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Portland cement concrete is known to have good fire resistance; however, its strength would be degraded after exposure to the temperatures of fire. Repeated low-velocity impacts are a type of probable accidental load in many types of structures. Although there is a rich body of literature on the residual mechanical properties of concrete after high temperature exposure, the residual repeated impact performance of concrete has still not been well explored. For this purpose, an experimental study was conducted in this work to evaluate the effect of high temperatures on the repeated impact strength of normal strength concrete. Seven identical concrete patches with six disc specimens each were cast and tested using the ACI 544-2R repeated impact setup at ambient temperature and after exposure to 100, 200, 300, 400, 500 and 500 °C. Similarly, six cubes and six prisms from each patch were used to evaluate the residual compressive and flexural strengths at the same conditions. Additionally, the scattering of the impact strength results was examined using three methods of the Weibull distribution, and the results are presented in terms of reliability. The test results show that the cracking and failure impact numbers of specimens heated to 100 °C reduced slightly by only 2.4 and 3.5%, respectively, while heating to higher temperatures deteriorated the impact resistance much faster than the compressive and flexural strengths. The percentage reduction in impact resistance at 600 °C was generally higher than 96%. It was also found that the deduction trend of the impact strength with temperature is more related to that of the flexural strength than the compressive strength. The test results also show that, within the limits of the adopted concrete type and conducted tests, the strength reduction after high temperature exposure is related to the percentage weight loss.
Raad A. Al-Ameri; Sallal R. Abid; G. Murali; Sajjad H. Ali; Mustafa Özakça. Residual Repeated Impact Strength of Concrete Exposed to Elevated Temperatures. Crystals 2021, 11, 941 .
AMA StyleRaad A. Al-Ameri, Sallal R. Abid, G. Murali, Sajjad H. Ali, Mustafa Özakça. Residual Repeated Impact Strength of Concrete Exposed to Elevated Temperatures. Crystals. 2021; 11 (8):941.
Chicago/Turabian StyleRaad A. Al-Ameri; Sallal R. Abid; G. Murali; Sajjad H. Ali; Mustafa Özakça. 2021. "Residual Repeated Impact Strength of Concrete Exposed to Elevated Temperatures." Crystals 11, no. 8: 941.
In this paper, 3D nonlinear finite element analyses (FEA) were conducted using the ABAQUS program to investigate the openings’ influences on voided slabs’ structural behaviors. In these FEAs, the quasi-static solution was adopted, and the concrete behavior was represented by the concrete damaged plasticity model (CDPM). CDPM parameters were calibrated versus voided slab's test results taken from the literature. The calibrated FEA model's efficiency to describe the opening effect was then verified by matching with external experimental observations of conventional slabs with openings. Finally, a parametric study was implemented, in which eleven slabs’ models with or without openings were contrasted. The considered variables were the size, shape, arrangement, and location of openings. The FEA results showed that the openings adversely affected the mechanical properties of voided slabs, and they became more influential as the interrupted reinforcement bars due to openings increased. However, constructing the opening near the support far away from the zone of high flexural stresses resulted in slight deteriorations in the strength, stiffness, and toughness of voided slabs.
Thaar S. Al-Gasham; Jasim M. Mhalhal; Sallal R. Abid. Quasi-static analysis of biaxial voided slabs with openings. Structures 2021, 33, 4176 -4192.
AMA StyleThaar S. Al-Gasham, Jasim M. Mhalhal, Sallal R. Abid. Quasi-static analysis of biaxial voided slabs with openings. Structures. 2021; 33 ():4176-4192.
Chicago/Turabian StyleThaar S. Al-Gasham; Jasim M. Mhalhal; Sallal R. Abid. 2021. "Quasi-static analysis of biaxial voided slabs with openings." Structures 33, no. : 4176-4192.
The use of expanded clay aggregate (ECA) for developing lightweight concrete results in strength-reduction properties. However, the ECA-based concrete strength properties can be improved by adding steel fibre (SF), glass fibre mesh (GFM) and multi-walled nano-carbon tubes (MWCNT). The combined effect of MWCNT, GFM, SF and ECA-based concrete and its strength properties is still unexplored. It is worth drawing a logical conclusion concerning the impact on the strength of concrete by incorporating the materials mentioned above. Two-stage expanded clay aggregate fibrous concrete (TECAFC) is a new concrete type and an emerging research area in material engineering. The casting method of TECAFC includes the two essential phases as follows. First, ECA and fibres are filled into the empty cylindrical mould to develop a natural skeleton. Second, the grout comprising cement, sand and MWCNT, are injected into the developed skeleton to fill voids. In this research, eight mixtures were prepared with 0.1 and 0.2% of MWCNT, 2.5% dosage of SF and three different layers of GFM inserted between the two layers of concrete. These eight mixtures were divided into two series of three mixtures each, in addition to two reference mixtures that include no SF or GFM. The first series of mixtures was comprised of 0.1% of MWCNT and 2.5% of SF and one, two and three layers of GFM insertion. The second series was the same as the first series and the dosage of MWCNT was taken as 0.2%. All cylindrical specimens were tested under drop mass impact as per the suggestions made by the ACI Committee 544. The test results showed that incorporating steel fibres and GFM improved the cracking and failure impact resistance by more than 270 and 1100%, respectively, and increased the impact ductility index by more than 220%, significantly contributing to steel fibres.
Gunasekaran Murali; Sallal Abid; Mugahed Amran; Roman Fediuk; Nikolai Vatin; Maria Karelina. Combined Effect of Multi-Walled Carbon Nanotubes, Steel Fibre and Glass Fibre Mesh on Novel Two-Stage Expanded Clay Aggregate Concrete against Impact Loading. Crystals 2021, 11, 720 .
AMA StyleGunasekaran Murali, Sallal Abid, Mugahed Amran, Roman Fediuk, Nikolai Vatin, Maria Karelina. Combined Effect of Multi-Walled Carbon Nanotubes, Steel Fibre and Glass Fibre Mesh on Novel Two-Stage Expanded Clay Aggregate Concrete against Impact Loading. Crystals. 2021; 11 (7):720.
Chicago/Turabian StyleGunasekaran Murali; Sallal Abid; Mugahed Amran; Roman Fediuk; Nikolai Vatin; Maria Karelina. 2021. "Combined Effect of Multi-Walled Carbon Nanotubes, Steel Fibre and Glass Fibre Mesh on Novel Two-Stage Expanded Clay Aggregate Concrete against Impact Loading." Crystals 11, no. 7: 720.
A full-scale 3D thermo-mechanical Finite Element (FE) model was conducted in this research to investigate the effect of open-field thermal loads on the structural response of box-girder bridges. A box-girder bridge with a span of 50 m was analyzed for temperature, radiation and displacement fields using COMSOL Multiphysics. To verify the FE model, a full-scale experimental box-girder segment was constructed and instrumented with temperature, radiation and other sensors. From the experimental records, three days with extreme temperature and radiation measurements were selected. The stresses and displacements are discussed at specific points along the 24 h of the selected days and at specific times along critical sections. The FE analysis showed that the vertical and lateral stress distributions exhibited approximately similar behaviors to their corresponding temperature distributions with minor differences but with reversed sign. The results also showed that the maximum stress was compressive, which was −3.35 MPa in summer −3.83 MPa in winter. On the other hand, the maximum vertical and lateral displacements were 12.5 and 1.2 mm, respectively in summer and 2.7 and 1.9 mm in winter.
Sallal.R. Abid; Nildem Tayşi; Mustafa Özakça; Junqing Xue; Bruno Briseghella. Finite element thermo-mechanical analysis of concrete box-girders. Structures 2021, 33, 2424 -2444.
AMA StyleSallal.R. Abid, Nildem Tayşi, Mustafa Özakça, Junqing Xue, Bruno Briseghella. Finite element thermo-mechanical analysis of concrete box-girders. Structures. 2021; 33 ():2424-2444.
Chicago/Turabian StyleSallal.R. Abid; Nildem Tayşi; Mustafa Özakça; Junqing Xue; Bruno Briseghella. 2021. "Finite element thermo-mechanical analysis of concrete box-girders." Structures 33, no. : 2424-2444.
Twelve ECC beams with three different fiber types, along with four normal concrete beams, were tested in this study to evaluate the influence of cross-sectional hollowing on their flexural performance. The fiber types used were nylon monofilament (NM), low-cost untreated polyvinyl alcohol (PVA), and polypropylene (PP). Three different square hole sizes of 60, 80, and 100 mm with cross-sectional hollowing ratios of 0.16, 0.28, and 0.44, respectively, were adopted for each group of beams in addition to a solid beam. All beams were tested under four-point loading using a displacement-controlled testing machine. The test results showed that ECC beams can mostly withstand higher cracking and ultimate loads compared to their corresponding normal concrete versions. The results also showed that both the ductility and toughness of the ECC beams are higher than those of the normal concrete beams and that the ductility values of the hollow beams with a hole size of 60 mm are higher than those of the corresponding solid beams. Moreover, hollow ECC beams with hole sizes of 60 and 80 mm exhibited a higher ductility than a solid normal concrete beam.
Ahmmad A. Abbas; Farid H. Arna ’Ot; Sallal R. Abid; Mustafa Özakça. Flexural behavior of ECC hollow beams incorporating different synthetic fibers. Frontiers of Structural and Civil Engineering 2021, 15, 399 -411.
AMA StyleAhmmad A. Abbas, Farid H. Arna ’Ot, Sallal R. Abid, Mustafa Özakça. Flexural behavior of ECC hollow beams incorporating different synthetic fibers. Frontiers of Structural and Civil Engineering. 2021; 15 (2):399-411.
Chicago/Turabian StyleAhmmad A. Abbas; Farid H. Arna ’Ot; Sallal R. Abid; Mustafa Özakça. 2021. "Flexural behavior of ECC hollow beams incorporating different synthetic fibers." Frontiers of Structural and Civil Engineering 15, no. 2: 399-411.
Based on experimental records from a composite beam with a steel section and topping concrete flange, a finite element thermal analysis model was conducted and verified. The experimental beam was provided with 14 embedded and surface temperature sensors inside the concrete flange and on the steel section. The temperature records from the experimental beam were collected for two winter months. The finite element thermal model was conducted to simulate the thermal response of composite beams under the influence of open-field thermal conditions. The model solves for the conduction of heat in concrete and steel considering the different boundary conditions that include; solar radiation, reflected radiation, temperature of air and the speed of the ambient air. To verify the introduced thermal model, the predicted temperatures at the 14 thermocouples were compared with the experimental ones along the 24 hours of three days with different weather conditions. The comparisons showed that for the three days, the model could capture the temperature-time behavior accurately for all thermocouples with moderately low average absolute errors of 0.4 to 2.0 °C. Another notice was that the maximum errors in the steel section were higher than in concrete.
Faten I. Mussa; Sallal R. Abid; Nildem Tayşi. Design Temperatures for Composite Concrete-Steel Girders: A-Verification of the Finite Element Model. IOP Conference Series: Materials Science and Engineering 2021, 1090, 012108 .
AMA StyleFaten I. Mussa, Sallal R. Abid, Nildem Tayşi. Design Temperatures for Composite Concrete-Steel Girders: A-Verification of the Finite Element Model. IOP Conference Series: Materials Science and Engineering. 2021; 1090 (1):012108.
Chicago/Turabian StyleFaten I. Mussa; Sallal R. Abid; Nildem Tayşi. 2021. "Design Temperatures for Composite Concrete-Steel Girders: A-Verification of the Finite Element Model." IOP Conference Series: Materials Science and Engineering 1090, no. 1: 012108.
Long-term metrological records for Adana city, which is located in the Mediterranean region in Turkey, were facilitated in this study together with a verified finite element thermal model. The aim of this study is to investigate the sectional temperature gradients in concrete-steel composite bridge girders. Solar radiation and air temperature history of more than 50 years was used, and a practical-size typical composite bridge girder was modeled for six selected months that represent the conditions of the four seasons in Adana. The analysis showed that the behaviors of positive vertical and lateral temperature gradients in summer were completely different from those in winter, while the negative temperature gradients exhibited similar sectional distributions in all seasons. The results also showed that the maximum vertical temperature gradient occurred in summer, while the maximum lateral temperature gradient occurred in winter. The maximum positive vertical gradients occurred at the top concrete surface in summer and within the steel web in winter. For the investigated conditions, the recorded maximum positive vertical gradients in summer and winter were approximately 15.0 and 12.2 °C, respectively, while the maximum positive lateral temperature gradients in summer and winter were approximately 6.1 and 10.9 °C, respectively.
Faten I. Mussa; Sallal R. Abid; Nildem Tayşi. Design Temperatures for Composite Concrete-Steel Girders: B-Case Study. IOP Conference Series: Materials Science and Engineering 2021, 1090, 012109 .
AMA StyleFaten I. Mussa, Sallal R. Abid, Nildem Tayşi. Design Temperatures for Composite Concrete-Steel Girders: B-Case Study. IOP Conference Series: Materials Science and Engineering. 2021; 1090 (1):012109.
Chicago/Turabian StyleFaten I. Mussa; Sallal R. Abid; Nildem Tayşi. 2021. "Design Temperatures for Composite Concrete-Steel Girders: B-Case Study." IOP Conference Series: Materials Science and Engineering 1090, no. 1: 012109.
The self-compacting concrete (SCC) was invented to overcome the compaction problems in deep sections, owing to its perfect workability characteristics. Steel fibers when used with SCC would affect the required fluidity characteristics but improve its impact resistance. In this research, an experimental work was conducted to evaluate the impact response of micro-steel fiber-reinforced SCC, under flexural impact. A 5.47 kg free-falling mass was dropped repeatedly from 100 mm height on the top center of 270 mm-length beam specimens. Eight mixtures with two design grades of 30 and 50 MPa were prepared to distinguish the normal and high-strength SCCs. The distinguishing variable for each design grade was the fiber content, where four volumetric contents of 0%, 0.5%, 0.75%, and 1.0% were used. The test results showed that the impact resistance and ductility were significantly improved due to the incorporation of micro-steel fibers. The percentage improvements were noticeably higher at failure stage than at cracking stage. For the 30 MPa mixtures, the maximum percentage improvements at cracking and failure stages were 543% and 836%, respectively. Weibull’s linear correlations with R2 values of 0.84 to 0.97 were obtained at the failure stage, which meant that the impact failure number followed the Wiebull distribution.
Sallal R. Abid; Murali Gunasekaran; Sajjad H. Ali; Ahmed L. Kadhum; Thaar S. Al-Gasham; Roman Fediuk; Nikolai Vatin; Maria Karelina. Impact Performance of Steel Fiber-Reinforced Self-Compacting Concrete against Repeated Drop Weight Impact. Crystals 2021, 11, 91 .
AMA StyleSallal R. Abid, Murali Gunasekaran, Sajjad H. Ali, Ahmed L. Kadhum, Thaar S. Al-Gasham, Roman Fediuk, Nikolai Vatin, Maria Karelina. Impact Performance of Steel Fiber-Reinforced Self-Compacting Concrete against Repeated Drop Weight Impact. Crystals. 2021; 11 (2):91.
Chicago/Turabian StyleSallal R. Abid; Murali Gunasekaran; Sajjad H. Ali; Ahmed L. Kadhum; Thaar S. Al-Gasham; Roman Fediuk; Nikolai Vatin; Maria Karelina. 2021. "Impact Performance of Steel Fiber-Reinforced Self-Compacting Concrete against Repeated Drop Weight Impact." Crystals 11, no. 2: 91.
This research aims to examine the fracture toughness of hybrid fibrous geopolymer composites under mode II. For this purpose, eight geopolymer mixtures were cast and tested to evaluate the influence of steel and synthetic fiber hybridization on mode II fracture response. The first mixture was plain and was kept as a reference, while steel, polypropylene and glass fibers were used in the rest seven mixtures. The first three of which were mono-reinforced with one of the three fibers, while the rest of the four were hybrids reinforced with combinations of steel and synthetic fibers. The Brazilian center notched disc and the double notched cube test configurations were used to evaluate the mode II fracture toughness of the eight mixtures. The results of the tests showed that steel fibers played the vital role in enhancing the fracture toughness, where the mixtures S1.6 and S1.3G0.3 showed the best performance. The results also showed that increasing the notch depth decreased the fracture toughness with an approximate linear decrement fashion. It was found that the use of double-notched cubes resulted in much higher fracture toughness than the Brazilian notched discs, where the ratio of normalized fracture toughness of the disc specimens to cube specimens was approximately 0.37 to 0.47. This is attributed to the concentration of stresses along one defined path in the disc specimens compared to the multi-path stresses in the cube specimens. In addition, the accompanied tensile stresses in the disc specimens may lead to a mode I fracture before the designed mode II fracture.
Sallal R. Abid; Gunasekaran Murali; Mugahed Amran; Nikolai Vatin; Roman Fediuk; Maria Karelina. Evaluation of Mode II Fracture Toughness of Hybrid Fibrous Geopolymer Composites. Materials 2021, 14, 349 .
AMA StyleSallal R. Abid, Gunasekaran Murali, Mugahed Amran, Nikolai Vatin, Roman Fediuk, Maria Karelina. Evaluation of Mode II Fracture Toughness of Hybrid Fibrous Geopolymer Composites. Materials. 2021; 14 (2):349.
Chicago/Turabian StyleSallal R. Abid; Gunasekaran Murali; Mugahed Amran; Nikolai Vatin; Roman Fediuk; Maria Karelina. 2021. "Evaluation of Mode II Fracture Toughness of Hybrid Fibrous Geopolymer Composites." Materials 14, no. 2: 349.
This research aims to experimentally evaluate the behaviour of multi-layered fibrous cementitious composites with intermediate Glass Fibre Meshes (GFM) under repeated projectile load. The impact load was subjected through a convex edge projectile needle at a low velocity on cylindrical specimens of three-layered fibrous cementitious composites, which have two different steel fibre distributions. In series A mixtures, a constant steel fibre dosage of 2.5% by volume was used. On the other hand, the fibre dosage of the outer layers was 3.0%; while it was 1.5% in the middle layer of series B mixtures. The number of intermediate GFM was the variable that distinguishes the mixtures of each series. The resistance to projectile impacts was evaluated on the basis of penetration depth, near surface distortion, weight loss, damage ratio and failure pattern. The test results showed that due to the combined effect of steel fibre and GFM, significantly lower weight losses were recorded for series A and B specimens compared with reference specimens. However, the different fibre distributions (series B) led to lower penetration depths and weight losses with less surface distortion compared with the fixed fibre distribution (series A). The reduction in the destroyed front surface area of series A specimens compared with reference specimens ranged from 27.8 to 38.1%; while that of series B specimens ranged from 34.8 to 53.4%. In addition, a simplified analytical model was introduced to predict the ejected composite mass. The model predictions were found to be in good agreement with the experimental masses.
G. Murali; Sallal R. Abid; Hakim S. Abdelgader; Y. H. Mugahed Amran; Mohammad Shekarchi; Krzysztof Wilde. Repeated Projectile Impact Tests on Multi-Layered Fibrous Cementitious Composites. International Journal of Civil Engineering 2021, 19, 635 -651.
AMA StyleG. Murali, Sallal R. Abid, Hakim S. Abdelgader, Y. H. Mugahed Amran, Mohammad Shekarchi, Krzysztof Wilde. Repeated Projectile Impact Tests on Multi-Layered Fibrous Cementitious Composites. International Journal of Civil Engineering. 2021; 19 (6):635-651.
Chicago/Turabian StyleG. Murali; Sallal R. Abid; Hakim S. Abdelgader; Y. H. Mugahed Amran; Mohammad Shekarchi; Krzysztof Wilde. 2021. "Repeated Projectile Impact Tests on Multi-Layered Fibrous Cementitious Composites." International Journal of Civil Engineering 19, no. 6: 635-651.
An experimental attempt was conducted in this paper, aiming at enhancing the shear and flexural behaviors of deep beams, where steel plates were applied as web reinforcement. Three beams having the same details were prepared using normal concrete strength. Their dimensions were 1250 mm long, 300 mm deep, and 150 mm wide. The specimens were designed to fail in shear, and therefore, they were supplied with two bars with a 20 mm diameter in addition to the top and skin reinforcement. For web reinforcement, the steel plates were cut in dimensions of 4×20 mm and then were applied as closed rectangular stirrups with the longer side (20 mm) aligned in the plane of the beam section. The beams were inspected by applying four-point bending with three shear span to the effective depth ratios (a/d) of 0.75, 1.25 and 1.75. The experimental outcomes revealed that the shear strength, stiffness, and toughness of deep beams enhanced as the a/d ratio dropped.
Thaar S Al-Gasham; Jasim M Mhalhal; Sallal R Abid. Evaluating planner hoop steel plates as web reinforcement for deep reinforced concrete beams. IOP Conference Series: Materials Science and Engineering 2020, 988, 012031 .
AMA StyleThaar S Al-Gasham, Jasim M Mhalhal, Sallal R Abid. Evaluating planner hoop steel plates as web reinforcement for deep reinforced concrete beams. IOP Conference Series: Materials Science and Engineering. 2020; 988 (1):012031.
Chicago/Turabian StyleThaar S Al-Gasham; Jasim M Mhalhal; Sallal R Abid. 2020. "Evaluating planner hoop steel plates as web reinforcement for deep reinforced concrete beams." IOP Conference Series: Materials Science and Engineering 988, no. 1: 012031.
Solar radiation and air temperature hourly, daily and seasonally variation is of a noticeable impact on bridge girders and other exposed structures. The time-dependent changing of the mean temperature of the girder and the complete superstructure is the key parameter to calculate support movements and rotations. Based on an experimental measurement from a steel beam installed in an open environment, the mean temperature variation of steel beams could be studied and modeled in this investigation. The experimental records included steel temperatures of web and flanges, solar radiation and air temperature and speed. The recorded thermal measurements were used to obtain correlation relationships that describe the mean temperatures of the web, flanges and the whole beam in terms of wind speed, air temperature and solar radiation. These correlation relationships were validated using a part of the experimental data. The results showed that predicted models has good correlation coefficients.
Sallal R Abid; Hussein Al-Bugharbee. Experimental records based-simplified modeling of mean temperatures of steel beams in open environment. IOP Conference Series: Materials Science and Engineering 2020, 988, 012034 .
AMA StyleSallal R Abid, Hussein Al-Bugharbee. Experimental records based-simplified modeling of mean temperatures of steel beams in open environment. IOP Conference Series: Materials Science and Engineering. 2020; 988 (1):012034.
Chicago/Turabian StyleSallal R Abid; Hussein Al-Bugharbee. 2020. "Experimental records based-simplified modeling of mean temperatures of steel beams in open environment." IOP Conference Series: Materials Science and Engineering 988, no. 1: 012034.
In this work, prediction of the maximum temperature in steel beam is investigated under the effects of the atmospheric thermal loads. The current work presents a nonlinear formula that relates the steel beam maximum temperature to the solar radiation, air temperature and wind speed. The datasets were obtained experimentally from an I-section steel beam that was installed in the field. The data cover the surface temperature at different locations on the beam section, air temperature, solar radiation and wind speed, which were recorded over 21 summer days. Two different correlation formulas were introduced and their performance was compared. Based on the results obtained in this study, the beam maximum temperature can be predicted accurately with a correlation coefficient of approximately 0.94 from solar radiation, air temperature, wind speed and their duplicates.
Sallal R Abid; Hussein Al-Bugharbee. Prediction of the maximum temperature of steel I-beam under the effect of environment parameters. IOP Conference Series: Materials Science and Engineering 2020, 988, 012033 .
AMA StyleSallal R Abid, Hussein Al-Bugharbee. Prediction of the maximum temperature of steel I-beam under the effect of environment parameters. IOP Conference Series: Materials Science and Engineering. 2020; 988 (1):012033.
Chicago/Turabian StyleSallal R Abid; Hussein Al-Bugharbee. 2020. "Prediction of the maximum temperature of steel I-beam under the effect of environment parameters." IOP Conference Series: Materials Science and Engineering 988, no. 1: 012033.
In this investigation, the influence of the shear span to the effective depth ratio on the mechanical properties of deep beams was expansively illustrated. For this aim, three specimens representing deep beams with a medium scale were prepared using the same concrete grade. The specimens had similar dimensions of 1250 ×300×150 mm and identical details of reinforcement. The beams were subjected to a four-points load test, which was gradual until the specimens failed. Three different a/d ratios were inspected; 0.75, 1.25, and 1.75. the experimental observations were compared in terms of deformations, ultimate loads, stiffness, ductility, and toughness. The results of tests indicated that the a/d had a considerable influence on the mechanical characteristics of deep beams, except for ductility.
Hussain A. Jabir; Jasim M Mhalhal; Thaar S Al-Gasham; Sallal R. Abid. Mechanical characteristics of deep beams considering variable a/d ratios: an experimental investigation. IOP Conference Series: Materials Science and Engineering 2020, 988, 012030 .
AMA StyleHussain A. Jabir, Jasim M Mhalhal, Thaar S Al-Gasham, Sallal R. Abid. Mechanical characteristics of deep beams considering variable a/d ratios: an experimental investigation. IOP Conference Series: Materials Science and Engineering. 2020; 988 (1):012030.
Chicago/Turabian StyleHussain A. Jabir; Jasim M Mhalhal; Thaar S Al-Gasham; Sallal R. Abid. 2020. "Mechanical characteristics of deep beams considering variable a/d ratios: an experimental investigation." IOP Conference Series: Materials Science and Engineering 988, no. 1: 012030.
Ultra-high performance (UHP) concrete is a special type of fibrous cementitious composite that is characterized by high strength and superior ductility, toughness, and durability. This research aimed to investigate the resistance of ultra-high performance fiber-reinforced concrete (UHPFRC) against repeated impacts. An adjusted repeated drop mass impact test was adopted to evaluate the impact performance of 72 UHPFRC disc specimens. The specimens were divided into six mixtures each of 12 discs. The only difference between the mixtures was the types of fibers used, while all other mixture components were the same. Three types of fibers were used: 6 mm micro-steel, 15 mm micro-steel, and polypropylene. All mixtures included 2.5% volumetric content of fibers, however with different combinations of the three fiber types. The test results showed that the mixtures with the 15 mm micro-steel fiber absorbed a higher number of impact blows until cracking compared to other mixtures. The mixture with pure 2.5% of 15 mm micro-steel fiber exhibited the highest impact resistance, with percentage increases over the other mixtures ranging from 25 to 140%. In addition, the Weibull distribution was used to investigate the cracking impact resistance of UHP at different levels of reliability.
Hussain A. Jabir; Sallal R. Abid; Gunasekaran Murali; Sajjad H. Ali; Sergey Klyuev; Roman Fediuk; Nikolai Vatin; Vladimir Promakhov; Yuriy Vasilev. Experimental Tests and Reliability Analysis of the Cracking Impact Resistance of UHPFRC. Fibers 2020, 8, 74 .
AMA StyleHussain A. Jabir, Sallal R. Abid, Gunasekaran Murali, Sajjad H. Ali, Sergey Klyuev, Roman Fediuk, Nikolai Vatin, Vladimir Promakhov, Yuriy Vasilev. Experimental Tests and Reliability Analysis of the Cracking Impact Resistance of UHPFRC. Fibers. 2020; 8 (12):74.
Chicago/Turabian StyleHussain A. Jabir; Sallal R. Abid; Gunasekaran Murali; Sajjad H. Ali; Sergey Klyuev; Roman Fediuk; Nikolai Vatin; Vladimir Promakhov; Yuriy Vasilev. 2020. "Experimental Tests and Reliability Analysis of the Cracking Impact Resistance of UHPFRC." Fibers 8, no. 12: 74.
Multi-layered Prepacked aggregate fibrous composite (MLPAFC) is a new type of concrete, which is prepared in two subsequent stages of aggregate-fibre skeleton prepacking and cementitious grouting. In this study, ten MLPAFC mixtures were prepared in three subsequent layers incorporating different contents of four different types of steel fibres. Long and short hooked-end and crimped steel fibers were adopted with 3.0 and 1.5% dosages for the outer and interior layers, respectively. In-between the three MLPAFC layers, two layers of Glass Fiber Mesh (GFM) were inserted in five of the ten mixtures. The impact response of the MLPAFC mixtures was evaluated using two test methods. In the first, the ACI 544-2R repeated free-falling weight test was followed using disk specimens, while flexural free-falling weight on prism specimens was the second adopted impact test. Moreover, Weibull distribution was used to statistically analyse the discrepancies of the obtained experimental impact records. The impact tests results revealed that MLPAFC can absorb significantly high energy under falling weight impact due to its structure and the dual crack arresting activity of both steel fibers and GFM. The cracking number of impacts of MLPAFC cylindrical specimens without GFM was increased by approximately 530–870% compared reference specimens, while increment percentages reaching 1350% were recorded at failure stage. The impact resistance of MLPAFC prisms under flexural impact was noticeably improved, yet with lower percentages than cylindrical specimens. The insertion of intermediate GFMs let to additional developments in the impact strength of both cylindrical and prism specimens.
G. Murali; Sallal R. Abid; Y.H. Mugahed Amran; Hakim S. Abdelgader; Roman Fediuk; Arikatla Susrutha; K. Poonguzhali. Impact performance of novel multi-layered prepacked aggregate fibrous composites under compression and bending. Structures 2020, 28, 1502 -1515.
AMA StyleG. Murali, Sallal R. Abid, Y.H. Mugahed Amran, Hakim S. Abdelgader, Roman Fediuk, Arikatla Susrutha, K. Poonguzhali. Impact performance of novel multi-layered prepacked aggregate fibrous composites under compression and bending. Structures. 2020; 28 ():1502-1515.
Chicago/Turabian StyleG. Murali; Sallal R. Abid; Y.H. Mugahed Amran; Hakim S. Abdelgader; Roman Fediuk; Arikatla Susrutha; K. Poonguzhali. 2020. "Impact performance of novel multi-layered prepacked aggregate fibrous composites under compression and bending." Structures 28, no. : 1502-1515.
This paper aims to experimentally and numerically investigate the flexural behavior of laced reinforced concrete moderately deep beams. The study focuses on the influence of the lacing angle (30, 45, and 60°) and the ratio of the tension reinforcement (0.33, 1.13, and 2.01%). Six beams were fabricated, with a cross-sectional width of 150 mm and a depth of 240 mm, and 1530 mm in length. In five specimens, lacings were employed as shear reinforcement instead of the conventional stirrups. A reference beam was fabricated with conventional vertical stirrups. All beam specimens were subjected to the four-point bending up to failure with effective and shear spans of 1400 and 400 mm, respectively. Compared to the reference beam, laced beams experienced significant stiffness enhancements of up to 43.7%. However, the improvement in the ultimate load did not exceed 10%. The recorded strains in lacings clearly signify the efficiency of lacings in resisting the longitudinal and diagonal tension stresses induced along the flexural and shear spans. Moreover, a nonlinear finite element analysis was performed using ABAQUS, based on which parametric studies were conducted. Parametric studies showed that the ductility was significantly increased with the increase of lacings bar diameter, while the ultimate load capacity was only slightly enhanced.
Thaar Al-Gasham; Jasim M. Mhalhal; Sallal Abid. Flexural Behavior of Laced Reinforced Concrete Moderately Deep Beams. Case Studies in Construction Materials 2020, 13, e00363 .
AMA StyleThaar Al-Gasham, Jasim M. Mhalhal, Sallal Abid. Flexural Behavior of Laced Reinforced Concrete Moderately Deep Beams. Case Studies in Construction Materials. 2020; 13 ():e00363.
Chicago/Turabian StyleThaar Al-Gasham; Jasim M. Mhalhal; Sallal Abid. 2020. "Flexural Behavior of Laced Reinforced Concrete Moderately Deep Beams." Case Studies in Construction Materials 13, no. : e00363.
Experimental tests were conducted in this study to introduce two simplified modifications to the setup of the ACI 544-2R repeated impact test aiming to reduce the results scattering of this test. The first modification is the using of sand bedding as a replacement to the steel baseplate, while the second is the using of notched specimens that are either centrally line notched or cross notched and loaded through a line or cross knife-like load transferring steel plate. Hence, the drop impact load is distributed along the specimen’s notch using the topping knife-like plate. To evaluate the proposed modification techniques, 90 cylindrical high performance concrete specimens were tested in six groups. The test results showed that, in notched specimens, the cracks were formed along the projections of notches, while several random cracks were formed in those without notches. The results also showed that the effect of fine sand bedding depends on the loading pattern, and that the dispersion of results can be reduced by using notched specimens with the load distributed along these notches. Using line notched specimens with sand bedding was found to exhibit the lowest results dispersion among the six investigated loading cases. The COV reduced by more than 60% compared to the current ACI 544-2R testing technique. At 90% level of confidence with a maximum error of 10%, the minimum required number of specimens is 55 for the ACI 544-2R test procedure, while only 7 specimens are required if sand bedding with line notch specimens are used.
Sallal R. Abid; Munther L. Abdul Hussein; Sajjad H. Ali; Ala'a F. Kazem. Suggested modified testing techniques to the ACI 544-R repeated drop-weight impact test. Construction and Building Materials 2020, 244, 118321 .
AMA StyleSallal R. Abid, Munther L. Abdul Hussein, Sajjad H. Ali, Ala'a F. Kazem. Suggested modified testing techniques to the ACI 544-R repeated drop-weight impact test. Construction and Building Materials. 2020; 244 ():118321.
Chicago/Turabian StyleSallal R. Abid; Munther L. Abdul Hussein; Sajjad H. Ali; Ala'a F. Kazem. 2020. "Suggested modified testing techniques to the ACI 544-R repeated drop-weight impact test." Construction and Building Materials 244, no. : 118321.
Steel fiber has become a proven material that can significantly alter the behavior of different types of concrete mixtures from brittle to more ductile ones. Rich literature is currently available on the mechanical properties of steel fiber-reinforced self-compacting concrete. However, the investigation of the impact resistance of this material to drop weight is still required to enrich the knowledge about its behavior under different loading conditions. An experimental work was conducted in this research to evaluate the performance of steel fiber-reinforced self-compacting concrete under repeated impact loading using the repeated blows test recommended by ACI 544-2R. The tests investigated the effect of drop weight and drop height in addition to fiber content. Straight micro-steel fibers were incorporated in three volumetric contents of 0.5, 0.75 and 1.0% and were compared with a similar plain mixture. The test equipment was adjusted to conduct repeated impact loading from different drop-heights and using different drop-weights. The adopted drop-heights were 450, 575 and 700 mm, while the adopted drop-weights were 4.5, 6.0 and 7.5 kg. The combination of the adopted drop-heights and weights composes four loading cases in addition to the standard loading case with a drop-weight and drop-height of 4.5 kg and 450 mm. The inclusion of micro steel fiber was found to significantly increase the impact resistance of self-compacting concrete with percentage developments ranging from 150 to 860% compared to plain samples. The specimens tested under 4.5 kg and 450 mm drop weight and height exhibited the highest percentage improvement in impact resistance among the five loading cases. The results also showed that the impact ductility of fibrous specimens was up to 24% higher than that of plain specimens.
Sallal R. Abid; Munther L. Abdul-Hussein; Nadheer S. Ayoob; Sajjad H. Ali; Ahmed L. Kadhum. Repeated drop-weight impact tests on self-compacting concrete reinforced with micro-steel fiber. Heliyon 2020, 6, e03198 .
AMA StyleSallal R. Abid, Munther L. Abdul-Hussein, Nadheer S. Ayoob, Sajjad H. Ali, Ahmed L. Kadhum. Repeated drop-weight impact tests on self-compacting concrete reinforced with micro-steel fiber. Heliyon. 2020; 6 (1):e03198.
Chicago/Turabian StyleSallal R. Abid; Munther L. Abdul-Hussein; Nadheer S. Ayoob; Sajjad H. Ali; Ahmed L. Kadhum. 2020. "Repeated drop-weight impact tests on self-compacting concrete reinforced with micro-steel fiber." Heliyon 6, no. 1: e03198.
In this work, 14 reinforced concrete solid and hollow beams were tested under four-point bending test to evaluate the flexural behavior of hollow concrete beams. The experimental program focused on two main variables which are the size reduction percentage and the inclusion of steel fiber. In addition, the longitudinal reinforcement ratio and the presence of lateral stirrups were also within the investigated parameters. Four solid beams in addition to 10 hollow beams with central square holes with side lengths of 60, 80, and 100 mm were fabricated to evaluate the test parameters. These beams were either reinforced with 1% steel fiber or contain no fiber. The flexural performance of the beams was evaluated using the load–deflection behavior, flexural ductility, stiffness and toughness. In addition to the experimental work, analytical formulas were introduced to evaluate the cracking and peak loads of the hollow beams. The test results showed that ductility of hollow beams with size reductions of 16% and 28.4% was higher than that of the reference solid beam, while the ductility of the hollow beam with 44.4% size reduction was quite comparable to that of the solid beam. Moreover, the toughness values of the hollow beams were higher by 19 to 37% than that of the reference solid beam. Based on the obtained results, it can be concluded that hollow reinforced concrete beams with 1.0% steel fiber and with size reduction up to 44.4% can replace solid beams without suffering significant reductions in strength, ductility and toughness.
Ahmmad A. Abbass; Sallal R. Abid; Farid H. Arna'Ot; Raad A. Al-Ameri; Mustafa Özakça. Flexural response of hollow high strength concrete beams considering different size reductions. Structures 2019, 23, 69 -86.
AMA StyleAhmmad A. Abbass, Sallal R. Abid, Farid H. Arna'Ot, Raad A. Al-Ameri, Mustafa Özakça. Flexural response of hollow high strength concrete beams considering different size reductions. Structures. 2019; 23 ():69-86.
Chicago/Turabian StyleAhmmad A. Abbass; Sallal R. Abid; Farid H. Arna'Ot; Raad A. Al-Ameri; Mustafa Özakça. 2019. "Flexural response of hollow high strength concrete beams considering different size reductions." Structures 23, no. : 69-86.