Publications Scientifiques

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Author: search.filters.author.Safi, BrahimSubject: search.filters.subject.Mortar

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Now showing 1 - 6 of 6
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    Effect of metakaolin as partially cement replacement on the compressive strength of standard mortars
    (2021) Amrane, Belaid; Souici, Khaled; Hami, Brahim; Kennouche, Salim; Safi, Brahim
    This study presents the effect of incorporating synthesized metakaolin on the compressive strength of standard mortars for a constant water/binder ratio of 0.5. Synthesized metakaolin mixtures with cement replacement of 5, 10, 15 and 20% were tested. From the results, it was observed that 15 % replacement level was the optimum level in terms of compressive strength. Beyond 15 % replacement levels, the strength was decreased but remained higher than the control mixture. Compressive strength of 52 MPa was achieved at 15 % replacement. This investigation has shown that it is possible to produce high strength mortars using local kaolin.
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    Influence of superplasticizer doped by Nano-silica on the rheological and mechanical properties of cement mortars
    (2019) Daoui, Abdelhakim; Safi, Brahim; Zerizer, Abdellatif
    Previous research indicates that the inclusion of nanosilica (NS) modifies the properties of the fresh and hardened state, compared to the traditional mineral additions. Some authors estimate that the appropriate percentage of Nano-silica should be small because of difficulties caused by agglomeration to particles during mixing, while others indicate that 10% by weight, if adjustments are made to the formulation to avoid an excess of self-drying and micro cracks that could impede strength. For this purpose, the present work aim to see the effect of the introduction mode of the nanosilica on the rheological and physic mechanical properties of cement mortars. In this study, NS was used either powdered with cement or in solution with the superplasticizer (Superplasticizer doped in nanosilicafigure (a)). Results show that the use of nanosilica powder (replacing cement on the one hand) has a negative influence on the rheological parameters and the rheological behavior of cementitious pastes. However, the introduction of nanosilica in solution in thesuperplasticizer (SP) was significantly improved the rheological parameters and the rheological behavior of cementitious pastes. Indeed, more the dosage of NS-doped SP increases more the shear stress and viscosities of the cementitious pastes become more fluid and manageable. A significant reduction of shear stress and plastic viscosity were observed that due to the increase in superplasticizer. A dosage of 1.5% NS-doped SP gave adequate fluidity and the shear rate was lower.
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    Mechanical behavior and chemical durability of marble-based mortar: Application to panels subjected to punching
    (Elsevier, 2019) Chahour, Kahina; Safi, Brahim
    The main purpose of this paper is to use marble as sand in the mortar composition and to study the impact of natural sand replacement on mortar properties, such as mechanical strength, rheology and durability of different mortar mixtures at different curing ages up to 56 days. Natural sand (NS) was substituted by marble sand at different percentages (0%, 30%, 50%, 70% and 100% by weight of NS). The fresh property (workability), hardened properties (compressive, flexural and punching strength), compactness (ultrasonic wave speed) and durability (acid and water resistance) of the mortars studied were evaluated. A complementary study on mechanical behavior of panels elaborated with the studied mortars has been conducted; the test results have shown that mortar with 50% and 100% of substitution rate give better results for compactness, compressive and flexural strength. The punching strength obtained by the punching shear test has been significantly improved by the increase of natural sand substitution rate. However, panels carried out marble-based mortars with 70% of marble sand have given a punching strength similar to that obtained by control mortar panel (100% natural sand). This result has been also proven by the improvement of the mechanical behavior of slab made with 100% marble mortar. Results of durability estimated by acid attack have shown that loss in weight of mortar mixtures decreases with the increase of the percentage marble sand. Whereas, beyond 50% of marble sand content, water permeability increases compared to that of mortar control
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    Use of refractory bricks as sand replacement in self-compacting mortar
    (Taylor & Francis Online, 2017) Aboutaleb, Djamila; Safi, Brahim; Chahour, Kahina; Belaid, Amrane
    This present work investigate the possibility of using refractory bricks (RB) as fine aggregates (by partial and total substitution of natural sand) in self-compacting mortars (SMCs). For this, an experimental study was carried out to evaluate physical and mechanical properties ((bulk density, compressive and flexural strength) of the self-compacting mortars (SCMs) with partial and total substitution of natural sand (NS) by crushed refractory bricks (RB) at different ratio (BR/S= 0, 10, 30, 50 et 100%) by weight. The results obtained show that the RB (0/5 mm class), can be used as fine aggregates for self-compacting mortar, without affecting the essential properties of mortar. However, the performances of RB-based mortar (100% as sand), were better and are suitable for a fluid concrete (such as self- compacting concrete)
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    Use of wood waste (Aleppo pine) as a superplasticiser in self-compacting mortars
    (2014) Daoui, Abdelhakim; Safi, Brahim; Rezak, M.; Zerizer, A.
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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