Drying Shrinkage Mechanisms in Portland Cement Paste

Hansen, Will

doi:10.1111/j.1151-2916.1987.tb05002.x

Cited by 173 publications

(82 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Strong evidence that hysteresis due to creep is unimportant in very mature pastes can be found in the work of Hansen [55]. Figure 2 of the cited paper shows that shrinkage is described by a single function of water content even though the time taken to reach this water content differs by up to 3 orders of magnitude.…”

Section: Continuum Modeling Of Reversible Drying Shrinkagementioning

confidence: 72%

“…On shorter time scales, time dependence can be observed, but Hansen's results [55] indicate that this time dependence is due to the transient movement of water in the pores and is not inconsistent with a unique relationship between water content and length locally.…”

Section: Continuum Modeling Of Reversible Drying Shrinkagementioning

confidence: 84%

“…The Bangham equation [55,63,64] describes the shrinkage due to the change in surface tension resulting from the dependence of adsorbed layer thickness on RH. We treat the system at 100% RH, when all solid surfaces are covered by water and there is little or no liquid-vapor interface area, as the reference state and calculate surface tension and shrinkage relative to this case.…”

Section: B Macroscopic Length Change Due To Surface Energymentioning

confidence: 99%

See 2 more Smart Citations

Hysteresis from Multiscale Porosity: Modeling Water Sorption and Shrinkage in Cement Paste

et al. 2015

View full text Add to dashboard Cite

Cement paste has a complex distribution of pores and molecular-scale spaces. This distribution controls the hysteresis of water sorption isotherms and associated bulk dimensional changes (shrinkage). We focus on two locations of evaporable water within the fine structure of pastes, each having unique properties, and we present applied physics models that capture the hysteresis by dividing drying and rewetting into two related regimes based on relative humidity (RH). We show that a continuum model, incorporating a poreblocking mechanism for desorption and equilibrium thermodynamics for adsorption, explains well the sorption hysteresis for a paste that remains above approximately 20% RH. In addition, we show with molecular models and experiments that water in spaces of ≲1 nm width evaporates below approximately 20% RH but reenters throughout the entire RH range. This water is responsible for a drying shrinkage hysteresis similar to that of clays but opposite in direction to typical mesoporous glass. Combining the models of these two regimes allows the entire drying and rewetting hysteresis to be reproduced accurately and provides parameters to predict the corresponding dimensional changes. The resulting model can improve the engineering predictions of long-term drying shrinkage accounting also for the history dependence of strain induced by hysteresis. Alternative strategies for quantitative analyses of the * Corresponding author. hmj@mit.edu PHYSICAL REVIEW APPLIED 3, 064009 (2015) 2331-7019=15=3(6)=064009 (17) 064009-1

show abstract

Section: Continuum Modeling Of Reversible Drying Shrinkagementioning

confidence: 72%

Section: Continuum Modeling Of Reversible Drying Shrinkagementioning

confidence: 84%

Section: B Macroscopic Length Change Due To Surface Energymentioning

confidence: 99%

See 1 more Smart Citation

Hysteresis from Multiscale Porosity: Modeling Water Sorption and Shrinkage in Cement Paste

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The surface free energy change is given by the Gibbs adsorption equation (Bentz et al 1998;Hansen 1987;Houst et al 1983).…”

Section: Water Content and Shrinkage Behavior Of Aacsmentioning

confidence: 99%

Microstructure and Shrinkage Behavior of Autoclaved Aerated Con-crete(AAC) -Comparison of Vietnamese and Japanese AACs-

Lam

Asamoto

Matsui

2018

ACT

View full text Add to dashboard Cite

We investigated the microstructure and shrinkage behavior of autoclaved aerated concrete (AAC) from several manufacturers in Vietnam comparing with Japanese AAC. Three types of Vietnamese AAC and one type of Japanese AAC were used for powder X-ray diffraction, scanning electron microscopy, mercury intrusion porosimetry, and shrinkage tests. The experimental results show that the main hydration products of AAC that used fly ash as silica materials is semi-crystalline calcium silicate hydrate, while the ones of others are tobermorite; but the tobermorite crystals of AACs from some manufacturers in Vietnam are disordered structures and lack of interlocking among tobermorite crystals. The pore size distribution of all Vietnamese AAC are single peak, whereas Japanese AAC is bimodal. The pore distribution characteristics of AACs significantly influenced their shrinkage behavior and the shrinkage of Vietnamese AAC is higher than that of Japanese AAC at intermediate relative humidity (RH). The capillary tension is the principle shrinkage mechanism for AAC materials at high RH (above about 65%) to cause local minimum shrinkage of Japanese AAC at high RHs, while the change in surface free energy is dominant at low RH conditions.

show abstract

“…The shrinkage mechanism of hardened cement paste is still under discussion, and several theories such as the surface energy theory, capillary tension theory, and disjoining (or hydration pressure) theory exist, with a combination of them having been proposed thus far (Powers 1965;Feldman and Sereda 1968;Wittmann 1968;Hansen 1987;Beaudoin et al 2010;Maruyama 2010). In addition to these theories, hardened cement paste under the first desorption process shows irreversible shrinkage due to colloidal alternation of C-S-H (Helmuth and Turk 1967;Maruyama et al 2015).…”

Section: Modulus Of Elasticity Shrinkage and Thermal Expansion Coefmentioning

confidence: 99%

Numerical Approach towards Aging Management of Concrete Structures: Material Strength Evaluation in a Massive Concrete Structure under One-Sided Heating

Maruyama

Igarashi

2015

ACT

View full text Add to dashboard Cite

For the purpose of performance evaluation of an existing reinforced concrete member, a chemo-thermo-hygro model to predict the spatial and temporal changes of physical properties of concrete in the member, named the "Computational Cement-Based Material Model (CCBM)", was proposed. This proposed simulation model includes models of rate of hydration of cement minerals, phase composition, and resultant properties of cement paste (i.e., compressive strength, Young's modulus, Poisson's ratio, thermal expansion coefficient, autogenous shrinkage, drying shrinkage, heat capacity, heat transfer coefficient, water vapor sorption isotherms, and water transfer coefficient). Furthermore, the model for compressive strength of concrete considered the variation in cement paste strength due to its colloidal features as well as micro-defects produced around aggregate due to differences in volume between aggregates and mortar upon heating and drying. The concrete properties of spatial distribution and temporal changes were evaluated by coupling these models with heat and water transport. Validation of these models was achieved by using existing experimental data. Using this CCBM, a thick concrete wall made with moderate Portland cement with a water-to-cement ratio of 0.55 under one-sided heating was simulated and potential problems that can arise during an integrity evaluation were discussed. If the required compressive strength, which was assessed within 91 days of placement, remains unchanged, an additional hydration process can build an adequate strength margin to overcome the risk of strength reduction due to heat and drying. However, in the case that the required strength is increased due to a re-evaluated risk, such as the magnitude of an earthquake, performance evaluation is not trivial as the core sample taken from the side where the execution of sampling is possible could exhibit a greater strength than the average strength of the target concrete member. Therefore, numerical evaluation might aid in this kind of situation.

show abstract

Drying Shrinkage Mechanisms in Portland Cement Paste

Cited by 173 publications

References 17 publications

Hysteresis from Multiscale Porosity: Modeling Water Sorption and Shrinkage in Cement Paste

Hysteresis from Multiscale Porosity: Modeling Water Sorption and Shrinkage in Cement Paste

Microstructure and Shrinkage Behavior of Autoclaved Aerated Con-crete(AAC) -Comparison of Vietnamese and Japanese AACs-

Numerical Approach towards Aging Management of Concrete Structures: Material Strength Evaluation in a Massive Concrete Structure under One-Sided Heating

Contact Info

Product

Resources

About