Journal of Materials and Engineering Structures

15-23

Authors: Kabiru MUSTAPHA, Sefiu Adekunle BELLO, Yiporo DANYUO, Tobi OSHIFOWORA

The roles of Composite materials in a variety of engineering applications have increased due to their enhanced strength and modulus, especially polymer-based composites which is one of the commercially available composites. The uniaxial tensile properties of polyethylene matrix reinforced with coconut coir fibers has been studied and the results from experiments and analytical models are presented. The compositional dependence of tensile strength, stiffness (elastic modulus), modulus of resilience and ductility are explored for different proportions of the constituent materials through experiments and analytical models. The results from experiments showed that the properties measured were greatly affected by the fiber mass fraction with optimized properties obtained at fiber content of 10 wt%.

39-51

Authors: Fouzia MOSTEFA, Nasr-Eddine BOUHAMOU, Salima AGGOUNE, Habib MESBAH

This work aims to study the feasibility of making a geopolymer cement based on dredged sediments, from the Fergoug dam (Algeria). Sedimentary clays were characterized before and after calcination by X-ray diffraction, thermogravimetric analysis (ATG / ATD), spectroscopy (FTIR) and XRF analysis. The reactivity of the calcined products was measured using isothermal calorimetric analysis (DSC) on pastes prepared by mixing an alkaline solution of sodium hydroxide (NaOH) 8 M in an amount allowing to have a Na / Al ratio close to 1. Also, cubic mortar samples were prepared with a ratio of liquid to binder not: 0.8. The results obtained allowed to optimize the calcination time of 5 hours for a better reactivity of these sediments, and a concentration of 8 M of sodium hydroxide and more suitable to have the best compressive strength. Our study offer great prospects for upgrading the sediments used as geopolymer cements in mortars

63-81

Authors: D.J.G. PINHEIRO, M.A.R. LOJA, I.C.J. BARBOSA, J. MILHO

The present research work intends to perform a wide set of structural analyses upon corrugated composite laminated panels and based on these analyses, to assess their mechanical response in correspondence to the constructive solutions, which may range from the composite materials selection to the geometrical features and other modelling parameters. To improve the mechanical performance of those panels one may consider enhancing their geometrical characteristics, their corrugation shape configuration and the materials used to build them. In this latter case, when considering materials selection, laminated composites may also constitute an important alternative. In any case it is considered necessary to assess the impact that each of these parameters may have in the static and in the free vibration behaviour of the structures, in a comprehensive and detailed way. To achieve the main objective of this research work, a comprehensive and diversified set of case studies is considered in order to characterize the influence that each of the modelling, material and geometrical parameters and characteristics may have in the mechanical response of a corrugated panel. This study allowed concluding that for the wide set of design parameters considered, the fibre orientation and corrugation parameters are the ones responsible for the majority of the significantly improved performances.

93-103

Authors: Parveen SIHAG, Munish KUMAR, Varun SINGH

High strength concrete (HCS) define as the concrete that meets unique mixture of performance uniformity requirements that cannot be reached routinely using conventional constituents and regular mixing, placing, and curing events. The modeling of such type of concrete is very difficult. In this investigation, the performance of the gaussian process (GP) regression, support vector Machine (SVM) and artificial neural network (ANN) were compared to estimate the 28th day compressive strength of the HSC. Total data set consists of 83 data out of which 70 % of total dataset used to train the model and residual 30% used to test the models. The model accuracy was depend upon the five performance evaluation parameter which were correlation coefficient (R), Bias, mean square error (MAE), root mean square error (RMSE) and Nash-Sutcliffe model efficiency (E). The results recommend that ANN model is more accurate to predict the compressive strength as compare to GP and SVM based models. Sensitivity analysis indicated that Cement (C), Silica fume (SF), Fly ash (FA) and Water (W) are the most valuable constituents in which compressive strength of the HCS is mainly depend for this data set.

119-126

Authors: TrongHa NGUYEN

Initial stiffness and moment resistance are two parameters that formed the hardness of the connection between columns and beams. This problem has been studied based on empirical of many authors in the world. In this research been used initial stiffness and moment resistance models the proposed model of Aleksander K., for reliability assessment of frame steel under the internal force of semi-rigid joints when random input parameters. A stochastic model for the design of frame steel considering semi-rigid and Monte Carlo reliability analysis. This program is written by using the Matlab programming language. Then, various numerical tests are performed to illustrate the studied method.

141-152

Authors: Faiza KLOUCHE, Karim BENDANI, Ahmed BENAMAR, Hanifi MISSOUM, Nadia LAREDJ

In civil engineering, electro-osmosis is a technique used as a means of dehydration, treatment of fine soils for the improvement and remediation. It is also used in agriculture for the desalinization of soils. In this study, the effect of electro-osmosis on the properties of a fine soil of the Ain Nouissy-Mostaganem region under a difference of electric potential was analyzed. The objective is to study the behavior of the water flow and the modification of some parameters, such as the electrical conductivity, the pH and the Atterberg limits during and after the electrokinetic process. These parameters make it possible to understand and control the performance of this technique with respect to the treatment under consideration. Soil heating during this process was approached through the surface temperature, indicating a loss of relative energy when the voltage gradient exceeds an optimal value.