Plastic Shrinkage Cracking of Self-compacting Concrete: Influence of Capillary Pressure and Dormant Period

Sayahi, Faez; Emborg, Mats; Hedlund, Hans; Ćwirzeń, Andrzej

doi:10.2478/ncr-2019-0012

Cited by 13 publications

(6 citation statements)

References 24 publications

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“…This value is somewhat lower to −5.2 and −6.5 mm/m in SC-M-1-20RHA and SC-M-1-10CC+10RHA, respectively. This high plastic shrinkage value of SC-M at this stage is due to the particles settlement caused by gravity leading to an increased packing density of the SC-M and forcing the free water to rise to the surface of the SC-M, resulting in bleeding, as previously explained by [ 69 ], and evaporation of moisture from the surfaces of the SC-M leading to the formation of water menisci, which eventually create a negative capillary pressure that contracts the SC-M particles and consequently causes volumetric contraction, similar to was reported by [ 70 , 71 ]. It has been reported that the use of shrinkage-reducing admixtures (SRA) reduced the plastic shrinkage of SCC at this stage of hydration by reducing the internal friction angle between SCC particles due to their high fluidity and delaying the setting time of SCC [ 69 ].…”

Section: Resultssupporting

confidence: 72%

“…Finally, after 16 h of hydration, the plastic shrinkage remains constant until the end of the measurement. The reason for the plastic shrinkage of the SC-M beyond 7 h of hydration could be due to the continuous evaporation of moisture from the SC-M surfaces and volume reduction due to water consumption by the hydration process, as previously observed by [54,70,71]. In general, the reduction in plastic shrinkage after 7 h of hydration due to the partial replacement of CC and RHA in SC-M could be attributed to the fact that both act as nuclei for the formation of hydration products at an early time of hydration, thereby increasing the volume of hydration product and densifying the SC-M microstructure, as observed previously by [73] when studying the dominant factors on the early hydration of metakaolin-cement paste.…”

Section: Formation Of Hydrate Phases From the Hardened Scpsupporting

confidence: 56%

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Properties of Self-Compacting Concrete Produced with Optimized Volumes of Calcined Clay and Rice Husk Ash—Emphasis on Rheology, Flowability Retention and Durability

Muhammad

Thienel

2023

Materials

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The durability of concrete requires a dense microstructure which can be achieved by using self-compacting concrete (SCC). Both calcined clay (CC) and rice husk ash (RHA) are promising supplementary cementitious materials (SCMs) that can partially replace cement, but their use in SCC is critical due to their higher water demand (WD) and specific surface area (SSA) compared to cement. The effect of partial substitution of cement at 20 vol-% with binary and ternary blends of CC and RHA on flowability retention and durability of SCC was investigated. The empirical method of SCC design was adopted considering the physical properties of both CC and RHA. The deformability of the SCC was evaluated using the slump flow and J-ring tests. The T500 time and the V-funnel test were used to assess the viscosity of the SCC. The flowability retention was monitored by the plunger method, and flow resistance was determined based on the rheological measurements of SCC. The evolution of the hydrate phases of the binder in SCC was determined by thermogravimetric analysis, while the durability was evaluated by a rapid chloride migration test. Cement partial replacement with 20 vol-% CC has no significant effect on fresh SCC, flowability retention, compressive strength and durability properties. On the other hand, 20 vol-% RHA requires a higher dosage of SP to achieve self-compactability and increase the viscosity of SCC. Its flowability retention is only up to 30 min after mixing and exhibited higher flow resistance. It consumes more calcium hydroxide (CH) and improves the compressive strength and chloride resistance of SCC. The ternary blending with CC and RHA yielded better fresh SCC properties compared to the binary blend with RHA, while an improved chloride penetration resistance could be achieved compared to the binary CC blend.

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Section: Resultssupporting

confidence: 72%

Section: Formation Of Hydrate Phases From the Hardened Scpsupporting

confidence: 56%

Properties of Self-Compacting Concrete Produced with Optimized Volumes of Calcined Clay and Rice Husk Ash—Emphasis on Rheology, Flowability Retention and Durability

Muhammad

Thienel

2023

Materials

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“…Increasing the evaporation rate increases the build-up rate of the negative capillary pressure in concrete and vice versa when the evaporation rate is decreased [4]. Numerous researchers have also shown that the negative capillary pressure build-up is affected by factors such as particle size distribution, bleeding, admixtures, additions, specimen geometry and the water/cement ratio [3,6,12,[14][15][16][17]. Due to all these factors influencing the negative capillary pressure build-up, the capillary pressure mechanism has been identified in the literature as the primary mechanism for plastic shrinkage [4,10,14,18].…”

Section: Figmentioning

confidence: 99%

“…When plastic shrinkage occurs and the concrete is restrained, tensile stresses are induced and if the concrete did not develop sufficient strength to withstand the induced stresses, plastic shrinkage cracks will form [1,2]. The induced tensile stresses are caused by the build-up of negative capillary pressure within the fresh concrete [3]. If the negative capillary pressure builds up at a high rate and reaches a critical capillary pressure, plastic shrinkage cracking may occur [4].…”

Section: Introductionmentioning

confidence: 99%

Preventing plastic shrinkage cracking by monitoring the capillary pressure build-up in self-compacting concrete

Deysel

Boshoff²,

Smit³

2022

MATEC Web Conf.

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Plastic shrinkage cracking is a problem for the service life, aesthetics and durability of concrete members. It occurs when tensile stresses are induced in fresh concrete, through plastic shrinkage that is restrained. Plastic shrinkage is caused by negative capillary pressure build-up, but the capillary pressure of fresh concrete can be controlled to prevent plastic shrinkage. In this paper, the control of capillary pressure to prevent plastic shrinkage cracking using high-capacity capillary pressure sensors is explored. The capillary pressure behaviour of a self-compacting concrete mix design in various evaporation rates was determined. Capillary pressure boundaries for concrete wetting to relieve tensile stresses were identified. The effectiveness of wetting fresh concrete at a predefined capillary pressure boundary was investigated.

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“…e shrinkage of a GRC-PLC composite panel includes temperature shrinkage, drying shrinkage, plastic shrinkage, carbonization shrinkage, and autogenous shrinkage. Faez Sayahi et al [39] believe that cement shrinkage and deformation is the main cause of cracking. erefore, the composite panel cracks can be reflected by monitoring the shrinkage strain of the panel.…”

Section: Drying Shrinkage Performance Of Grc-plc Compositementioning

confidence: 99%

New Anticracking Glass‐Fiber‐Reinforced Cement Material and Integrated Composite Technology with Lightweight Concrete Panels

Chen

Deng

Cheng

et al. 2021

Advances in Civil Engineering

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Glass-fiber-reinforced cement (GRC) is a widely used decorative material for wall facades. Conventional GRC products have poor crack resistance, low construction efficiency, poor integration, and few environmental benefits, hence failing to meet the requirements of building industrialization. To realize an integrated composite wall made from GRC and precast lightweight concrete (PLC) with a lasting anticrack effect, the anticracking properties of GRC material as well as the connection mode of GRC and PLC layers were studied. Through long-term shrinkage test, the influence of fiber content, rubber powder content, and expansion agent content on the crack resistance of GRC material was systematically analyzed. At the same time, the influence of connection mode on the crack resistance of the GRC layer after compositing with precast lightweight concrete (PLC) was analyzed. The results showed that adding fiber can effectively improve the flexural strength of the GRC and reduce drying shrinkage, whereas adding rubber powder can effectively improve its toughness and crack resistance. The addition of U-type expansion agent (UEA) can impart the cement mortar with a certain degree of microexpansion performance and help improve the drying shrinkage of the GRC. Compared with other compounding methods, the smooth connection of the GRC and PLC can effectively reduce the shrinkage of the GRC surface layer and improve its crack resistance. So, the new GRC material has good crack resistance performance and facade effect. These research studies provide an experimental basis for the large-scale application of the panel, and it has great advantages in improving the efficiency of prefabricated building construction.

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Plastic Shrinkage Cracking of Self-compacting Concrete: Influence of Capillary Pressure and Dormant Period

Cited by 13 publications

References 24 publications

Properties of Self-Compacting Concrete Produced with Optimized Volumes of Calcined Clay and Rice Husk Ash—Emphasis on Rheology, Flowability Retention and Durability

Properties of Self-Compacting Concrete Produced with Optimized Volumes of Calcined Clay and Rice Husk Ash—Emphasis on Rheology, Flowability Retention and Durability

Preventing plastic shrinkage cracking by monitoring the capillary pressure build-up in self-compacting concrete

New Anticracking Glass‐Fiber‐Reinforced Cement Material and Integrated Composite Technology with Lightweight Concrete Panels

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