Journal of Materials and Engineering Structures

333-346

Authors: S. Bawa, S.P. Singh

The paper presents the results of an investigation conducted to study the influence of fiber hybridization on the compressive strength, flexural strength, flexural fatigue and flexural toughness of the Hybrid Fiber Reinforced Self Compacting Concrete (HyFRSCC). The Steel Fibers (SF) and Polypropylene Fibers (PPF) at 1% by volume of concrete have been used. The PPF and SF proportions used are 100% PPF, 75% PPF + 25% SF, 50% PPF + 50% SF, 25% PPF + 75% SF and 100% SF. The flexural toughness parameters were calculated using procedure laid down in JCI Method, ASTM C-1018 C and ASTM 1609/C 1609 M. The flexural fatigue tests were conducted at stress levels of 0.65, 0.7, 0.75, 0.8, 0.85 and 0.9. The Weibull parameters have been calculated using the graphical method and the method of moments. The results indicate that the mix with a fiber combination of 25% PPF + 75% SF can be adjudged as the optimum combination for HyFRSCC in terms of compressive strength, flexural strength and flexural toughness. Gradual replacement of steel fibers with polypropylene fibers has been found to reduce the variability in fatigue life data of HyFRSCC.

355-370

Authors: Abdelhafid Nouali, Mohammed Matallah

Under seismic loading, some structural elements are subjected to combined solicitations (bending-shear for instance). The flexural ductility of a reinforced concrete element reduces its shear capacity. In fact, during plastic dissipation (by cracking), the transfer mechanisms of the shear force are impacted, which can lead to a brittle failure. The description of this interaction is based firstly on a good estimation of the flexural ductility. The bending behavior of reinforced concrete elements are influenced by the size effect. The objective of this work is to propose an approach for describing the flexure--shear interaction taking into account the size effect. Comparisons with experimentation show the capacity of the proposed approach to describe the above mentioned phenomena.

387-398

Authors: Ahmed Sahli, Fatiha Arab mohamed, Sara Sahli

This article has been retracted at the request of the Editors-in-Chief, according to the Publication Ethics Policy and Publication Malpractice Statement. Please see: http://revue.ummto.dz/index.php/JMES/about/editorialPolicies#custom-2 This note is published, 26 June 2020

419-426

Authors: Ajay Kumar Agarwal

It is very important to ensure that the fly ash produced, after adsorbing metal ions from aqueous solution, is disposed of in a manner that it does not adversely affect the environment. In this study, the used fly ash loaded with heavy metal ions is solidified with cement and sand mixture in a certain ratio. The studies reveal that cement solidified fly ash does not reduce the compressive strength of this mortar cube and also does not leach out the adsorbed metal ions in presence of water over a period of time. It makes cement solidified fly ash safe for use in various Civil Engineering purposes without adversely affecting the environment. The results of this study also suggest that fly ash may be a promising adsorbent for environmental technologies in the future.

223-236

Authors: Mohamed Saad, Djamel Ouinas

This paper deals with numerical analysis of dynamic behavior of a curvilinear graphite / epoxy composite shell under the effect of different impact loads at low speeds. Damage is assumed to initiate when one of Hashin’s failure criteria is satisfied, and its evolution is modeled by Mindlin’s Formulation with geometric non-linearity. This has been accomplished by developing a user defined subroutine and implementing it in the FE software ABAQUS. From strains supplied by ABAQUS the material subroutine uses a micromechanics approach based on the method of cells and values of material parameters of constituents to calculate average stresses in an FE, and checks for Hashin’s failure criteria. If damage has initiated in the material, the subroutine evaluates the damage developed, computes resulting stresses, and provides them to ABAQUS. The computed time histories of the impact loads acting are found to agree well with the numerical ones available in the literature, and various damage and failure modes agree qualitatively with those observed in tests.

253-268

Authors: Khaled Mansouri, Idir Belaidi, Abdelmalek Atia

The innovative architectures design of agile machines dedicated to the machining at high speed requires the implementation of analytical and numerical models for the optimization of the kinematic, static and dynamic behavior of the machine, taking into account the elastic deformations and their compensation at level of machine control. In the context of multi-objective optimization, the first part is to identify the parameters and variables inherent to each constituent element of a DELTA robot type machine, the purpose is to optimize the essential elements of its structure. This requires a formulation of the multi-objective problem by expressing the objective functions, the constraints and the corresponding search spaces, as well as the resolution of the problem by the use of high-performance mathematical methods and tools (genetic algorithms, etc.).

279-288

Authors: Tourkia Guerzou, Abdelkader Mebrouki, Joao Castro-Gomes

The aim of this study was concretes waste recovery by replacing natural aggregates (NA) by recycled aggregates (RA) at rates of 0%, 50% and 100%. Recycled aggregates coming from construction and demolition waste (CDW) present a low quality compared to natural aggregates, the water absorption being their main drawback. Quantities of water absorbed and their variations in times were measured according to the European standard (EN 1097-6). Adding absorbed water during mixing have caused concretes segregations and an excess volume of water was observed at the surface of the concrete. The added water was not totally absorbed by aggregates. The pre-saturation of aggregates 24 hours before mixing and introducing them as a component in concrete was the best method. The initially saturated aggregates did not consume concretes mixture water. Workability by slump test and mechanical strengths developed with pre-saturated aggregates (100 % RA) and (50% RA - 50% NA) were measured on concretes, and then were compared to those of the reference concretes made with 100 % of natural aggregates.

305-315

Authors: Mohammed el Amin Bourouis, Abdeldjalil Zadjaoui, Abdelkader Djedid

In the last decade, a number of empirical correlations have been proposed to connect the compression index to other soil parameters, such as liquid limit, plasticity index and the void index. This paper presents a correlation study between the physical properties and compression index which was conducted on normally consolidated clay by the hybridization of two approaches (artificial neuronal networks and genetic algorithms). A comparison was made between the measured experimentally and predictions compression indexes. The obtained results indicate that the Neuro-genetic model has the ability to accurately predict the compression index thus be used in practice by geotechnicians.

111-122

Authors: Florian Ion T. Petrescu, Relly Victoria Petrescu, MirMilad Mirsayar

Mechanical systems in motion type parallel structures are solid, fast and accurate. Between mobile systems parallel the best known and used system is that of a Stewart platforms, as being and the oldest system, quickly, solid and accurate. The paper presents a few main elements of the Stewart platforms. In the case where a motto element consists of a structure composed of two elements in a relative movement from the point of view of the train of propulsion and especially in the dynamic calculations, it is more convenient to represent the motto element as a single moving item. The paper presents an exact, original analytical geometry method for determining the kinematic and dynamic parameters of a parallel mobile structure. Compared with other methods already known, the presented method has the great advantage of being an exact analytical method of calculation and not one iterative-approximately.

137-151

Authors: K. Senthil, S. Rupali, Navjit Kaur

The numerical investigations has been carried out on reinforced concrete structures against blast loading to demonstrate the accuracy and effectiveness of the finite element based numerical models. The size of building was considered 3 ×3 × 3 m and whereas the size of beam and column was 0.3 m, arbitrary. The thickness of roof slab was 120 mm, whereas the reinforced concrete wall on all four sides was 0.2 m. The simulations were carried out through finite element code ABAQUS/CAE. The inelastic behavior of concrete has been incorporated through concrete damage plasticity model and the model includes compressive and tensile behavior. The elastic and plastic behavior of steel reinforcement bar has been incorporated using Johnson-cook model includes the effect of state of stress, temperature and strain rate. The simulations were carried out against varying standoff distance, mass of TNT, locations of blast origin and thickness of roof slab to examine the resistance of building. The response of structural elements were studied in light of deflection, impulsive velocity, von-Mises stresses, compression and tension damage of concrete. The results indicate that the standoff distance has great influence on the survivability of reinforced concrete slab and wall.

163-172

Authors: Hafida Marouf, Abdelaziz Semcha, Noureddine Mahmoudi, Nasreddine Bouhamou, Mahfoud Benzerzour, Walid Maherzi

The siltation as a natural phenomenon threatens the performance of harbors by reducing their docking volume compared to dams in terms of water storage, as well as their life span. An alarming rate of siltation is noted in the various basins requires an urgent cleaning operations. In a context of valorization of the sludge resulted from the dredging operations of the basins of the Oran’s port and those of the Bouhanifia’s dam which are located in Western Algeria, it is a question of studying possibilities which are offered by the use of these vases in the design of bricks building. The followed methodology is based on a physicochemical and mineralogical characterization of the two vases to reveal the one closest to the standards recommended for the manufacture of the baked brick. After analyzing sediments dredged in the port of Oran, it turned out that there is a dominance of sandy sediments, which are not recoverable in the areas of bricks we have targeted. Sustainability tests were performed on several sludge dam samples at different temperatures and percentages of water. The results gave a satisfaction in mechanical strength and durability for a firing temperature of 850 ° C and a percentage of water of 20%.

185-205

Authors: Praveen Kannam, Venkateswara Rao Sarella, Rathish Kumar Pancharathi

Of all the different kinds of failures in concrete, shear failure is a sudden and brittle and occurs abruptly without any prior warning. To avoid these types of failures in concrete, beams are traditionally reinforced with stirrups at closer spacing based on design. An experimental study was carried out to study the shear behavior of steel fiber reinforced self-compacting concrete (SCC) beams with recycled concrete aggregate (RCA) as a complete replacement of both natural coarse and fine aggregate. The experimental program consists of 24 beams of which 12 beams were cast with natural aggregate and remaining 12 beams were cast using recycled aggregates as a complete replacement of natural aggregates. Due to the use of recycled concrete aggregates as coarse and fine aggregates, the compressive strength reduced by 7.8% and 8% for 30 and 70 MPa Concrete. The ultimate shear strength reduced by 14% and 12% due to use of recycled concrete aggregates for SCC30 and SCC70 beams respectively. The investigation indicates that the ultimate load and ultimate shear strength decreases as the spacing of stirrups increased. It was observed from the experimental results that addition of steel fibers enhanced the mechanical properties of both natural aggregate based self-compacting concrete (NASCC) and recycled aggregate based self-compacting concrete (RASCC). Also due to the addition of steel fibers the performance of SCC beams has improved. The shear strength obtained experimentally was compared with the existing models in the literature and the correlation was found to be satisfactory

15-22

Authors: Rasheed Abdulwahab, Tunde Monsuru Akinleye, Hussein Sahid Taiye

Concrete is a versatile construction material comprising of cement, aggregates, water and occasionally admixture. It is very good in compression and weak in tension. To complement for the deficiency in the tensile zone; cracks, reinforcements (steel, fibre, etc.) have been found suitable. A good example of fibre is polypropylene. A concrete grade (M20) was batched and synthetic fibre (polypropylene) was used. Two categories of concrete specimens; with and without propylene fibre. The fibre was introduced in varying percentages (0.2%, 0.4%, and 0.6%) by weight of concrete. The compressive strength of concrete containing 0.4% polypropylene fibre at 28 days has the highest value of 32.22N/mm2 as compared to 30.22N/mm2, 30.49N/mm2 and 30.39N/mm2 for 0%, 0.2%, and 0.6% respectively. The splitting tensile strength at 7 days increases from 6.176 N/mm2 to 8.386 N/mm2 as the percentage of fibre increases from 0% to 0.4%.

33-45

Authors: Bachir Bouderba, Abdelrahmane Bekaddour Benyamina

The abrupt change in the properties of composite materials across the interface between different materials can cause strong inter-laminar stresses leading to delineation, cracking and other damage mechanisms. To remedy these defects, functional gradient materials (FGM), in which the properties of materials vary constantly, have been proposed. The purpose of this paper is to analyze the thermomechanical bending behavior of ceramic / metal thick plates (FGM). This work presents a model employing a new transverse shear function. The numerical results obtained by the present analysis are presented and compared with those available in the literature. It can be concluded that this theory is effective and simple for static analysis of FGM plates in thermal environments.

57-72

Authors: Taghreed Kh. Mohammad Ali

In this paper, the modulus of elasticity of lightweight concrete contains polyethylene terephthalate (PET) as fine, coarse aggregate and fiber was estimated by using experimental data from different literatures. The ratios of PET fiber range from 0.5% -1.5%. The modulus of elasticity increased by 8% for 0.5% PET fiber, and decreased by 45% when the concrete contains 1.5% PET fiber. The replacement of the fine or the coarse aggregate by using PET varies between 2.0% - 100%, and this caused decreasing the modulus of elasticity within range 1%-79%. This decreasing effected by shape and size of PET particles, strength of concrete, using of fly ash or silica fume, type of curing and ratio of aggregate to cement. More than 160 data sets, obtained by many investigators using various materials, have been collected and analyzed statistically to introduce the new formula of calculating the modulus of elasticity of concrete contained PET. The compressive strengths of the considered concretes range from 8.1 to 54 MPa. The modulus of elasticity of collected data range from 5.9 to 49 GPa. As a result, a practical equation, which is taken into consideration the ratio of PET as an aggregate or fiber, is proposed.

81-93

Authors: Souhila Benkaci, Dehbia Abir, Aziz Oumellal, Boualem Remini

The objective of this present work is to produce a synthetic distribution map of sensitivity degrees to erosion on the level of the high and middle Cheliff basin, by using the superposition model of cards “model builder” on ArcMapTM. The latter is exposed to a serious problem of soil degradation causes siltation of the majority of the dams distributed on his whole. Indeed, four classes of erosion vulnerability have been distinguished (weak, average, strong and very strong) where the strongly vulnerable areas cover the most part of the basin. The map produced provides an excellent decision-making tool for managers, in order to better target their preventive intervention strategies.