Authors:Aboubakeur Boukhelkhal, Lakhdar Azzouz, Benabed Benchaa, Akram Salah E Belaidi Abstract: This research studies the effect of waste marble powder (WMP) as substitute of Portland cement on strength and durability of self-compacting concrete (SCC) in order to produce SCC with reduced impact environmental. For this purpose, five mixtures were designed in which four mixtures contained WMP at substitution levels of 5, 10, 15, 20%, and mixture included only the Portland cement as control mix. The realized tests are compressive strength at 3, 7 and 28 days, water capillary absorption, water absorption by immersion and sulfate attack. The results show a reduction in the compressive strength with increasing WMP content. The use of WMP was found to increase both of the water capillary absorption and water absorption by immersion. SCC containing WMP subjected to magnesium sulfate attack presented a lower expansion and higher resistance to sulfate aggressions. PubDate: 2018-02-19 Issue No:Vol. 4 (2018)
Authors:Mohamed Guendouz, Djamila Boukhelkhal Abstract: The large development in the consumption of rubber is observed in the recent years, which leads to an increase of the production of rubber related waste. Rubbers are not hazardous waste, but they constitute a hazard for both environment and health, in case of fire in storage sites. So, recycling appears as one of the best solutions for disposing of rubber waste.This paper presents an experimental investigation dealing with the valorisation of rubber waste, specifically rubber obtained from old shoes sole waste. The waste rubbers are used form (0/5 mm) to mixes as addition at percentage (10%, 20%, 30% and 40%) in sand concrete. The physical (workability, bulk density), mechanical (compressive and flexural strength) and thermal properties are studied and analysed.The results indicate that the incorporation of rubber waste particles in sand concrete contributes to increase the workability and reduce the bulk density of all studied sand concrete. The obtained results show that mechanical performance (compressive and flexural strength) decreases when the rubber content increases. Nevertheless, the presence of rubber aggregate leads to a significant reduction in thermal conductivity, which improves the thermal insulation performances of sand concrete. This study insures that reusing of recycled rubber waste in sand concrete gives a positive approach to reduce the cost of materials and solve some environmental problems. PubDate: 2018-02-19 Issue No:Vol. 4 (2018)
Authors:Sihem Latreche, Leila Sriti Abstract: The building envelope is the first barrier to protect against external climatic variations. Generally, it consists of two types of walls: opaque walls (walls and roof) and transparent walls (Windows). The design characteristics of the enclosure strongly affect the occupants' thermal comfort, as well as the building energy consumption. The constructive choices relating to structural elements, in particular, walls, roofing and openings are generally considered in the thermal exchanges between the building and its environment. In the present study, which is based on experimental analysis in the self-generated residential sector in Biskra (Algeria), where a warm and arid climate predominates, we aim to evaluate the thermal impact of certain architectural and constructive parameters that are specific to residential habitat self-produced in Biskra. This paper summarizes the main results obtained from an in situ measurement campaign that evaluated the essential parameters of thermal comfort such as ambient and surface temperature, air velocity, and humidity. These parameters were used as indicators to measure the impact of the envelope material characteristics on its climatic adaptability. This paper also presents some recommendations for optimizing the choice of building materials specific to the self-produced residential in order to improve its thermal performance while preserving the essentials of its specificities. PubDate: 2018-02-19 Issue No:Vol. 4 (2018)
Authors:Mohammed Touhami Gouasmi, Ahmed Soufiane Benosman, Taïbi Hamed Abstract: Plastic waste recycling for the development of new building materials, such as cementitious composites, appears to be one of the best solutions to get rid of this type of waste. This operation has many economic and ecological advantages. The present study proposes some solutions for the recovery of plastic waste from PET (polyethylene terephthalate) bottles in order to obtain, after heat treatment at 290 °C followed by step cooling, a light composite material (PET-siliceous sand) with a hardness close to that of natural rock. The structure of the material obtained is characterized first; then the effect of this composite, with different substitution rates of natural aggregate, on the behavior of an industrial screed is studied. Afterwards, some specific recommendations for the uses of this screed, and possibly of the composite itself, are given. Although the main effects of certain polymeric additives on the mechanical properties of mortars are known, the mechanisms that are responsible for these effects are not yet well understood. Techniques such FTIR, XRD, SEM and differential scanning calorimetry (DSC) are analytical tools that can be used for the characterization and expertise of this type of composites, particularly the industrial composite screeds. Results from the present article enabled us to state that the composition of the materials obtained remains qualitatively unchanged and that no chemical interaction was observed between the mineral species and the waste PET lightweight aggregate (WPLA) or the composite itself; in fact, no new compounds were formed. In addition, the differential scanning calorimetry (DSC) technique allowed us to conclude that the addition of WPLA has an influence on cement hydration. The thermo-mechanical characterization of WPLA made it possible to observe an excellent arrangement between the PET and siliceous sand. Therefore, the development of WPLA may be another solution for a number of applications in the field of eco-materials for construction and building. PubDate: 2018-02-19 Issue No:Vol. 4 (2018)
Authors:Hafida Bouchelaghem, Abderrezak Bezazi, Messaouada Boumaaza, Naziha Benzannache, Fabrizio Scarpa Abstract: Externally bonded reinforcement using Fiber Reinforced Polymer (FRP) is a good response to the concern represented by the need for rehabilitation of concrete structures. These techniques are more and more attractive because of their fast and low labour costs, very good strength to weight ratio, good fatigue properties, and non-corrosive characteristics of FRP. The present work is an experimental study investigating the mechanical behaviour under a uni-axial loading of short concrete columns reinforced by composite materials. These are constituted of glass fibers GFRP (bidirectional fabric of two surface densities 500 and 300 g/m2), carbon CFRP (unidirectional sheet of density per unit area of 230 g/m2) and polyester and epoxy resin respectively. The investigation aims at demonstrating the effectiveness of FRP reinforcement through highlighting the effect of thickness (FRP number of folds), the nature of the reinforcement (glass, carbon or Hybrid), and the orientation of the fibers. The axial lengths shortening along with the radial expansion are measured using the strain gauges glued to the outer surfaces of the composite jacket via a Wheatstone bridge. These measurements are saved to a PC through an acquisition card. The results obtained clearly show that the columns reinforced with CFRP folds allow an important increase in the compressive rupture stress in comparison with those reinforced with GFRP folds. The gains in compressive strength, in axial and in radial strains of the confined concrete with the different FRPs used are identified and quantified. It has further been demonstrated that the tested columns mechanisms depend strongly on the type of fiber reinforcements. PubDate: 2018-02-19 Issue No:Vol. 4 (2018)
Authors:Nabil Kazi Tani, Ahmed Soufiane Benosman, Hamed Taïbi, Mohamed Mouli Abstract: Composites mortars based on plastic aggregates are often considered as an innovative materials of the future because of their potential and the advantages they present. In this paper, a comparative study was carried out on the effect of magnesium sulfate MgSO4 (5%) attack on the durability of composite mortars modified by recycled polyethylene terephthalate (PET). Laboratory tests were accomplished on limestone sand and cement mortars where the blended Portland cement was partially replaced by various volume fractions of PET plastic aggregates. Mechanical properties measured on specimens were used to assess the changes in the compressive strengths of PET-mortar composites exposed to MgSO4 attack at different ages, mainly the Young modulus of elasticity. Based on experimental compressive tests on selected specimens and there densities, the evolution of static Young modulus of elasticity has been discussed in accordance to predicted models proposed by (ACI-318) and (BS-8110) codes of practice. In addition, a comparative analysis has been carried out for corrosion resistance coefficients K of referenced mortar to those modified with plastic aggregates. It can be noted that, the corrosion resistance coefficients decrease as much as composite specimens are exposed to MgSO4 corrosive medium. For the case of modified composites, the values of K based on predicted Young modulus before and after immersion are better than the ones calculated for the unmodified mortar. Therefore, ACI 318 prediction model is recommended code for design and investigation works related to reparation mortars, screeds, pavements…etc. Also, it can be concluded that adding PET plastic aggregates by volume to blend Portland cement act to improve the corrosive resistance of this cement against MgSO4 aggressive medium. PubDate: 2018-02-19 Issue No:Vol. 4 (2018)
Authors:Boumaaza Messaouada, Abderrezak Bezazi, Hafida Bouchelaghem, Naziha Benzannache, Sofiane Amziane, Fabrizio Scarpa Abstract: Nowadays, finding new approaches to attenuate the effects of the catastrophic shear failure mode for reinforced concrete beams is a major challenge. Generally the bending failure is ductile. It allows a redistribution of the stresses providing an early warning, whereas the rupture by shear is fragile and sudden which can lead to detrimental consequences for the structures. This research focuses on the repair of deep beams in reinforced concrete shear subjected to 4-point bending. After being preloaded at different levels of their ultimate loads, the beams are repaired by bonding a composite material made of an epoxy resin reinforced by glass fibers. The main objective of this study is to contribute to the mastery of a new method developed by the authors that consists by banding the cracks in critical zones in order to avoid fragile ruptures due to the shear force. This new technique led to better results in terms of mechanical properties when compared to conventional methods, notably the absence of the debonding of the composite found in the case of the repairs of the beams by bands or U-shaped composites. The feasibility, the performances and the behavior of the beams have been examined. The experimental approach adopted using this new technique has shown the influence of the type of loading on the fatigue behavior. In addition, the repair performed led to a considerable improvement in the fatigue durability of the preloaded beam. PubDate: 2018-02-19 Issue No:Vol. 4 (2018)
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