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Full-Text Articles in Architecture
Synergistic Effect Of Shrinkage Mitigating Materials On Rheological Properties Of Flowable And Thixotropic Cement Paste, Kamran Aghaee, Ricarda Sposito, Kamal Khayat
Synergistic Effect Of Shrinkage Mitigating Materials On Rheological Properties Of Flowable And Thixotropic Cement Paste, Kamran Aghaee, Ricarda Sposito, Kamal Khayat
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This study investigates the effect of individual and combined additions of CaO-based expansive agent (EA), shrinkage reducing admixture (SRA), and super absorbent polymer (SAP) on key characteristics of flowable cement paste mixtures proportioned with a water-to-cement ratio of 0.40. Of special interest is the effectiveness of these admixtures to mitigate shrinkage of cementitious materials for 3D printing. Static and dynamic yield stress, plastic and apparent viscosities, and thixotropy were evaluated at 20-min intervals up to 90 min. Compressive strength development and autogenous shrinkage were also determined. A factorial design approach was developed to evaluate the synergetic effects of the shrinkage …
Homogenous Flow Performance Of Steel Fiber-Reinforced Self-Consolidating Concrete For Repair Applications: Developing A New Empirical Set-Up, Naimeh Nouri, Masoud Hosseinpoor, Ammar Yahia, Kamal Khayat
Homogenous Flow Performance Of Steel Fiber-Reinforced Self-Consolidating Concrete For Repair Applications: Developing A New Empirical Set-Up, Naimeh Nouri, Masoud Hosseinpoor, Ammar Yahia, Kamal Khayat
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In this study, a new empirical Square-Box test was employed to evaluate the homogeneous flow performance of fiber-reinforced self-consolidating concrete (FR-SCC) under confined-flow conditions that are typical of repair applications. The Square-Box set-up consisted of a closed-circuit box, providing 2.4-m flow distance and a closed-surface cross section of 100-mm width and 200-mm height, equipped with 0 and 4 rows of reinforcing bar grids with 45-mm clear spacing. The flow performance was assessed in terms of dynamic stability and passing ability. The investigated mixtures were considered as diphasic suspensions of fiber-coarse aggregate (F-A > 5 mm) in suspending mortars containing particles finer …
Quantifying The Workability Of Calcium Sulfoaluminate Cement Paste Using Time-Dependent Rheology, Sukanta K. Mondal, Adam Welz, Carrie Clinton, Kamal Khayat, Aditya Kumar, Monday Uchenna Okoronkwo
Quantifying The Workability Of Calcium Sulfoaluminate Cement Paste Using Time-Dependent Rheology, Sukanta K. Mondal, Adam Welz, Carrie Clinton, Kamal Khayat, Aditya Kumar, Monday Uchenna Okoronkwo
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Poor workability is a common feature of calcium sulfoaluminate (CSA) cement paste. Multiple chemical admixtures, such as set retarders and dispersants, are frequently employed to improve the workability and delay the setting of CSA cement paste. A quantitative assessment of the compatibility, efficiency, and the effects of the admixtures on cement paste workability is critical for the design of an appropriate paste formulation and admixture proportioning. Very limited studies are available on the quantitative rheology-based method for evaluating the workability of calcium sulfoaluminate cement pastes. This study presents a novel and robust time-dependent rheological method for quantifying the workability of …
The Effect Of Sodium Polymethacrylate On The Rheology Of The Positive Paste And Performance Of The Lead-Acid Battery, Julian Kosacki, Dimitri Feys, Fatih Dogan
The Effect Of Sodium Polymethacrylate On The Rheology Of The Positive Paste And Performance Of The Lead-Acid Battery, Julian Kosacki, Dimitri Feys, Fatih Dogan
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Due to its rheological properties, positive lead-acid battery paste can be difficult to spread on lead current collectors accurately and efficiently under industry machinery and setting. Sodium polymethacrylate dispersant was studied as an effective positive paste additive that could lower the yield stress of the paste without affecting paste density and battery performance. Under a four-blade vane rheometer setup, stress growth and oscillatory amplitude strain sweep experiments evaluated the rheological properties of positive paste with the addition of varying amounts of sodium polymethacrylate. Further, the electrochemical effects of sodium polymethacrylate were also evaluated in 2V batteries by testing positive active …
Pumping Of Concrete: Understanding A Common Placement Method With Lots Of Challenges, Dimitri Feys, Geert De Schutter, Shirin Fataei, Nicos S. Martys, Viktor Mechtcherine
Pumping Of Concrete: Understanding A Common Placement Method With Lots Of Challenges, Dimitri Feys, Geert De Schutter, Shirin Fataei, Nicos S. Martys, Viktor Mechtcherine
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Several million cubic meters of concrete are pumped daily, as this technique permits fast concrete placement. Fundamental research has been performed and practical guidelines have been developed to increase the knowledge of concrete behavior in pipes. However, the pumping process and concrete behavior are not fully understood. This paper gives an overview of the current knowledge of concrete pumping. At first, the known physics governing the flow of concrete in pipes are introduced. A series of experimental techniques characterizing concrete flow behavior near a smooth wall to predict pressure-flow rate relationships are discussed, followed by recent developments in the use …
Novel Tri-Viscous Model To Simulate Pumping Of Flowable Concrete Through Characterization Of Lubrication Layer And Plug Zones, Tooran Tavangar, Masoud Hosseinpoor, Ammar Yahia, Kamal Khayat
Novel Tri-Viscous Model To Simulate Pumping Of Flowable Concrete Through Characterization Of Lubrication Layer And Plug Zones, Tooran Tavangar, Masoud Hosseinpoor, Ammar Yahia, Kamal Khayat
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In this study, computational fluid dynamics (CFD) was employed to simulate the pipe flow of 18 self-consolidating and four highly workable concrete mixtures in a 30-m long pumping circuit. Pressure loss (ΔP) in 100- and 125-mm diameter (DP) pipelines was measured under low (1.2–6.2 l/s) and high (8.1–16.4 l/s) flow rates (Q). The numerical simulation was successfully carried out using a two-fluid model and a new variable-viscosity single-fluid approach, namely double-Bingham and tri-viscous models, respectively. The radial variation of rheological properties of the concrete across the pipe section, representing the plug flow, sheared concrete, and lubrication layer (LL) zones was …
Viscosity Modifying Agents: Key Components Of Advanced Cement-Based Materials With Adapted Rheology, Hela Bessaies-Bey, Kamal Khayat, Marta Palacios, Wolfram Schmidt, Nicolas Roussel
Viscosity Modifying Agents: Key Components Of Advanced Cement-Based Materials With Adapted Rheology, Hela Bessaies-Bey, Kamal Khayat, Marta Palacios, Wolfram Schmidt, Nicolas Roussel
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Viscosity modifying agents (VMAs) are essential ingredients for the production of flowable cement-based materials. This paper presents an overview of commonly used VMAs and attempts to shed some light on the underlying physics at the origin of their mechanisms of action. The main molecular parameters of VMA controlling the rheological properties of the cement pore solution are highlighted. As the mechanisms of action of VMAs in cement-based materials are closely related to their affinity with the surface of cement particles, the adsorption of the main VMA types is discussed. The effect of VMAs on flow properties and stability of cement-based …