ◽  
Xianyu Jin ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Concrete Beams ◽  
Fractal Theory ◽  
Reinforced Concrete Beams ◽  
Variation Method ◽  
Uniform Corrosion ◽  
Loading Level ◽  
Slag Powder ◽  
Steel Bars ◽  
Natural Corrosion

In this work, the non-uniform corrosion characteristics of steel bars in stressed reinforced concrete beams after accelerated depassivation and seven-year outdoor natural corrosion is analyzed using fractal theory. 3D laser scanning and 3D reconstruction technology are applied to collect the cross-sectional area along the steel bars and obtain the corrosion curves. The non-uniformity of corrosion is analyzed by fractal dimensions which is calculated by variation method. The results indicate that the initial loading level and loading zone have some influence on non-uniform characteristics of steel bars. For an ordinary concrete beam, the increase of load can cause a reduction of fractal dimension of corrosion curves by 5%, which indicates the non-uniformity of corrosion will increase with the increase of load level. The fractal dimension in the bending zone is lower than that in the tension–shear zone, which indicates that corrosion is more non-uniform in bending zone. However, the loading level and loading zone have a slight influence on corrosion level, and the maximum difference of corrosion level caused by load is merely 0.23%. Furthermore, the corrosion level increases with the decrease of fractal dimension, suggesting that the non-uniformity of corrosion increases with the growth of corrosion level. The incorporation of slag powder can help reduce the non-uniformity of corrosion, but the influence on reduction of the corrosion level is about 0.25%. For concrete structures under marine environment, application of slag powder is a good method to slow down the corrosion and reduce the non-uniformity of corrosion.

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