Journal of Building Materials and Structures

j. build. mater. struct.

Description

Journal of Building Materials and Structures (JBMS) is an open access, peer-reviewed journal, published by the University Amar Telidji-Laghouat, with no publication fee that publishes, in English, in all areas of building materials and engineering structures. The journal welcomes the submission of manuscripts that meet the general criteria of significance and academic excellence. JBMS offers a meeting targeted for specialists around the world to publish and discuss all topics related to the building materials and structures. From 2019, JBMS will publish 04 issues per year. JBMS topics include, but are not limited to: research on elaboration and characterization of building materials, experimental techniques and microstructural properties and structural engineering.


5

Volumes

10

Numéros

54

Articles


Predicting Shear Strength of RC Columns Using Artificial Neural Networks

Said Aly,  Gordon Nicolas, 

Résumé: A primary objective in the seismic design of structures is to ensure that the capacity of individual members of a structure exceeds the associated demands. For reinforced concrete (RC) columns, several parameters involving steel and concrete material properties control behavior and strength. Furthermore, it is unrealistic to simply consider the shear strength calculation as the sum of concrete and steel contributions while accounting for axial force when, in fact, all those parameters are interacting. Consequently, it is challenging to reasonably estimate the shear capacity of a column while accounting for all the factors. This study investigates the viability of using artificial neural networks (ANN) to estimate the shear capacity of RC columns. Results from ANN are compared with both experimental values and calculated values, using semi-empirical and empirical formulas from the literature. Results show that ANNs are significantly accurate in predicting shear strength when trained with accurate experimental results, and meet or exceed the performance of existing empirical formulas. Accordingly, ANNs could be used in the future for analytical predictions of shear strength of RC members.

Mots clés: reinforced concrete, neural network, artificial intelligence, shear, seismic, columns


CORROSION BEHAVIOR OF REINFORCING STEEL IN CONCRETE ELEMENTS IN ALKLINE MEDIUM

Bourenane Nadjette,  Sedira Nora,  Hamlaoui Youcef, 

Résumé: Corrosion of steel in reinforcement concrete is complex. When chloride ions and oxygen reach reinforcing steel, corrosion is initiated. The deterioration process starts with expansions of the bare steel substrate thenafter cracks in the concrete are developed. The aim of this work is to determine firstly, through the electrochemical technic, the critical concentration of chloride ions which are responsible for the initiation of the dissolution step. Then, the effect of the external parameters on the rate of penetration of the chloride ions into the concrete are also evaluated. For this propose, the electrochemical bahavior of the steel of construction “E24” is studied in carbonate medium without and with different concentrations of chloride ions. The effetct of various parameters such as temperature, ions concentration and solution pH was also evaluated through the evolution of the open ncircuit potential, d.c polarisation measurment and electrochemical impedance spectroscopy. The d.c polarisation and EIS results shows that the addition of 0.5M CaCl2 (as critical concentration) to the saturated Ca(OH)2 solution, brings to a rapid and a continuoes dissolution of the susbstrate where after 3 hours of immersion time the whole surface of the susbtarte was covered the corrosion products. This is may be due to specific adsorption of Cl-. According to Raman, SEM and EDS analyses of the surface after immersion in the corrosive media, the composition of rust layer is mainly composed of -FeOOH, -FeOOH and -Fe2O3.

Mots clés: Reinforcing Steel; d.c polarization; SIE; alkaline medium; chloride ions


Behavior of Recycled Asphalt to the Fatigue

Bordjiba Abdelhak,  Guenfoud Hamza, 

Résumé: Climatic and traffic effects are the causes of aging of the surface layer of asphalt, which leads to the necessary renovation of the latter. The use of waste from the tread layer provides a viable and beneficial solution for the environment and the economy. However, this solution must meet the requirement of sustainable development, which necessitates that a road has a very long lifespan. In this study we investigated the performance of recycled asphalt in terms of fatigue (as an element of life-cycle control). All the formulas were tested by the fatigue test in order to define the influence of the proportions of the asphalt aggregates, penetrability of the new binder used, and the manufacturing temperature. The results obtained showed the relationship between the contribution binder (reproduced between the new binder and the old binder) and the fatigue resistance under the influence of the parameters that we have mentioned above. At the end an optimization study has been carried in order to determine exactly the doses required to formulate recycled asphalt resisted to fatigue, the optimization seeks to maximize the asphalt aggregates and minimized the temperature of manufacture with a class of the binder compatible.

Mots clés: Asphalt;fatigue; Binder; Environment; Penetrability


Analysis Static Bending for Functionally Graded Materials Plates (FGM) Using High Order Shear Deformation Theory

Merdaci S,  Boutaleb S,  Hellal H,  Benyoucef S, 

Résumé: In this paper, the analysis of the mechanical bending of functionally graded plates of a rectangular plate simply supported subjected to transverse static loading. in this work the refined high order theory is used and is presented. The number of unknown functions involved is reduced to merely four, as against five in other shear deformation theories. The developed models are variably consistent, have a strong similarity with the classical plate theory in many aspects, do not require correction to the shear factor, and give rise to variations transverse shear stresses such as transverse shear parabolically varies across the shear thickness and satisfies surface conditions without stresses. Equilibrium equations are obtained by applying the principle of virtual works. The mathematical expressions of the arrow, the stresses are obtained using Navies approach to solve the system of equilibrium equations. The influence of mechanical loading and the change of the parameter of the material on mechanical behavior of the plate P-FGM are represented by a numerical example. Numerical results obtained by the present theory are compared with available solutions, from which it can be concluded that the proposed theory is accurate and simple in analyzing the static bending behavior of functionally graded plates.

Mots clés: FGM ; Rectangular plate ; Bending ; High order theory RPT


MICROSTRUCTURAL STUDIES OF MATERIALS DD1 AND KT2 BY X-RAY DIFFRACTION

عبد الغاني العاقل, 

Résumé: In this work, we have studied two Kaolin .kaolin DD1which consists of two main phases (kaolinite and Halloysite) and Tamazert kaolin .kaolin KT2 whose main constituents are kaolinite, quartz and mica. Our choice was set on the component that is Kaolinite because of the existence of the latter in both kaolins. A correction of Lorentz-Polarization was carried out prior to the diffraction data, which has been achieved using LWL program dome. The true profile was extracted by this program. The methods used for the micro structural analysis of the present in the two Kaolins are the Warren - Averbach and the Williamson – Hall methods Scherrer's relationship has been applied in cases where the compound is devoid of strains. The study revealed that the kaolin Kaolinite DD1 is devoid of micro constraints. Which similar analysis has shown that the Kaolinite in KT2 incorporates the strains. This was confirmed by the Williamson - Hall method as well as Fourier analysis. The evaluation of strains in the Kaolinite of KT2 has been dome the method of Warren - Averbach and Williamson – Hall diagram. The average value of this constraint found by the first method us 0.15 and 0.21 by the second method gave. The average size of crystallites of the Kaolinite in DD1 was found between 29 Å and 230 Å. by the method of Warren - Averbach and about 118 Å by the method of Williamson - Hall. Range the second Kaolinite the Kaolinite KT2, the size obtained was respectively 98 Å and 130 Å using to by methods. The study of the size distribution showed that the dominant size of Kaolinite in DD1 and KT2 is about 40 Å (42%) and 58 Å (32%). respectively.

Mots clés: DRX, LWL methods, Crystallites size, microdéfomation, Williamson-Hall and Warren & Averbach methods.


Development of High Thermal Stability Geopolymer Composites Enhanced by Nano Metakaolin.

El Nagar Abdeen,  Khater Hisham, 

Résumé: This paper deals with study of thermal stability of geopolymer composites enhanced by nano metakaolin materials and exposed to high firing temperature up to 1000 °C. The main geopolymer made up of water cooled slag having various kaolin ratios. The activators used are Na2SiO3 and NaOH in the ratio of 3:3. The thermo-physical, micro-structural and mechanical properties of the geopolymers before and after the exposure to elevated temperatures of 300, 500, 600 800 and 1000 °C have been investigated. The fire shrinkage of the geopolymer specimens increased by increasing temperature up to 1000 oC. Also, the fire shrinkage increased slowly up to 500 °C. The mechanical strength of geopolymer specimens increased with temperature up to 500 oC. The good thermo-physical and mechanical properties for these geopolymer composites increase the possibility of vast application of these eco-friendly materials in construction sectors.

Mots clés: firing shrinkage, geopolymer composites, slag, kaolin, nano metakaolin.


Effect of natural pozzolan and calcined paper sludge as pozzolanic additions on the physicals and mechanicals properties of heat treated self-compacting mortars

Ghernouti Youcef,  Safi Brahim,  Rabehi Bahia, 

Résumé: The aim of this research work was to investigate the effect of thermal treatment on strength development of self-compacting mortars (SCMs) based on two pouzolanic materials: Natural Pozzolan and calcined paper waste sludge, were used in the binders of SCMs. To evaluate the effect of heat treatment, a serial of the specimens were exposed to room temperature and another serial were exposed to heating regime (at temperature 60°C for a period of 14 h). The fresh and hardened properties of all mortars were evaluated. the obtained result show that the mechanical strength at 14 days of all mortar treated are almost similar or sometimes better to those not treated mortars tested at 28 days, which reduces the curing time for precast elements.

Mots clés: Heat treatment ; self-compacting mortars ; pozolanic materials ; calcined paper sludge


FINITE ELEMENT MODELING OF STRENGTHENED BEAMS USING CFRP

Barour Sabiha,  Zergua Abdesselam, 

Résumé: Deteriorating and damage of some structural elements influence negatively their strength and the bearing capacity. However, it is necessary to take some measures improve structural performance. In this context, the composite material is often used to strengthen the damaged parts. This paper presents a model to analyse the effect of carbon fiber reinforced polymer strengthening of beams under four point bending. Finite element software ANSYS 12.0 has been used for modeling the beams by conducting non linear static analysis. The SOLID 65 and SHELL 181 elements have been used to, respectively; model the 3D concrete beams and the composite layer. Constitutive properties of different components (concrete and FRP) have been incorporated. The predicted Finite element analysis results for the load-midspan deflection are compared to the measured experimental data. Close agreement was found between the predicted and measured results at all stages of loading for both models developed.

Mots clés: Finite element analysis, modeling, strengthened, FRP.


Effect of thickness stretching on the natural frequencies of laminate-faced sandwich plates using a new layerwise model

بلعربي محمد وجدي,  تاتي عبد الوهاب,  خشعي عبد الحق, 

Résumé: The current work investigates the effect of thickness stretching on the natural frequencies of laminate-faced sandwich plates using new layerwise finite element model. The proposed model assumes higher-order displacement field for the core and first-order displacement field for the face sheets. Thanks for enforcing the continuity of the interlaminar displacement, the number of variables is independent of the number of layers. The consistent mass matrix and the element stiffness matrix are derived using the Hamilton’s principle. The performance and reliability of the proposed formulation are demonstrated by comparing the author’s results with those obtained using the three-dimensional elasticity theory, analytical solutions and other advanced finite element models.

Mots clés: Layerwise ; Finite element ; Sandwich plates ; Free vibration