Browsing by Author "Boumchedda, Khaled"

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    Optimizing Foam Concrete Performance Using Mixed Foaming Method: Impact of Mixing Speed, Mixing Duration, And Foam Dosage
    (South Florida Journal of Development, 2024) Galoul, Riadh; Boumchedda, Khaled; Mebtouche, Farouk
    Foamed concrete has gained significant attention, especially in the field of thermal insulation and acoustic insulation. However, all production methods are based on the pre-foaming method, while the mixed foaming method is an infrequent approach that should be considered and could be challenging. For this reason, this paper attempt to highlight this method and valuate it on par with the pre-foaming method in the production of foamed concrete, both in terms of structure and performance. These performances are directly dependent on the pore structure of this material (pore size, porosity rate, and pore distribution). Therefore, a process has been developed for sample preparation to achieve a final product with a well-controlled size and distribution of porosity, meeting the desired performance criteria. This process involves varying the following parameters: mixing speed (from 400 to 1000 rpm), mixing time (from 2 to 12 minutes), and the dosage of foaming agent (from 0.05 to 0.2%). The effect of mixing speed, mixing duration and the dosage of the foaming agent on the generated foam rate, density, structure at the millimeter scale, structure at the micrometer scale, and thermal conductivity was demonstrated. The obtained results show that with a generated foam rate extending to 79%, a density reaching 428 kg/m3, and a thermal conductivity achieving 0.181 w/k.m, the mixed foaming method becomes an important and competitive approach to the pre- foaming method in the production of foamed concrete.
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    Performance of Earth Blocks Based on Recycled Dam Sediment and Reinforced with Alfa Fibers : Experimental Study
    (Taylor and Francis, 2025) Gueffaf, Nezha; Rabehi, Bahia; Boumaaza, Messaouda; Boumchedda, Khaled; Belaadi, Ahmed; M. S. Abdullah, Mahmood; Klimkina, Iryna; A. al-Lohedan, Hamad; Al-Khawlani, Amar; Chetbani, Yazid
    River and dam dredged sediments are regarded as waste. Waste sediment disposal involves financial resources and raises issues regarding the environment. Reusing dredged sediments to make building materials like adobe bricks can offer an alternative way to handle and value this waste. Compressed earth blocks (CEB) are environmentally friendly building materials made from clay soil or sediments dam with fibers. Natural fibers addition improves mechanical and thermal characteristics of adobe bricks. The goal of this study was to use Alfa fibers (AF) from Algeria to create adobe bricks from the sediments of the Koudiat Acerdoune dam. This study presents an experimental study of earth blocks stabilized with 10% cement and reinforced with AF fibers at different volume fraction dosages (0.75%, 1.5%, and 2.5%). The new composite of these sediments’ capillary absorption, shrinkage, compressive strength, flexural strength, and thermal conductivity was examined. With a flexural strength of 2.30 MPa and a compressive strength of 8.12 MPa for 2.5% AFs, as well as a decrease in thermal conductivity, the fiber/cement formulations demonstrated the best mechanical performance, according to the results of the analysis
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    Preparation and characterization of biocomposites based on chitosan and biomimetic hydroxyapatite derived from natural phosphate rocks
    (Elsevier, 2021) Brahimi, Salim; Ressler, Antonia; Boumchedda, Khaled; Hamidouche, Mohamed; Kenzour, Abdeghani; Djafar, Rabah; Antunović, Antunovic; Bauer, Leonard; Hvizdoš, Pavol; Ivanković, Hrvoje
    Highly porous chitosan/hydroxyapatite (CS/HA) biocomposite scaffolds were prepared using the freeze-gelation method. A starting biomimetic HA powder was synthesized by a wet precipitation method using an abundant natural phosphate (NP) ore as raw material. Then, CS/HA scaffolds with different weight ratios (100/0; 90/10; 80/20; 70/30) have been prepared. The used powders and synthesized scaffolds were characterized by XRF, ICP-MS, FTIR, TG-DSC, XRD, SEM, and cell viability. The results showed that the precipitated raw powder was mainly composed of HA and amorphous calcium phosphate (ACP) with some traces of Mg2+, SiO42−, Sr2+, Na+ and Fe2+ ions which were usually found in such mineral NP precursors. The heat treatment of the raw powder at more than 750 °C leads to the formation of Mg-substituted β-tricalcium phosphate (β-TCMP). Moreover, the culture of human embryonic kidney cells indicated the non-cytotoxicity of the as-prepared powder. On the other hand, the elaborated CS/HA scaffolds exhibited a highly porous structure with well-interconnected pores and homogeneously dispersed HA particles. The measurement of swelling capacity under physiological conditions revealed that the addition of HA to the CS matrix effectively decreased the swelling percentage. The obtained results suggest that the elaborated CS/HA composites may have effective potential as biocompatible scaffolding materials for bone tissue engineering
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    Study, with Different Characterization Techniques, of theFormation of Cordierite from both Natural and ActivatedAlgerian DD3 Kaolin
    (Taylor and Francis Online, 2020) Kheloui, Meriem; Boumchedda, Khaled; Naitbouda, Abdelyamine
    The work presented in this article deals with the synthesis of a cordierite ceramics,using a natural Algerian kaolin named DD3 of black colour, located in the region ofDjbel Dbagh in Guelma. A synthesis was also carried out on bleached DD3 kaolin obtainedby activation of hydrochloric acid on natural kaolin in order to eliminate the manganeseoxide (which is responsible for the blackish colour) while enlarging the applicationfield in industry (e.g. luxury porcelain). Preparation of this cordierite was carried out byadding the precipitated magnesium hydroxide and a silica deficit for each type of kaolin.Mixtures of pellet finely milled and pressed as pelleted powders were sintered at differenttemperatures (1150o, 1250o and 1350oC) for 2 h before being characterized. The resultsobtained by X-ray diffraction showed that the cordierite phase crystallized at 1250oCfor both types of black and bleached samples, which was confirmed by Ramanspectroscopy. Scanning electron microscopy was used to observe densification,homogeneity as well as the size of the sample constituents. Their coefficients of thermalexpansion were respectively 1.9510–6 and 1.6910–6 oC–1 between 23o and 800oC, whichallowed their use in automobile catalytic converters