Autogenous deformations of cement pastes

Baroghel-Bouny, Véronique; Mounanga, Pierre; Khelidj, Abdelhafid; Loukili, Ahmed; Rafaï, Noureddine

doi:10.1016/j.cemconres.2004.10.020

Cited by 161 publications

(36 citation statements)

References 23 publications

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“…The best way to suppress moisture gradients and the related size effect is to proceed by sealing samples. This has been done by BaroghelBouny and Kheirbek [8], on sealed cylinders of hardened cement paste, and for a large range of the water-cement ratio. It was very difficult for them to find a test procedure for tree sealed conditions that completely suppressed any mass exchange with the ambient medium.…”

Section: Swelling or Shrinkage : What Is Specific To Cement Hydration?mentioning

confidence: 99%

Swelling, shrinkage and creep: a mechanical approach to cement hydration

Acker¹

2004

Mat. Struct.

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Recent advances in physical understanding of creep and shrinkage of cement paste suggest a novel approach to setting and hardening processes. In high-strength concrete, due to a low water-cement ratio, self-desiccation occurs immediately after setting, and capillary pressure produces compaction of the assembly of hydrating cement grains. For higher watercement ratio, water possibly can withstand cavitation, but then the volumetric balance of hydration requires that water move through the solid skeleton. According to Darcy's law, water only can be displaced by a gradient of hydraulic pressure, as long as the water pressure remains lower than its cavitation threshold. This water pressure only can be equilibrated by a compaction of the solid matrix, with compressive contacts particularly between the C-S-H layers. In both cases, with or without liquid-gas menisci, hydration acts like a distributed pumping of water, the liquid phase is under tension, and the solid skeleton is compressed. The high affinity of C-S-H for water and the viscoplastic behavior of the cement gel can explain the evolution of the contact between two hydrating cement grains and the formation of a continuous and cohesive bridge. Swelling and shrinkage then can be analyzed as two co-existing mechanisms, whose balance is controlled by the permeability of the solid matrix. RF~SUMF~ Les progrks accomplis r~cemment clans la comprehension des m~canismes de retrait et de fluage des matdriaux h base de ciment apportent un nouvel

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Section: Swelling or Shrinkage : What Is Specific To Cement Hydration?mentioning

confidence: 99%

Swelling, shrinkage and creep: a mechanical approach to cement hydration

Acker¹

2004

Mat. Struct.

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“…Moreover, for comparison, the autogenous shrinkage strains, provided by Lee et al [60] and by Baroghel-Bouny et al [63] for similar concrete mixtures, are shown. Whereas the water to cement ratio as well as the aggregate to cement ratio of the concrete mixtures investigated in the studies [60], [63] and in the present study are quite similar, the maximum aggregate size of the respective concrete mixtures is quite different, ranging from 19 and 20 mm for the mixtures described in the studies [60,63] to 32 mm (Table 1) for the one investigated in the present study. The size and shape of the specimens used in Lee et al [60] and in Baroghel-Bouny et al [63] and in the present study are different.…”

Section: Resultsmentioning

confidence: 93%

Comprehensive study of concrete creep, shrinkage, and water content evolution under sealed and drying conditions

Theiner

Drexel

Neuner

et al. 2017

Strain

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A comprehensive study of the time-dependent behaviour of concrete, enhanced by measuring the evolution of the respective mass water content, is presented. Compressive creep as well as shrinkage are investigated on sealed and unsealed specimens in terms of the concrete age at loading of 2, 7, and 28 days, respectively, at a loading level of 30% of the compressive strength at loading. In addition, on the basis of the collected measurement data, the impact of load application on the moisture content is studied and the Pickett effect is re-examined. The obtained set of material data consists of basic and drying creep strains for different concrete ages at loading, autogenous shrinkage strains as well as combined autogenous and drying shrinkage strains, the evolution of the mass water content, the water desorption isotherm, and the time-dependent evolution of Young's modulus and the compressive strength. It provides a consistent set of material data for a particular concrete grade and will be available for calibrating and validating concrete models. KEYWORDS basic and drying creep, concrete, mass water content, Pickett effect, shrinkage

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“…The measured total shrinkage includes both drying and autogenous shrinkage (thermal deformation can be ignored due to the small cross-section of the samples (Baroghel-Bouny et al, 2006)). For very low w/c, the contribution of autogenous shrinkage to the total shrinkage can be comparable to that of drying shrinkage (Soliman, 2011).…”

Section: Shrinkagementioning

confidence: 99%

Effect of partially hydrated cementitious materials on early-age shrinkage of ultra-high-performance concrete

Soliman

Nehdi

2013

Magazine of Concrete Research

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The effect of adding partially hydrated cementitious materials (PHCM) on the early-age shrinkage of ultra-highperformance concrete (UHPC) is investigated. UHPC mixtures incorporating a shrinkage-reducing admixture (SRA) are also tested for comparison. Combined effects of PHCM and SRA in reducing early-age shrinkage are explored. Results indicate a significant improvement in the early-age compressive strength of UHPC mixtures due to PHCM addition.SRA was effective in reducing shrinkage; however, PHCM achieved excellent early-age shrinkage reduction when used alone or combined with SRA. PHCM mitigates undesirable behaviour induced by SRA, including setting time delays and reduction in mechanical properties. The addition of PHCM provides an ecological and economic technique for producing precast and cast-in-place self-restraining shrinkage concrete. Indeed, unused/returned concrete can be recycled in new mixtures to enhance mechanical strength and resistance to shrinkage, and to mitigate set retardation effects.

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Autogenous deformations of cement pastes

Cited by 161 publications

References 23 publications

Swelling, shrinkage and creep: a mechanical approach to cement hydration

Swelling, shrinkage and creep: a mechanical approach to cement hydration

Comprehensive study of concrete creep, shrinkage, and water content evolution under sealed and drying conditions

Effect of partially hydrated cementitious materials on early-age shrinkage of ultra-high-performance concrete

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