Effects of shrinkage reducing admixture in shrinkage compensating concrete under non-wet curing conditions

Collepardi, M.; Borsoi, A.; Collepardi, S.; Olagot, Jean Jacob Ogoumah; Troli, R.

doi:10.1016/j.cemconcomp.2004.09.020

Cited by 209 publications

(117 citation statements)

References 2 publications

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“…Expansion agents, also known as shrinkage reducing admixtures, are special products developed to increase the volume of concrete through specific chemical reactions. According to the surveyed literature 4) there are two main types of expansion agents: those based on ettringite formation and those based on the formation of calcium hydroxide. In this study, an expansion agent of the second type was used.…”

Section: Research Motivationmentioning

confidence: 99%

Influence of Random Cracks on the Shear Behavior of Reinforced Concrete Beams Containing Steel Fibers

Toma

Miki

Niwa

2007

JSCE JOURNAL OF MATERIALS, CONCRETE STRUCTURES AND PAVEMENTS

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The present study is aimed at investigating the influence of random cracks on the shear behavior of RC beams with steel fibers. For this purpose, several amounts of expansion agent and two percentages of steel fibers were used. From the strain history during the curing period of time, some sort of chemical prestress could be observed due to the use of expansion agent. Random cracks were successfully created and the pattern showed different crack densities, defined as the ratio between the area of the cracks and the uncracked area of concrete, for each beam. In some cases, a significant increase in the peak load was observed. In other cases only the deformability of beams was improved due to the addition of steel fibers.

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Section: Research Motivationmentioning

confidence: 99%

Influence of Random Cracks on the Shear Behavior of Reinforced Concrete Beams Containing Steel Fibers

Toma

Miki

Niwa

2007

JSCE JOURNAL OF MATERIALS, CONCRETE STRUCTURES AND PAVEMENTS

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“…For example, concrete expansion can be initiated chemically by the reaction of expansive additives. The use of expansive concrete can reduce concrete shrinkage (shrinkage-compensating) and establish internal compressive concrete stresses (chemical pre-stressing) in concrete structures (Klein et al 1961;Muguruma 1968;Okamura and Tsuji 1972;Tsuji 1973;1980;Nagataki and Gomi 1998;Collepardi et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Shear Strength of Reinforced Concrete Beams: Concrete Volumetric Change Effects

Nakarai

Morito

Ehara

et al. 2016

ACT

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Volumetric changes in concrete may affect the structural performance of reinforced concrete structures and their durability. It has been revealed that autogenous shrinkage of high-strength concrete decreases reinforced concrete beam's shear strength compared with low-shrinkage concrete. High-drying shrinkage of concrete may also decrease the shear strength of reinforced concrete beams using normal-strength concrete. In this study, the effects of drying shrinkage and expansion of normal-strength concrete on the shear strength of reinforced concrete beams with/without stirrups were investigated. Six concrete mix proportions, using different aggregates and admixtures, were used to control concrete volumetric changes. The used concrete showed a large range in volumetric change and high-shrinkage concrete caused shrinkage-induced cracking in the beams before loading. Loading test results showed that drying shrinkage and expansion decreased and increased the shear strength, respectively. The decrease or increase in measured shear strength as a result of volumetric changes was well reproduced by the proposed equation. The equation included the new concept of strain change in tension reinforcement caused by concrete shrinkage or expansion, which was proposed previously for autogenous shrinkage of high-strength concrete.

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“…The expansion process of Betonamit isn't quite fully understood and as a result two schools of thought emerged to explain such a process [3]:…”

Section: Expansion Mechanismsmentioning

confidence: 99%

Rock Breakage Using Expansive Cement

Dessouki¹,

Mitri²

2011

ENG

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Expansive cements are powdery materials which produce expansive stresses during the moist curing process. These cements are classified as shrinkage-compensated or self-stressing cements. The shrinkage compensated is used in the construction industry and will not be investigated in this paper. Self-Stressing cement is widely used in the demolition & fragmentation industry and will be the main focus of this report. The objective of this paper is to discuss the relationship between Sulfate-compounds on the expansion time and degree of expansion of Betonamit expansive cement. Based on literature [1], expansion time is directly proportional to sulfate content when mixed with Portland cement. Hence, as the sulfate content of the cement mixture increases, expansion time increases. However, in this research project the effect of Portland cement was removed to further examine the effect of sulfate on Betonamit only. This phenomenon was investigated using various concentrations of 4 different Sulfate-compounds. The results proved the possibility of decreasing the expansion time of Betonamit and, quite remarkably, a much greater degree of expansion was obtained.

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Effects of shrinkage reducing admixture in shrinkage compensating concrete under non-wet curing conditions

Cited by 209 publications

References 2 publications

Influence of Random Cracks on the Shear Behavior of Reinforced Concrete Beams Containing Steel Fibers

Influence of Random Cracks on the Shear Behavior of Reinforced Concrete Beams Containing Steel Fibers

Shear Strength of Reinforced Concrete Beams: Concrete Volumetric Change Effects

Rock Breakage Using Expansive Cement

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