Proceedings of the 4th International Symposium on Materials and Sustainable Development

The crude acid whey is a cheese rejection derived from the manufacture of soft cheeses and fresh dough, by its fermentable biomolecules; it represents a real factor of biological pollution of freshwater ecosystems (Wadi of Mina, Relizane, Algeria). Our study aims to analyze the effect of membrane treatment (ultrafiltration) on the physicochemical parameters (COD, turbidity, Brix, pH, salinity and electrical conductivity) and foaming properties (foaming capacity and diameter of air bubbles) of crude acid whey by applying physical, chemical and interfacial analysis methods. The results have shown that a variability has been noted for the physicochemical parameters COD(CAW: 1159 mg/l, PCAW: 525 mg/l and CCAW: 1355 mg/l), turbidity(CAW: 237.66NTU, PCAW: 0.86NTU and CCAW: 72.1NTU), Brix(CAW: 7.45%, PCAW: 5.8% and CCAW: 10%), pH(CAW: 4.6, PCAW: 4.6 and CCAW: 4.9), salinity(CAW: 3.58 g/l, PCAW: 3.95 g/l and CCAW: 3.77 g/l) and electrical conductivity(CAW: 5.8 mS/cm, PCAW: 6.39 mS/cm and CCAW: 6.4 mS/cm) and interfacial properties (foaming capacity and diameter of air bubbles) of crude acid whey and its fractions after ultrafiltration (concentrate and permeate). It is concluded from this study that the ultrafiltration of crude acid whey has changed its physicochemical and foaming behavior in function to the operating conditions and to the composition of the studied whey.

The CoSoTIA (Concentrated Solar Technologies for Industrial Applications) project initiated by the CRTI center in collaboration with the URMPE unit concerns the study and development of CSP solar concentrators for industrial applications. In the present work, we present decision support tools for the choice of a solar concentration technology for sites in Algeria. They will be used for the comparison between different technologies of solar concentration e.g.: cylindro-parabolic, parabolic, solar tower, etc. The models used include project costs and site characteristics; they incorporate also engineering knowledge (economic, social, technical and environmental). The information needed for decision-making produced by these tools is: the total cost of the project, indicators with economic, social, technical and environmental aspects. The case studies presented were conducted under the SAM Advisor environment, which was developed to evaluate the capacities to implement CSP project in order to produce expertise for the different actors through an application on a given site (by the client). Four case sites in Algeria and for two types of solar concentrator plant are studied and presented. A comparative study was conducted and for each site the best CSP was deduced and commented.

Nowadays, the choice of composite materials to manufacture medical orthopedic prostheses is largely accepted for its intrinsic resistance, ease of molding and machining, compatibility with human skin and also for economic aspects. Because of population aging and the need to repair broken or damaged human members, composite materials offer a very large variety of solutions to strongly satisfy such demands in the form of prostheses. These materials consist mainly of a consolidated resin reinforced with glass, carbon or natural fibers. Advantageous properties made them the most requested materials in the manufacturing of prosthetic devices for orthopedic use by people with movement disabilities. The present work considers a composite material made with carbon fibers, perlon (insulating layer) and an epoxy-based orthocyclic laminating resin. Both mechanical and morphological properties are analyzed. It is found that the composite made of carbon fibers/perlon/epoxy resin lower has lower mechanical resistance compared to carbon fiber/epoxy resin composite, but its adherence and its contact with human skin are ameliorated. For the fibrous reinforcements, carbon, glass or perlon, the mechanical properties on the proposed composite material (PVA- (C-4P-C) -PVA) are comparable to literature values. Based on uniaxial tensile tests, the elastic modulus is 626 MPa and the yield stress which is 57 MPa. Finally, SEM observations revealed that both composites exhibit similar damage mechanisms with higher intensity when perlon is present. This is due to the nature of the perlon in the composite material which exhibits more anisotropy. The main encountered damage mechanism is laminate decohesion which takes places between carbon plies and perlon. Such condition contributes to more interlaminar delamination and more brittleness of the material when subjected to high loads.

The article aims to study the mechanical properties of the studied concretes, namely sand concrete without lignocellulosic materials (SC), sand concrete lightened by barley straw which content is 15 kg/m³ (BSC), sand concrete lightened by barley straw and wood shavings which content is 35 kg/m³ (BWSC) and sand concrete lightened by wood shavings which content is 60 kg/m³ (WSC). The objective is to target the best composition of the three lightweight sand concretes, which constitutes the best compromise between the studied properties. The first part was devoted to study the mechanical properties, namely the flexural strength, compressive strength, elasticity modulus in flexion and elasticity modulus in compression. However, the second part was reserved to study the cracking analysis of studied concretes by video microscope in order to appreciate the lignocellulosic materials effect on toughness and ductility.

The results show that as the content of lignocellulosic materials increases, the mechanical properties decrease as was predictable. Another relation was found between the porosity accessible to water and the compressive strength of the studied concretes. This relation was defined according to a polynomial equation whose correlation coefficient approaches 1. The cracking analysis shows the advantageous barley straw effect, separate and in combination for cracking propagation compared to wood shavings alone. Nevertheless, the advantage is in favour of concrete (BSC), from the point of view of improving the deformation capacity of concrete, that is to say ductility and toughness, this is mainly due to the particularity of barley straw in terms of tensile strength, straw flexibility, geometric shape and surface appearance. This barley straw particularity is an advantage compared to the wood shavings, it may contribute favourably to improve the ductility and consequently to increase the propagation resistance of the crack.

The global annual production of plastics rose sharply from 1.5 up to 359 million tons during the period between the years 1950 and 2018. A large proportion of plastic products and goods, such as bottles of water and soda, food packaging, etc., are thrown away right after their first use, causing the generation of considerable amounts of post-consumer plastic waste. Reusing solid plastic wastes to produce other innovative materials, such as recycled plastic aggregate concrete, is considered as one of the most economical and cost-effective alternatives. This work is part of an ambitious sustainable development program. For this purpose, PVC waste is used in the form of aggregates (sand 0/3 and coarse aggregate 3/8) in the preparation of a number of concrete specimens. These plastic aggregates were used as partial replacement of natural aggregates at the following substitution rates: 25%, 50% and 75%. The experimental results obtained indicate that there is a difference between the physical and mechanical properties of plastic wastes-based concretes and those containing natural aggregates. The use of plastic aggregates in concrete improves the thermal insulation of concrete which can be considered as part of a construction solution, to improve a building’s thermal efficiency.

Algeria is the largest country in Africa by in terms of land area, which makes it contain large quantities of agricultural residues. The aim of this study is the valorisation of the huge amount of agricultural residue of date palm rachis available in Algeria to be used as reinforcement in bio-composite materials for various industrial applications. The analysis of the morphology of the of the date palm rachis cross-section allowed us to identify two main types of fibres according to their microstructure: vascular bundles and fibre strands. The chemical and molecular structure analysis of the date palm rachis fibres was examined by Fourier transform infrared spectroscopy (FTIR). The tensile properties of the fibre extracted were investigated under tensile loading test. The experimental results obtained for the tensile strength, Young’s modulus and strain at break of the fibres have been analysed, because of their dispersion, using three-parameter and two-parameter Weibull statistical laws. The tensile strength and Young’s modulus of the fibre strand were found to be about than four times higher than for the vascular bundle and their predicted model was determined. The tensile properties obtained for the investigated fibre were compared with other lignocelluloses fibres, existing in the literature, and it shows its great potential for use as reinforcement in bio-composite materials.

The reactive powder concretes (RPC) are new concretes with a particle diameter of not more than 600 μm and very high compressive, tensile strengths and an excellent durability. In this experimental investigation we study this new generation of micro-concretes, in obtaining high initial and final mechanical performances using local materials. The Portland cement, materials rich in silica (slag, silica fume and quartz) and new steel fibers’ aspect ratios has been reinforced the concrete RPC. Specimens’ preparation, curing regimes and testing procedures to evaluate the effect of heat treatment, steel fiber percentage compressive strength, flexural strength, deformability and modulus of elasticity of RPCFs were discussed. A compressive strength of 134 MPa, indirect tensile strength of 2.7 MPa, heting temperature of 90 °C, 2.5% steel fiber have been achieved for reinforced RPC contains 945 kg/m³ cement content and silica fume content 30% of cement weight. Also, the relationship between the relative value and the modulus of elasticity developed for a fiber-reinforced reactive concrete is greater than that of the unbound fiber. By eliminating the granular phase in the RPC and the abundance of dune sand (southern Algeria) and granulated slag, the use of RPC in Algeria with local materials meets economic and ecological requirements.

This article investigates the relationship between the initial matric suction and hydraulic conductivity (saturated and unsaturated) and the water retention curve were controlled during a laboratory test. Three materials were used during this study: bentonite and two types of geomaterials (tuff and crushed sand) for use as landfill liners. First, the mixture of 10% bentonite - 20% crushed sand - 70% tuff was selected on the basis of the minimum saturated hydraulic conductivity (k_sat) by oedometric and triaxial tests. The results showed that the effect of the initial variation in suction from 0.4 MPa to 1.5 MPa does not make a difference in the k_sat values; the values are between 10⁻⁸ m/s and 10⁻¹¹ m/s. Then, the effect of the initial suction on the water retention curve was studied using suction control methods. The water retention curves showed that the air entry value (AEV) increases with decreasing initial water content and that an AEV for micropores is about 40 MPa for all curves. The unsaturated hydraulic conductivity (K_w) study with different initial suction was measured with an original vapor equilibrium technique (VET). The results showed that the K_w varied between 3 × 10⁻¹⁷ m/s and 4 × 10⁻¹⁵ m/s in all cases of the initial suction over a 90-day period. In addition, the Van Genuchten hydraulic conductivity model is compared to the experimental results. Results measured showed a high affinity with the Van Genuchten model. This allows a k_w(s) function to be established over a large range of suction. Finally, the effect of the initial suction on the saturated and unsaturated hydraulic conductivity of this mixture is not apparent for the much lower (Sr > 80%, k = k_sat) and very high suction values, respectively.

An empirical study on the chemical characteristics, swelling characteristics, mineralogical characteristics, hydraulic conductivity, shear strength and unconfined compressive strength of compacted tuff /sandy soil/bentonite mixtures used as landfill lining is presented in this paper. Landfill leachate was used to determine the effect of pollution on the parameters of these mixtures for each experiment. To carry out this study, three materials, including bentonite and two types of soils, namely tuff and sandy wastes (crushed sand), were collected in the Laghouat - South Algerian region. A study of the geotechnical properties of all selected materials and mixtures was initially performed. X-ray diffraction (XRD) results showed that the dissolution of minerals and montmorillonite content modified by landfill leachate decreased swelling characteristics and slightly increased saturated hydraulic conductivity. The pH and electrical conductivity measurements of leachate contaminated mixtures revealed a decrease in pH values and an increase in electrical conductivity values. In terms of shear strength, it increased with increased crushed sand content. The shear strength of the previously contaminated optimal mixture showed an increase in cohesion (C_uu) and a decrease in the friction angle (φ_uu). The results of unconfined compressive strength at the age of 90 days reached 1400 kPa for mixtures containing 70% and 80% tuff. This strength develops with increased deposition of cementitious materials (CaCO₃). In addition, the unconfined compressive strength of the contaminated mixture was increased. According to the results, the mixture of 10% bentonite/20% crushed sand/70% tuff responds to the structural criteria for compacted soil liners.

The aim of this work is the isolation, identification, production, characterization and properties of biosurfactant producing fungal strain. The fungal strain FS11 was isolated from water oil field collected in southern Algeria and identified as Aspergillus sp. FS11. In an attempt to provide cost-effective carbon source for biosurfactants production, crude olive mill wastewater (OMW) was used as fermentative medium for 9 days under conditions of pH 5, temperature of 28 °C and agitation of 150 rpm. After cultivation period, the emulsification index value E₂₄ reached 76% and ST reduction from 72 to 42 ± 0.20 mN/m. TLC and FTIR analysis of the crude extract, showed that crude biosurfactant was partially characterized as glycolipoprotein complex. The crude biosurfactant presented interesting properties such us; significant reduction in surface tension, important emulsifying activity and stability over a wide range of pH (2 to 12), temperature (4–100 °C) and salinity (1–10%). More interestingly, the produced biosurfactant, have proved great potential application in MEOR microbial enhanced oil recovery (removal rate greater than 50%).

Fiber composite technology is based on taking advantage of the high strength and high stiffness of fibers, which are combined with matrix materials of similar/ dissimilar natures in various ways, creating inevitable interfaces. In fiber composites, both the fiber and the matrix retain their original physical and chemical identities, yet together they produce a combination of mechanical properties that cannot be achieved with either of the constituents acting alone, due to the presence of an interface between these two constituents. Fibre-matrix interface is known to have contribution to the mechanical performance of fibre-reinforced composite by its potential for load transfer between the fibre and the matrix. The understanding of the interface (or interphase) in composites is the central point of this interdisciplinary effort. In this work, we are interested in the qualitative study of the interface by the means of’ a micromechanical test, which defined by a behavior of a fiber embedded in a matrix block (test pull-out) to characterize the fiber/matrix interfacial adhesion solicited in traction. Initially, a theoretical study of the test is highlighted. Equations which give the evolution of the normal constraints to the level of the enchased filament and the sheath of matrix surrounding it, as well as the shear stress on the level of the interface are presented. In second place, we have to carry out a simulation of the mathematical equations under Matlab by varying the various parameters which present an influencing on the value of the interfacial shear stress, such as, the geometry of the model, embedded length of the fiber, fiber diameter and loading conditions, including components (fiber, matrix, interface). Curves are plotted and of interpretations are presented.

This paper presents an experimental study of the effect of mesoscopic buckles defect and shear deformation of the reinforcement, which result from shaping, on the low velocity impact behavior of a composite laminate. The material studied is a glass/polyester composite with three layers of mat and one layer of taffeta fabric. To assess the properties induced on the final composite, plates with calibrated defects and deformations were manufactured. Results of the impact tests and observations performed on the materials with calibrated defects identified a negative effect of buckling on elastic parameters and revealed greater damage relative to the healthy material. The reinforcement shear had a beneficial effect on the impact properties of the laminate, which was attributed to the increase in local fiber density.

Plaster is a building material widely used in finishing buildings work, known for its qualities, which allow it a growing demand in the construction market; it is a favorable material to protection of the environment, very malleable, low density, also its thermal and sound insulation, regulator of the hygrometry of the enclosures and decorative, but the fragility of plaster poses a problem in design of decorative pieces with a langue size dimension, which causes problems for the users; in this study the plaster will be reinforced by fiber from waste plastic and powder glass, by introducing ratio (1 and 2% for plastic fiber and 5 and 10% of glass powder) of the introducing volume of reference specimens plaster studied. The results shows the positive effect of the introducing the waste plastic fiber and glass, that the results shows increasing the values of stress in flexion testing of reinforcing plaster beams, and also improving of the fragile behavior, in the other hand including waste glass has improving too the density various comparing in to reference plaster beam.

Most of the old buildings in Algeria were built before the appearance of the Algerian seismic regulation. They were designed to resist the vertical loads without considering the impact of the earthquake. In this case, compliance with the RPA against the earthquake is necessary to ensure the safety of these structures. The solution adopted in the present research is the reinforcement by the insertion of reinforced concrete bracing shear walls in both directions of the structure. The objective of this article is the study of the influence of reinforcement on the strength of the resistance of the structure and the methodology of compliance with RPA 99 version 2003 of a building built before the appearance of the first Algerian seismic code RPA 81. The results obtained after reinforcement, from a Pushover analysis in terms of ductility demand µ_D, the elastic stiffness of the structure K_e, The stiffness performance point K_p and the global degradation indicator I_d show an increase in capacity in terms of displacement and shear force.

The depletion of natural deposits of aggregates and the difficulties to open new quarries make it necessary to look for new sources of supply. Recycling and waste recovery are now considered as an alternative solution in the future. Aggregates are considered essential components in the composition of ordinary concrete or concrete for specific use. Such utilization of recycled aggregates is of great importance from a technical and environmental point of view. The present study concerns the use of aggregates from the crushing of concrete waste as a replacement for natural aggregates with a sand of standardized particle size of determined fractions. An experimental program for the characterization of a local recycled concrete based on prepared sand was planned. Four types of concrete were formulated including a control concrete mixture with crushed aggregates, 8/16 recycled concrete gravel fraction and prepared sand. The substitution amount of the fine fraction of prepared sand was 15% for slag and 10% pozzolan as mineral additions. The principal objective of this research work is to study the effect of partial substitution of recycled aggregates on the physical and mechanical characteristics and on the resistance to aggressive environments of a local recycled concrete based on prepared sand. The results obtained show the positive effect of using a recycled local sand-based concrete on the mechanical properties of concrete while keeping an acceptable workability for the studied concrete mixtures.

Concreting in hot regions (eg. southern regions of Algeria) suffers from enormous difficulties in the conservation of materials, mixing, setting up, setting and hardening concrete. The consequences pose major short- and long-term problems, in terms of both fresh and hardened behavior, affecting the good performance and long-term performance of concrete, as well as its durability especially in aggressive environments. Coal waste in the Bechar region are abundant and a worrying waste. The incorporation of aggregates of waste is a recovery method and a contribution to environmental protection. This study was carried out to investigate the effects of temperature and coal waste (heap) addition on concrete strength under simulated hot weather conditions. The study consists of comparing the properties of a reference concrete with concretes incorporating aggregate of coal waste (heap) at six levels of heap as content (1, 2, 3, 4, 5 and 6% fine aggregate replacement) and two levels of temperature (25 and 50 °C). The simulation of the hot climate in the laboratory is subjected to temperature 50 °C with relative humidity of about 10%, wind speed at 10 km/h and E/C ratio constant between all mixtures. The results revealed that coal waste (heap) inclusion was more effective can be used for enhancement of properties of concrete. The optimum heap as content varied between 1 to 4%. However, the strength at higher temperatures was positively affected by inclusion of coal waste.

Modern technologies based on the exploitation of the typical thin film properties (adhesion, thermal stability, low porosity, desirable stoichiometry), have strongly developed to become one of the most essential industrial interests during recent years. TiN coatings, for example, usually used to edge retention and corrosion resistance on machine tools besides, it discovered applications in the nuclear industry as hard facing material mainly due to its high thermal stability. This work aims to develop and characterize, titanium nitride thin films deposited by the magnetron sputtering method on silicon and XC100 steel substrates, containing 1% wt. of carbon, under (N₂ and Ar) mixed atmosphere. The influence of nitrogen concentration on the structural, mechanical and tribological properties of the coatings was determined by EDS, DRX, AFM, MEB, Nano-indentation and alternative tribometer test. By varying the nitrogen flow rate from 0 to 20 sccm, it’s thus formed a titanium nitrides mixture (Ti₂N and TiN). The study’s interest in the mechanical behavior of titanium nitride films on this steel type, and in this range of nitrogen percentage, is particularly because the obtained hardness, and adhesion in this area are extremely important. Also, the deposited titanium thin films on the XC100 steel show that the hardness achievement in the inter-critical area is as important as that obtained in the uncoated XC100 due to the change in the phase’s proportion.