Nowadays, the reuse of waste is a challenge that every country in the world is facing in order to preserve the planet and introduce a circular economy. The chemical composition of some steel waste suggests that there are potentially appropriate substances for reuse, since this type of slag undergoes a process similar to that of cement in its manufacture. The advantages for the environment are obvious, as it valorises waste that is deposited in landfills. This paper studies the field of stainless steel, because its composition is different from that of carbon steel, and the replacement of cement with material or waste produced in the manufacture of stainless steel in a concrete matrix. This paper presents the results of replacing 25% of cement with material or waste produced in the manufacture of stainless steel in a concrete matrix whose values in the substitutions carried out were around 21% and 25% in terms of increased resistance capacity. These results have been obtained by carrying out tests, in terms of both strength and environmental capacity, allowing us to determine viable applications for the use of steel waste to improve the performance of cement or at least match it.
In the area of civil engineering and especially hydraulic structures, we find multiple anomalies that weakens mechanical characteristics of dikes, one of the most common anomalies is erosion phenomenon specifically pipe flow erosion which causes major damage to dam structures. This phenomenon is caused by a hole which is the result of the high pressure of water that facilitate the soil migration between the two sides of the dam. It becomes only a question of time until the diameter of the hole expands and causes destruction of the dam structure. This problem pushed physicist to perform many tests to quantify erosion kinetics, one of the most used tests to have logical and trusted results is the HET (hole erosion test). Meanwhile there is not much research regarding the models that govern these types of tests. Objectives: In this paper we modeled the HET using modeling software based on the Navier Stokes equations, this model tackles also the singularity of the interface structure/water using wall laws for a flow turbulence. Methods/Analysis: The studied soil in this paper is a clay soil, clay soil has the property of containing water more than most other soils. Three wall laws were applied on the soil / water interface to calculate the erosion rate in order to avoid the rupture of such a structure. The modlisitation was made on the ANSYS software. Findings: In this work, two-dimensional modeling was carried of the soil.in contrast of the early models which is one-dimensional model, the first one had shown that the wall-shear stress which is not uniform along the whole wall. Then using the linear erosion law to predict the non-uniform erosion along the whole length. The previous study found that the wall laws have a significant impact on the wall-shear stress, which affects the erosion interface in the fluid/soil, particularly at the hole's extremes. Our experiment revealed that the degraded profile is not uniform. Doi: 10.28991/cej-2021-03091742 Full Text: PDF
Problem statement: Internal soil erosion is a real threat for hydraulic infrastructures. In
its final stage it develops in piping involving the formation and progression of a continuous void
inside the soil between the upstream and downstream sides. The hole erosion test was introduced to
characterize kinematics of piping in terms of the time left to rupture. Actual modeling approaches of
this test are essentially one dimensional. The wall shear stress generated by the flow is assumed to be
uniform, so that erosion rate is also uniform along the hole length. Experimental observations show
however an irregular profile of the eroded hole. Approach: In this study an axisymmetric extension
representation of the hole erosion test was performed. The biphasic flow at the origin of surface
erosion occurring in the porous soil sample was modeled by means of the renormalization group
based k-ε turbulence equations. Fluent software package was used to perform the numerical
modeling. Results: This had enabled to estimate the wall shear stress which was found to be non
uniform along the hole length. Erosion rate was then estimated by using a classical law. Its variations
as affected by the applied gradient pressure, fluid density as well as the actual fluid/soil interface
roughness were analyzed. In particular, wall roughness and clay concentration were found to
increase noticeably the erosion rate. Conclusion/Recommendations: Predicting erosion rate at the
start of piping formation can be done by the proposed model. Flow features are however very
complex in the real HET configuration. In particular, clay concentration does not vary equally along
the hole length. The erosion law coefficients are variable. Transport phenomenon of some soils
particles that detach is present in the problem. Further investigations including these aspects should
be performed in order to render more profoundly the complex physics involved in this experiment
Like all municipalities, the city of Mohammedia has to bear a significant cost for the treatment of its waste. In all, €2·72 million has been spent on the collection and processing of 78 608 t of household and similar waste produced in 2013. The urban commune of Mohammedia, which has a daily waste production of 0·807 kg per capita, has been trying to reduce waste production by upstream sorting and recovery; whereas waste reduction is only possible at the source. Treatment processes only could reduce the amount of waste that has to be disposed of. A study of the waste arisings through characterisation of the household waste produced by the city of Mohammedia enabled to know how much waste is generated, how much waste is recyclable, the percentage of fermentable organic materials, the percentage of non-recyclable materials and the estimated cost of disposal of such waste.
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