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Dr. Hilal El-Hassan
United Arab Emirates University

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Research Keywords & Expertise

0 Cement
0 Mechanical Properties
0 Sustainability
0 geopolymer
0 Carbonation

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Cement
Mechanical Properties
geopolymer
Carbonation
Sustainability
performance evaluation
microstructure analysis
Fiber Reinforced Polymers (FRPs)
alkali-activated materials

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Short Biography

Dr. Hilal El-Hassan is an Associate Professor of Structural and Materials Engineering at the Department of Civil and Environmental Engineering at the UAEU. He earned his Ph.D. degree from McGill University, Montreal, Canada. Dr. El-Hassan’s research is in the area of civil engineering materials. His most recent work has focused on the recycling of industrial wastes in cement-free geopolymer and alkali-activated concrete. He has also examined the durability performance of glass fiber-reinforced polymers encased in concrete and evaluated the performance of permeable concrete pavement made with recycled aggregates and slag. Further, Dr. El-Hassan has studied the carbonation curing of concrete masonry units. He has been directly involved in a large number of research and consultancy projects summing to over 5 million dirhams. He has disseminated his research works in over 40 international journals and conference proceedings.

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Journal article
Published: 28 July 2021 in Buildings
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This study evaluates the performance of alkali-activated slag-fly ash blended concrete made with recycled concrete aggregates (RCA) and reinforced with steel fibers. Two blends of concrete with ground granulated blast furnace slag-to-fly ash ratios of 3:1 and 1:1 were used. Natural aggregates were substituted with RCA, while macro steel fibers with 35 mm of length and aspect ratio of 65 were incorporated in RCA-based mixtures at various volume fractions. Fine aggregates were in the form of desert dune sand. Mechanical and durability characteristics were investigated. Experimental results revealed that RCA replacement decreased the compressive strength of plain concrete mixtures with more pronounced reductions being perceived at higher replacement percentages. Mixtures made with 30%, 70%, and 100% RCA could be produced with limited loss in the design compressive strength upon incorporating 1%, 2%, and 2% steel fibers, by volume, respectively. In turn, splitting tensile strength was comparable to the NA-based control while adding at least 1% steel fiber, by volume. Moreover, higher water absorption and capillary sorptivity and lower ultrasonic pulse velocity, bulk resistivity, and abrasion resistance were reported during RCA replacement. Meanwhile, incorporation of steel fibers densified the concrete and enhanced its resistance to abrasive forces, water permeation, and water transport. Analytical regression models were developed to correlate hardened concrete properties to the 28-day cylinder compressive strength.

ACS Style

Hilal El-Hassan; Abdalla Hussein; Jamal Medljy; Tamer El-Maaddawy. Performance of Steel Fiber-Reinforced Alkali-Activated Slag-Fly Ash Blended Concrete Incorporating Recycled Concrete Aggregates and Dune Sand. Buildings 2021, 11, 327 .

AMA Style

Hilal El-Hassan, Abdalla Hussein, Jamal Medljy, Tamer El-Maaddawy. Performance of Steel Fiber-Reinforced Alkali-Activated Slag-Fly Ash Blended Concrete Incorporating Recycled Concrete Aggregates and Dune Sand. Buildings. 2021; 11 (8):327.

Chicago/Turabian Style

Hilal El-Hassan; Abdalla Hussein; Jamal Medljy; Tamer El-Maaddawy. 2021. "Performance of Steel Fiber-Reinforced Alkali-Activated Slag-Fly Ash Blended Concrete Incorporating Recycled Concrete Aggregates and Dune Sand." Buildings 11, no. 8: 327.

Journal article
Published: 18 July 2021 in Sustainability
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Reutilizing industrial by-products and recycled concrete aggregates (RCA) to replace cement and natural aggregates (NA) in concrete is becoming increasingly important for sustainable development. Yet, experimental evidence is needed prior to the widespread use of this sustainable concrete by the construction industry. This study examines the performance of alkali-activated slag concrete made with RCA and reinforced with steel fibers. Natural coarse aggregates were replaced with RCA. Steel fibers were added to mixes incorporating RCA at different volume fractions. Desert dune sand was used as fine aggregate. The mechanical and durability properties of plain and steel fiber-reinforced concrete made with RCA were experimentally examined. The results showed that the compressive strength did not decrease in plain concrete mixes with 30 and 70% RCA replacement. However, full replacement of NA with RCA resulted in a 20% reduction in the compressive strength of the plain mix. In fact, 100% RCA mixes could only be produced with compressive strength comparable to that of an NA-based control mix in conjunction with 2% steel fiber, by volume. In turn, at least 1% steel fiber, by volume, was required to maintain comparable splitting tensile strength. Furthermore, RCA replacement led to higher water absorption and sorptivity and lower bulk resistivity, ultrasonic pulse velocity, and abrasion resistance. Steel fiber incorporation in RCA-based mixes densified the concrete and improved its resistance to abrasion, water permeation, and transport, thereby enhancing its mechanical properties to exceed that of the NA-based counterpart. The hardened properties were correlated to 28-day cylinder compressive strength through analytical regression models.

ACS Style

Hilal El-Hassan; Jamal Medljy; Tamer El-Maaddawy. Properties of Steel Fiber-Reinforced Alkali-Activated Slag Concrete Made with Recycled Concrete Aggregates and Dune Sand. Sustainability 2021, 13, 8017 .

AMA Style

Hilal El-Hassan, Jamal Medljy, Tamer El-Maaddawy. Properties of Steel Fiber-Reinforced Alkali-Activated Slag Concrete Made with Recycled Concrete Aggregates and Dune Sand. Sustainability. 2021; 13 (14):8017.

Chicago/Turabian Style

Hilal El-Hassan; Jamal Medljy; Tamer El-Maaddawy. 2021. "Properties of Steel Fiber-Reinforced Alkali-Activated Slag Concrete Made with Recycled Concrete Aggregates and Dune Sand." Sustainability 13, no. 14: 8017.

Book chapter
Published: 09 June 2021 in Cement Industry - Optimization, Characterization and Sustainable Application
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Globally, carbon dioxide concentration has immensely increased post the industrial revolution. With more greenhouse gases generated from human activities, more radiation is being absorbed by the Earth’s atmosphere, causing an increase in global temperature. The phenomenon is referred to as the greenhouse gas effect. Alone, the cement industry contributes to approximately 5–8% of the global greenhouse gas emissions. Scientists and environmentalists have proposed different scenarios to alleviate such emissions. Among these, accelerated carbonation curing has been advocated as a promising mechanism to permanently sequester carbon dioxide. It has been applied to numerous construction applications, including concrete masonry blocks, concrete paving blocks, ceramic bricks, concrete pipes, and cement-bonded particleboards. Experimental results have shown that not only does it significantly reduce the carbon emissions, it also improves the mechanical and durability properties of carbonated products. The process enhances material performance, offers environmental benefits, and provides an excellent means to recycle carbon dioxide.

ACS Style

Hilal El-Hassan. Accelerated Carbonation Curing as a Means of Reducing Carbon Dioxide Emissions. Cement Industry - Optimization, Characterization and Sustainable Application 2021, 1 .

AMA Style

Hilal El-Hassan. Accelerated Carbonation Curing as a Means of Reducing Carbon Dioxide Emissions. Cement Industry - Optimization, Characterization and Sustainable Application. 2021; ():1.

Chicago/Turabian Style

Hilal El-Hassan. 2021. "Accelerated Carbonation Curing as a Means of Reducing Carbon Dioxide Emissions." Cement Industry - Optimization, Characterization and Sustainable Application , no. : 1.

Journal article
Published: 15 May 2021 in Buildings
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This study aims to examine the potential use of a geopolymeric matrix as a sustainable alternative to commercial mortars in carbon fabric-reinforced matrix composites. Single-lap shear tests were conducted to examine the bond behavior at the fabric-matrix interface. Test parameters included the type of matrix (geopolymeric and cementitious matrices) and the bonded length (50 to 300 mm). The geopolymeric matrix was a blend of fly ash/ground granulated blast furnace slag activated by an alkaline solution of sodium silicate and sodium hydroxide. The bond behavior of the geopolymeric-matrix specimens was characterized and compared to that of similar specimens with a cementitious matrix. The specimens failed due to fabric slippage/debonding at the fabric-matrix interface or fabric rupture. The effective bond lengths of the geopolymeric- and cementitious-matrix specimens were 150 and 170 mm, respectively. The geopolymeric-matrix specimens exhibited higher fabric strains, higher ultimate loads, and a steeper strain profile along the bonded length than those of their cementitious-matrix counterparts. New bond-slip models that characterize the bond behavior at the fabric-matrix interface for geopolymeric- and cementitious-matrix specimens were developed. Both models exhibited equal maximum shear stress of 1.2 MPa. The geopolymeric-matrix model had, however, higher fracture energy and higher slip at maximum shear stress than those of the cementitious matrix model.

ACS Style

Feras Abu Obaida; Tamer El-Maaddawy; Hilal El-Hassan. Bond Behavior of Carbon Fabric-Reinforced Matrix Composites: Geopolymeric Matrix versus Cementitious Mortar. Buildings 2021, 11, 207 .

AMA Style

Feras Abu Obaida, Tamer El-Maaddawy, Hilal El-Hassan. Bond Behavior of Carbon Fabric-Reinforced Matrix Composites: Geopolymeric Matrix versus Cementitious Mortar. Buildings. 2021; 11 (5):207.

Chicago/Turabian Style

Feras Abu Obaida; Tamer El-Maaddawy; Hilal El-Hassan. 2021. "Bond Behavior of Carbon Fabric-Reinforced Matrix Composites: Geopolymeric Matrix versus Cementitious Mortar." Buildings 11, no. 5: 207.

Research article
Published: 03 May 2021 in European Journal of Engineering Education
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Curriculum-based exit exams play a crucial role in program assessment and measuring student achievement of program learning outcomes (PLOs). This study aims to examine the validity of using an internal exit exam as a direct assessment tool to evaluate student learning and attainment of PLOs. The validation entails evaluating and correlating students’ performance in the exit exam to that in corresponding coursework and their perception regarding attainment of the PLOs. Results highlighted inferior student performance in the exit exam compared to corresponding coursework, with a moderate degree of correlation at the program level. The survey response analysis indicated that students tended to overestimate their attainment level of PLOs and their preparation for the exit exam was not sufficient. Findings of this study would assist in the continuous improvement of prospective engineering programs and provide a framework for a proper analysis capable of examining the validity of curriculum-based assessment tools.

ACS Style

Hilal El-Hassan; Mohamed Hamouda; Tamer El-Maaddawy; Munjed Maraqa. Curriculum-based exit exam for assessment of student learning. European Journal of Engineering Education 2021, 1 -25.

AMA Style

Hilal El-Hassan, Mohamed Hamouda, Tamer El-Maaddawy, Munjed Maraqa. Curriculum-based exit exam for assessment of student learning. European Journal of Engineering Education. 2021; ():1-25.

Chicago/Turabian Style

Hilal El-Hassan; Mohamed Hamouda; Tamer El-Maaddawy; Munjed Maraqa. 2021. "Curriculum-based exit exam for assessment of student learning." European Journal of Engineering Education , no. : 1-25.

Research article
Published: 19 February 2021 in Journal of Sustainable Cement-Based Materials
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The use of alkali-activated materials to produce concrete is a promising technology. However, information on the optimum curing regime required to maximize the performance of such concrete is lacking. This paper examines the fresh and hardened properties and microstructure characteristics of alkali-activated slag-fly ash blended concrete subjected to various curing regimes. Results showed that the optimum curing regime for alkali-activated blended concrete mixtures made with 0 and 25% fly ash was a combination of water and subsequent air curing, while that for mixes made with 50% fly ash was continuous water curing. Among these mixes, that incorporating 25% fly ash presented superior density, bulk resistivity, water absorption, compressive strength, and modulus of elasticity. Microstructure analysis revealed that the reaction products were an intermix of calcium aluminosilicate hydrate and sodium aluminosilicate hydrate. Analytical regression models were also developed to correlate the hardened properties of alkali-activated slag-fly ash blended concrete.

ACS Style

Hilal El-Hassan; Ehab Shehab; Abdelrahman Al-Sallamin. Effect of curing regime on the performance and microstructure characteristics of alkali-activated slag-fly ash blended concrete. Journal of Sustainable Cement-Based Materials 2021, 10, 289 -317.

AMA Style

Hilal El-Hassan, Ehab Shehab, Abdelrahman Al-Sallamin. Effect of curing regime on the performance and microstructure characteristics of alkali-activated slag-fly ash blended concrete. Journal of Sustainable Cement-Based Materials. 2021; 10 (5):289-317.

Chicago/Turabian Style

Hilal El-Hassan; Ehab Shehab; Abdelrahman Al-Sallamin. 2021. "Effect of curing regime on the performance and microstructure characteristics of alkali-activated slag-fly ash blended concrete." Journal of Sustainable Cement-Based Materials 10, no. 5: 289-317.

Journal article
Published: 01 January 2021 in International Journal of Civil Infrastructure
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ACS Style

Omar Najm; Hilal El-Hassan; Amr El-Dieb; Hamad Aljassmi. Utilization of a Bayesian Network Algorithm to Predict the Compressive Strength of Concrete. International Journal of Civil Infrastructure 2021, 4, 33 -40.

AMA Style

Omar Najm, Hilal El-Hassan, Amr El-Dieb, Hamad Aljassmi. Utilization of a Bayesian Network Algorithm to Predict the Compressive Strength of Concrete. International Journal of Civil Infrastructure. 2021; 4 ():33-40.

Chicago/Turabian Style

Omar Najm; Hilal El-Hassan; Amr El-Dieb; Hamad Aljassmi. 2021. "Utilization of a Bayesian Network Algorithm to Predict the Compressive Strength of Concrete." International Journal of Civil Infrastructure 4, no. : 33-40.

Journal article
Published: 01 January 2021 in International Journal of Civil Infrastructure
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ACS Style

Mohammed Alzard; Hilal El-Hassan; Tamer El-Maaddawy. Life Cycle Inventory for the Production of Recycled Concrete Aggregates in the United Arab Emirates. International Journal of Civil Infrastructure 2021, 4, 78 -84.

AMA Style

Mohammed Alzard, Hilal El-Hassan, Tamer El-Maaddawy. Life Cycle Inventory for the Production of Recycled Concrete Aggregates in the United Arab Emirates. International Journal of Civil Infrastructure. 2021; 4 ():78-84.

Chicago/Turabian Style

Mohammed Alzard; Hilal El-Hassan; Tamer El-Maaddawy. 2021. "Life Cycle Inventory for the Production of Recycled Concrete Aggregates in the United Arab Emirates." International Journal of Civil Infrastructure 4, no. : 78-84.

Journal article
Published: 01 January 2021 in International Journal of Civil Infrastructure
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ACS Style

Shahrukh Shoaib; Hilal El-Hassan; Bilal El-Ariss; Tamer El-Maaddawy. Workability and Early-Age Strength of Recycled Aggregate Concrete Incorporating Basalt Fibers. International Journal of Civil Infrastructure 2021, 4, 68 -77.

AMA Style

Shahrukh Shoaib, Hilal El-Hassan, Bilal El-Ariss, Tamer El-Maaddawy. Workability and Early-Age Strength of Recycled Aggregate Concrete Incorporating Basalt Fibers. International Journal of Civil Infrastructure. 2021; 4 ():68-77.

Chicago/Turabian Style

Shahrukh Shoaib; Hilal El-Hassan; Bilal El-Ariss; Tamer El-Maaddawy. 2021. "Workability and Early-Age Strength of Recycled Aggregate Concrete Incorporating Basalt Fibers." International Journal of Civil Infrastructure 4, no. : 68-77.

Review article
Published: 22 December 2020 in Journal of Cleaner Production
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Ladle slag is a by-product of secondary steel treatment. A typical management option for ladle slag is stockpiling in open yards. Given the massive production quantities of such material, this disposal mechanism has posed major environmental concerns over the years. The construction industry is a potential area that may recycle ladle slag as a sustainable replacement to cement binder, thereby reducing the consumption of cement, conserving natural resources, and alleviating greenhouse gas emissions. Accordingly, this paper provides a state-of-the-art review of the generation, characteristics, and reaction mechanisms of ladle slag. The effect of utilizing ladle slag on the fresh and hardened properties and microstructure of alkali-activated mortar and cement-based conventional and self-compacting concrete is also reviewed. Findings highlighted that utilizing ladle slag by the concrete industry is possible with favorable properties when certain preprocessing measurements, such as milling, sieving, and gypsum addition, are implemented. Furthermore, it is concluded that the degree of reaction and performance of alkali-activated mortar and concrete are dependent on the curing temperature and the type and components of the alkaline activator solution. Also, the replacement of 20% cement with ladle slag does not compromise the strength and durability aspects of cement-based concrete. From an environmental perspective, ladle slag is considered a non-hazardous material suitable for use in construction applications. The research gaps in the existing knowledge and future research directions are also identified.

ACS Style

Omar Najm; Hilal El-Hassan; Amr El-Dieb. Ladle slag characteristics and use in mortar and concrete: A comprehensive review. Journal of Cleaner Production 2020, 288, 125584 .

AMA Style

Omar Najm, Hilal El-Hassan, Amr El-Dieb. Ladle slag characteristics and use in mortar and concrete: A comprehensive review. Journal of Cleaner Production. 2020; 288 ():125584.

Chicago/Turabian Style

Omar Najm; Hilal El-Hassan; Amr El-Dieb. 2020. "Ladle slag characteristics and use in mortar and concrete: A comprehensive review." Journal of Cleaner Production 288, no. : 125584.

Conference paper
Published: 01 November 2020 in Proceedings of the 4th International Conference on Civil, Structural and Transportation Engineering (ICCSTE'19)
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ACS Style

Shahrukh Shoaib; Hilal El-Hassan; Bilal El-Aris; Tamer El Maaddawy. Early-Age Strength and Workability of Basalt Fiber ReinforcedConcrete Made with Recycled Aggregates – A Pilot Study. Proceedings of the 4th International Conference on Civil, Structural and Transportation Engineering (ICCSTE'19) 2020, 1 .

AMA Style

Shahrukh Shoaib, Hilal El-Hassan, Bilal El-Aris, Tamer El Maaddawy. Early-Age Strength and Workability of Basalt Fiber ReinforcedConcrete Made with Recycled Aggregates – A Pilot Study. Proceedings of the 4th International Conference on Civil, Structural and Transportation Engineering (ICCSTE'19). 2020; ():1.

Chicago/Turabian Style

Shahrukh Shoaib; Hilal El-Hassan; Bilal El-Aris; Tamer El Maaddawy. 2020. "Early-Age Strength and Workability of Basalt Fiber ReinforcedConcrete Made with Recycled Aggregates – A Pilot Study." Proceedings of the 4th International Conference on Civil, Structural and Transportation Engineering (ICCSTE'19) , no. : 1.

Conference paper
Published: 01 November 2020 in Proceedings of the 4th International Conference on Civil, Structural and Transportation Engineering (ICCSTE'19)
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ACS Style

Mohammed Alzard; Hilal El-Hassan; Tamer El Maaddawy. Development of a Life Cycle Inventory Dataset for Recycled Concrete Aggregates in the City of Abu Dhabi. Proceedings of the 4th International Conference on Civil, Structural and Transportation Engineering (ICCSTE'19) 2020, 1 .

AMA Style

Mohammed Alzard, Hilal El-Hassan, Tamer El Maaddawy. Development of a Life Cycle Inventory Dataset for Recycled Concrete Aggregates in the City of Abu Dhabi. Proceedings of the 4th International Conference on Civil, Structural and Transportation Engineering (ICCSTE'19). 2020; ():1.

Chicago/Turabian Style

Mohammed Alzard; Hilal El-Hassan; Tamer El Maaddawy. 2020. "Development of a Life Cycle Inventory Dataset for Recycled Concrete Aggregates in the City of Abu Dhabi." Proceedings of the 4th International Conference on Civil, Structural and Transportation Engineering (ICCSTE'19) , no. : 1.

Journal article
Published: 09 September 2020 in Water
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This study investigates the impact of eggshell particle size and solid-to-water (s/w) ratio on lead (Pb2+) removal from aqueous solution. Collected raw eggshells were washed, crushed, and sieved into two particle sizes (2+ removal experiments were conducted at different s/w ratios with initial Pb2+ concentrations of up to 70 mg/L. The contribution of precipitation to Pb2+ removal was simulated by quantifying removal using eggshell water, whereas sorbed Pb2+ was quantified by acid digestion. Results indicated that eggshell particle sizes did not affect Pb2+ removal. High removal (up to 99%) of Pb2+ was achieved for low initial Pb2+ concentrations (2+ by eggshells. Yet, this role decreased as the s/w ratio and initial concentration of Pb2+ increased. A predictive relationship that relates the normalized removal capacity of eggshells to the s/w ratio was developed to potentially facilitate the design of the reactor.

ACS Style

Mohamed A. Hamouda; Haliemeh Sweidan; Munjed A. Maraqa; Hilal El-Hassan. Mechanistic Study of Pb2+ Removal from Aqueous Solutions Using Eggshells. Water 2020, 12, 2517 .

AMA Style

Mohamed A. Hamouda, Haliemeh Sweidan, Munjed A. Maraqa, Hilal El-Hassan. Mechanistic Study of Pb2+ Removal from Aqueous Solutions Using Eggshells. Water. 2020; 12 (9):2517.

Chicago/Turabian Style

Mohamed A. Hamouda; Haliemeh Sweidan; Munjed A. Maraqa; Hilal El-Hassan. 2020. "Mechanistic Study of Pb2+ Removal from Aqueous Solutions Using Eggshells." Water 12, no. 9: 2517.

Research article
Published: 25 August 2020 in Journal of Sustainable Cement-Based Materials
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The flexural performance of steel fiber-reinforced concrete made with recycled concrete aggregates (RCA) and desert dune sand was investigated. Natural aggregates were replaced by 30, 70, and 100% RCA. Steel fibers were incorporated into mixes in 1, 2, and 3% volume fractions. To evaluate the flexural behavior of plain and steel fiber-reinforced RCA concrete mixes, three- and four-point bending tests were conducted. Experimental results showed that RCA replacement had a predominant impact on compression behavior compared to steel fiber addition, while the latter was more influential on flexural performance. Higher pre-peak slope, flexural strength, deflection, toughness, and equivalent flexural ratio were noted when steel fibers were added to RCA-based concrete tested under four-point bending. Similar improvement in flexural performance was reported from load-crack mouth opening displacement curves of three-point bending tests. Accordingly, analytical regression models were developed to correlate the different properties obtained from these two flexural bending test results.

ACS Style

Nancy Kachouh; Hilal El-Hassan; Tamer El-Maaddawy. Influence of steel fibers on the flexural performance of concrete incorporating recycled concrete aggregates and dune sand. Journal of Sustainable Cement-Based Materials 2020, 10, 165 -192.

AMA Style

Nancy Kachouh, Hilal El-Hassan, Tamer El-Maaddawy. Influence of steel fibers on the flexural performance of concrete incorporating recycled concrete aggregates and dune sand. Journal of Sustainable Cement-Based Materials. 2020; 10 (3):165-192.

Chicago/Turabian Style

Nancy Kachouh; Hilal El-Hassan; Tamer El-Maaddawy. 2020. "Influence of steel fibers on the flexural performance of concrete incorporating recycled concrete aggregates and dune sand." Journal of Sustainable Cement-Based Materials 10, no. 3: 165-192.

Conference paper
Published: 08 July 2020 in High Performance Fiber Reinforced Cement Composites 6
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This paper examines the performance of 3D-printed concrete made with locally abundant desert dune sand. Cement was replaced by up to 10% silica fume and 30% fly ash to reduce its detrimental environmental footprint. The water-to-binder ratio used in the mix ranged between 0.35 and 0.40. Also, a superplasticizer was added in the range of 1 to 3%, by binder mass. Concrete mixes were proportioned to attain optimum fresh and hardened properties. A control mix with crushed dolomitic limestone aggregates served as a reference. The performance of 3D-printed concrete mixes was assessed based on slump flow, pumpability, and compressive strength. Experimental results showed a reduction in slump flow and pumpability with an increase in dune sand content. In turn, the compressive strength increased by 3% when 20% dune sand was utilized, but decreased by an average of 3% for every additional 10% subsequently. Concrete mixes incorporating a superplasticizer and higher water-to-binder ratio exhibited improved workability. While the former caused limited change to compressive strength, the latter resulted in a notable decrease. Upon replacing cement with silica fume and fly ash, the slump flow and pumpability increased. In fact, 3D-printed concrete made with 3% superplasticizer, 20% fly ash, and 10% silica fume experienced a 230 and 79% increase in slump flow and pumpability, respectively. Compressive strength increased by an average of 4% for every 10% fly ash replacement. The incorporation of 10% silica fume improved the strength by an additional 14%. Analytical models were developed to correlate slump flow to pumpability and 3D-printed concrete compressive strength to that of typical concrete cubes, serving as guidelines to produce optimal concrete mixes for large-scale concrete 3D printers.

ACS Style

Hilal El-Hassan; Fady Alnajjar; Hamad Al Jassmi; Waleed Ahmed. Fresh and Hardened Properties of 3D-Printed Concrete Made with Dune Sand. High Performance Fiber Reinforced Cement Composites 6 2020, 225 -234.

AMA Style

Hilal El-Hassan, Fady Alnajjar, Hamad Al Jassmi, Waleed Ahmed. Fresh and Hardened Properties of 3D-Printed Concrete Made with Dune Sand. High Performance Fiber Reinforced Cement Composites 6. 2020; ():225-234.

Chicago/Turabian Style

Hilal El-Hassan; Fady Alnajjar; Hamad Al Jassmi; Waleed Ahmed. 2020. "Fresh and Hardened Properties of 3D-Printed Concrete Made with Dune Sand." High Performance Fiber Reinforced Cement Composites 6 , no. : 225-234.

Journal article
Published: 03 February 2020 in Construction and Building Materials
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The durability performance of basalt fiber-reinforced polymer (BFRP) reinforcing bars conditioned for 3, 6, and 9 months at temperatures of 20, 40, and 60 °C was investigated. BFRP specimens were exposed to two environments: moist concrete and an alkaline solution simulating the concrete pore solution. Correlations among tensile strength, moisture uptake, matrix digestion, and microstructure characteristics were furnished. The degree of deterioration was more sensitive to the conditioning temperature than the conditioning duration. The tensile strength retentions of the specimens conditioned in the alkaline solution at a temperature not exceeding 40 °C were comparable to those conditioned in the moist concrete environment irrespective of the conditioning duration. Conditioning in the alkaline solution at 60 °C for a duration ≥6 months had a more detrimental effect on the microstructure and strength of the BFRP than encasing in moist concrete. After 9 months of exposure at 60 °C, the specimens conditioned in the alkaline solution lost 29% of the initial tensile strength while those encased in moist concrete lost only 15%. The intensified tensile strength reduction caused by the former conditioning scheme was due to disintegration of the matrix and degraded fiber-matrix interfacial bond caused by a higher moisture uptake and development of more hydroxyl groups during conditioning. The accelerated aging test results were utilized to develop a master curve for service life prediction of BFRP bars.

ACS Style

Mohamed Al Rifai; Hilal El-Hassan; Tamer El-Maaddawy; Farid Abed. Durability of basalt FRP reinforcing bars in alkaline solution and moist concrete environments. Construction and Building Materials 2020, 243, 118258 .

AMA Style

Mohamed Al Rifai, Hilal El-Hassan, Tamer El-Maaddawy, Farid Abed. Durability of basalt FRP reinforcing bars in alkaline solution and moist concrete environments. Construction and Building Materials. 2020; 243 ():118258.

Chicago/Turabian Style

Mohamed Al Rifai; Hilal El-Hassan; Tamer El-Maaddawy; Farid Abed. 2020. "Durability of basalt FRP reinforcing bars in alkaline solution and moist concrete environments." Construction and Building Materials 243, no. : 118258.

Journal article
Published: 01 October 2019 in Journal of Materials in Civil Engineering
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ACS Style

Hilal El-Hassan; Said Elkholy. Performance Evaluation and Microstructure Characterization of Steel Fiber–Reinforced Alkali-Activated Slag Concrete Incorporating Fly Ash. Journal of Materials in Civil Engineering 2019, 31, 04019223 .

AMA Style

Hilal El-Hassan, Said Elkholy. Performance Evaluation and Microstructure Characterization of Steel Fiber–Reinforced Alkali-Activated Slag Concrete Incorporating Fly Ash. Journal of Materials in Civil Engineering. 2019; 31 (10):04019223.

Chicago/Turabian Style

Hilal El-Hassan; Said Elkholy. 2019. "Performance Evaluation and Microstructure Characterization of Steel Fiber–Reinforced Alkali-Activated Slag Concrete Incorporating Fly Ash." Journal of Materials in Civil Engineering 31, no. 10: 04019223.

Journal article
Published: 01 July 2019 in Construction and Building Materials
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ACS Style

Nancy Kachouh; Hilal El-Hassan; Tamer El Maaddawy. Effect of steel fibers on the performance of concrete made with recycled concrete aggregates and dune sand. Construction and Building Materials 2019, 213, 348 -359.

AMA Style

Nancy Kachouh, Hilal El-Hassan, Tamer El Maaddawy. Effect of steel fibers on the performance of concrete made with recycled concrete aggregates and dune sand. Construction and Building Materials. 2019; 213 ():348-359.

Chicago/Turabian Style

Nancy Kachouh; Hilal El-Hassan; Tamer El Maaddawy. 2019. "Effect of steel fibers on the performance of concrete made with recycled concrete aggregates and dune sand." Construction and Building Materials 213, no. : 348-359.

Conference paper
Published: 01 May 2019 in Proceedings of International Structural Engineering and Construction
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This paper aims to investigate the mechanical performance of steel fiber-reinforced geopolymer concrete made with fly ash and ground granulated blast furnace slag as blended aluminosilicate source material. To activate the binding phase, combinations of sodium silicate (SS) and sodium hydroxide (SH) solutions with three different molarities (8M, 10M, and 14M) were used. Steel fibers were added to the geopolymer concrete mix in varying proportions up to 3%, by volume. Constant binder, activator solution, and aggregate contents were adopted for all 13 mixes. Samples were cast and cured at ambient conditions for measuring the rheological and mechanical properties, including slump, modulus of elasticity, compressive strength, tensile splitting strength, and flexural strength. Experimental test results show that geopolymers made with higher molarity of SH were less workable but had improved mechanical performance. The effect of adding steel fibers on the mechanical performance was more apparent at an early age and in weaker geopolymer concretes. Additionally, scanning electron microscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy highlighted the co-existence of calcium aluminosilicate hydrate and sodium aluminosilicate hydrate gels.

ACS Style

Said Elkholy; Hilal El-Hassan. MECHANICAL AND MICRO-STRUCTURE CHARACTERIZATION OF STEEL FIBER-REINFORCED GEOPOLYMER CONCRETE. Proceedings of International Structural Engineering and Construction 2019, 6, 1 .

AMA Style

Said Elkholy, Hilal El-Hassan. MECHANICAL AND MICRO-STRUCTURE CHARACTERIZATION OF STEEL FIBER-REINFORCED GEOPOLYMER CONCRETE. Proceedings of International Structural Engineering and Construction. 2019; 6 (1):1.

Chicago/Turabian Style

Said Elkholy; Hilal El-Hassan. 2019. "MECHANICAL AND MICRO-STRUCTURE CHARACTERIZATION OF STEEL FIBER-REINFORCED GEOPOLYMER CONCRETE." Proceedings of International Structural Engineering and Construction 6, no. 1: 1.

Journal article
Published: 02 April 2019 in Construction and Building Materials
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The properties of pervious concrete made with recycled concrete aggregates (RCA) were investigated. Natural aggregates were replaced by RCA at levels of 0, 10, 20, 40, 70, and 100%. Slag was also incorporated to enhance the performance and sustainability of the concrete mixtures. Slump, hardened density, total void content, porosity, permeability, compressive strength, tensile splitting strength, flexural strength, and abrasion resistance were determined. Results showed that the RCA replacement led to an increase in total void content, porosity, and permeability, while a decrease in slump and hardened density was noted. The mechanical properties and abrasion resistance were adversely affected due to the weak RCA and aggregate-mortar interface. The clogging potential of pervious RCA concrete was also assessed over a simulated 20-year lifespan. Permeability could be restored to acceptable, but lower, levels through pressurized water washing. RCA limited the restoration of permeability of pervious concrete, while slag facilitated it. Analytical models were developed to correlate physical, transport, mechanical, and durability properties. Codified equations were assessed for their applicability. Experimental findings highlight the ability to use pervious RCA concrete in pavement applications.

ACS Style

Hilal El-Hassan; Peiman Kianmehr; Souhail Zouaoui. Properties of pervious concrete incorporating recycled concrete aggregates and slag. Construction and Building Materials 2019, 212, 164 -175.

AMA Style

Hilal El-Hassan, Peiman Kianmehr, Souhail Zouaoui. Properties of pervious concrete incorporating recycled concrete aggregates and slag. Construction and Building Materials. 2019; 212 ():164-175.

Chicago/Turabian Style

Hilal El-Hassan; Peiman Kianmehr; Souhail Zouaoui. 2019. "Properties of pervious concrete incorporating recycled concrete aggregates and slag." Construction and Building Materials 212, no. : 164-175.