Structural Concrete
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2022 ◽  
Vol 14 (2) ◽  
pp. 617
Dan Georgescu ◽  
Radu Vacareanu ◽  
Alexandru Aldea ◽  
Adelina Apostu ◽  
Cristian Arion ◽  

The article presents an original method to assess the sustainability of concrete. The method uses three parameters, namely, performance, lifetime and environmental impact, to calculate a sustainability index. The originality and simplicity of the proposed method is shown when finding the sustainability index, where the first two factors (service life and performance) are kept constant. This approach is possible within the context of the new proposals that specify the durability of structural concrete in EN 1992 and EN 206. It allows the classification of concrete according to its performance, through environmental action resistance classes (ERC). For this purpose, specific experimental methods were used in order to determine the performance of concrete exposed to carbonation. The concretes were prepared with two cement types with additions (CEM II/A-S and CEM II/A-M (S-LL)). Based on the carbonation resistance classes (first parameter—performance) and exposure classes, the thickness of the concrete cover layer was determined to ensure a certain service lifetime (second parameter—service lifetime). Lastly, the global warming potential was calculated for each composition, allowing the users of the method to select the compositions with the lowest environmental impact.

2022 ◽  
Vol 12 (1) ◽  
Zakaryaa Zarhri ◽  
William Rosado Martinez ◽  
Jose Antonio Dominguez Lepe ◽  
Ricardo Enrique Vega Azamar ◽  
Maritza Chan Juarez ◽  

This work presents a bibliometric study of the literature on the use of caucho in the construction to promote the interest of using rubber as a prime material to reduce pollution at a global level. Published papers in the period 1999-2020 in both databases, Scopus and Web of Science (WoS), are taken into account using the Methodi Ordinatio and the VOSviewer software. A total of 967 documents on the use of rubber in structural and non-structural concrete have been published in this period and 1182 authors have contributed on the subject. Since 2010, the interest of researchers in introducing rubber in construction has increased. China, USA and Australia are the countries with the greatest interest in investigating about rubber-concrete.

Rita Nemes ◽  
Mohammed A. Abed ◽  
Ahmed M. Seyam ◽  
Éva Lublóy

AbstractThe residual compressive strength of eight lightweight concrete mixtures containing three commercial grading (Liapor HD 5 N, Liapor HD 7 N, and Liapor 8F) of coarse lightweight aggregate (LWA) were determined after to expose at high temperatures. Eight mixes were produced, two by normal weight aggregate and the rest by different types of LWA. The produced concrete was analyzed after high temperature exposure and the effect of using LWA, the type of LWA, and compaction method was studied. To do so, visual inspection, residual compressive strength, crack pattern, spalling, and thermoanalytical analysis were conducted. Generally, it could be concluded that concrete formulations with LWA behave more advantageous up to 500 °C, compared to those with quartz gravel aggregates. Moreover, this study found that an ideal type of LWA to produce structural concrete was Liapor HD 5 N, which was used for producing the mixes L1 and L3.

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 76
Roberto Sañudo ◽  
Ignacio Jardí ◽  
José-Conrado Martínez ◽  
Francisco-Javier Sánchez ◽  
Marina Miranda ◽  

This manuscript presents the first measurement program and data collection on the Dinatrans track transition solution after it was installed in a track section in the north of Spain (Galicia). The Dinatrans solution was created to address the limitations of several track transition solutions. This novel solution consists of two inner and outer rails from slab track to ballast track, pads with different stiffness over sleepers of variable lengths installed from ballast track to slab track, and a simple substructure formed by non-structural concrete poured over the natural ground. The main objective of this research was to assess the suitability and the initial performance of the Dinatrans track transition solution. The measured variables for these initial real-world tests were vertical accelerations on sleepers, shear stress on rails, vertical displacements on rails and vertical displacements on sleepers. All measurements of these variables were obtained in an in-situ program by installing vertical accelerometers and LVDTs on the track structure and extensometer gauges on the rails and sleepers. The methodology and the procedures followed are described. The Dinatrans initial solution was compared with the Standard solution used in Spain using these initial measurements. This field analysis provides an initial understanding of the performance of the new track transition. Further measurements will be required to check the track transition performance over the long term; however, no maintenance works have been necessary since construction (2016).

Omnia Saad ◽  
Khaled S. Ragab ◽  
Omar Elnawawy ◽  
Yousef R. Alharbi ◽  

Using of Lightweight concrete (LWC) amounts to a lower cost and a better thermal performance due to its unique properties and light density. The main disadvantage in using lightweight concrete is that its mechanical properties are relatively poor. An effective method to improve the mechanical properties of lightweight concrete is using a dosage of nano-silica in the concrete mix. The gained enhancement of mechanical properties promotes a more serious discussion of structural applications of lightweight concrete. There exists an optimum dosage of nano-silica by which the mechanical properties enhancement is maximized. Increasing the nano-silica content beyond the optimum dosage degrades the mechanical properties. However, a fixed optimum dosage is not agreed upon in literature. This paper investigates the optimum dosage of NS to enhance the mechanical properties and microstructure of a lightweight concrete made with lightweight expanded clay aggregates (LECA). The results concluded that a dosage of 0.75% of nano-silica is optimum for the studied lightweight concrete mixes.

2021 ◽  
Vol 12 (1) ◽  
pp. 36
Alessandra Diotti ◽  
Luca Cominoli ◽  
Giovanni Plizzari ◽  
Sabrina Sorlini

In this paper, a new innovative technology for the treatment of returned concrete is proposed. This method is based on the application of physical–mechanical processes that allow to obtain new quality products: recycled aggregates, microfiltered water and cement sludge. Specifically, by means of a mechanical system equipped with buffer and Archimedes screws, fine (d < 5 mm) and coarse (d > 5 mm) aggregates are obtained. The water coming from the washing process is sent to a microfiltration process, where a filter membrane separates the liquid phase (microfiltered water) from the solid phase (cement sludge) and no type of potentially toxic additive is added. In this context, this paper investigates the feasibility of using all these components as new raw materials for sustainable concrete production. In particular, according to the requirements imposed by technical standards, an experimental program was developed, aimed at evaluating the physical, chemical, and mechanical properties of the analyzed materials. The results showed that both recycled aggregates, the microfiltered water and the cement sludge can be used to produce new structural concrete. In particular, it was proven that also the cement sludge, which generally represents the most critical component destined for disposal, can be reused as filler in the partial replacement of sand.

2021 ◽  
Vol 11 (1) ◽  
pp. 20-30
Elaf Hasan

n light of the conditions experienced by Syria and due to the destruction and demolition of its buildings built up rubble and occupied a large area of its territory. Therefore, it was necessary to develop an appropriate strategy to study these debris and provide the ideal solutions to be able to benefit from them as much as possible and thus mitigate the harmful impact on the environment and the surrounding environment. The work is divided into two parts: First: The study focuses  on one of the mechanisms of benefiting from  the recycled aggregate by using them in producing concrete, after studying their characteristics(Sieve Analysis-density- Absorption) and then mixing them with natural aggregate as replacement of natural coarse aggregate at different rates(15-30-45-75-100)%. Six concrete cubes were made for each mixture and 3 cubes were broken after 7 days and the other after 28 days . it was concluded The relationship between the percentage of recycled aggregates and compressive strength, as well as the relationship between the percentage of stones and the rate of Absorption The results showed that the acceptable percentage of replacement of natural aggregates with recycled aggregates may reach 100% with the recording of values of resistance of up to 21.9Mpa  . Second :The environmental and economic feasibility of using recycled aggregates has been studied the results showed that use 75% of the recycled aggregates in structural concrete works will reduce energy consumption and carbon dioxide emissions by 28% and 33%, respectively, and the economic saving rate is 63.71%. .   Through this study two objectives can be achieved:  First: removing large quantities of environmental pollution sources resulting from these wastes and thus achieving an environmental goal. Second: Provide other sources of concrete aggregates and thus protect the natural quarries and achieve an economic goal.

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