TY - JOUR

T1 - 2D bio-based nanomaterial as a green route to amplify the formation of hydrate phases of cement composites

T2 - Atomistic simulations and analytical characterization

AU - Chi, Yin

AU - Huang, Bo

AU - Saafi, Mohamed

AU - Fullwood, Nigel

AU - Lambert, Colin

AU - Whale, Eric

AU - Hepworth, David

AU - Ye, Jianqiao

N1 - This is the author’s version of a work that was accepted for publication in Construction and Building Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Construction and Building Materials, 299, 2021 DOI: 10.1016/j.conbuildmat.2021.123867

PY - 2021/9/13

Y1 - 2021/9/13

N2 - Ordinary Portland cement (OPC) is the binding element in concrete materials and, CO2 emissions associated with its manufacturing and use is about 8% of the world's CO2 emissions. The engineering properties of hardened concrete depend on the amount of the hydrate phases in OPC. If the growth of the hydrate phases could be increased, the performance of concrete would be significantly improved, and the consumption of OPC will be decreased, and its environmental footprint will be reduced. In this paper, we present a new green approach for controlling the growth of the hydrate phases in OPC using bio flakes composed of staked carrot-based two-dimensional (2D) nanosheets (CNSs) synthesized from carrot waste. Density-functional theory and reactive molecular dynamics (DFT-MD) simulations were carried out in conjunction with analytical characterization to examine the interfacial interaction between CNS with tricalcium silicate Ca3SiO5 (C3S), the main constituent of OPC and understand how they influence the growth of the hydrate phases in OPC. The DFT-MD simulations results show the 2D CNS dissolves due to its interfacial interaction with the highly reactive C3S, leading to a series of fast proton exchange in C3S. This in return accelerates the dissolution rate of C3S thereby amplifying the growth of the hydrate phases. The DFT-MD simulations also show that the dissolution of the 2D CNS creates new several organic compounds that enhance the mobility and dynamics of protons that further amplify the dissolution rate of C3S. The analytical results from scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermography analysis (TGA) and differential scanning calorimetry (DSC) show a significant growth of the hydrate products in OPC due to interfacial dissolution of C3S and some CNS thus, confirming the DFT-MD results. This work demonstrates that the growth of the hydrate products in OPC can be amplified by the addition of green and renewable 2D bio-based nanomaterials. This green approach provides a base for the design and development of low-carbon cementitious materials.

AB - Ordinary Portland cement (OPC) is the binding element in concrete materials and, CO2 emissions associated with its manufacturing and use is about 8% of the world's CO2 emissions. The engineering properties of hardened concrete depend on the amount of the hydrate phases in OPC. If the growth of the hydrate phases could be increased, the performance of concrete would be significantly improved, and the consumption of OPC will be decreased, and its environmental footprint will be reduced. In this paper, we present a new green approach for controlling the growth of the hydrate phases in OPC using bio flakes composed of staked carrot-based two-dimensional (2D) nanosheets (CNSs) synthesized from carrot waste. Density-functional theory and reactive molecular dynamics (DFT-MD) simulations were carried out in conjunction with analytical characterization to examine the interfacial interaction between CNS with tricalcium silicate Ca3SiO5 (C3S), the main constituent of OPC and understand how they influence the growth of the hydrate phases in OPC. The DFT-MD simulations results show the 2D CNS dissolves due to its interfacial interaction with the highly reactive C3S, leading to a series of fast proton exchange in C3S. This in return accelerates the dissolution rate of C3S thereby amplifying the growth of the hydrate phases. The DFT-MD simulations also show that the dissolution of the 2D CNS creates new several organic compounds that enhance the mobility and dynamics of protons that further amplify the dissolution rate of C3S. The analytical results from scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermography analysis (TGA) and differential scanning calorimetry (DSC) show a significant growth of the hydrate products in OPC due to interfacial dissolution of C3S and some CNS thus, confirming the DFT-MD results. This work demonstrates that the growth of the hydrate products in OPC can be amplified by the addition of green and renewable 2D bio-based nanomaterials. This green approach provides a base for the design and development of low-carbon cementitious materials.

KW - Density function theory (DFT)

KW - Reactive molecular dynamics simulation

KW - Cement hydration

KW - Tricalcium silicate

KW - Carrot nanosheet

M3 - Journal article

VL - 299

JO - Construction and Building Materials

JF - Construction and Building Materials

SN - 0950-0618

M1 - 123867

ER -