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Dr-Sameh Yehia

Suez University Faculty of Petroleum and Mining Engineering, Civil Engineering, Faculty Member

Helwan University - Faculty of Engineering, Civil department, Post-Doc

Misr International university, Department of Architecture, Faculty Member

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Dr. Sameh Yehia is an Egyptian author for different publications and books in the field of civil engineering (structural). He has work as an academic staff (faculty) member in many universities. You can visit him at:https://scholar.google.com/citations?user=dxZOr9wAAAAJ

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Papers by Dr-Sameh Yehia

Optimal Shape and Size of Holes in Hybrid Reinforced Concrete Beams

SVU-International Journal of Engineering Sciences and Applications, 2023

Hybrid reinforced concrete structures are efficient systems that include steel and fiber-reinforc... more Hybrid reinforced concrete structures are efficient systems that include steel and fiber-reinforced polymer (FRP) reinforcement advantages, which are called fiber steel reinforced concrete (FSRC). On the other hand, passing service pipes through creating holes in reinforced concrete (RC) beams completely changes their structural behavior. Besides, RC beams with holes require rigorous nonlinear finite element (NLFE) analysis which is not typically done by design engineers. The behavior of simply-supported FSRC beams (hybrid reinforced with basalt FRP (BFRP) and steel bars) having two end holes under the effect of four-point bending loading tests was investigated. Also, NLFE models were implemented in an extensive parametric study. The studied parameters included (1) hole shapes: circular, square, and rectangular shapes; (2) height/diameter: ho=0.2h, 0.3h, 0.4h, and 0.5h; and length: Lo=0.3h, 0.5h, 0.7h, and 1.0h (h: overall beam depth). Compared to a similar beam without holes, the holes produce reductions of up to 53%, 44%, 85%, 64%, and 58% in the beam's cracking load, ultimate strength, absorbed energy, post-cracking stiffness, and post-yield stiffness, respectively (the lowest in cases of circular holes). In order to obtain the beneficial behavior of FSRC beams, it is recommended to drill the beam with a hole size diameter of up to 0.4h and up to a hole size length of 0.3h for square holes. On the contrary, the effect of hybrid reinforcement gains less significant enhancement in the case of the rectangular holes.

The impact of using natural waste biopolymer cement on the properties of traditional/fibrous concrete

Innovative Infrastructure Solutions, 2023

The naturally occurring wastes contain a large number of active groups. In this study, shrimp she... more The naturally occurring wastes contain a large number of active groups. In this study, shrimp shell wastes were modified chemically to form chitosan. When mixing concrete with a natural polymer the result revealed a synergistic impact on the characteristics and functionality of the concrete structure. The formed chitosan was characterized by Fourier-Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Five concrete mixes were designed to achieve the study objective. For certain concrete mixes, admixtures such as a natural polymer (chitosan), and chemical (superplasticizer) were added with 0.05% by weight of the cement content. Those admixtures were added to study their behavior on the characteristics of the concrete mixes, and then compare test results with control concrete mixes. Also, the purpose of the experiment was expanded to study the impact of adding the admixtures to fibrous concrete, as this fibrous concrete faces interlocking due to steel fiber's presence in the fresh concrete mixture. The results indicated that concrete-embedded chitosan exhibited significant enhancement in the mechanical properties. Further, the surface shape of concrete was characterized by the presence of chitosan crystallites which spread and filled the spaces in the chitosan structure. Also, it's noted that chitosan can delay the rate of cement hydration to a small value, which may help in hot weathering concrete.

Strength of Hybrid Steel-BFRP Reinforced Concrete Beams with Openings in the D-Region Strengthened Internally and Externally

Buildings, MDPI, 2023

The opened beams always confused the designers due to the guidelines missing. In this research, s... more The opened beams always confused the designers due to the guidelines missing. In this research, six hybrid beams reinforced with mixed steel and basalt fiber-reinforced polymer (BFRP) bars and having constant cross-sections of 150 mm × 300 mm and a clear span of 1800 mm were cast and tested under a four-point loading setup. Generally, five beams had symmetrical rectangular openings with dimensions of 150 mm × 250 mm located at a distance of 250 mm (equivalent to the beam effective depth) from the beam support, while an additional solid beam served as a control. The studied parameters included the effect of using internal reinforcement (steel or BFRP bars) provided adjacent to the opening sides or by incorporating an external BFRP sheet around the opening corners. Also, double enhancement with internal steel reinforcement bars together with external strengthening BFRP sheet was investigated. The relevant results showed that the opened beam without enhancement lost 75% of the maximum load compared with the solid beam. Placing internal steel or BFRP bars around the openings increased the maximum load by 62% and 60%, respectively, compared to the non-enhanced opened beams. Using an external BFRP sheet to strengthen the opening corners of the beam enhanced the maximum load by 76% compared with the non-enhanced opened beam. Consequently, by combining both the internal steel reinforcement and external BFRP sheet around the openings, the maximum load increased by 137% compared with the non-enhanced opened beam. Ultimately, a numerical analysis of the three-dimensional finite element model was performed to confirm the experimental findings, and the relevant results showed compatibility correlations with the experimental ones. Also, the effect of various parameters such as BFRP reinforcement ratio and number of BFRP sheet layers around the openings was investigated by adapting the validated numerical model.

Short-Term Efficiency of Using Sustainable BFRP Bars in Post-Tensioning Systems for One-Way RC Slab

JES. Journal of Engineering Sciences

Basalt Fiber Reinforced Polymer (BFRP) bars are manufactured from sustainable natural materials. ... more Basalt Fiber Reinforced Polymer (BFRP) bars are manufactured from sustainable natural materials. BFRP Young's modulus constitutes weak performance to the serviceability limits in the structural reinforced concrete (RC) elements, but using post-tensioning systems controls the serviceability limits. Nine RC slabs were tested under a four-point bending scheme. However, the efficiency of using the BFRP posttensioning system bars as a main reinforcement of RC slabs was evaluated in two different stress levels of 10% and 50% of the rupture strength of the bars. Also, the near-surface mounted (NSM) external strengthening post-tensioning BFRP system by two different stress levels of 10% and 30% of the rupture strength was investigated. Additionally, the hybrid reinforcement performance of both steel and BFRP bars was studied. The relevant results showed that the posttensioning BFRP systems significantly enhanced the ultimate load and vertical deflection of the RC slabs if the stress level was 50% and 30% for the internally reinforced and externally strengthened slabs, respectively. BFRP bars in hybrid RC slabs achieved more energy absorption. At the same reinforcement area, the internal bonded BFRP bars can achieve a higher ultimate load than the unbonded external BFRP bars by 11%. Furthermore, the increment rate in prestressing losses for RC slabs with higher prestressing levels of BFRP bars was less than that of slabs with lower prestressing levels of BFRP bars. Consequently, the efficiency of the external post-tensioning system was 95.78% for the RC slab with a 50% stress level after 1000 hrs, and it's recommended as a design guideline.

Behavior and Correlations between different Mechanical Properties of Fly Ash-based Geopolymer Concrete

by Dr-Sameh Yehia and Sameh Yehia

SVU-International Journal of Engineering Sciences and Applications, 2023

Undoubtedly, the interest in using Geopolymer Concrete (GPC) recently speared. Hence, it's essent... more Undoubtedly, the interest in using Geopolymer Concrete (GPC) recently speared. Hence, it's essential to study the behavior of GPC. In the current research, the mechanical properties of GPC were studied to investigate the performance at the time interval of 28 days to 90 days. The study extended to include water absorption, water permeability, and sulfate attack tests. The experimental work program was conducted to cover the effect of the curing method (steamer with 60°C or warm air) in addition to the curing period (seven days or three days). Also, the bond strength was investigated between steel reinforcement bars and concrete. Furthermore, the GPC ingredients were captured internally using a scanning electron microscope (SEM) to analyze their integrity. The results showed that the recorded slump value of the GPC mixture was more than the conventional concrete (CC) mixture by 130%, afterward the GPC mixture became stickier, and hardening happened. The GPC mixtures achieved significant enhancement, and the strength was highly developed after 28 days more than CC, especially for GPC cured in a steamer at 60°C for seven days, which reached the limits of high-strength Geopolymer Concrete (HSGPC) after 90 days.

Short-Term Efficiency of Using Sustainable BFRP Bars in Post-Tensioning Systems for One-Way RC Slabs

JES Journal of Engineering Sciences , 2023

Basalt Fiber Reinforced Polymer (BFRP) bars are manufactured from sustainable natural materials. ... more Basalt Fiber Reinforced Polymer (BFRP) bars are manufactured from sustainable natural materials. BFRP Young's modulus constitutes weak performance to the serviceability limits in the structural reinforced concrete (RC) elements, but using post-tensioning systems controls the serviceability limits. Nine RC slabs were tested under a four-point bending scheme. However, the efficiency of using the BFRP posttensioning system bars as a main reinforcement of RC slabs was evaluated in two different stress levels of 10% and 50% of the rupture strength of the bars. Also, the near-surface mounted (NSM) external strengthening post-tensioning BFRP system by two different stress levels of 10% and 30% of the rupture strength was investigated. Additionally, the hybrid reinforcement performance of both steel and BFRP bars was studied. The relevant results showed that the posttensioning BFRP systems significantly enhanced the ultimate load and vertical deflection of the RC slabs if the stress level was 50% and 30% for the internally reinforced and externally strengthened slabs, respectively. BFRP bars in hybrid RC slabs achieved more energy absorption. At the same reinforcement area, the internal bonded BFRP bars can achieve a higher ultimate load than the unbonded external BFRP bars by 11%. Furthermore, the increment rate in prestressing losses for RC slabs with higher prestressing levels of BFRP bars was less than that of slabs with lower prestressing levels of BFRP bars. Consequently, the efficiency of the external post-tensioning system was 95.78% for the RC slab with a 50% stress level after 1000 hrs, and it's recommended as a design guideline.

Review on the Effect of Shear Connectors on Composite Deck Slabs

International Journal of Advanced Engineering, Management and Science, 2020

This paper presents a review on the effect of shear connectors on composite deck slabs. Composite... more This paper presents a review on the effect of shear connectors on composite deck slabs. Composite deck slabs consist of profile deck sheet and concrete. Several researchers have been studying the behaviour of composite slab but due to its complex behaviour yet it is not completely understood. The behaviour of composite slab directly depends on the deformability and contact strength. Here, some important literature reviews regarding composite slab behavior incorporating different profiles were discussed.

Flexural Behavior of Lightweight Polymer Concrete Slab Reinforced with Glass Fiber Reinforced Polymer Bars

by Dr-Sameh Yehia and Mayadah W. Falah

International Journal of Engineering Research & Technology (IJERT), 2022

The flexural behavior of polymer impregnated lightweight concrete reinforced with fiberglass-rein... more The flexural behavior of polymer impregnated lightweight concrete reinforced with fiberglass-reinforced polymer (GFRP) bars was examined in this research. The primary distinction between lightweight and regular concrete is the reduced density mass. Using lightweight concrete minimizes the structure's dead load, allowing the structural designer to shrink the size of the column, footing, and other load-bearing elements. Because lightweight concrete is non-structural, polyester is employed in structural engineering to create a new generation of lightweight concrete impregnated with polymer. In addition, to resist flexural and tensile stress, glass fiber reinforced polymer (GFRP) is used in slabs.

Behavior of Tensile Strength for Fibrous for Fibrous Geopolymer Concrete

Al-Azhar University Civil Engineering Research Magazine ( CERM ), 2022

The aim of this study is to achieve benefit from industrial waste locally in Egypt to produce Geo... more The aim of this study is to achieve benefit from industrial waste locally in Egypt to produce Geopolymer concrete (GPC) reinforced by steel fiber. Experimental program focused on the tensile behavior of GPC. The first stage is the study and testing of the mechanical properties of the materials used and casting conventual concrete with Portland cement, The second stage is the work and pouring of 9 mixtures of different quantities (200-300-400 kg/mᶾ) of geopolymer concrete only and mixed, reinforced with steel fiber with different ratio (1% - 2%).making (slump, compressive, flexure, splitting strength, modules of elasticity and micro structure test) at the age of 27 days on the all mixes, the results were analyzed and compared with ordinary concrete and geopolymer reinforced by steel fiber.

Effect of Sulphate Attack on Compressive Strength of Geopolymer Concrete

International Journal of Scientific & Engineering Research, 2022

Traditional Ordinary Portland cement concrete (OPC) was the second most used material next to the... more Traditional Ordinary Portland cement concrete (OPC) was the second most used material next to the water, despite its widespread use in construction, OPC is not environmentally beneficial due to its high energy consumption and CO2 emissions during production. The Endeavour to develop an environment-friendly concrete had offered many alternatives. Geopolymer is a binder that can act as an alternative to Portland cement. The utilization of Geopolymer concrete as an alternative material adds sustainability to the environment by reducing gas emissions associated with cement production. This paper was focused on the behavior of Geopolymer concrete exposure to sulfate attack. The main purpose of this study was to evaluate the effect of sulfate attack on the compressive strength of Geopolymer concrete with low calcium fly ash-based concrete, compared to ordinary Portland cement concrete with similar exposure. To achieve this goal, cubic samples of the dimension of 100x100x100 were cast for compressive strength for Geopolymer Concrete (GPC) and ordinary Portland Cement Concrete (OPC) mixes. The samples were immersed in magnesium sulfate solution at a concentration of 100 gm per liter for 90 days after curing, the GPC curing in a steamer at 60°C for three days and the OPC concrete was cured in water for 28 days. The test results of compressive strengths for GPC were 38.2 to 53 MPa and for OPC was 42.5.2 to 50.5 MPa, these values confirm the significant achievement for GPC performance in resisting sulfate attack.

Behavior of RC Beams Retrofitted/Strengthened With External Post-Tension System

This paper presents a study on the flexural behavior of strengthened RC beams using external post... more This paper presents a study on the flexural behavior of strengthened RC beams using external posttensioning technique under the effect of cyclic loads. Post tensioning techniques is a new method to improve the behavior of cracked and sound beams. This new technique was used in this research to improve the behavior of cracked and un-cracked beams. The study consists of two stages, the first stage is an experimental program which is carried out in lap to test casted beams, and the second stage is a theoretical program which was carried out to verify the results of experimental program. The behavior of RC beams in different levels of cracks was studied, crack pattern was observed and failure type was recorded. Comparisons between the behaviors of different RC beams were performed. The experimental study included using of prestressing steel bars, GFRP bars and the effect of different percentage of shear reinforcement was also taken into consideration. Specimens were tested under the eff...

Influence of Nano-Silica Addition on Properties of Fresh and Hardened Cement Mortar

The aim of this study is to investigate the influence of adding nano-silica particles, on the pro... more The aim of this study is to investigate the influence of adding nano-silica particles, on the properties of fresh and hardened cement mortar through measurements of workability, compressive and flexure strengths in addition to measuring by SEM analysis. Nano-silica particles with size of 19 nm have been used as a cement addition by 1, 3, 5, 7 and 10 % by weight of cement content. Results indicated that the cement mortar workability decrease with increasing nano-silica addition. On the other hand, the percentage of 7 % of nanosilica recorded as optimum percentage in compressive and flexure strength measured for cement mortar mixed with the nano-silica. The improvement in compressive and flexure strength measured as 55.7 % and 46.9 % respectively, compared with the conventional mortar, especially at early ages. In addition, the scanning electron microscope (SEM) analysis of the microstructures showed that the nano silica filled the cement paste pores, more homogeneity for cement paste...

Behavior of Fibrous Light Weight Concrete in Comparison to Traditional Fibrous Concrete

This paper presents a focused study on hardened properties of traditional fibrous concrete in com... more This paper presents a focused study on hardened properties of traditional fibrous concrete in comparison to fibrous light weight concrete. Fibrous concrete is made in order to achieve tangible improvement in mechanical properties of hardened concrete. It is now well established that, one of the important properties of steel fiber reinforced concrete (SFRC/SFRLWC) is to superior resistance to cracking and crack propagation. Using fibers in virgin concrete could be capable of transfer brittle failure mode of virgin concrete to semi-ductile failure mode. As a result of this ability to stitching cracks, fiber composites possess increased compressive strength, splitting tensile strength and flexural strength. An experimental program is established to obtain the optimum volume fraction for using steel fiber then study the effects of optimum steel fiber percentage on the traditional and light weight concrete. The experimental program consist of two phases, the first one focused on testing ...

3D-Modelling of Stratified Reinforced Concrete Slabs

1Professor, Faculty of Engineering, Helwan University, Egypt 2Associate Professor, Faculty of Eng... more 1Professor, Faculty of Engineering, Helwan University, Egypt 2Associate Professor, Faculty of Engineering, Suez University, Egypt 3Assistant Professor, Faculty of Engineering and Applied Sciences, Nile University, Egypt. 3Assistant Professor, Faculty of Engineering, Helwan University, Egypt 4PhD. Student, Dept. of civil Engineering, The higher institute of engineering at el shorouk city, Egypt. ---------------------------------------------------------------------***---------------------------------------------------------------------Abstract This study aims to present a suitable model for analyzing reinforced concrete slabs fabricated by stratified concrete using finite element method. Stratified Concrete consist of two or more types of concrete; in particular, of composite materials consisting of High Strength Concrete (HSC) (60MPa) and Normal Strength Concrete (NSC) (25MPa). A nonlinear three-dimensional finite element analysis has been used to conduct an analytical investigation ...

Certificate of Recognition (Reviewer)

Behavior Of Low Compressive Strength Short Columns Strengthened With External GFRP Strips/Jacket Techniques

This paper presents a study on behavior of short columns strengthened with GFRP techniques. Relat... more This paper presents a study on behavior of short columns strengthened with GFRP techniques. Relatively recent materials like fiber reinforced polymers (FRP), have been used to strengthen circular short columns. Glass fiber external sheets were used in the circumferential direction to confine circular columns. Six specimens were tested under an axial load. The main concentric purpose of this study is to evaluate the effect of GFRP confining with different techniques in strengthening deficient columns (low compressive strength concrete). This study achieved comparison between GFRP strengthened columns (strips/jacket) and control columns. Two techniques were used external confinement, using external strips of GFRP wraps and GFRP jackets. Test results revealed that the two techniques enhances the axial load carrying capacity of the columns significantly for both reinforced and unreinforced specimens. Test results, comparisons and analysis are shown herein.

An experimental and numerical study for investigating the promising stratified reinforced concrete slabs

It is well known that through the structural design, the safety and economic considerations of th... more It is well known that through the structural design, the safety and economic considerations of the project represent major factors, which must be always in mind. From this point of view, the concept and idea of “Stratified Concrete” were developed. Stratified Concrete consists of two or more types of concrete; in particular, composite materials consisting of High Strength Concrete (HSC) and Normal Strength Concrete (NSC). This study showed the flexural behavior for stratified sections (HSC-NSC) by taking a short time lap (1 h) between the two mixes to get a good bond between them. An experimental program was conducted to investigate the flexural behavior of NSC (25 MPa), HSC (60 MPa), and three HSC-NSC with the effect of changing the thickness of the HSC layer of slabs (20, 40, 75 mm) that had subjected to double static loads. As well, these slabs’ experimental results were numerically verified. The most important achievement is the success of the idea of casting different strengths...

Effect of Steel Fibers and GFRP Sheet on the Behavior of Lightweight Concrete Specimens Using Waste Lightweight Sand Bricks

International Journal of Engineering Research and

High performance traditional and optimized lightweight fibrous concrete was investigated by using... more High performance traditional and optimized lightweight fibrous concrete was investigated by using steel fibers and glass fiber reinforced polymer (GFRP) sheet, double action of Fibers. Basically, fibers could controlled the cracking of concrete, crack propagation and crack width. However, using fibers capable of enhancing failure mode of concrete to semiductile or ductile mode. Experimental work was consist of two phases, the first phase was focused on cast traditional fibrous concrete specimens in addition to control specimens to compare obtained results. These specimens were cubes, cylinders and prisms, which were tested after seven, fourteen and twenty eight days. Three percentages of round crimped (corrugated) steel fibers (0.5%, 1% and 1.5%) were used to get the optimum percentage. The second phase was concerned with cast lightweight concrete specimens by using the obtained optimum percentage of steel fibers. Specimens were cast by using waste lightweight sand bricks as an coarse aggregate (replacement percentage 50% of actual weight). The effect of strengthening with external GFRP sheet was studied for traditional and lightweight concrete specimens. The results confirmed that, steel fibers and GFRP sheet (external strengthening) increased the studied mechanical properties with competitive values in comparison to traditional concrete.

Low Cost Housing in Egypt by Using Stabilized Soil Bricks

International Journal of Civil, Mechanical and Energy Science

Residential housing is one of the major priorities in Egypt. The cost of apartment in different r... more Residential housing is one of the major priorities in Egypt. The cost of apartment in different regions can charge the person over budget money and per disability of people the slums appears with uncivilized environment. Construction material like cement consumes a lot of energy to produce final product which make an additional burden on state economy. This paper presents a simple technique to build low-cost housing by using new materials abundantly available in nature with low cost to improve sustainability and green energy. The compressive strength of compressed stabilized earth building bricks depends upon the soil type, amount of stabilizer and the compaction pressure used to form the bricks with dimension of 25x12x6cm. Experimental program was carried out on specimens and seven tests were applied. Each test consists of five masonry prisms assemblage cast with stabilized bricks. These tests are compressive strength, shear strength, in-plane tensile strength, and flexural tensile strength. The results are encouraging and promising to use these bricks in green constructions as low cost housing and national projects. A comparative study approved the cost effectiveness of using the stabilized bricks, as a load bearing wall system, instead of using the traditional skeleton structures by about 34% in case of one story building.

Efficiency of using Polymer Impregnated Porous Concrete in Structural Engineering Applications

International Journal of Current Engineering and Technology

This paper presents a focused study on properties of porous concrete to widen its application to ... more This paper presents a focused study on properties of porous concrete to widen its application to structural engineering. Mechanical properties like compressive strength, indirect tensile strength, flexural strength and physical properties like density, permeability and porosity are studied. To determine those parameters, twenty-seven cubes, cylinders and prisms were tested. Also, three polymer impregnated porous concrete slabs were tested under pure bending moment to study the efficiency of selected resin to integrate particle of concrete to achieve a new generation in using porous concrete in structural engineering. Three different cement content specimens of porous concrete were considered, studied cement contents are 200 kg/m 3 , 300 kg/m 3 and 400 kg/m 3. The results show that, increasing the cement content can increase the compressive strength, indirect tensile strength and flexural strength. Density of porous concrete is less than conventional concrete by 21% but permeability factor recorded higher value compared to conventional concrete by sixteen times. Increasing the cement content has no significant effect on either ultimate load or maximum deflection of polymer impregnated porous concrete slabs but the results recorded an achievement to use this concrete in structural engineering applications and give an easy way to cast special concrete like polymer concrete without special tools.

Optimal Shape and Size of Holes in Hybrid Reinforced Concrete Beams

SVU-International Journal of Engineering Sciences and Applications, 2023

Hybrid reinforced concrete structures are efficient systems that include steel and fiber-reinforc... more Hybrid reinforced concrete structures are efficient systems that include steel and fiber-reinforced polymer (FRP) reinforcement advantages, which are called fiber steel reinforced concrete (FSRC). On the other hand, passing service pipes through creating holes in reinforced concrete (RC) beams completely changes their structural behavior. Besides, RC beams with holes require rigorous nonlinear finite element (NLFE) analysis which is not typically done by design engineers. The behavior of simply-supported FSRC beams (hybrid reinforced with basalt FRP (BFRP) and steel bars) having two end holes under the effect of four-point bending loading tests was investigated. Also, NLFE models were implemented in an extensive parametric study. The studied parameters included (1) hole shapes: circular, square, and rectangular shapes; (2) height/diameter: ho=0.2h, 0.3h, 0.4h, and 0.5h; and length: Lo=0.3h, 0.5h, 0.7h, and 1.0h (h: overall beam depth). Compared to a similar beam without holes, the holes produce reductions of up to 53%, 44%, 85%, 64%, and 58% in the beam's cracking load, ultimate strength, absorbed energy, post-cracking stiffness, and post-yield stiffness, respectively (the lowest in cases of circular holes). In order to obtain the beneficial behavior of FSRC beams, it is recommended to drill the beam with a hole size diameter of up to 0.4h and up to a hole size length of 0.3h for square holes. On the contrary, the effect of hybrid reinforcement gains less significant enhancement in the case of the rectangular holes.

The impact of using natural waste biopolymer cement on the properties of traditional/fibrous concrete

Innovative Infrastructure Solutions, 2023

The naturally occurring wastes contain a large number of active groups. In this study, shrimp she... more The naturally occurring wastes contain a large number of active groups. In this study, shrimp shell wastes were modified chemically to form chitosan. When mixing concrete with a natural polymer the result revealed a synergistic impact on the characteristics and functionality of the concrete structure. The formed chitosan was characterized by Fourier-Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Five concrete mixes were designed to achieve the study objective. For certain concrete mixes, admixtures such as a natural polymer (chitosan), and chemical (superplasticizer) were added with 0.05% by weight of the cement content. Those admixtures were added to study their behavior on the characteristics of the concrete mixes, and then compare test results with control concrete mixes. Also, the purpose of the experiment was expanded to study the impact of adding the admixtures to fibrous concrete, as this fibrous concrete faces interlocking due to steel fiber's presence in the fresh concrete mixture. The results indicated that concrete-embedded chitosan exhibited significant enhancement in the mechanical properties. Further, the surface shape of concrete was characterized by the presence of chitosan crystallites which spread and filled the spaces in the chitosan structure. Also, it's noted that chitosan can delay the rate of cement hydration to a small value, which may help in hot weathering concrete.

Strength of Hybrid Steel-BFRP Reinforced Concrete Beams with Openings in the D-Region Strengthened Internally and Externally

Buildings, MDPI, 2023

The opened beams always confused the designers due to the guidelines missing. In this research, s... more The opened beams always confused the designers due to the guidelines missing. In this research, six hybrid beams reinforced with mixed steel and basalt fiber-reinforced polymer (BFRP) bars and having constant cross-sections of 150 mm × 300 mm and a clear span of 1800 mm were cast and tested under a four-point loading setup. Generally, five beams had symmetrical rectangular openings with dimensions of 150 mm × 250 mm located at a distance of 250 mm (equivalent to the beam effective depth) from the beam support, while an additional solid beam served as a control. The studied parameters included the effect of using internal reinforcement (steel or BFRP bars) provided adjacent to the opening sides or by incorporating an external BFRP sheet around the opening corners. Also, double enhancement with internal steel reinforcement bars together with external strengthening BFRP sheet was investigated. The relevant results showed that the opened beam without enhancement lost 75% of the maximum load compared with the solid beam. Placing internal steel or BFRP bars around the openings increased the maximum load by 62% and 60%, respectively, compared to the non-enhanced opened beams. Using an external BFRP sheet to strengthen the opening corners of the beam enhanced the maximum load by 76% compared with the non-enhanced opened beam. Consequently, by combining both the internal steel reinforcement and external BFRP sheet around the openings, the maximum load increased by 137% compared with the non-enhanced opened beam. Ultimately, a numerical analysis of the three-dimensional finite element model was performed to confirm the experimental findings, and the relevant results showed compatibility correlations with the experimental ones. Also, the effect of various parameters such as BFRP reinforcement ratio and number of BFRP sheet layers around the openings was investigated by adapting the validated numerical model.

Short-Term Efficiency of Using Sustainable BFRP Bars in Post-Tensioning Systems for One-Way RC Slab

JES. Journal of Engineering Sciences

Basalt Fiber Reinforced Polymer (BFRP) bars are manufactured from sustainable natural materials. ... more Basalt Fiber Reinforced Polymer (BFRP) bars are manufactured from sustainable natural materials. BFRP Young's modulus constitutes weak performance to the serviceability limits in the structural reinforced concrete (RC) elements, but using post-tensioning systems controls the serviceability limits. Nine RC slabs were tested under a four-point bending scheme. However, the efficiency of using the BFRP posttensioning system bars as a main reinforcement of RC slabs was evaluated in two different stress levels of 10% and 50% of the rupture strength of the bars. Also, the near-surface mounted (NSM) external strengthening post-tensioning BFRP system by two different stress levels of 10% and 30% of the rupture strength was investigated. Additionally, the hybrid reinforcement performance of both steel and BFRP bars was studied. The relevant results showed that the posttensioning BFRP systems significantly enhanced the ultimate load and vertical deflection of the RC slabs if the stress level was 50% and 30% for the internally reinforced and externally strengthened slabs, respectively. BFRP bars in hybrid RC slabs achieved more energy absorption. At the same reinforcement area, the internal bonded BFRP bars can achieve a higher ultimate load than the unbonded external BFRP bars by 11%. Furthermore, the increment rate in prestressing losses for RC slabs with higher prestressing levels of BFRP bars was less than that of slabs with lower prestressing levels of BFRP bars. Consequently, the efficiency of the external post-tensioning system was 95.78% for the RC slab with a 50% stress level after 1000 hrs, and it's recommended as a design guideline.

Behavior and Correlations between different Mechanical Properties of Fly Ash-based Geopolymer Concrete

by Dr-Sameh Yehia and Sameh Yehia

SVU-International Journal of Engineering Sciences and Applications, 2023

Undoubtedly, the interest in using Geopolymer Concrete (GPC) recently speared. Hence, it's essent... more Undoubtedly, the interest in using Geopolymer Concrete (GPC) recently speared. Hence, it's essential to study the behavior of GPC. In the current research, the mechanical properties of GPC were studied to investigate the performance at the time interval of 28 days to 90 days. The study extended to include water absorption, water permeability, and sulfate attack tests. The experimental work program was conducted to cover the effect of the curing method (steamer with 60°C or warm air) in addition to the curing period (seven days or three days). Also, the bond strength was investigated between steel reinforcement bars and concrete. Furthermore, the GPC ingredients were captured internally using a scanning electron microscope (SEM) to analyze their integrity. The results showed that the recorded slump value of the GPC mixture was more than the conventional concrete (CC) mixture by 130%, afterward the GPC mixture became stickier, and hardening happened. The GPC mixtures achieved significant enhancement, and the strength was highly developed after 28 days more than CC, especially for GPC cured in a steamer at 60°C for seven days, which reached the limits of high-strength Geopolymer Concrete (HSGPC) after 90 days.

Short-Term Efficiency of Using Sustainable BFRP Bars in Post-Tensioning Systems for One-Way RC Slabs

JES Journal of Engineering Sciences , 2023

Basalt Fiber Reinforced Polymer (BFRP) bars are manufactured from sustainable natural materials. ... more Basalt Fiber Reinforced Polymer (BFRP) bars are manufactured from sustainable natural materials. BFRP Young's modulus constitutes weak performance to the serviceability limits in the structural reinforced concrete (RC) elements, but using post-tensioning systems controls the serviceability limits. Nine RC slabs were tested under a four-point bending scheme. However, the efficiency of using the BFRP posttensioning system bars as a main reinforcement of RC slabs was evaluated in two different stress levels of 10% and 50% of the rupture strength of the bars. Also, the near-surface mounted (NSM) external strengthening post-tensioning BFRP system by two different stress levels of 10% and 30% of the rupture strength was investigated. Additionally, the hybrid reinforcement performance of both steel and BFRP bars was studied. The relevant results showed that the posttensioning BFRP systems significantly enhanced the ultimate load and vertical deflection of the RC slabs if the stress level was 50% and 30% for the internally reinforced and externally strengthened slabs, respectively. BFRP bars in hybrid RC slabs achieved more energy absorption. At the same reinforcement area, the internal bonded BFRP bars can achieve a higher ultimate load than the unbonded external BFRP bars by 11%. Furthermore, the increment rate in prestressing losses for RC slabs with higher prestressing levels of BFRP bars was less than that of slabs with lower prestressing levels of BFRP bars. Consequently, the efficiency of the external post-tensioning system was 95.78% for the RC slab with a 50% stress level after 1000 hrs, and it's recommended as a design guideline.

Review on the Effect of Shear Connectors on Composite Deck Slabs

International Journal of Advanced Engineering, Management and Science, 2020

This paper presents a review on the effect of shear connectors on composite deck slabs. Composite... more This paper presents a review on the effect of shear connectors on composite deck slabs. Composite deck slabs consist of profile deck sheet and concrete. Several researchers have been studying the behaviour of composite slab but due to its complex behaviour yet it is not completely understood. The behaviour of composite slab directly depends on the deformability and contact strength. Here, some important literature reviews regarding composite slab behavior incorporating different profiles were discussed.

Flexural Behavior of Lightweight Polymer Concrete Slab Reinforced with Glass Fiber Reinforced Polymer Bars

by Dr-Sameh Yehia and Mayadah W. Falah

International Journal of Engineering Research & Technology (IJERT), 2022

The flexural behavior of polymer impregnated lightweight concrete reinforced with fiberglass-rein... more The flexural behavior of polymer impregnated lightweight concrete reinforced with fiberglass-reinforced polymer (GFRP) bars was examined in this research. The primary distinction between lightweight and regular concrete is the reduced density mass. Using lightweight concrete minimizes the structure's dead load, allowing the structural designer to shrink the size of the column, footing, and other load-bearing elements. Because lightweight concrete is non-structural, polyester is employed in structural engineering to create a new generation of lightweight concrete impregnated with polymer. In addition, to resist flexural and tensile stress, glass fiber reinforced polymer (GFRP) is used in slabs.

Behavior of Tensile Strength for Fibrous for Fibrous Geopolymer Concrete

Al-Azhar University Civil Engineering Research Magazine ( CERM ), 2022

The aim of this study is to achieve benefit from industrial waste locally in Egypt to produce Geo... more The aim of this study is to achieve benefit from industrial waste locally in Egypt to produce Geopolymer concrete (GPC) reinforced by steel fiber. Experimental program focused on the tensile behavior of GPC. The first stage is the study and testing of the mechanical properties of the materials used and casting conventual concrete with Portland cement, The second stage is the work and pouring of 9 mixtures of different quantities (200-300-400 kg/mᶾ) of geopolymer concrete only and mixed, reinforced with steel fiber with different ratio (1% - 2%).making (slump, compressive, flexure, splitting strength, modules of elasticity and micro structure test) at the age of 27 days on the all mixes, the results were analyzed and compared with ordinary concrete and geopolymer reinforced by steel fiber.

Effect of Sulphate Attack on Compressive Strength of Geopolymer Concrete

International Journal of Scientific & Engineering Research, 2022

Traditional Ordinary Portland cement concrete (OPC) was the second most used material next to the... more Traditional Ordinary Portland cement concrete (OPC) was the second most used material next to the water, despite its widespread use in construction, OPC is not environmentally beneficial due to its high energy consumption and CO2 emissions during production. The Endeavour to develop an environment-friendly concrete had offered many alternatives. Geopolymer is a binder that can act as an alternative to Portland cement. The utilization of Geopolymer concrete as an alternative material adds sustainability to the environment by reducing gas emissions associated with cement production. This paper was focused on the behavior of Geopolymer concrete exposure to sulfate attack. The main purpose of this study was to evaluate the effect of sulfate attack on the compressive strength of Geopolymer concrete with low calcium fly ash-based concrete, compared to ordinary Portland cement concrete with similar exposure. To achieve this goal, cubic samples of the dimension of 100x100x100 were cast for compressive strength for Geopolymer Concrete (GPC) and ordinary Portland Cement Concrete (OPC) mixes. The samples were immersed in magnesium sulfate solution at a concentration of 100 gm per liter for 90 days after curing, the GPC curing in a steamer at 60°C for three days and the OPC concrete was cured in water for 28 days. The test results of compressive strengths for GPC were 38.2 to 53 MPa and for OPC was 42.5.2 to 50.5 MPa, these values confirm the significant achievement for GPC performance in resisting sulfate attack.

Behavior of RC Beams Retrofitted/Strengthened With External Post-Tension System

This paper presents a study on the flexural behavior of strengthened RC beams using external post... more This paper presents a study on the flexural behavior of strengthened RC beams using external posttensioning technique under the effect of cyclic loads. Post tensioning techniques is a new method to improve the behavior of cracked and sound beams. This new technique was used in this research to improve the behavior of cracked and un-cracked beams. The study consists of two stages, the first stage is an experimental program which is carried out in lap to test casted beams, and the second stage is a theoretical program which was carried out to verify the results of experimental program. The behavior of RC beams in different levels of cracks was studied, crack pattern was observed and failure type was recorded. Comparisons between the behaviors of different RC beams were performed. The experimental study included using of prestressing steel bars, GFRP bars and the effect of different percentage of shear reinforcement was also taken into consideration. Specimens were tested under the eff...

Influence of Nano-Silica Addition on Properties of Fresh and Hardened Cement Mortar

The aim of this study is to investigate the influence of adding nano-silica particles, on the pro... more The aim of this study is to investigate the influence of adding nano-silica particles, on the properties of fresh and hardened cement mortar through measurements of workability, compressive and flexure strengths in addition to measuring by SEM analysis. Nano-silica particles with size of 19 nm have been used as a cement addition by 1, 3, 5, 7 and 10 % by weight of cement content. Results indicated that the cement mortar workability decrease with increasing nano-silica addition. On the other hand, the percentage of 7 % of nanosilica recorded as optimum percentage in compressive and flexure strength measured for cement mortar mixed with the nano-silica. The improvement in compressive and flexure strength measured as 55.7 % and 46.9 % respectively, compared with the conventional mortar, especially at early ages. In addition, the scanning electron microscope (SEM) analysis of the microstructures showed that the nano silica filled the cement paste pores, more homogeneity for cement paste...

Behavior of Fibrous Light Weight Concrete in Comparison to Traditional Fibrous Concrete

This paper presents a focused study on hardened properties of traditional fibrous concrete in com... more This paper presents a focused study on hardened properties of traditional fibrous concrete in comparison to fibrous light weight concrete. Fibrous concrete is made in order to achieve tangible improvement in mechanical properties of hardened concrete. It is now well established that, one of the important properties of steel fiber reinforced concrete (SFRC/SFRLWC) is to superior resistance to cracking and crack propagation. Using fibers in virgin concrete could be capable of transfer brittle failure mode of virgin concrete to semi-ductile failure mode. As a result of this ability to stitching cracks, fiber composites possess increased compressive strength, splitting tensile strength and flexural strength. An experimental program is established to obtain the optimum volume fraction for using steel fiber then study the effects of optimum steel fiber percentage on the traditional and light weight concrete. The experimental program consist of two phases, the first one focused on testing ...

3D-Modelling of Stratified Reinforced Concrete Slabs

1Professor, Faculty of Engineering, Helwan University, Egypt 2Associate Professor, Faculty of Eng... more 1Professor, Faculty of Engineering, Helwan University, Egypt 2Associate Professor, Faculty of Engineering, Suez University, Egypt 3Assistant Professor, Faculty of Engineering and Applied Sciences, Nile University, Egypt. 3Assistant Professor, Faculty of Engineering, Helwan University, Egypt 4PhD. Student, Dept. of civil Engineering, The higher institute of engineering at el shorouk city, Egypt. ---------------------------------------------------------------------***---------------------------------------------------------------------Abstract This study aims to present a suitable model for analyzing reinforced concrete slabs fabricated by stratified concrete using finite element method. Stratified Concrete consist of two or more types of concrete; in particular, of composite materials consisting of High Strength Concrete (HSC) (60MPa) and Normal Strength Concrete (NSC) (25MPa). A nonlinear three-dimensional finite element analysis has been used to conduct an analytical investigation ...

Certificate of Recognition (Reviewer)

Behavior Of Low Compressive Strength Short Columns Strengthened With External GFRP Strips/Jacket Techniques

This paper presents a study on behavior of short columns strengthened with GFRP techniques. Relat... more This paper presents a study on behavior of short columns strengthened with GFRP techniques. Relatively recent materials like fiber reinforced polymers (FRP), have been used to strengthen circular short columns. Glass fiber external sheets were used in the circumferential direction to confine circular columns. Six specimens were tested under an axial load. The main concentric purpose of this study is to evaluate the effect of GFRP confining with different techniques in strengthening deficient columns (low compressive strength concrete). This study achieved comparison between GFRP strengthened columns (strips/jacket) and control columns. Two techniques were used external confinement, using external strips of GFRP wraps and GFRP jackets. Test results revealed that the two techniques enhances the axial load carrying capacity of the columns significantly for both reinforced and unreinforced specimens. Test results, comparisons and analysis are shown herein.

An experimental and numerical study for investigating the promising stratified reinforced concrete slabs

It is well known that through the structural design, the safety and economic considerations of th... more It is well known that through the structural design, the safety and economic considerations of the project represent major factors, which must be always in mind. From this point of view, the concept and idea of “Stratified Concrete” were developed. Stratified Concrete consists of two or more types of concrete; in particular, composite materials consisting of High Strength Concrete (HSC) and Normal Strength Concrete (NSC). This study showed the flexural behavior for stratified sections (HSC-NSC) by taking a short time lap (1 h) between the two mixes to get a good bond between them. An experimental program was conducted to investigate the flexural behavior of NSC (25 MPa), HSC (60 MPa), and three HSC-NSC with the effect of changing the thickness of the HSC layer of slabs (20, 40, 75 mm) that had subjected to double static loads. As well, these slabs’ experimental results were numerically verified. The most important achievement is the success of the idea of casting different strengths...

Effect of Steel Fibers and GFRP Sheet on the Behavior of Lightweight Concrete Specimens Using Waste Lightweight Sand Bricks

International Journal of Engineering Research and

High performance traditional and optimized lightweight fibrous concrete was investigated by using... more High performance traditional and optimized lightweight fibrous concrete was investigated by using steel fibers and glass fiber reinforced polymer (GFRP) sheet, double action of Fibers. Basically, fibers could controlled the cracking of concrete, crack propagation and crack width. However, using fibers capable of enhancing failure mode of concrete to semiductile or ductile mode. Experimental work was consist of two phases, the first phase was focused on cast traditional fibrous concrete specimens in addition to control specimens to compare obtained results. These specimens were cubes, cylinders and prisms, which were tested after seven, fourteen and twenty eight days. Three percentages of round crimped (corrugated) steel fibers (0.5%, 1% and 1.5%) were used to get the optimum percentage. The second phase was concerned with cast lightweight concrete specimens by using the obtained optimum percentage of steel fibers. Specimens were cast by using waste lightweight sand bricks as an coarse aggregate (replacement percentage 50% of actual weight). The effect of strengthening with external GFRP sheet was studied for traditional and lightweight concrete specimens. The results confirmed that, steel fibers and GFRP sheet (external strengthening) increased the studied mechanical properties with competitive values in comparison to traditional concrete.

Low Cost Housing in Egypt by Using Stabilized Soil Bricks

International Journal of Civil, Mechanical and Energy Science

Residential housing is one of the major priorities in Egypt. The cost of apartment in different r... more Residential housing is one of the major priorities in Egypt. The cost of apartment in different regions can charge the person over budget money and per disability of people the slums appears with uncivilized environment. Construction material like cement consumes a lot of energy to produce final product which make an additional burden on state economy. This paper presents a simple technique to build low-cost housing by using new materials abundantly available in nature with low cost to improve sustainability and green energy. The compressive strength of compressed stabilized earth building bricks depends upon the soil type, amount of stabilizer and the compaction pressure used to form the bricks with dimension of 25x12x6cm. Experimental program was carried out on specimens and seven tests were applied. Each test consists of five masonry prisms assemblage cast with stabilized bricks. These tests are compressive strength, shear strength, in-plane tensile strength, and flexural tensile strength. The results are encouraging and promising to use these bricks in green constructions as low cost housing and national projects. A comparative study approved the cost effectiveness of using the stabilized bricks, as a load bearing wall system, instead of using the traditional skeleton structures by about 34% in case of one story building.

Efficiency of using Polymer Impregnated Porous Concrete in Structural Engineering Applications

International Journal of Current Engineering and Technology

This paper presents a focused study on properties of porous concrete to widen its application to ... more This paper presents a focused study on properties of porous concrete to widen its application to structural engineering. Mechanical properties like compressive strength, indirect tensile strength, flexural strength and physical properties like density, permeability and porosity are studied. To determine those parameters, twenty-seven cubes, cylinders and prisms were tested. Also, three polymer impregnated porous concrete slabs were tested under pure bending moment to study the efficiency of selected resin to integrate particle of concrete to achieve a new generation in using porous concrete in structural engineering. Three different cement content specimens of porous concrete were considered, studied cement contents are 200 kg/m 3 , 300 kg/m 3 and 400 kg/m 3. The results show that, increasing the cement content can increase the compressive strength, indirect tensile strength and flexural strength. Density of porous concrete is less than conventional concrete by 21% but permeability factor recorded higher value compared to conventional concrete by sixteen times. Increasing the cement content has no significant effect on either ultimate load or maximum deflection of polymer impregnated porous concrete slabs but the results recorded an achievement to use this concrete in structural engineering applications and give an easy way to cast special concrete like polymer concrete without special tools.