Study on the Influence of Three Factors on Mass Loss and Surface Fractal Dimension of Concrete in Sulfuric Acid Environments

2021 ◽  
Vol 5 (4) ◽  
pp. 146
Author(s):  
Jie Xiao ◽  
Xiang Long ◽  
Long Li ◽  
Haibo Jiang ◽  
Yaowen Zhang ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Sulfuric Acid ◽  
Mass Loss ◽  
Ph Value ◽  
Concrete Specimen ◽  
River Sand ◽  
Cement Ratio ◽  
Surface Fractal Dimension ◽  
Water Cement Ratio ◽  
Surface Fractal

When exposed to sulfuric acid environments, the service life of concrete structures would be reduced due to the high alkalinity of concrete. The influence of three factors including water/cement ratio, the pH value of the solution, and the chemical composition of the aggregate on the resistance of concrete subjected to sulfuric acid has been widely investigated by previous researchers. This paper aims to investigate the influence of these three factors on the durability evaluation indicators including mass loss and surface fractal dimension through orthogonal experiments, which has been reported rarely in previous research. Four combinations of coarse and fine aggregate including gravel and river sand, gravel and crushed marble sand, crushed marble stone and river sand, and crushed marble stone and marble sand were adopted, and three water/cement ratios including 0.35, 0.45, and 0.55 were selected, and the sulfuric acid solution pH values 0.95, 2, and 4 were chosen in this paper. The results showed that the larger the water/cement ratio, the smaller the mass loss and the surface fractal dimension of the specimens, and with the decrease of the pH value of the sulfuric acid solution, the mass loss and the surface fractal dimension of the specimens would be increased. The concrete specimen containing gravel and river sand had the greatest surface fractal dimension and greatest mass loss, while the concrete specimen containing crushed marble sand had a smaller surface fractal dimension and a smaller mass loss. The dominant and secondary order of three factors on mass loss and surface fractal dimension of concrete subjected to sulfuric acid was the pH value of the solution > the chemical composition of the aggregate > the water/cement ratio.

scholarly journals Effect of Mound Soil on Concrete Produced with River Sand

2014 ◽  
Vol 2 (1) ◽  
pp. 75-82
Author(s):  
Elivs M. Mbadike ◽  
N.N Osadebe
Keyword(s):  
Compressive Strength ◽  
Research Work ◽  
Strength Test ◽  
Control Test ◽  
River Sand ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Compressive Strength Test ◽  
Average Compressive Strength

In this research work, the effect of mound soil on concrete produced with river sand was investigated. A mixed proportion of 1.1.8:3.7 with water cement ratio of 0.47 were used. The percentage replacement of river sand with mound soil is 0%, 5%, 10%, 20%, 30% and 40%. Concrete cubes of 150mm x 150mm x150mm of river sand/mound soil were cast and cured at 3, 7, 28, 60 and 90 days respectively. At the end of each hydration period, the three cubes for each hydration period were crushed and their average compressive strength recorded. A total of ninety (90) concrete cubes were cast. The result of the compressive strength test for 5- 40% replacement of river sand with mound soil ranges from 24.00 -42.58N/mm2 a against 23.29-36.08N/mm2 for the control test (0% replacement).The workability of concrete produced with 5- 40% replacement of river sand with mound soil ranges from 47- 62mm as against 70mm for the control test.

scholarly journals WATER ABSORPTION AND DRYING SHRINKAGE OF RECYCLED FOAMED AGGREGATE CONCRETE

2018 ◽  
Vol 30 (3) ◽  
Author(s):  
Chai Teck Jung ◽  
Tang Hing Kwong ◽  
Koh Heng Boon
Keyword(s):  
Water Absorption ◽  
Absorption Rate ◽  
Drying Shrinkage ◽  
Casting Process ◽  
Concrete Specimen ◽  
Sieve Analysis ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Water Absorption Rate ◽  
Foamed Concrete

Abstract: This paper presents some experimental results and discusses the used of recycled foamed aggregates as natural coarse aggregates replacement in producing concrete. The physical properties of recycled foamed aggregates concrete were investigated. The properties studied are water absorption and drying shrinkage from the concrete early ages until the periods of 56 days. The 100 mm x 100 mm cube specimen was used to study the water absorption at the age of 7, 28 and 56 days. Meanwhile, the 100 mm x 100 mm x 300 mm length prism had been casted and used for drying shrinkage test for recycled foamed aggregates concrete. The foamed aggregates was produced from crushing recycled foamed concrete blocks. It were coated with cement paste to reduce its water absorption ability during casting process. Superplasticizer was used to maintain the workability of fresh concrete with a slump vary between 50 mm to 100 mm. The physical tests were conducted on recycled foamed aggregates to determine their initial properties such as loose bulk density, sieve analysis and water absorption rate. Recycled foamed aggregate concretes were produced with varied water cement ratio. The results obtained indicated that the linear elastic relationship between water cement ratio and water absorption rate. The higher the water cement ratio of concrete specimen will obtained higher water absorption rate. Vice versa, the density is low for drying shrinkage. The water absorption decreased while drying shrinkage becomes more stabilized over curing period.

scholarly journals A review on the application of the theory of critical distance towards concrete

2018 ◽  
Vol 250 ◽  
pp. 03001 ◽  
Author(s):  
Mohamad Shazwan Ahmad Shah ◽  
Norhazilan Noor ◽  
Ahmad Beng Hong Kueh ◽  
Mohd. Nasir Tamin
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Mathematical Expression ◽  
Concrete Specimen ◽  
Critical Distance ◽  
Optimum Level ◽  
Additional Element ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Fracture Assessment

Theory of Critical Distance (TCD) is one of Fracture Mechanics numerical model that has gone through tremendous laboratory works and validation. Hence, it has been proven to be precise in broad perspectives in the field. Recently, TCD research related to fracture, especially fatigue on concrete are growing but the depth of study is still shallow and deficient compared to metal and steel. Thus, this made the fracture assessment in concrete obscures and governs by uncertainties. Previous efforts have managed to optimize TCD but the results only valid if the water-cement ratio of a concrete specimen in its optimum level. When the water-cement ratio is adjusted to a higher or lower from its optimum level, the output errors showed inconsistency as reported by Luca Susmel (2016). Therefore, this research aims to optimize the Theory of Critical Distance (TCD) by incorporating water-cement ratio and the interaction of microstructure matrix. The optimization involves few stages and finite element. If Theory of Critical Distance (TCD) can be improved by considering concrete’s additional element in its mathematical expression, it will definitely contribute to betterment in assessing concrete infrastructure around the globe.

A Microcontact Model Developed for Asperity Heights with a Variable Profile Fractal Dimension, A Surface Fractal Dimension, Topothesy, and Non-Gaussian Distribution

2009 ◽  
Vol 25 (1) ◽  
pp. 103-115
Author(s):  
J. L. Liou ◽  
J. F. Lin
Keyword(s):  
Fractal Dimension ◽  
Contact Area ◽  
Distribution Functions ◽  
Real Contact Area ◽  
Contact Deformation ◽  
Surface Fractal Dimension ◽  
Surface Fractal ◽  
Deformation Regime ◽  
The Mean ◽  
Non Gaussian

AbstractThe cross sections formed by the contact asperities of two rough surfaces at an interference are islandshaped, rather than having the commonly assumed circular contour. These island-shaped contact surface contours show fractal behavior with a profile fractal dimension Ds. The surface fractal dimension for the asperity heights is defined as D and the topothesy is defined as G. In the study of Mandelbrot, the relationship between D and Ds was given as D = Ds + 1 if these two fractal dimensions are obtained before contact deformation. In the present study, D, G, and Ds are considered to be varying with the mean separation (or the interference at the rough surface) between two contact surfaces. The D-Ds relationships for the contacts at the elastic, elastoplastic, and fully plastic deformations are derived and the inceptions of the elastoplastic deformation regime and the fully plastic deformation regime are redefined using the equality of two expressions established in two different ways for the number of contact spots (N). The contact parameters, including the total contact force and the real contact area, were evaluated when the size distribution functions (n) for the three deformation regimes were available. The results indicate that both the D and Ds parameters in these deformation regimes increased with increasing the mean separation (d*). The initial plasticity index before contact deformation (ψ)0 is also a factor of importance to the predictions of the contact load (F*t) and contact area (At*) between the model of variable D and G, non-Gaussian asperity heights and circular contact area and the present model of variable D and G, non-Gaussian asperity heights and fractal contact area.

Effect of Oxidation Treatment on Surface Fractal Dimension of Activated Carbon Fiber

2002 ◽  
Vol 31 (1) ◽  
pp. 76-77
Author(s):  
Zheng-Hong Huang ◽  
Feiyu Kang ◽  
Jun-Bing Yang ◽  
Kai-Ming Liang ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Activated Carbon ◽  
Carbon Fiber ◽  
Activated Carbon Fiber ◽  
Oxidation Treatment ◽  
Surface Fractal Dimension ◽  
Surface Fractal

Application of Fractal Theory on River Bed Form

2012 ◽  
Vol 212-213 ◽  
pp. 236-240 ◽  
Author(s):  
Yin Jun Zhou ◽  
Fei Li ◽  
Li Chen ◽  
Zhong Wu Jin ◽  
Jun Wang
Keyword(s):  
Fractal Dimension ◽  
Surface Area ◽  
Fractal Theory ◽  
Irregular Boundary ◽  
Surface Fractal Dimension ◽  
Surface Fractal ◽  
River Bed ◽  
Bed Form ◽  
Fractal Characteristics ◽  
River Pattern

Fractal theory is used to describe river bed form. Based on improvements in some aspects of Surface area – Scale Method, such as, estimation of surface area, boundary treatment and so on, the calculation method of surface fractal dimension with irregular boundary is obtained, and the new method has good application on the bed surface fractal dimension calculation. The fractal characteristics of river bed surface morphology are discussed by combination with river-pattern, river regime, river process and changes of BSD. BSD can be used to study some related problems, such as analysis of river regime, distinction of river pattern, calculation of river resistance and so on.

Optimal surface fractal dimension for heat and fluid flow in microchannels

2010 ◽  
Vol 97 (8) ◽  
pp. 084101 ◽  
Author(s):  
Yongping Chen ◽  
Chengbin Zhang ◽  
Mingheng Shi ◽  
George P. Peterson
Keyword(s):  
Fractal Dimension ◽  
Fluid Flow ◽  
Surface Fractal Dimension ◽  
Surface Fractal ◽  
Optimal Surface ◽  
Heat And Fluid Flow
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