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Missouri University of Science and Technology

Stability

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

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Full-Text Articles in Engineering

Viscosity Modifying Agents: Key Components Of Advanced Cement-Based Materials With Adapted Rheology, Hela Bessaies-Bey, Kamal Khayat, Marta Palacios, Wolfram Schmidt, Nicolas Roussel Feb 2022

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 …


A Stabilized Rbf Collocation Scheme For Neumann Type Boundary Value Problems, Nicolas Ali Libre, Arezoo Emdadi, Edward J. Kansa, Mohammad Rahimian, Mohammad Shekarchi Jan 2008

A Stabilized Rbf Collocation Scheme For Neumann Type Boundary Value Problems, Nicolas Ali Libre, Arezoo Emdadi, Edward J. Kansa, Mohammad Rahimian, Mohammad Shekarchi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The numerical solution of partial differential equations (PDEs) with Neumann boundary conditions (BCs) resulted from strong form collocation scheme are typically much poorer in accuracy compared to those with pure Dirichlet BCs. In this paper, we show numerically that the reason of the reduced accuracy is that Neumann BC requires the approximation of the spatial derivatives at Neumann boundaries which are significantly less accurate than approximation of main function. Therefore, we utilize boundary treatment schemes that based upon increasing the accuracy of spatial derivatives at boundaries. Increased accuracy of the spatial derivative approximation can be achieved by h-refmement reducing the …