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Missouri University of Science and Technology

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2022

Molecular dynamics

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Full-Text Articles in Architecture

Enhancement Of Cement Paste With Carboxylated Carbon Nanotubes And Poly(Vinyl Alcohol), Yuyang Zhao, Jinrui Zhang, Gang Qiao, Dongshuai Hou, Biqin Dong, Hongyan Ma May 2022

Enhancement Of Cement Paste With Carboxylated Carbon Nanotubes And Poly(Vinyl Alcohol), Yuyang Zhao, Jinrui Zhang, Gang Qiao, Dongshuai Hou, Biqin Dong, Hongyan Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Cement has been a major consumable material for construction in the world since its invention, but its low flexural strength is the main defect affecting the service life of structures. To adapt cement-based materials to a more stringent environment, carboxylated carbon nanotubes (CNTs-COOH) and poly(vinyl alcohol) (PVA) are proposed to enhance the mechanical properties of cement paste. This study systematically verifies the synergistic effect of CNTs-COOH/PVA on the performance of cement paste. First, UV-Vis spectroscopy and FTIR spectroscopy prove that CNTs-COOH can provide attachment sites for PVA and PVA can improve the dispersion and stability of CNTs-COOH in water, which …


Molecular Insight Into The Fluidity Of Cement Pastes: Nano-Boundary Lubrication Of Cementitious Materials, Muhan Wang, Kaixuan Zhang, Xiang Ji, Pan Wang, Hongyan Ma, Jun Zhang, Dongshuai Hou Jan 2022

Molecular Insight Into The Fluidity Of Cement Pastes: Nano-Boundary Lubrication Of Cementitious Materials, Muhan Wang, Kaixuan Zhang, Xiang Ji, Pan Wang, Hongyan Ma, Jun Zhang, Dongshuai Hou

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The workability mechanism of fresh concrete at the molecular level remains essentially unexplored. To understand the molecular origin for cement fluidity, molecular dynamics and Density Function Theory (DFT) were utilized to construct a shear model of Calcium-Silicate-Hydrate (C-S-H) layers. The structure, dynamics, and reactivity of ultra-confined pore solution between C-S-H gels are systematically investigated. Under shear loading, periodic oscillation of friction force is observed as the typically Couette flow and the interfacial friction force is reduced from 35.2 Kcal/mol·Å to 3.3 Kcal/mol·Å with water content increasing. All of the systems contain breakage of noncovalent bonds of water-Ca and water-water in …