Journal of Materials and Engineering Structures

3-10

Authors: Mohamed Hassan, Ahmed Abdel Rahman, Alaa Sherif, Mostafa Osman, Asmaa Ahmed

Flat plates are favor structure systems usually used in parking garages and high-rise buildings due to its simplicity for construction. However, flat plates have some inherent structural problems, due to high shear stress surrounding the supporting columns which cause a catastrophic brittle type of failure called "Punching Shear Failure". Several solutions are used to avoid punching shear failure, including the use of drop panels or punching shear reinforcement. The latter is being a more sophisticated solution from the structural ductility, the architectural and the economical point of view. This study aims at investigating the effect of stirrups as shear reinforcement in enhancing the punching strength of interior slab-column connections. A total of four full-scale interior slab-column connections were tested up to failure. All slabs had a side length of 1700 mm and 160 mm thickness with 200 mm x 200 mm square column. The test parameters were the presence of shear reinforcement and stirrups concentration around the supporting column. The test results showed that the distribution of stirrups over the critical punching shear zone was an efficient solution to enhance not only the punching shear capacity but also the ductility of the connection. Furthermore, the concentrating of stirrups shear reinforcement in the vicinity of the column for the tested slabs increases the punching shear capacity by 13 % compared to the uniform distribution at same amount of shear reinforcement.

25-36

Authors: Rahul Sharma, Rizwan A Khan

An investigation is carried out on the development of Self Compacting Concrete (SCC) using copper slag (CS) as fine aggregates with partial and full replacement of sand. Six different SCC mixes (60% OPC and 40% Fly Ash) with 0% as control mix, 20%, 40%, 60%, 80% and 100% of copper slag substituting sand with constant w/b ratio of 0.45 were cast and tested for fresh properties of SCC. Compressive strength and splitting tensile strength were evaluated at different ages and microstructural analysis was observed at 120 days. It has been observed that the fluidity of SCC mixes was significantly enhanced with the increment of copper slag. The test results showed that the compressive strength increases up to 60% copper slag as replacement of sand, beyond which decrease in strength was observed. The highest compressive strength was obtained at 20% copper slag substitution at different curing ages among all the mixes, except for 7 days curing. The splitting tensile strength of the CS substituted mixes in comparison to control concrete was found to increase at all the curing ages but the remarkable achievement of strength was detected at 60% copper slag replacement. The microscopic view from Scanning electron microscopy (SEM) demonstrated more voids, capillary channels, and micro cracks with the increment of copper slag as substitution of sand as compared to the control mix.

51-61

Authors: Samuel Olufemi FOLAGBADE

In order to support the use of cement combination concrete in construction, this paper investigated the resistance of Portland cement and some binary and ternary cement concretes containing fly ash, silica fume and metakaolin to air permeability at equal water/cement ratios and strengths. At equal water/cement ratios, while fly ash binary cement concretes have higher coefficients of air permeability than Portland cement concrete due to delayed pozzolanic reactivity, silica fume and metakaolin binary cement concretes have comparable coefficients with Portland cement concrete due to their higher fineness, improved particle packing and higher pozzolanic reactivity. Consequently, the ternary cement concretes have coefficients comparable with that of Portland cement concrete. At equal strengths, while silica fume and metakaolin binary cement concretes have higher coefficients than Portland cement concrete, fly ash binary cement concretes have lower coefficients which reduced with increasing content of fly ash. Consequently, all the ternary cement concretes have lower coefficients which reduced with increasing total replacement level due to the beneficial effect of fly ash. Hence, high volume fly ash would be required to increase the resistance of concrete to air permeability at equal strength.

149-160

Authors: Houssam Khelalfa

Soil treatment by vibroflotation is a recent technique for improving soil with poor geo-mechanical properties. In addition, this treatment minimizes the risk of liquefaction and the instability of the caisson. This work allows us to establish a two-dimensional numerical simulation of a real vibroflotation test, based on our model and our hypothesis of modeling this mechanism in finite elements. On the other hand, the work consists in making a two-dimensional numerical study of the stability of the caisson carried out on the treated soil, in order to verify its influence on the stability of the structure. The calculation results will be compared with in-situ measurements to validate the numerical model.

167-180

Authors: Sudarshan D. Kore, A. K. Vyas

In the present study attempts have been made to obtain sustainable and cost effective concrete product by use of marble waste. Aggregate obtained from marble quarry waste was used as 75% part of coarse aggregate and rest was conventional coarse aggregate. It was observed that, compressive strength was almost same as that of the control concrete. Durability properties like permeability and chloride ion penetration improved by approximately 30% and 15%, respectively. Resistance to acids and carbonation were least affected. Cost comparison showed with 20% less cement requirement, 14% reduction in cost of concrete was achieved when marble waste was used with packing density approach for design of concrete mixes. By minimizing the cement content without losing mechanical and durability properties of concrete resulting in reduction of global cement production from 4.2 billion tons to 3.36 billion tons and correspondingly it reduces CO2 emission from 3.95 billion tons by 0.79 billion tons.

197-204

Authors: Abdulwahab Rasheed, Tunde Monsuru Akinleye

The high demand for sandcrete block for the development of physical infrastructures in Nigeria makes it important in building and construction industry. This research assessed three local methods of producing sandcrete blocks of sizes nine (9’’) and six (6’’) inches respectively. The methods used in producing the blocks were manual compaction, hand ramming and power operated method. Mix ratio of 1:9; a head pan of cement to nine head pans of sharp sand was used in all the methods. The materials (sand & cement) were thoroughly mixed until a homogenous mix with uniform color was obtained. Curing was done by sprinkling water on the specimens three times daily for 28 days and the compressive strength of the blocks was determined on the 7th, 14th, 21st, 28th days respectively. The study revealed that compaction has greater effect on the compressive strength of sandcrete blocks in the sense that blocks produced using vibrating machine has the highest compressive strength amongst the three methods.

95-106

Authors: Berrabah Hamza Madjid, Adda Bedia El Abbas, Zemri Amine

This study concerns the dynamic behavior of composite beams gradually evaluated through the thickness materials. Our work is devoted to the analysis of natural frequencies of composite beams FGM used in building structures in civil engineering often subjected to vibration loads due to earthquakes. The vibration characteristics of specific beams such as free and orthotropic fixed beams are studied without including deformation due to shear and rotational inertia. We introduce the effects of transverse deformation due to shear and rotational inertia for the accurate prediction of normal frequencies. An application to carbon nanotubes was investigated.

117-128

Authors: M. R. Sanjay, G. R. Arpitha, L. Laxmana Naik, K. Gopalakrishna, B. Yogesha

This research work has been focusing on Hemp fibers has an alternative reinforcement for fiber reinforced polymer composites due to its eco-friendly and biodegradable characteristics. This work has been carried out to evaluate the mechanical properties of hemp/E-glass fabrics reinforced polyester hybrid composites. Vacuum bagging method was used for the preparation of six different kinds of hemp/glass fabrics reinforced polyester composite laminates as per layering sequences. The tensile, flexural, impact and water absorption tests of these hybrid composites were carried out experimentally according to ASTM standards. It reveals that an addition of E-glass fabrics with hemp fabrics can increase the mechanical properties of composites and decrease the water absorption of the hybrid composites.

35-57

Authors: N Singh, S P Singh

The paper reviews the studies on one of the important durability properties of concrete i.e. Carbonation. One of the main causes of deterioration of concrete is carbonation, which occurs when carbon dioxide (CO2) penetrates the concrete’s porous system to create an environment with lower pH around the reinforcement in which corrosion can proceed. Carbonation is a major cause of degradation of concrete structures leading to expensive maintenance and conservation operations. Herein, the importance, process and effect of various parameters such as water/cement ratio, water/binder ratio, curing conditions, concrete cover, super plasticizers, type of aggregates, grade of concrete, porosity, contaminants, compaction, gas permeability, supplementary cementitious materials (SCMs)/ admixtures on the carbonation of concrete has been reviewed. Various methods for estimating the carbonation depth are also reported briefly

75-82

Authors: Mohamed Saad, Djamel Ouinas

Composite materials currently occupy an important place in all industrial sectors their sensitivity to the same impacts at low velocity raises some preoccupations to limit their scope .On the basis of a numerical simulation, the code of calculation Abaqus 6.14, was used to simulate the impact behavior to predict the damage to the fibers and the matrix of the composite structures subjected to any impact. This work deals with the evolution of the damage on the individual layers of a plate composite graphite / epoxy laminated [0m / 90n ] s composite under dynamic loading effect different velocity of the impactor and the evolution of the deformation energy as a result of different speeds of impact and the various layers of the composite structure.

2-13

Authors: Berrabah Hamza Madjid, Adda Bedia El Abbas, Tounsi Abdelouahed

In this study, non unified local shear deformation theory is proposed to consider the bending and buckling of nano beams. This theory is based on the assumption that the cross-sectional and planar displacements consist of bending and shear components, shear components do not contribute to the bending moments. Motion equations are derived using the Hamilton’s principle. Analytical solutions for deformation, buckling load, and the natural frequency are presented to a nano simply supported beam, and the results obtained are compared to those proposed by the nonlocal Timoshenko beam theory and Reddy beam theories.

23-33

Authors: Rabah Chaid, Laurent Molez, Malika Sabria Mansour, Aïssa Talah

This article is part of a summary of the work developed in conjunction with the Laboratory of Civil Engineering and Mechanical Engineering from INSA Rennes and Research Unit: Materials, Processes and Environment, University of Boumerdes. One of the objectives was indeed to promote, through studies of variants, the use of local cementitious additions in the formulation of high performance concretes (HPC). The binding contribution of mineral additions to the physical, mechanical and durability of concrete was evaluated by an experimental methodology to subjugate their original granular and pozzolanic effect. The results show that the contribution of couple cement - slag intensification of the matrix is higher than that obtained when the cement is not substituted by addition. Therefore, a significant improvement in performance of concretes was observed, despite the adverse action immersion cycles - drying maintained for 365 days.