Wet creep of hardened hydraulic cements — Example of gypsum plaster and implication for hydrated Portland cement

Pachon-Rodriguez, Edgar Alejandro; Guillon, Emmanuel; Houvenaghel, Geert; Colombani, Jean

doi:10.1016/j.cemconres.2014.05.004

Cited by 27 publications

(15 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Apparently this water is important to viscous flow both during drying and under load. This may suggest rather than the interlayer water, the lubricating effects of water between the globules [77], and any dissolutionprecipitation processes therein may be a source of creep in cementing materials [78].…”

Section: Comments On Creep and Shrinkagementioning

confidence: 99%

Quantitative discrimination of the nano-pore-structure of cement paste during drying: New insights from water sorption isotherms

Jennings

Kumar²,

Sant

2015

Cement and Concrete Research

147

View full text Add to dashboard Cite

A new ability to quantitatively evaluate the complex pore system of cement pastes, using water sorption isotherms, is used to illuminate: (a) evolutions of microstructure during drying, (b) the mechanisms that control drying shrinkage, and (c) a novel method to compute the original w/c (i.e., water-to-cement ratio, mass basis). Each of these points has significant implications on concrete performance and durability in engineering practice. We show that irreversible changes in the nanostructure during first drying are associated with changes in the pores that empty between ≈85-and-45% relative humidity (RH). It is also shown that water in the interlayer space (e.g., similar to clays) of the binding calcium-silicate-hydrate (C-S-H) phase, does not empty until drying below ≈25% RH. However, this water, once removed, does not completely re-saturate the pore spaces even at nearly 100% RH -for time scales on the order of weeks. With the ability to specifically identify the volume of pores associated with the C-S-H gel, as opposed to the larger capillary pores and the smaller interlayer spaces, a method for computing the original w/c (and hence cement content), of cementitious material is proposed. These results suggest improved methods for evaluating and modeling the engineering behavior of cement-based materials.

show abstract

Section: Comments On Creep and Shrinkagementioning

confidence: 99%

Quantitative discrimination of the nano-pore-structure of cement paste during drying: New insights from water sorption isotherms

Jennings

Kumar²,

Sant

2015

Cement and Concrete Research

147

View full text Add to dashboard Cite

show abstract

“…1 Thus, hydrationinduced dissolution alone is insufficient to explain the long-term deformation of cement paste. In addition to the inherent C-S-H viscoelasticity/viscoplasticity, which likely contributes to the long-term creep/relaxation of cement paste, another mechanism that was recently proposed by Grasley et al 18 and subsequently by Pachon-Rodriguez *Conventional cement chemistry notation will be used: C = CaO, S = SiO 2 , H = H 2 O. et al 19 and Pignatelli et al 8 is studied in this study: stressinduced dissolution of solid hydration products.…”

Section: Introductionmentioning

confidence: 99%

Creep and relaxation of cement paste caused by stress‐induced dissolution of hydrated solid components

Grasley

Bullard

et al. 2018

J Am Ceram Soc

View full text Add to dashboard Cite

The creep and relaxation of cement paste caused by dissolving solid hydration products is evaluated in this work. According to the second law of thermodynamics, dissolution or precipitation of solid constituents may be altered by the change in stress/strain fields inside cement paste via alteration of the stress power or strain energy. Thus, it is hypothesized that stress‐induced dissolution can affect the overall creep/relaxation behavior of cement composites. A novel, fully coupled thermodynamic, mechanical, and microstructural model (TM2) that uses the finite element method was developed to predict the time‐evolving properties of cement paste under prescribed strains and to test the hypothesis. In the model, the strain energy was incorporated to accurately predict the effect of stress and strain fields on cement microstructure change. From the simulation results, depending on the stress/strain levels and the choice of the domain (over which the thermodynamic equilibrium is enforced), stress‐induced dissolution of solid constituents can lead to significant creep/relaxation.

show abstract

“…Due to the abundance of necessary raw materials, and the inexpensive nature of ordinary portland cement stress exists. Such a process has recently been reported to control creep in gypsum plaster [18] and has been suggested to potentially also apply to hydrated cement solids [18]. According to this model, under appropriate moisture levels, creep would be a consequence of the dissolution of C-S-H in inter--granular water (i.e., including capillary water, and some of the gel water [15]) in high--stress regions.…”

Section: Introductionmentioning

confidence: 99%

A dissolution-precipitation mechanism is at the origin of concrete creep in moist environments

Pignatelli

Kumar

Alizadeh

et al. 2016

The Journal of Chemical Physics

View full text Add to dashboard Cite

Long--term creep (i.e., deformation under sustained load) is a significant material response that needs to be accounted for in concrete structural design. However, the nature and origin of creep remains poorly understood, and controversial. Here, we propose that concrete creep at RH (relative humidity) ≥ 50%, but fixed moisture--contents (i.e., basic creep), arises from a dissolution--precipitation mechanism, active at nanoscale grain contacts, as is often observed in a geological context, e.g., when rocks are exposed to sustained loads, in moist environments. Based on micro--indentation and vertical scanning interferometry experiments, and molecular dynamics simulations carried out on calcium-silicate-hydrates (C-S-H's), the major binding phase in concrete, of different compositions, we show that creep rates are well correlated to dissolution rates -an observation which supports the dissolution--precipitation mechanism as the origin of concrete creep. C-S-H compositions featuring high resistance to dissolution, and hence creep are identified -analysis of which, using topological constraint theory, indicates that these compositions present limited relaxation modes on account of their optimally connected (i.e., constrained) atomic networks.

show abstract

Wet creep of hardened hydraulic cements — Example of gypsum plaster and implication for hydrated Portland cement

Cited by 27 publications

References 39 publications

Quantitative discrimination of the nano-pore-structure of cement paste during drying: New insights from water sorption isotherms

Quantitative discrimination of the nano-pore-structure of cement paste during drying: New insights from water sorption isotherms

Creep and relaxation of cement paste caused by stress‐induced dissolution of hydrated solid components

A dissolution-precipitation mechanism is at the origin of concrete creep in moist environments

Contact Info

Product

Resources

About