Publications by Paul Bowen | EPFL Graph Search

CementFF4: Formal atomic charge polarizable force field for cementitious systems – Bulk and surface

Paul Bowen, Karen Scrivener, Manuel Cordova, Ziga Casar

A general-purpose formal charge polarizable force field for cementitious systems, CementFF4, is presented. The force field includes the following species: Ca, Si, O, H, Al, Zn, OH− and H2O. The force field is a significant extension of previous force field ...

Pergamon-Elsevier Science Ltd2025

Impact of pore solution composition and superplasticizers on the interparticle forces and rheology of metakaolin suspensions

Paul Bowen

This study focuses on the influence of pH, aqueous phase composition and superplasticizers on the particle interactions in pure metakaolin suspensions. It was found increasing pH up to 11 led to the decrease of the particle agglomeration due to the higher ...

2025

pyCSH: Automated atomic-level structure generation of bulk C-S-H and investigation of their intrinsic properties

Paul Bowen, Karen Scrivener, Ziga Casar

A new Python code for the automated generation of realistic bulk calcium silicate hydrate (C-S-H) structures is introduced. The code was used to generate 400 structures with Ca/Si of 1.3, 1.5, 1.7, and 1.9. The generated structures are in excellent agreeme ...

Pergamon-Elsevier Science Ltd2024

Surface properties of clinker phases and clay minerals characterized by inverse gas chromatography (IGC) and their link to reactivity

Paul Bowen, Karen Scrivener, Franco Alberto Zunino Sommariva

This paper presents a preliminary study of the characterization of the surface energy properties of clinker phases (C3S and C3A), kaolin and metakaolin by Inverse Gas Chromatography (IGC). For this, a reliable measurement methodology was developed. By look ...

Pergamon-Elsevier Science Ltd2024

Influence of the sintering atmosphere on the physico-chemical properties and the osteoclastic resorption of β-tricalcium phosphate cylinders

Paul Bowen, Duncan Thomas Lindsay Alexander, Gabrielle Anne Laguisma Sblendorio

One of the most widely used materials for bone graft substitution is β-Tricalcium phosphate (β-TCP;β- Ca3(PO4)2). beta-TCP is typically produced by sintering in air or vacuum. During this process, evaporation of phosphorus ...

Elsevier Sci Ltd2023

Towards an improved understanding of the β-TCP crystal structure by means of “checkerboard” atomistic simulations

Paul Bowen, Duncan Thomas Lindsay Alexander, Gabrielle Anne Laguisma Sblendorio

The large variability of biological responses to beta-TCP implants reported in the literature could possibly be related to subtle differences in the beta-TCP crystal structure. The structure contains one partially occupied site Ca(4). In order to better un ...

2023

Atomic-Level and Surface Structure of Calcium Silicate Hydrate Nanofoils

Paul Bowen, Karen Scrivener, Aslam Kunhi Mohamed, Ziga Casar

Deciphering the calcium silicate hydrate (C-S-H) surface is crucial for unraveling the mechanisms of cement hydration and property development. Experimental observations of C-S-H in cement systems suggest a surface termination which is fundamentally differ ...

AMER CHEMICAL SOC2023

Atomic-Level Structure of Zinc-Modified Cementitious Calcium Silicate Hydrate

Paul Bowen, Karen Scrivener, Manuel Cordova, David Lyndon Emsley, Anna Morales Melgares, Pinelopi Moutzouri, Ziga Casar, Amrit Venkatesh

It has recently been demonstrated that the addition of zinc can enhance the mechanical strength of tricalcium silicates (C3S) upon hydration, but the structure of the main hydration product of cement, calcium silicate hydrate (C-S-H), in zinc modified form ...

AMER CHEMICAL SOC2022

A method for the reliable and reproducible precipitation of phase pure high Ca/Si ratio (>1.5) synthetic calcium silicate hydrates (C-S-H)

Paul Bowen, Karen Scrivener, Maya Nicole Harris, Grace Simpson

Various methods have been developed to synthesize C-S-H; however, these methods have only allowed for the successful production of pure-phase C-S-H with Ca:Si of 1.5 or less. Attempts to form higher Ca:Si ratios by these methods gives C-S-H (Ca:Si 1.5 or l ...

Pergamon-Elsevier Science Ltd2022

Effect of minor amounts of beta-calcium pyrophosphate and hydroxyapatite on the physico-chemical properties and osteoclastic resorption of beta-tricalcium phosphate cylinders

Paul Bowen, Gabrielle Anne Laguisma Sblendorio

beta-Tricalcium Phosphate (beta-TCP), one of the most used bone graft substitutes, may contain up to 5 wt% foreign phase according to standards. Typical foreign phases include beta-calcium pyrophosphate (beta-CPP) and hydroxyapatite (HA). Currently, the ef ...

KEAI PUBLISHING LTD2022

Molecular dynamic simulations of cementitious systems using a newly developed force field suite ERICA FF

Paul Bowen, Masood Valavi, Ziga Casar

A force field suite, ERICA FF has been developed for the simulation of cementitious systems. It has been validated for structural, energetic and mechanical properties. It covers the species Ca, OH, sulfate, water, Si, Al, Na, K and Cl. We have simulated st ...

Pergamon-Elsevier Science Ltd2022

Chemically pure beta-tricalcium phosphate powders: Evidence of two crystal structures

Paul Bowen, Duncan Thomas Lindsay Alexander, Gabrielle Anne Laguisma Sblendorio

The question whether beta-tricalcium phosphate (beta-TCP) can form a solid solution with beta-calcium pyrophosphate (beta-CPP) and/or hydroxyapatite (HA) has still not been solved. For this reason, wet-chemically synthesized beta-TCP powders with only 20 p ...

ELSEVIER SCI LTD2021

Understanding of the factors slowing down metakaolin reaction in limestone calcined clay cement (LC3) at late ages

Paul Bowen, Mohsen Ben Haha, Karen Scrivener, François Henri Avet, Yosra Briki

Factors which could explain the slowing down of the metakaolin reaction in LC3 blends are investigated. Portlandite availability and the presence of aluminium ions in the pore solution are shown not to be limiting factors. ...

Pergamon-Elsevier Science Ltd2021

Iron incorporation in synthetic precipitated calcium silicate hydrates

Paul Bowen, Jirawan Siramanont, David Lyndon Emsley, Brennan James Walder

Effect of Fe3+ on the precipitation of synthetic calcium silicate hydrates (C-S-H) under controlled conditions has been evaluated. Using extremely basic either initial calcium nitrate or sodium silicate solutions (pH > 11), incipient formation of ferrihydr ...

Pergamon-Elsevier Science Ltd2021

Interactions of Tris with rutile surfaces and consequences for in vitro bioactivity testing

Paul Bowen, Ulrich Aschauer

Tris(hydroxymethyl)aminomethane (Tris) has been used as the buffer in bioactivity testing for over two decades and has become a standard choice for the scientific community. While it is believed to be non-interacting, the extent of its interactions with ti ...

Elsevier2021

Spark Plasma Sintering of Ceramics: From Modeling to Practice

Paul Bowen, Michael Stuer, Zhe Zhao

Summarizing the work of nearly a decade of research on spark plasma sintering (SPS), a review is given on the specificities and key factors to be considered in SPS of ceramic materials, based on the authors’ own research. Alumina is used primarily as a mod ...

2020

Porous granules by freeze granulation of Pickering emulsions stabilized with halloysite particles

Paul Bowen

Pickering emulsions stabilized with a natural silicate mineral, halloysite, were dried by freeze granulation in order to prepare porous granules. Different formulations were studied, by varying the pH of the suspension, the ionic strength and with the addi ...

ELSEVIER2020

The Atomic-Level Structure of Cementitious Calcium Aluminate Silicate Hydrate

Paul Bowen, Karen Scrivener, Aslam Kunhi Mohamed, Jirawan Siramanont, David Lyndon Emsley, Brennan James Walder, Maya Nicole Harris, Pierrick Berruyer, Pinelopi Moutzouri, Mattia Negroni

Despite use of blended cements containing significant amounts of aluminum for over 30 years, the structural nature of aluminum in the main hydration product, calcium aluminate silicate hydrate (C-A-S-H), remains elusive. Using first-principles calculations ...

2020

Cathodoluminescent screen imaging system for seeded blob detection in toroidal plasma experiment

Paul Bowen, Ambrogio Fasoli, Ivo Furno, Carlos Morais, Paolo Ricci, Marcelo Baquero Ruiz, Fabian Manke

We designed and built a diagnostic based on a cathodoluminescent screen for the detection of turbulent plasma structures with high spatial resolution. The screen is coated with a low threshold energy cathodoluminescent powder that emits light when exposed ...

2020

Global uncertainty-sensitivity analysis on mechanistic kinetic models: From model assessment to theory-driven design of nanoparticles

Paul Bowen, Andrea Testino, Agnese Carino, Mohammad Reza Andalibi

Recently, we developed a population balance framework describing the precipitation of calcium-silicate-hydrate, a key nanomaterial in the construction industry and with potential applications in biomedicine, environmental remediation, and catalysis. In thi ...

2020