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Full-Text Articles in Architectural Engineering
Prediction Of Self-Consolidating Concrete Properties Using Xgboost Machine Learning Algorithm: Part 1–Workability, Amine El Mahdi Safhi, Hamed Dabiri, Ahmed Soliman, Kamal Khayat
Prediction Of Self-Consolidating Concrete Properties Using Xgboost Machine Learning Algorithm: Part 1–Workability, Amine El Mahdi Safhi, Hamed Dabiri, Ahmed Soliman, Kamal Khayat
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The Interest in Implementing Self-Consolidating Concrete (SCC) in Major Construction Projects Has Increased Significantly in Recent Years. This Paper Reports the Results of an Extensive Survey of Experimental Data of More Than 1700 SCC Mixtures from over 100 Studies Published in the Last Decade. the Survey Included the SCC Mixture Proportioning, Key Fresh Properties Including Flowability, Passing Ability, and Segregation Resistance, as Well as Some of the Derived Properties (E.g., Paste Volume). the Statistical Analysis of the Reported Parameters Showed Wide Variations in Values. the Outcome of the Survey Indicates that SCC Mixture Design and Workability Properties Do Not Systematically …
The Use Of Gpr To Investigate The Effect Of Steel Fiber Distribution On The Mechanical Behavior Of Frc, Paola Machado Barreto Manhães, José Tavares Araruna Júnior, Genda Chen, Neil Lennart Anderson, Erik Valloti Pereira, Flávio De Andrade Silva
The Use Of Gpr To Investigate The Effect Of Steel Fiber Distribution On The Mechanical Behavior Of Frc, Paola Machado Barreto Manhães, José Tavares Araruna Júnior, Genda Chen, Neil Lennart Anderson, Erik Valloti Pereira, Flávio De Andrade Silva
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The present work focuses on the steel fiber distribution in self-consolidating concrete short beams. The objective is to assess the feasibility of the ground penetrating radar (GPR) in evaluating the homogeneity of fibers within concrete materials, for use in testing laboratories to study the modes of placing and compaction employed for preparing specimens during quality control or material development. Self-consolidating concrete beams were cast, tested, and evaluated. A GPR survey employing a concrete scanning system with a shielded 1.2 GHz center frequency was performed on self-consolidating casted short beams just before a monotonic four-point bending test was carried out. After …
Evaluating Prediction Models Of Creep And Drying Shrinkage Of Self-Consolidating Concrete Containing Supplementary Cementitious Materials/Fillers, Micheal Asaad, George Morcous
Evaluating Prediction Models Of Creep And Drying Shrinkage Of Self-Consolidating Concrete Containing Supplementary Cementitious Materials/Fillers, Micheal Asaad, George Morcous
Durham School of Architectural Engineering and Construction: Faculty Publications
Supplementary cementitious materials (SCMs) and fillers play an important role in enhancing the mechanical properties and durability of concrete. SCMs and fillers are commonly used in self-consolidating concrete (SCC) mixtures to also enhance their rheological properties. However, these additives could have significant effects on the viscoelastic properties of concrete. Existing models for predicting creep and drying shrinkage of concrete do not consider the effect of SCM/filler on the predicted values. This study evaluates existing creep and drying shrinkage models, including AASHTO LRFD, ACI209, CEB-FIP MC90-99, B3, and GL2000, for SCC mixtures with different SCMs/fillers. Forty SCC mixtures were proportioned for …
Rheological Properties Considering The Effect Of Aggregates On Concrete Slump Flow, Tae Yong Shin, Jae Hong Kim, Seong Ho Han
Rheological Properties Considering The Effect Of Aggregates On Concrete Slump Flow, Tae Yong Shin, Jae Hong Kim, Seong Ho Han
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Rheology of concrete allows us to understand the flow behavior of concrete and further extend the quantitative evaluation of its construction performance. The use of a concrete rheometer is promising for the purpose but sometimes limited high associated cost and procedure complexity. This study proposes a simulation-based model that correlates the slump flow test results to a concrete's rheological properties, allowing quantitative evaluation through this simple method. The proposed model is based on single-fluid simulation using the volume-of-fluid method, with an extension to accommodate the partial segregation of coarse aggregates. Either the channel flow or the L-shaped panel filling of …
Effect Of Placement Characteristics On Scc Lateral Pressure Variations, A. F. Omran, Y. M. Elaguab, Kamal Khayat
Effect Of Placement Characteristics On Scc Lateral Pressure Variations, A. F. Omran, Y. M. Elaguab, Kamal Khayat
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Lateral pressure exerted by fresh concrete on vertical formwork systems controls significantly the design of the formwork systems. Several factors including, material properties, placement conditions, and formwork characteristics can affect formwork lateral pressure. This paper presents the results of an extensive experimental work aimed at studying the influence of concrete temperature (10-32 °C), casting depth (up to 13 m), placement rate (2-30 m/h), waiting period between successive lifts, as well as concrete thixotropy on lateral pressure characteristics. The increase of concrete temperature is shown to accelerate the stiffening rate of the concrete leading to reduction in initial lateral pressure. For …
Effects Of Mix Design Parameters And Rheological Properties On Dynamic Stability Of Self-Consolidating Concrete, B. Esmaeilkhanian, Kamal Khayat, A. Yahia, D. Feys
Effects Of Mix Design Parameters And Rheological Properties On Dynamic Stability Of Self-Consolidating Concrete, B. Esmaeilkhanian, Kamal Khayat, A. Yahia, D. Feys
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Stability is a crucial property for successful placement and performance of self-consolidating concrete (SCC). Dynamic stability refers to the segregation resistance of concrete during flow and is not thoroughly described in literature to date. In this research, a newly developed dynamic stability test, the Tilting-box test, was employed to evaluate the effect of different mix design parameters on the dynamic segregation of SCC. Paste volume, water-to-binder ratio (w/b), maximum size of aggregate (MSA), aggregate density, and aggregate grain-size distribution were shown to affect the dynamic stability of SCC, while the coarse aggregate shape did not have a significant influence. The …
Shear Strength Of Chemically Based Self-Consolidating Concrete Beams: Fracture Mechanics Approach Versus Modified Compression Field Theory, Mahdi Arezoumandi, Jeffery S. Volz
Shear Strength Of Chemically Based Self-Consolidating Concrete Beams: Fracture Mechanics Approach Versus Modified Compression Field Theory, Mahdi Arezoumandi, Jeffery S. Volz
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
An experimental investigation was conducted to study the shear strength of full-scale beams constructed with both chemically based self-consolidating concrete (SCC) and conventional concrete (CC). This experimental program consisted of 12 beams without stirrups with three different longitudinal reinforcement ratios. The beams were tested under a simply supported four-point loading condition. The experimental shear strengths of the beams were compared with the shear provisions of both U.S. and international design codes. Furthermore, the shear strengths of the beams were evaluated based on fracture mechanics approaches, modified compression field theory (MCFT), and a shear database of CC specimens. Results of this …
Form Pressure Generated By Fresh Concrete: A Review About Practice In Formwork Design, Tilo Proske, Kamal Khayat, Ahmed Omran, Olaf Leitzbach
Form Pressure Generated By Fresh Concrete: A Review About Practice In Formwork Design, Tilo Proske, Kamal Khayat, Ahmed Omran, Olaf Leitzbach
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In this paper, several current industrial practices in formwork design are presented focusing on the normative calculation of the form pressure. Most of the current Standards are devoting for the design of the formwork for the normal vibrated concrete. Currently, the Standards are being updated to include provisions for the newly adapted concrete, such as the flowable concrete and self-consolidating concrete. However, the experience with these methods is still limited. The available methods for calculating the formwork pressure for the flowable concrete and SCC are based on measuring the shear strength of concrete using different concepts, such as the setting …
Development Of A Tribometer To Characterize Lubrication Layer Properties Of Self-Consolidating Concrete, Dimitri Feys, Kamal Khayat, Aurelien Perez-Schell, Rami Khatib
Development Of A Tribometer To Characterize Lubrication Layer Properties Of Self-Consolidating Concrete, Dimitri Feys, Kamal Khayat, Aurelien Perez-Schell, Rami Khatib
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The Last Decade, Significant Advances Have Been Made in Investigating, Understanding and Predicting the Flow Characteristics during Pumping of Concrete. Kaplan Developed Theoretical Equations based on the Rheological and Tribological Properties of Concrete to Predict Pumping Pressures. Several Tribometers Were Developed to Characterize the Flow Properties of Concrete Along a Smooth Wall, But None of Them Allows the Use of Highly Workable Concretes. the Main Reason is that for the Calculation of the Yield Stress and Viscous Constant of the Lubrication Layer, the Concrete is Not Allowed to Be Sheared. in This Paper, a New Design for the Concrete Tribometer …
Portable Pressure Device To Evaluate Lateral Formwork Pressure Exerted By Fresh Concrete, Ahmed F. Omran, Kamal H. Khayat
Portable Pressure Device To Evaluate Lateral Formwork Pressure Exerted By Fresh Concrete, Ahmed F. Omran, Kamal H. Khayat
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Use of a reliable and accurate measuring system to determine lateral pressure exerted on formwork by self-consolidating concrete can lead to economic and safe formwork systems. In this paper, a portable and field-compatible pressure device is developed to enable factors affecting lateral pressure of fresh concrete on formwork system to be explored prior to conducting onsite full-scale tests. The pressure device requires a sample of 16 L of fresh concrete to determine lateral pressure envelope that can be exerted by a concrete column of up to 13 m in height. The pressure device enables the simulation of such concrete head …
An Experimental Study On Shear Strength Of Chemically-Based Self-Consolidating Concrete, Mahdi Arezoumandi, Jeffery S. Volz
An Experimental Study On Shear Strength Of Chemically-Based Self-Consolidating Concrete, Mahdi Arezoumandi, Jeffery S. Volz
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
An experimental investigation was conducted to compare the shear strength of full-scale beams constructed with chemically based, self-consolidating concrete (SCC) with conventional concrete (CC). This experimental program consisted of 16 rectangular beams (12 without shear reinforcing and 4 with shear reinforcing in the form of stirrups), 8 beams for each mix design. Additionally, three different longitudinal reinforcement ratios were evaluated within the test matrix. The beam specimens were tested under a simply supported four-point condition. The experimental shear strengths of the beams were compared with both the shear provisions of selected standards (U.S., Australia, Canada, Europe, and Japan) and a …
Statistical Modelling Of The Coupled Effect Of Mix Design And Rebar Spacing On Restricted Flow Characteristics Of Scc, Yahia Ammar, Khayat H. Kamal, Sayed Mohammed
Statistical Modelling Of The Coupled Effect Of Mix Design And Rebar Spacing On Restricted Flow Characteristics Of Scc, Yahia Ammar, Khayat H. Kamal, Sayed Mohammed
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Self-consolidating concrete (SCC) is designed to exhibit high deformability and stability to maintain homogenous suspension of coarse aggregate particles in the mortar during flow to ensure adequate passing ability of the concrete through restricted areas and the filling of the formwork without any consolidation. Proper deformability and uniform suspension of coarse aggregate particles in the matrix are key parameters to ensure successful casting and adequate in situ performance. the required flow properties of concrete are affected by the rheological properties of the mixture and the characteristics of the cast element, including the level of reinforcement. the mixture proportioning of SCC …
An Experimental Study On Bond Strength Of Reinforcing Steel In Self-Consolidating Concrete, Trevor J. Looney, Mahdi Arezoumandi, Jeffery S. Volz, John J. Myers
An Experimental Study On Bond Strength Of Reinforcing Steel In Self-Consolidating Concrete, Trevor J. Looney, Mahdi Arezoumandi, Jeffery S. Volz, John J. Myers
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
An experimental investigation was conducted to compare the bond strength of reinforcing steel in self-consolidating concrete (SCC) with conventional concrete (CC). This study investigated two different compressive strengths of SCC as well as CC. the experimental program consisted of 24 pull-out specimens as well as 12 full-scale beams (three for each concrete type and strength). the pull-out specimens were based on RILEM recommendations, and the beam specimens were tested under a simply supported four-point loading condition. the CC test results served as a control and were used to evaluate the results from the SCC pull-out and beam specimen tests. Furthermore, …
Development And Testing Of Chemically-Based Self-Consolidating Concrete, Mahdi Arezoumandi, Mark Ezzell, Jeffery S. Volz
Development And Testing Of Chemically-Based Self-Consolidating Concrete, Mahdi Arezoumandi, Mark Ezzell, Jeffery S. Volz
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Self-consolidating concrete (SCC) has the potential to significantly reduce costs associated with concrete construction. SCC is a highly flowable, Non segregating concrete that has a variety of advantages over conventional concrete (CC). However, SCC is not without its problems, which can include increased creep and shrinkage, as well as decreased bond and shear strength. the goal of this research project was to evaluate the creep, shrinkage, and shear behavior of a chemically Based SCC mix. One of the benefits of a chemically Based approach is the potential to eliminate the negative side effects of many SCC mixes. the investigation included …
High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 2: Structural Behavior, Jared E. Brewe, John J. Myers
High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 2: Structural Behavior, Jared E. Brewe, John J. Myers
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The design of prestressed concrete members is restricted by the requirement that the extreme compressive fiber stress at midspan be less than 60% of the concrete compressive strength at release of prestressing. the purported purpose of this limit is to provide serviceability performance, but it places unnecessary limits on the capability of the materials. for this research program, six prestressed concrete girders were produced with high-strength, self-consolidating concrete and subjected to elevated compressive fiber stress levels ranging from 65% to 84% of initial concrete compressive strength at release of prestressing. Part 1 of this series analyzed time-dependent prestress losses and …
High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 1: Prestress Loss And Camber Behavior, Jared E. Brewe, John J. Myers
High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 1: Prestress Loss And Camber Behavior, Jared E. Brewe, John J. Myers
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The design of prestressed concrete members is restricted by the requirement that the extreme compressive fiber stress at midspan of simply supported members be less than 60% of the concrete compressive strength at release of prestressing. the purported purpose of this limit is to address serviceability performance, but it places unnecessary limits on the capability of the materials. for this research program, six prestressed concrete girders were produced with high-strength self-consolidating concrete and subjected to compressive fiber stress levels ranging from 65% to 84% of the concrete compressive strength at release of prestressing. Time dependent concrete surface strains were measured …