Browsing by Author "Saidi, M."

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    Development and structural study of cements containing additions of industrial waste
    (2010) Saidi, M.; Hamiane, M.; Safi, Brahim; Benmounah, A.
    Certain mineral additions exploit a very significant role the behavior and the ageing of the works in the corrosive conditions and one can use them like barriers against the aggressiveness and the phenomenon of corrosion of the concretes. Cements made up of additions can be recommended especially in massive works, the stoppings, maritime and underground constructions and in the cementing of the oil wells. The use of the adequate additions ensures the long-term stability and durability of the concretes of the underground, maritime works and the cementing of the oil wells… etc. To this end, within the framework of valorization of these additions (active and inert), in this study we were interested only in the study of the influence of incorporation of limestone, pozzolana, slag, tuff and dust electrostatic precipitator (crushed finely) like active addition in the matric E of cement, its effect on the behavior and ageing of cement S made up and on the microstructure of the concrete by a structural characterization by XRD
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    Effect of size and stacking of glass fibers on the mechanical properties of the fiber-reinforced-mortars (FRMs)
    (2011) Saidi, M.; Safi, Brahim; Benmounah, A.; Aribi, C.
    In modern day construction practice, repair and rehabilitation of structures have taken a prominent role. Indeed, the recent trend of rehabilitating and strengthening unreinforced masonry reinforced with glass fibers. In this paper, the use of fiber-reinforced-mortars (FRMs) is proposed for construction rehabilitation and reconstruction applications. A single type of fiber (glass fiber) with different length is considered; short, long and mixed. Several specimens mortars reinforced with fibers are tested in compression and flexure. Also, the stack and the microstructure of the interface glass fibers-matrix cementitious of the reinforced specimen, was examined. The results showed a remarkable increase in the mechanical resistances (50%), an important reduction of the brittleness of the reinforced mortars (lengthening higher than 40%) and a good ductility. That made it possible to increase considerably the safety of our constructions with a better esthetic aspect
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    Effets des sulfates sur le comportement rhéologique des pâtes cimentaires
    (2009) Benmounah, A.; Samar, M.; Kheribet, R.; Saidi, M.; Safi, Brahim
    L’utilisation des adjuvants qui tend à se généraliser dans la formulation des bétons autoplaçants, nécessite la prise en compte de la composition chimique du ciment, et plus particulièrement de sa teneur en SO3 qui peut inhiber ou limiter l’action de ces adjuvants (superplastifiants). Dans le but d’apporter notre contribution à la compréhension de ces phénomènes dus à la présence de SO3 dans le ciment , nous nous proposons d’évaluer l’action de certains sulfates en incorporant des ajouts sulfatés de natures différentes, à la pâte de ciment. A cet effet, notre travail aura trait à l’étude des propriétés rhéologiques et des caractéristiques physiques des pâtes obtenues à base de deux types de ciment, en l’occurrence, le CPA et le CRS. L’expérimentation portera sur deux rapports : E/C =0,30 pour lequel le polynaphtalène sulfonate (PNS) est utilisé comme superplastifiant et E/C = 0,50 (sans superplastifiant). Les résultats obtenus montrent que la présence des sulfates entraîne des comportements rhéologiques différents qui sont fonctions de la nature des sulfates et des ciments utilisés
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    The fatigue flexural behavior of fiber reinforced concrete : effect of the parameters of coarse aggregates
    (Academic Journals, 2015) Dilmi, Hamid; Aribi, C.; Safi, Brahim; Bezzazi, Boudjema; Saidi, M.
    The effect of the coarse aggregate type on the fatigue flexural behavior of concrete was investigated in this work. Three types of the coarse aggregates were selected from three different careers (CA1, CA2 and CA3). The mechanical parameters of these aggregates were determined (Los Anglos and Micro Deval). Prismatic specimens (70×70×280 mm) for each concrete mixture were made with aggregates of each source. The flexural fatigue tests were conducted on these concrete samples with varying levels of loading of 55 to 80% and the ultimate flexural strength. The test frequency is around 80 Hz and it is automatically determined by pulsing the fatigue machine for a resonance situation (the phase shift is δ=0) between the mass-spring-specimen system. The obtained results show that the aggregates which have the similar parameters (Micro Deval and LA), provide better adhesion with cement paste, and therefore a greater bending strength. The strength evolution at short-term age is typical for specimens based on aggregates with low wear resistance by triturate (a high Micro Deval coefficient). Regarding the fatigue flexural behavior, the concrete specimens based on CA1, which have similar coefficients of Los Angeles and Micro Deval (respectively 18 and 16) present the behavior (load/cycle numbers) close to that of the model prototype of the Wöhler curve. This can be explained by a high homogeneity of the charge distribution during fatigue test compared to other concrete mixtures. Also, it was noted that the relationship between the endurance limit and the coefficient of Los Angeles is inversely proportional: The aggregates which have good strength to fragmentation (low coefficient of LA), as aggregates CA2 case give an endurance limit at around 70% max bending load
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    Impedance spectroscopy studies on steatite with B 2 O ceramics materials from Algerian palygorskite
    (International Institute for the Science of Sintering (IISS), 2021) Khalfaoui, K.; Boumchedda, K.; Chaouchi, A.; Saidi, M.; Lamrani, N.
    B2O3 was used to reduce the sintering temperature of steatite (named MSB) dielectric ceramics. Electrical properties of this composition have been studied using impedance spectroscopic method to get better understanding of the electrical conduction, dielectric relaxation mechanism, and microstructure –electrical properties relationship of the materials as a function of temperature and frequency. These samples were prepared by a solid-state reaction technique and their single phase formation was confirmed by the X-ray diffraction technique. Dielectric and complex impedance spectroscopic studies were carried out in a wide frequency (102-106 Hz) and temperature (30-500oC) range. The dielectric constants decrease with increasing frequency for each sample, and then stabilize at frequencies lower than 100 kHz. The dielectric constant increases with the addition of B2O3. The nature of frequency dependence of ac conductivity of MSB follows the Jonscher power law and calculated DC conductivity follows Arrhinius behavior. The Nyquist plot (Z″ vs Zʹ) revealed the presence only of the grain boundary effect from 350oC onwards. The occurrence of single arc in the complex modulus spectrum of MSB compositions confirms the single-phase characteristics, and also confirms the presence of non-Debye type of multiple relaxations in the material
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    Physico-chemical and rheological characterization of water-based mud in the presence of polymers
    (Springer, 2015) Safi, Brahim; Zarouri, S.; Chabane-Chaouache, R.; Saidi, M.; Benmounah, A.
    Under the geological conditions of wells and during the drilling operation, some of the water-based mud compositions are sometimes not effective for the drilling success of the oil wells (case of the oil wells in the south Algeria). For this, the aim of this study is to examine the influence of polymer types [carboxymethylcellulose (CMC) and polyanionic cellulose (PAC)] on the physico-chemical and rheological properties of water-based drilling muds. A mud samples were prepared with a polymers (PAC or CMC) according to mud formulations currently used in the wells drilling. The properties are controlled at such values that the mud provides optimum performance. For this purpose, the physico-chemical (pH, Pb: mud alkalinity) and rheological (apparent viscosity, yield point, and behavior rheological) were measured out on the studied muds. According to the obtained results, the rheological characteristics of studied muds (yield point and plastic viscosity) were clearly improved in the polymers presence. However, it should be noted that the PAC has given the better results compared to the CMC at a concentration of 8 g/l. By against in the temperature presence (hot rolling), the CMC is a good controller agent of mud filtrate compared to those containing the PAC for the same concentration
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    Rheology and zeta potential of cement pastes containing calcined silt and ground granulated blast-furnace slag
    (2011) Safi, Brahim; Benmounah, A.; Saidi, M.
    This study aimed to analyse the re-use of dam silt as a supplementary binder for self-compacting concrete (SCC). When burnt, silt becomes more reactive because the kaolin it contains is converted into metakaolin. Portland cement, calcined or burnt silt and ground granulated blast furnace slag were used in this research. Cement pastes were prepared with blends containing two or three of these materials. The replacement ratio for burnt silt in both cases was 10% and 20% by cement weight and the ratio for the slag was a constant 30% by weight of the blend. Rheological and zeta potential tests were conducted to evaluate paste electrokinetics and rheological behaviour. The findings showed that burnt silt is apt for use as an addition to cement for SCC manufacture
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    The use of plastic waste as fine aggregate in the self-compacting mortars : effect on physical and mechanical properties
    (Elsevier, 2013) Safi, Brahim; Saidi, M.; Aboutaleb, Djamila; Maallem, M.
    This work aims to study the possibility of recycling waste plastic (polyethylene terephthalate (PET) used for the bags manufacture) as a fine aggregate instead of sand in the manufacturing of the self-compacting mortars. For this, an experimental study was carried out to evaluate physical and mechanical properties of the self-compacting mortars (SCMs) with plastic wastes. The sand is substituted with the plastic waste at dosages (0%, 10%, 20%, 30% and 50% by weight of the sand).The physical (bulk density, porosity, water absorption and ultrasonic pulse velocity testing) and mechanical (bulk compressive and flexural strength) properties of SCMs were evaluated and a complementary study on micro-structural of the interface of cementitious matrix and plastic waste. The measurements of physical and mechanical properties show that, in term of the density for materials, the mortars with 50% of plastic waste give better results than other proportion of the waste. Those mortars have a mechanical strength acceptable for lightweight materials. According to results obtained a reduction of 15% and 33% for mortar containing 20–50% plastic waste. A microscopic study of the interfacial zone (plastic–binder) has shown that there is an adhesion between plastic and cement paste (case 28 days of hydration)