Christophe Labbez - Academia.edu (original) (raw)

Papers by Christophe Labbez

HAL (Le Centre pour la Communication Scientifique Directe), May 1, 2022

This study investigates the effect of gluconate, a carboxylate ion, and three uncharged hexitols,... more This study investigates the effect of gluconate, a carboxylate ion, and three uncharged hexitols, D-sorbitol, D-mannitol and D-galactitol on the solubility of C-S-H. Thermodynamic modeling is used to determine the kind and amount of Ca-organic-silicate-OH complexes that potentially form in the conditions studied. All the organics form complexes with calcium and hydroxide, In addition, heteropolynuclear organics complexes with calcium, hydroxide and silicate are observed at high pH values and high calcium concentrations: Ca 2 Hex 2 (H 3 SiO 4) 2 (OH) 2 0 , Ca 2 Hex 2 (H 2 SiO 4)(OH) 2-2 and Ca 3 Gluc 2 (H 3 SiO 4) 2 (OH) 2 0 , with the exception of mannitol. The strength of complexation with silicate decreases in the order gluconate > sorbitol > galactitol. The adsorption of the selected organics on portlandite and C-S-H systems follows the order gluconate >> sorbitol > mannitol ~ galactitol. For C-S-H, a typical Langmuir isotherm is found only when buffered with Ca(OH) 2. The adsorption on C-S-H increases with the Ca/Si ratio.

HAL (Le Centre pour la Communication Scientifique Directe), Jun 14, 2009

International audienc

Cement and Concrete Research, Sep 1, 2022

Applicable Analysis, May 26, 2022

This collaborative work started in 2014 and was delayed for several years. In the spring of 2020 ... more This collaborative work started in 2014 and was delayed for several years. In the spring of 2020 it was resumed but Andro Mikelic was struck by the illness that took him away in November 2020.

Applicable Analysis

This collaborative work started in 2014 and was delayed for several years. In the spring of 2020 ... more This collaborative work started in 2014 and was delayed for several years. In the spring of 2020 it was resumed but Andro Mikelic was struck by the illness that took him away in November 2020.

Cement and Concrete Research

The nucleation of the C-S-H gel is a complex process, key to controlling the hydration kinetics a... more The nucleation of the C-S-H gel is a complex process, key to controlling the hydration kinetics and microstructure development of cement. In this paper, a mechanism for the crystallization step during the C-S-H gel non-classical nucleation is proposed and explored by atomistic simulation methods. In the proposed mechanism portlandite precursor monolayers undergo a chemically induced transformation by condensation of silicate dimmers, forming C-S-H monolayers. We studied by DFT and nudged elastic band the structural transformation from bulk portlandite to a tobermorite-like calcium hydroxide polymorph, and the silicate condensation reaction at portlandite surface. Then, both processes are studied together, investigating the topochemical transformation from a portlandite monolayer to a C-S-H monolayer at room conditions using targeted molecular dynamics and umbrella sampling methods. Comparing the free energy of the process with thermodynamic data we conclude that the proposed mechanism is a potential path for C-S-H formation.

The thesis will be publicly defended on Thursday 24th of May 2012, 10.30 in

Cement and Concrete Research, Nov 1, 2021

The current paper investigates the impact of gluconate, D-sorbitol, D-mannitol and D-galactitol o... more The current paper investigates the impact of gluconate, D-sorbitol, D-mannitol and D-galactitol on calcium speciation at high pH values by i) solubility measurements of portlandite (Ca(OH)2) and ii) potentiometric titration measurements of calcium salt solutions. Thermodynamic modeling was used to fit the chemical activities of Ca 2+ and OHions and thus to determine the strength and kind of the different Ca-organic-hydroxide complexes. The strength of complex formation with Ca decreases in the order gluconate >> sorbitol > mannitol > galactitol, which follows the same order as sorption on portlandite. Heteropolynuclear gluconate complexes with calcium and hydroxide dominate the Ca-speciation in the presence of portlandite, while for sorbitol ternary CaSorbOH + complexes were dominant under alkaline conditions. We expect that these results will help in better understanding the influence of gluconate and hexitols on the hydration of alite and Portland cement.

HAL (Le Centre pour la Communication Scientifique Directe), Nov 1, 2021

This work focuses on the investigation of ongoing processes in the pre-and postnucleation stage o... more This work focuses on the investigation of ongoing processes in the pre-and postnucleation stage of C-S-H precipitation at pH 12 and pH 13. Calcium induces the condensation of smaller silicate species to bigger oligomers in the prenucleation stage. By titration in combination with ion-selective electrodes, the effects of additives on the formation of C-S-H can be monitored and quantified in terms of calcium binding, nucleation times, supersaturation, and the post-nucleation behavior showing detailed differences between polymers. Negatively charged polymers inhibit nucleation, neutral or almost neutral polymers do not have an influence on nucleation time and supersaturation and the rare promotion of nucleation has been identified with cationic polymers. The post-nucleation data show the polymer influence on solubility and C/S ratio of the precipitated phase and stabilization of primary nucleated particles against further aggregation or growth. This work can be regarded as a step towards better control of C-S-H precipitation.

Calcium silicate hydrates (C-S-H), the main components of hydrated cement, are known for being re... more Calcium silicate hydrates (C-S-H), the main components of hydrated cement, are known for being responsible of its cohesion. In this respect, they act as "glue" for the other solid components of mortar or concrete and thus strongly influence the mechanical properties of the outcoming material. Given the scarce knowledge about the influence of polymers on the growth and nucleation of C-S-H, this work focuses on the investigation of ongoing processes in the pre-and postnucleation stage of C-S-H precipitation. With the help of titration in combination with ion selective electrodes, effects of additives on the formation of C-S-H can be monitored and quantified resulting in new insights into the C-S-H formation in the presence of additives. Thus, this work can be regarded as a step towards a facilitated design of tailor-made C-S-H, which might result in superior cementitious materials on the long term.

arXiv (Cornell University), Aug 4, 2023

Cement and Concrete Research

Wet chemistry C-S-H precipitation experiments were performed under controlled conditions of solut... more Wet chemistry C-S-H precipitation experiments were performed under controlled conditions of solution supersaturation in the presence and absence of gluconate and three hexitol molecules. Characterization of the precipitates with SAXS and cryo-TEM experiments confirmed the presence of a multi-step nucleation pathway. Induction times for the formation of the amorphous C-S-H spheroids were determined from light transmittance. Analysis of those data with the classical nucleation theory revealed a significant increase of the kinetic prefactor in the same order as the complexation constants of calcium and silicate with each of the organics. Finally, two distinct precipitation regimes of the C-S-H amorphous precursor were identified: i) a nucleation regime at low saturation indexes (SI) and ii) a spinodal nucleation regime at high SI where the free energy barrier to the phase transition is found to be of the order of the kinetic energy or less.

The present paper investigates the influence of gluconate and hexitol additives on the precipitat... more The present paper investigates the influence of gluconate and hexitol additives on the precipitation mechanism and kinetics of C-S-H. To this end, wet chemistry C-S-H precipitation experiments were performed under controlled conditions of solution supersaturation-under varying silicate concentration, while the transmittance of the solution was followed. This allowed determining induction times for the formation of C-S-H precursors in the presence and absence of gluconate and three hexitol molecules. Characterization of the precipitates was performed via small angle X-ray scattering and cryo-transmission electron microscopy experiments, which allowed the identification of a multi-step nucleation pathway also in the presence of the organics. Analysis of the induction time data in the framework of the classical nucleation theory revealed a significant increase of the kinetic pre-factor, which is associated to physical rates of cluster collision and aggregation during the nucleation process. Values of the kinetic pre-factor increase in the same order as the complexation constants of calcium and silicate with the each of the organics. This points to a retarding mechanism of crystallization related to steric hindrance of the aggregation of the early formed clusters via adsorption of the organics at their surfaces.

Cement and Concrete Research

This study investigates the effect of gluconate, a carboxylate ion, and three uncharged hexitols,... more This study investigates the effect of gluconate, a carboxylate ion, and three uncharged hexitols, D-sorbitol, D-mannitol and D-galactitol on the solubility of C-S-H. Thermodynamic modeling was used to determine the kind and amount of Ca-organic-silicate-OH complexes that potentially form in the conditions studied. All the organics form complexes with calcium and hydroxide, In addition, heteropolynuclear organics complexes with calcium, hydroxide and silicate are observed at high pH values and high calcium concentrations: Ca2Hex2(H3SiO4)2(OH)2 0 , Ca2Hex2(H2SiO4)(OH)2-2 and Ca3Gluc2(H3SiO4)2(OH)2, with the exception of mannitol. The strength of complexation with silicate decreases from gluconate > sorbitol > galactitol. The adsorption of the selected organics on portlandite and C-S-H systems follows the order gluconate >> sorbitol > mannitol ~ galactitol. For C-S-H system buffered with Ca(OH)2, a typical Langmuir isotherm was found and adsorption on C-S-H increased with the Ca/Si ratio as well as with the increase of the organic concentration.

Chemistry of Materials, 2018

Despite a millennial history and the ubiquitous presence of cement in everyday life the molecular... more Despite a millennial history and the ubiquitous presence of cement in everyday life the molecular processes underlying its hydration behavior, like the formation of calcium-silicate-hydrate (C-S-H), the binding phase of concrete, are mostly unexplored. Using time-resolved potentiometry and turbidimetry combined with dynamic light scattering, small angle X-ray scattering and cryo-TEM we demonstrate C-S-H formation to proceed via a complex two-step pathway. In the first step, amorphous and dispersed spheroids are formed, whose composition is depleted in calcium compared to C-S-H and charge compensated with sodium. In the second step these amorphous spheroids crystallize to tobermorite-type C-S-H. The crystallization is accompanied by a sodium/calcium cation exchange and aggregation. Understanding the formation of C-S-H via amorphous liquid precursors may allow for a better understanding of the topography of the nucleation in cement paste and thus the percolation of hydration products leading to the mechanical setting as well as the retarding effect of known chemical species like aluminum ions and polycarboxylate ethers.

Physical Chemistry Chemical Physics, 2017

We proposed a simple and versatile method to calculate the effective pair potential between charg... more We proposed a simple and versatile method to calculate the effective pair potential between charged colloids which can easily be used in popular molecular simulation program packages and extended to non-spherical particles.

The Journal of Chemical Physics, 2018

A good understanding and determination of colloidal interactions is paramount to comprehend and m... more A good understanding and determination of colloidal interactions is paramount to comprehend and model the thermodynamic and structural properties of colloidal suspensions. In concentrated aqueous suspensions of colloids with a titratable surface charge, this determination is, however, complicated by the density dependence of the effective pair potential due to both the many-body interactions and the charge regulation of the colloids. In addition, colloids generally present a size distribution which results in a virtually infinite combination of colloid pairs. In this paper, we develop two methods and describe the corresponding algorithms to solve this problem for arbitrary size distributions. An implementation in Nim is also provided. The methods, inspired by the seminal work of Torres et al., [J. Chem. Phys. 128, 154906 (2008)] are based on a generalization of the cell and renormalized jellium models to polydisperse suspensions of spherical colloids with a charge regulating boundar...

Physical Review Letters

Monte-Carlo simulations, fully constrained by experimental parameters, are found to agree well wi... more Monte-Carlo simulations, fully constrained by experimental parameters, are found to agree well with a measured phase diagram of aqueous dispersions of nanoparticles with a moderate size polydispersity over a broad range of salt concentrations, cs, and volume fractions, φ. Upon increasing φ, the colloids freeze first into coexisting compact solids then into a body centered cubic phase (bcc) before they melt into a glass forming liquid. The surprising stability of the bcc solid at high φ and cs is explained by the interaction (charge) polydispersity and vibrational entropy.

Science Advances

Calcium silicate hydrate (C-S-H) is the binder in concrete, the most used synthetic material in t... more Calcium silicate hydrate (C-S-H) is the binder in concrete, the most used synthetic material in the world. The main weakness of concrete is the lack of elasticity and poor flexural strength considerably limiting its potential, making reinforcing steel constructions necessary. Although the properties of C-S-H could be significantly improved in organic hybrids, the full potential of this approach could not be reached because of the random C-S-H nanoplatelet structure. Taking inspiration from a sea urchin spine with highly ordered nanoparticles in the biomineral mesocrystal, we report a bioinspired route toward a C-S-H mesocrystal with highly aligned C-S-H nanoplatelets interspaced with a polymeric binder. A material with a bending strength similar to nacre is obtained, outperforming all C-S-H-based materials known to date. This strategy could greatly benefit future construction processes because fracture toughness and elasticity of brittle cementitious materials can be largely enhanced on the nanoscale.

The Journal of Physical Chemistry C

HAL (Le Centre pour la Communication Scientifique Directe), May 1, 2022

This study investigates the effect of gluconate, a carboxylate ion, and three uncharged hexitols,... more This study investigates the effect of gluconate, a carboxylate ion, and three uncharged hexitols, D-sorbitol, D-mannitol and D-galactitol on the solubility of C-S-H. Thermodynamic modeling is used to determine the kind and amount of Ca-organic-silicate-OH complexes that potentially form in the conditions studied. All the organics form complexes with calcium and hydroxide, In addition, heteropolynuclear organics complexes with calcium, hydroxide and silicate are observed at high pH values and high calcium concentrations: Ca 2 Hex 2 (H 3 SiO 4) 2 (OH) 2 0 , Ca 2 Hex 2 (H 2 SiO 4)(OH) 2-2 and Ca 3 Gluc 2 (H 3 SiO 4) 2 (OH) 2 0 , with the exception of mannitol. The strength of complexation with silicate decreases in the order gluconate > sorbitol > galactitol. The adsorption of the selected organics on portlandite and C-S-H systems follows the order gluconate >> sorbitol > mannitol ~ galactitol. For C-S-H, a typical Langmuir isotherm is found only when buffered with Ca(OH) 2. The adsorption on C-S-H increases with the Ca/Si ratio.

HAL (Le Centre pour la Communication Scientifique Directe), Jun 14, 2009

International audienc

Cement and Concrete Research, Sep 1, 2022

Applicable Analysis, May 26, 2022

This collaborative work started in 2014 and was delayed for several years. In the spring of 2020 ... more This collaborative work started in 2014 and was delayed for several years. In the spring of 2020 it was resumed but Andro Mikelic was struck by the illness that took him away in November 2020.

Applicable Analysis

This collaborative work started in 2014 and was delayed for several years. In the spring of 2020 ... more This collaborative work started in 2014 and was delayed for several years. In the spring of 2020 it was resumed but Andro Mikelic was struck by the illness that took him away in November 2020.

Cement and Concrete Research

The nucleation of the C-S-H gel is a complex process, key to controlling the hydration kinetics a... more The nucleation of the C-S-H gel is a complex process, key to controlling the hydration kinetics and microstructure development of cement. In this paper, a mechanism for the crystallization step during the C-S-H gel non-classical nucleation is proposed and explored by atomistic simulation methods. In the proposed mechanism portlandite precursor monolayers undergo a chemically induced transformation by condensation of silicate dimmers, forming C-S-H monolayers. We studied by DFT and nudged elastic band the structural transformation from bulk portlandite to a tobermorite-like calcium hydroxide polymorph, and the silicate condensation reaction at portlandite surface. Then, both processes are studied together, investigating the topochemical transformation from a portlandite monolayer to a C-S-H monolayer at room conditions using targeted molecular dynamics and umbrella sampling methods. Comparing the free energy of the process with thermodynamic data we conclude that the proposed mechanism is a potential path for C-S-H formation.

The thesis will be publicly defended on Thursday 24th of May 2012, 10.30 in

Cement and Concrete Research, Nov 1, 2021

The current paper investigates the impact of gluconate, D-sorbitol, D-mannitol and D-galactitol o... more The current paper investigates the impact of gluconate, D-sorbitol, D-mannitol and D-galactitol on calcium speciation at high pH values by i) solubility measurements of portlandite (Ca(OH)2) and ii) potentiometric titration measurements of calcium salt solutions. Thermodynamic modeling was used to fit the chemical activities of Ca 2+ and OHions and thus to determine the strength and kind of the different Ca-organic-hydroxide complexes. The strength of complex formation with Ca decreases in the order gluconate >> sorbitol > mannitol > galactitol, which follows the same order as sorption on portlandite. Heteropolynuclear gluconate complexes with calcium and hydroxide dominate the Ca-speciation in the presence of portlandite, while for sorbitol ternary CaSorbOH + complexes were dominant under alkaline conditions. We expect that these results will help in better understanding the influence of gluconate and hexitols on the hydration of alite and Portland cement.

HAL (Le Centre pour la Communication Scientifique Directe), Nov 1, 2021

This work focuses on the investigation of ongoing processes in the pre-and postnucleation stage o... more This work focuses on the investigation of ongoing processes in the pre-and postnucleation stage of C-S-H precipitation at pH 12 and pH 13. Calcium induces the condensation of smaller silicate species to bigger oligomers in the prenucleation stage. By titration in combination with ion-selective electrodes, the effects of additives on the formation of C-S-H can be monitored and quantified in terms of calcium binding, nucleation times, supersaturation, and the post-nucleation behavior showing detailed differences between polymers. Negatively charged polymers inhibit nucleation, neutral or almost neutral polymers do not have an influence on nucleation time and supersaturation and the rare promotion of nucleation has been identified with cationic polymers. The post-nucleation data show the polymer influence on solubility and C/S ratio of the precipitated phase and stabilization of primary nucleated particles against further aggregation or growth. This work can be regarded as a step towards better control of C-S-H precipitation.

Calcium silicate hydrates (C-S-H), the main components of hydrated cement, are known for being re... more Calcium silicate hydrates (C-S-H), the main components of hydrated cement, are known for being responsible of its cohesion. In this respect, they act as "glue" for the other solid components of mortar or concrete and thus strongly influence the mechanical properties of the outcoming material. Given the scarce knowledge about the influence of polymers on the growth and nucleation of C-S-H, this work focuses on the investigation of ongoing processes in the pre-and postnucleation stage of C-S-H precipitation. With the help of titration in combination with ion selective electrodes, effects of additives on the formation of C-S-H can be monitored and quantified resulting in new insights into the C-S-H formation in the presence of additives. Thus, this work can be regarded as a step towards a facilitated design of tailor-made C-S-H, which might result in superior cementitious materials on the long term.

arXiv (Cornell University), Aug 4, 2023

Cement and Concrete Research

Wet chemistry C-S-H precipitation experiments were performed under controlled conditions of solut... more Wet chemistry C-S-H precipitation experiments were performed under controlled conditions of solution supersaturation in the presence and absence of gluconate and three hexitol molecules. Characterization of the precipitates with SAXS and cryo-TEM experiments confirmed the presence of a multi-step nucleation pathway. Induction times for the formation of the amorphous C-S-H spheroids were determined from light transmittance. Analysis of those data with the classical nucleation theory revealed a significant increase of the kinetic prefactor in the same order as the complexation constants of calcium and silicate with each of the organics. Finally, two distinct precipitation regimes of the C-S-H amorphous precursor were identified: i) a nucleation regime at low saturation indexes (SI) and ii) a spinodal nucleation regime at high SI where the free energy barrier to the phase transition is found to be of the order of the kinetic energy or less.

The present paper investigates the influence of gluconate and hexitol additives on the precipitat... more The present paper investigates the influence of gluconate and hexitol additives on the precipitation mechanism and kinetics of C-S-H. To this end, wet chemistry C-S-H precipitation experiments were performed under controlled conditions of solution supersaturation-under varying silicate concentration, while the transmittance of the solution was followed. This allowed determining induction times for the formation of C-S-H precursors in the presence and absence of gluconate and three hexitol molecules. Characterization of the precipitates was performed via small angle X-ray scattering and cryo-transmission electron microscopy experiments, which allowed the identification of a multi-step nucleation pathway also in the presence of the organics. Analysis of the induction time data in the framework of the classical nucleation theory revealed a significant increase of the kinetic pre-factor, which is associated to physical rates of cluster collision and aggregation during the nucleation process. Values of the kinetic pre-factor increase in the same order as the complexation constants of calcium and silicate with the each of the organics. This points to a retarding mechanism of crystallization related to steric hindrance of the aggregation of the early formed clusters via adsorption of the organics at their surfaces.

Cement and Concrete Research

This study investigates the effect of gluconate, a carboxylate ion, and three uncharged hexitols,... more This study investigates the effect of gluconate, a carboxylate ion, and three uncharged hexitols, D-sorbitol, D-mannitol and D-galactitol on the solubility of C-S-H. Thermodynamic modeling was used to determine the kind and amount of Ca-organic-silicate-OH complexes that potentially form in the conditions studied. All the organics form complexes with calcium and hydroxide, In addition, heteropolynuclear organics complexes with calcium, hydroxide and silicate are observed at high pH values and high calcium concentrations: Ca2Hex2(H3SiO4)2(OH)2 0 , Ca2Hex2(H2SiO4)(OH)2-2 and Ca3Gluc2(H3SiO4)2(OH)2, with the exception of mannitol. The strength of complexation with silicate decreases from gluconate > sorbitol > galactitol. The adsorption of the selected organics on portlandite and C-S-H systems follows the order gluconate >> sorbitol > mannitol ~ galactitol. For C-S-H system buffered with Ca(OH)2, a typical Langmuir isotherm was found and adsorption on C-S-H increased with the Ca/Si ratio as well as with the increase of the organic concentration.

Chemistry of Materials, 2018

Despite a millennial history and the ubiquitous presence of cement in everyday life the molecular... more Despite a millennial history and the ubiquitous presence of cement in everyday life the molecular processes underlying its hydration behavior, like the formation of calcium-silicate-hydrate (C-S-H), the binding phase of concrete, are mostly unexplored. Using time-resolved potentiometry and turbidimetry combined with dynamic light scattering, small angle X-ray scattering and cryo-TEM we demonstrate C-S-H formation to proceed via a complex two-step pathway. In the first step, amorphous and dispersed spheroids are formed, whose composition is depleted in calcium compared to C-S-H and charge compensated with sodium. In the second step these amorphous spheroids crystallize to tobermorite-type C-S-H. The crystallization is accompanied by a sodium/calcium cation exchange and aggregation. Understanding the formation of C-S-H via amorphous liquid precursors may allow for a better understanding of the topography of the nucleation in cement paste and thus the percolation of hydration products leading to the mechanical setting as well as the retarding effect of known chemical species like aluminum ions and polycarboxylate ethers.

Physical Chemistry Chemical Physics, 2017

We proposed a simple and versatile method to calculate the effective pair potential between charg... more We proposed a simple and versatile method to calculate the effective pair potential between charged colloids which can easily be used in popular molecular simulation program packages and extended to non-spherical particles.

The Journal of Chemical Physics, 2018

A good understanding and determination of colloidal interactions is paramount to comprehend and m... more A good understanding and determination of colloidal interactions is paramount to comprehend and model the thermodynamic and structural properties of colloidal suspensions. In concentrated aqueous suspensions of colloids with a titratable surface charge, this determination is, however, complicated by the density dependence of the effective pair potential due to both the many-body interactions and the charge regulation of the colloids. In addition, colloids generally present a size distribution which results in a virtually infinite combination of colloid pairs. In this paper, we develop two methods and describe the corresponding algorithms to solve this problem for arbitrary size distributions. An implementation in Nim is also provided. The methods, inspired by the seminal work of Torres et al., [J. Chem. Phys. 128, 154906 (2008)] are based on a generalization of the cell and renormalized jellium models to polydisperse suspensions of spherical colloids with a charge regulating boundar...

Physical Review Letters

Monte-Carlo simulations, fully constrained by experimental parameters, are found to agree well wi... more Monte-Carlo simulations, fully constrained by experimental parameters, are found to agree well with a measured phase diagram of aqueous dispersions of nanoparticles with a moderate size polydispersity over a broad range of salt concentrations, cs, and volume fractions, φ. Upon increasing φ, the colloids freeze first into coexisting compact solids then into a body centered cubic phase (bcc) before they melt into a glass forming liquid. The surprising stability of the bcc solid at high φ and cs is explained by the interaction (charge) polydispersity and vibrational entropy.

Science Advances

Calcium silicate hydrate (C-S-H) is the binder in concrete, the most used synthetic material in t... more Calcium silicate hydrate (C-S-H) is the binder in concrete, the most used synthetic material in the world. The main weakness of concrete is the lack of elasticity and poor flexural strength considerably limiting its potential, making reinforcing steel constructions necessary. Although the properties of C-S-H could be significantly improved in organic hybrids, the full potential of this approach could not be reached because of the random C-S-H nanoplatelet structure. Taking inspiration from a sea urchin spine with highly ordered nanoparticles in the biomineral mesocrystal, we report a bioinspired route toward a C-S-H mesocrystal with highly aligned C-S-H nanoplatelets interspaced with a polymeric binder. A material with a bending strength similar to nacre is obtained, outperforming all C-S-H-based materials known to date. This strategy could greatly benefit future construction processes because fracture toughness and elasticity of brittle cementitious materials can be largely enhanced on the nanoscale.

The Journal of Physical Chemistry C