Publications Scientifiques
Permanent URI for this communityhttps://dspace.univ-boumerdes.dz/handle/123456789/10
Browse
11 results
Search Results
Item Effect of metakaolin as partially cement replacement on the compressive strength of standard mortars(2021) Amrane, Belaid; Souici, Khaled; Hami, Brahim; Kennouche, Salim; Safi, BrahimThis 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.Item Influence of superplasticizer doped by Nano-silica on the rheological and mechanical properties of cement mortars(2019) Daoui, Abdelhakim; Safi, Brahim; Zerizer, AbdellatifPrevious 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.Item Valorization of calcined kaolinitic clay used in high performance mortar(Université Omar Telidji de Laghouat, 2020) Mansour, S. M.; Ghernouti, Y.; Chaid, R.In this work, an experimental investigation was carried out to evaluate the potential of an industrial pozzolan, the metakaolin, on the behavior of mortar. The aim is to use metakaolin as a 10% partial replacement of cement. Its effect on the physico-mechanical properties of the mortar has been analyzed. The results show that the incorporation of metakaolin decreases the density of the dried mortar and increases that of the wet mortar but these remain lower than those of the control mortar. Moreover, thermal analysis ATD / ATG shows that in the heat flow curve appears two endothermic peaks which correspond to the loss of mass of the cement pastes. Heat flux of these pastes increases when metakaolin is used into the cement. In addition, metakaolin increases the compressive and flexural strengths of wet and dry mortars by approaching without exceeding those of the control mortar. The use of metakaolin as a cement substitution has shown its potential to be a pozzolanic material that can offer economic, environmental and technical benefits.Item Mechanical behavior and chemical durability of marble-based mortar: Application to panels subjected to punching(Elsevier, 2019) Chahour, Kahina; Safi, BrahimThe 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 controlItem Effects of calcined halloysite nano-clay on the mechanical properties and microstructure of low-clinker cement mortar(Elsevier, 2018) Allalou, Sara; Kheribet, Rabia; Benmounah, AbdelbakiThis paper explores the effects of calcined halloysite nano-clay (CHNC) on the physico-mechanical properties and microstructure of high volume slag (HVS) cement mortar. The principal objective of this research is to constitute a low-clinker cement mortar with high mechanical properties. Ordinary Portland cement clinker blended with 70% of ground granulated blast furnace slag (GBFS) was partially substituted with CHNC in ratios of 0%, 1%, 2%, 3%, 4%, 5% and 6% by weight. The results showed that the early age and long-term mechanical strengths of the slag cement mortars were significantly improved by the presence of CHNC. The slag cement containing 5 mass % of CHNC possessed the highest improvement of the mechanical properties and microstructure of hardened cement pastes and mortars. It was suggested that the higher pozzolanic activity of CHNC particles and the nucleation of calcium hydrosilicate (C–S–H) caused the enhanced strength developmentItem Use of refractory bricks as sand replacement in self-compacting mortar(Taylor & Francis Online, 2017) Aboutaleb, Djamila; Safi, Brahim; Chahour, Kahina; Belaid, AmraneThis 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)Item Use of wood waste (Aleppo pine) as a superplasticiser in self-compacting mortars(2014) Daoui, Abdelhakim; Safi, Brahim; Rezak, M.; Zerizer, A.Item Rheology of mortar and concrete containing mineral admixtures = Reologia zapraw i betonów z dodatkami mineralnymi(Foundation Cement, Lime, Concrete, 2013) Mansour, M.S.; Abadlia, Mohamed Tahar; Afalfiz, A.; Ladaoui, W.Item Study of calcined halloysite clay as pozzolanic material and its potential use in mortars(2012) Rabehi, B.; Boumchedda, K.; Ghernouti, Y.In this research, we will try to understand the mechanisms involved in the introduction of calcined clays in substitution for a portion of cement in the manufacture of mortars. This experimental work focuses on the recovery of a clay type haloysite quality three, from eastern Algeria. This clay comes from a region called Djbel Debbagh hence its name (DD3). The main objective of this study is to see the influence of the activated clay by calcination with different percentages of 5, 10, 15 and 20% in substitution of cement, on the physical-mechanical properties and behaviour of mortars towards chemical attacks. The study of pozzolanic activity allows to optimize a calcinations temperature of about 750°C, the study of its mechanical performance has shown an improvement of strength. Finaly the results of the durability test showed a good performance in different environmentsItem Strength and durability of mortar made with plastics bag waste (MPBW)(Springer, 2012) Ghernouti, Y.; Rabehi, B.The aim of this study is to explore the possibility of re-cycling a waste material that is now produced in large quantities, while achieving an improvement of the mechanical properties and durability of the mortar. This study examines the mechanical properties and the durability parameters of mortars incorporating plastics bag wastes (PBW) as fine aggregate by substitution of a variable percentage of sand (10, 20, 30 and 40 %). The influence of the PBW on the, compressive and flexural strength, drying shrinkage, fire resistance, sulfuric acid attack and chloride diffusion coefficient of the different mortars, has been investigated and analyzed in comparison to the control mortar. The results showed that the use of PBW enabled to reduce by 18–23 % the compressive strength of mortars containing 10 and 20 % of waste respectively, which remains always close to the reference mortar (made without waste). The replacement of sand by PBW in mortar slows down the penetration of chloride ions, improves the behavior of mortars in acidic medium and improves the sensitivity to cracking. The results of this investigation consolidate the idea of the use of PBW in the field of construction