Browsing by Author "Irekti, Amar"

Now showing 1 - 20 of 28

1ère [Première] conférence nationale éco-matériaux & énergies renouvelables 10 & 11 mai 2010 FSI, université UMBB de Boumerdès
(Unité de recherche des matériaux , procédés et environnement , Université M'Hamed Bougara de Boumerdès, 2010) Irekti, Amar
Actes de la conférence nationale sur la chimie des matériau
(Universite M'hamed Bougara Boumerdes, 2019) Irekti, Amar
Actes du 2ème colloque international matériaux et développement durable
(2015) Irekti, Amar
Cette conférence internationale constituera un cadre de rencontre d'échange et de partenariat entre universitaires et acteurs économiques. Elle sera animée par un ensemble d'éminents professeurs chercheurs et étudiants des différents continents en présence des industriels pour présenter et discuter des résultats de recherche récemment obtenus et le mode de leurs développements dans des différents domaines de génie des matériaux
Co-Precipitation Synthesis of NiFe2O4 Using NH4HCO3 as Precipitant: Characterization and Photocatalytic Degradation of Organic Pollutant
(Pleiades Publishing, 2024) Saadi S.; Kezzim A.; Irekti, Amar; Nas, Mehmet Salih; Guettaf, M.
Structural properties and the photocatalytic activity of the synthesized NiFe2O4 via co-precipitation process using NH4HCO3 as a precipitating agent were studied. The resulting sample was calcined at 550°C and the formation of pure ferrite phase with spinel structure was confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy methods. The morphology of this spinel was investigated using a scanning electron microscopy (SEM). The optical absorption spectroscopy obtained the optical band gap (Eg = 1.81 eV). This material was applied as a photocatalyst for the photodegradation under UV light of Congo Red (CR) a persistent and recalcitrant dye. The effect of catalyst dose, initial concentration, and pH on photocatalytic degradation was investigated. Degradation efficiency of 82% was achieved for 3 h with a catalyst dose of 0.5 g/L. Furthermore, the material exhibited better photocatalytic activity in an alkaline medium, and the degradation kinetics followed a pseudo-first-order reaction.
Dielectric behavior study of thermosetting matrices loaded
(2012) Irekti, Amar; Hami, B.; Aribi, Chouaib; Bezzazi, B.
The present study was prospective in nature and its purpose is twofold. It consists, on the one hand, to identify and characterize mineral fillers, secondly, to determine the dielectric properties of materials prepared using the epoxy resin mixed with local inorg anic fillers , very rich in silica such that: sandy, pozzolan, cullet and a small calcium carbonate amount. This application allows us to use the matrix developed as an electrical insulator. The results of our study show that the use of fillers further im proves the dielectric properties of these matrices. After 32 days of conditioning, the values of capacitance and resistance obtained are very remarkable. Comparing our results with previous work with the addition of pure silica, we note that our composites have better properties at a low cost. The hygro - thermal influence is much less important fo r the loaded resin. Our composites may be subject to external environmental influences and they have a range of wide usage in dielectric materials
Durability Indices of a Sealing Mortar Incorporating Blast Furnace Slag
(2025) Ikhaddalene, Soumia; Irekti, Amar; Oualit, Mehena
Ground granulated blast furnace slag generated from steel manufacturing presents environmental challenges, but it can be valuable when utilized as a supplementary material in concrete, contributing to the development of sustainable materials. In this research, a new sealing mortar was prepared by substituting 10% of the cement with slag (M10). This material can provide performance comparable to M234, a M0 sealer used for sealing and wedging supports and machine bases. The mechanical properties and durability indices of both M10 and M234 were compared to the reference mortar MISO, which is a laboratory-made mortar free of slag. XRD analysis was conducted to determine the crystallinity of the starting cement, and granulometry revealed a median size distribution of 23 μm for the slag after grinding. Capillary absorption and water-accessible porosity were tested for all samples.
Effect of Black Liquor from Date Palm on the Workability and Compressive Strength of Portland Cement and Concrete
(De Gruyter Open Sp. z o.o., 2019) Irekti, Amar; Oualit, M.; Siahmed, H.; Buncianu, D.; Zibouche, Fatima
Lignin is the second most abundant natural polymer. Due to the high content of carbon and hydrogen (C-H, C-C, C=O), it can be used as a potential dispersant for cement matrix. The objective of this study is to extract lignin from date palm and study its effect in the form of black liquor (BL) on the rheological and physic-mechanical properties of the cements and concrete. The lignin in black liquor form represents approximately 30 wt% dry weight of date palm. It is a heteropolymer composed primarily of methoxylated phenylpropylene alcohol monomeric units interconnected by a variety of stable carbon-carbon and carbon-oxygen-carbon (ether and esters) linkages. The results found show the positive effect on the workability of cement and concrete and confirms its dispersion effect by improving compressive strength of concrete during the early and the later ages of hydration.
Elaboration des matériaux composites a matrices thermodurcissables et charges minérales
(2011) Irekti, Amar
Le thème de recherche s'inscrit dans l'ensemble des travaux expérimentaux dans le laboratoire "Composites et Mécanique des Matériaux" de l'Unité de Recherche : Matériaux Procédés et Environnement 'URMPE', sur la mise en forme des matériaux composites. Dans l'élaboration des matériaux composites, la matrice joue un rôle de liant des différents renforts, permet de répartir les contraintes, d'apporter une bonne tenue chimique pour la structure et de donner la forme désirée au produit final. Mais, il reste toujours des inconvénients qui se présentent dans les caractéristiques physico-chimiques et mécaniques des matrices thermodurcissables. Notre travail consiste à faire une synthèse des matériaux composites avec des nouvelles formulations des matrices thermodurcissables (produits Granitex), par l'incorporation de forte proportions des charges minérales locales. Ces dernières confèrent à la matrice des propriétés qu'elle ne possède pas seule, d'une part, à réduire le prix de revient des matériaux composites, et d'autre part, à améliorer la mise en œuvre par l'augmentation de la viscosité et la diminution du retrait à sa valeur minimale. Elles ont aussi la faculté d'augmenter les propriétés électriques des matériaux, mais aussi d'améliorer la rigidité mécanique et touchent les propriétés physico-chimiques en permettant au matériau d'avoir une meilleure tenue aux agents chimique, ce qui permet à la nouvelle matrice de très large domaines d'utilisation tel que l'industrie automobile, l'industrie de fabrication des composants électriques, des équipements de sport et de loisirs et dans le revêtement des sols
Elaboration et caractérisation des matériaux composites à matrice thermodurcissable et charges minérales
(2015) Irekti, Amar
La présent travail a un caractère prospectif et son but est double. Il consiste, d'une part, à identifier et caractériser les nanocharges minérales, d'autre part, à déterminer les propriétés physico- chimiques des nanocomposites hybrides élaborés à l'aide d'une matrice de type Diglycidyl Ether de Bisphénol A mélangées à des nanocharges très riches en silice telles que : la fumée de silice, la pouzzolane et le laitier de haut fourneau. Plusieurs concentrations massiques wt% (5 à 60%) ont été étudiées en présence d'un diluant qui sert à réduire la viscosité du mélange. Dans la première partie de cette étude, on s'intéresse aux caractéristiques micro-structurelles, chimiques et rhéologiques des composites produits. La deuxième partie, s'intéresse aux constantes diélectriques et l'analyse thermique différentielle de ces nanocomposites pour tirer au clair les nouvelles températures de transition vitreuse Tg et les plages de dégradation qui seront plus élevées vu le rôle de la barrière thermique que jouent ces charges. En comparant nos résultats aux travaux déjà réalisés avec l'ajout de la silice pure, nous remarquons que nos composites présentent des propriétés meilleures avec un faible coût, ils présentent une gamme d'utilisation très large dans le domaine diélectrique
Etude expérimentale du comportement diélectrique et thermique des nano composites hybrides à matrice époxyde chargée
(2014) Irekti, Amar; Bezzazi, Boudjema; Aribi, Chouaib; Zibouche, Fatima
Evaluation of the performance of local cement for oil well cementing operations in Algeria
(2018) Oualit, Mehena; Irekti, Amar; Hami, Brahim
The cementing of oil wells is done using special cement called ‘’class G cement’’, whose properties should meet the requirements of the American Petroleum Institute (API). Algeria, which ranks high among the oil and gas producing countries, has recently begun production of petroleum cement. The aim of this work is to characterize and evaluate the performance of a locally manufactured cement sample intended for oil and gas well cementing operations in Algeria. In this paper, significant properties (thickening time, compressive strength and free water) as well as the rheological behavior of the cement slurry under specific conditions have been experimentally examined. Apart from the initial consistency, which could be resolved by incorporating additives, the results indicated that the locally produced cement meets the requirements of the API standards and can therefore be used for cementing oil and gas wells
Experimental study of dielectric properties of composite materials pozzolan/DGEBA
(2015) Irekti, Amar; Bezzazi, Boudjema; Smith, Agnès; Aribi, Chouaib
Experimental study of sandwich multilayer reinforced by glass fibre and agglomerated cork
(2014) Hami, Brahim; Irekti, Amar; Aribi, C.; Bezzazi, B.; Mir, A.
This paper presents an experimental study which is determined the mechanical properties of a composite material sandwich multilayer developed in the laboratory of mechanics of materials and composites, Materials Research Unit, process and en¬vironment. This type of sandwich is composed of four layers laminated based on an epoxy resin reinforced by woven glass fibres and mast between which three plates of agglomerated cork with stacked alternately laminated layers. Specimens for bending tests three and four points were prepared from the multilayer sandwich panels. A first series of static three-point bending tests shows a clear difference in the fracture behaviour for materials, laminate and cork. These materials have undergone a large plastic deformation without rupture achieve full sandwich, with the onset of delamination between layers laminated material and cork. In order to determine the bending stiffness modules D, the shear modulus and flexural N and the shear modulus of the soul Ga, we conducted a second test campaign four points bending. As a result, we can develop a variety of white cork produced in Algeria in order to use it in the construction and automotive industries
FTIR analysis and rheological behavior of bisphenol : a diglycidyl ether resin filled Fume-Silica
(2014) Irekti, Amar; Bezzazi, Boudjema; Boualam, Chahrazed; Aribi, Chouaib; Dilmi, Hamid
Silica-fume as fillers into polymers materials affect significantly the physical, mechanical and the electrical properties of the polymers. The polymer that we studied here is an epoxy based resin (STR) and silica fume (FS). This paper presents the dependency of the rheological behavior of the STR epoxy resin on the FS content within a temperature at which the reaction thermoset is neglected. We used a cone-plate viscometer for the study of the rheological behavior, and a scanning electron microscope is used for the analysis of the dispersion state of the FS in STR epoxy resin. Compared to the control without loads, an increase of 50% of the shear stress and the plastic viscosity were recorded for the composite. The software Rheowine viscometer enabled us to model and identified the rheological behavior of these mixtures with resin. The results obtained in this modeling, confirmed that the resin mixtures have shear-thinning rheological behavior, this last give us the model of Ostwald de Waele
FTIR analysis and thermal behavior Of microcomposite Pozzolan/ Dgeba
(2019) Irekti, Amar; Oualit, Mehena; Zibouche, Fatima; Buncianu, Dorel
In the present study six blends of Diglycidyl ether of bisphenol-A and pozzoan filler were synthesized by physical mixing at 100°C. Interaction among epoxide group of DGEBA, composition of fillers and anhydride group of curing agent discussed through FT-IR analysis. The TGA studies revealed a increase in thermal stability and the glass transition temperature (Tg). The integral procedure decomposition temperature increased from 571,3 °C to 617,9,3°C. The composites had a higher glass transition temperature than the neat epoxy resin. The coefficient of thermal expansion of the composites at the glassy and rubbery regions decreased with increasing ﬁller content. Scanning electron microscopy (SEM) indicated the presence of two-phase morphology in the blends
Influence of date palm liquor on rheological behavior of cement- based mortars
(2020) Irekti, Amar; Oualit, Mehena; Siahmed, Hamza
The cost of superplasticizer is increasing day by day because of high demand, scarcity of raw materials. From this, the extensive research and development works towards exploring new ingredients are required for producing sustainable and environment friendly construction materials. Date palm liquor is one such material that can be used as a chemical admixture which is obtained with Kraft process from the date-palm wood. In the present investigation black liquor is added to fresh concrete in different dosages, the concrete is then tested for rheological behavior, workability and compressive strength. From results it is shown that 1% replacement of water with black liquor increases the fresh properties of the concrete, 2% replacement of water with black pulp liquor increases the mechanical properties of the concrete and acts as a set retarder
Mechanical performance of metakaolin-based geopolymer mortar blended with multi-walled carbon nanotubes
(Elsevier, 2022) Oualit, Mehena; Irekti, Amar
In recent decades, the cement industry has been viewed as a major environmental problem mainly due to carbon dioxide CO2 emissions during the production of Portland Cement (PC). Among the solutions to this problem is to replace Portland cement-based materials with alkali-activated materials. Metakaolin-based geopolymer mortars are currently considered a serious alternative to ordinary Portland cement mortar due to its various advantages. The present experimental study aims to develop metakaolin-based geopolymer mortars reinforced with multi-walled carbon nanotubes (MWCNTs). The content of MWCNTs incorporated was 0.1; 0.2; 0.3, and 0.4 wt%, respectively, with respect to the mass of metakaolin. A mixture without the addition of carbon nanotubes was also prepared and used as a reference (control sample). The alkaline activation of metakaolin was carried out using aqueous sodium silicate solution having a molar ratio (SiO2/Na2O) equal to 1.77. Mechanical characterization of the hardened samples was performed after curing for 3, 7 and 28 days. The results indicate that the incorporation of multi-walled carbon nanotubes in the geopolymer matrices improves compressive strength. Microscopic analysis has shown that these carbon nanotubes contribute to the densification of the geopolymer matrix and give rise to crack bridging mechanisms. The highest value of the compressive strength was recorded using an alkali silicate content equal to 8 (expressed as a percentage of Na2O) combined with 0.2% of multi-walled carbon nanotubes in the geopolymer mortar. The integral absolute error (IAE) calculated on the compressive strength values at different curing ages are all within an acceptable range (0–10%)
Multilayer system of thermosetting polymers and specific confining : application to the walls of the hospital unit
(Photon Excellence Award-2014 : The Journal of Materials Science, 2014) Bouzid, Mohammed; Djadi, A.; Aribi, C.; Irekti, Amar; Bezzazi, B.; Halouene, F.
The nature of materials structuring our health institutions promote the development of germs. The sustainability of nosocomial infections remains significant (12% and 15%). One of the major factors being the portland cement which is brittle and porous. As part of a national plan to fight nosocomial infections, led by the University Hospital of Blida, we opted for a composite coating, application by multilayer model, composed of epoxy-polyester resin as a binder and calcium carbonate as mineral fillers. The application of composite materials reinforce the wall coating of hospital units and eliminates the hospital infectious areas. The resistance to impact, chemicals, raising temperature and to a biologically active environment, gives satisfactory results
Performance of recycled asphalt mixtures formulated with modified bitumen
(Gheorghe Asachi Technical University of Iasi, Romania, 2019) Oualit, Mehena; Irekti, Amar; Hami, Brahim
The maintenance of flexible roads or roads at end of life service generates high quantities of reclaimed asphalt pavement every year. The reuse of these materials, considered for a long time as waste, allows a substantial saving in transport, energy, and maintains dwindling natural resources. Recycling of asphalt also helps to reduce inert waste storage volumes, and conserve valuable landfill space. The applicability of recycled asphalt was tested in laboratory, and asphalt mixtures containing 20%, 40% and 50% of reclaimed asphalt pavement (RAP) were designed. Marshall and Duriez tests have been performed on various formulations using paving grade bitumen and modified bitumen as binders, the latter contains a quantity of Styrene /Butadiene / Styrene (SBS) polymer. This investigation led to the conclusion that the performance of recycled asphalt mixture containing 20% of RAP is significantly closer to those obtained with virgin asphalt mixture without recycled materials. In addition, the use of SBS polymer improves the properties of recycled asphalt mixtures even with high amounts of reclaimed asphalt pavement.
Rheological behavior of epoxy resin filled fume silica
(2014) Irekti, Amar; Bezzazi, Boudjema; Aribi, Chouaib; Hami, B.