Einfluss der Nachbehandlung auf das Karbonatisierungsverhalten von Beton aus klinkerarmen Zementen

Hainer, Stefan; Proske, Tilo; Graubner, Carl‐Alexander

doi:10.1002/best.201400042

Cited by 8 publications

(5 citation statements)

References 18 publications

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“…Although it is well known that the type and strength class of binder as well as w/c ratio affect the degree of hydration at early ages and thus the sorptivity of the cover concrete, the effect of curing (√ k c ), on carbonation rate is not systematically affected by the type of cement, as observed by, for example, , , , , , . However, it is well known, that the effect of curing on √ k c scatters, Fig.…”

Section: Durability Design: Model Input Variablesmentioning

confidence: 99%

Performance based durability design, carbonation part 1 – Benchmarking of European present design rules

Greve‐Dierfeld

Gehlen²

2016

Structural Concrete

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In each design situation the deemed-to-satisfy rules of selected countries were followed. The probabilistic calculations were mainly based on short-term carbonation data. However, some calculations were also based on long-term observation. The latter was implemented for independent validation purposes. The calculated reliability ranges are very broad and in some "unfavourable" situations, the deemed-to satisfy requirements do not guarantee the required limit state (LS) arget reliabilities for the particular exposure. In "favourable" situations less stringent demands would have been sufficient.

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Section: Durability Design: Model Input Variablesmentioning

confidence: 99%

Performance based durability design, carbonation part 1 – Benchmarking of European present design rules

Greve‐Dierfeld

Gehlen²

2016

Structural Concrete

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“…With regard to curing, there is no doubt that curing protects the near‐surface concrete from drying and thus affects the durability of near‐surface concrete. It is also well known that the carbonation rate decreases with increasing curing time and quality , . In general, the effect of curing on the absolute reduction in carbonation depth is greater for concretes with lower carbonation resistances.…”

mentioning

confidence: 97%

“…In general, the effect of curing on the absolute reduction in carbonation depth is greater for concretes with lower carbonation resistances. However, the reduction in carbonation rate due to curing is less affected by concrete composition , , . Consequently, the same curing conditions were adopted for all compositions.…”

mentioning

confidence: 99%

Performance‐based durability design, carbonation part 2 – Classification of concrete

Greve‐Dierfeld¹,

Gehlen

2016

Structural Concrete

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Performance-based durability design, carbonation part 2 -Classification of concreteAt present, prescriptive regulations with regard to concrete cover and composition are applied to provide sufficient durability of reinforced concrete members under exposure conditions with different degrees of severity. In view of current knowledge on deterioration mechanisms and their modelling, it is planned to change from these deemed-to-satisfy specifications to a performancebased design approach in future standards. In such specifications, concrete durability design is based on the statistically characterized performance of concrete, determined in standardized tests with respect to defined classes of concretes with similar performance. This paper presents the results of a study in which concrete mixes were tested and analysed with respect to their carbonation resistance. Compositions with similar performance are grouped into carbonation resistance classes. These classes are described statistically and requirements for performance testing are given. In addition, composition requirements are introduced in order to determine concrete performance depending on mix composition prescriptively. Finally, an example is given for the assessment of concrete performance with regard to carbonation. This work was carried out at the request of JWG under CEN TC 250/SC2 and CEN TC 104/SC1 as an input and starting point for the ongoing committee work to implement the methodology from the fib Model Code for Concrete Structures 2010 in the next generation (2021) of European concrete standards.

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“…When the state of CO2 is between supercritical fluid state and natural atmospheric environment, the carbonation of cement-based materials belongs to accelerated carbonation. Techniques have been developed in recent years to take advantages of the above carbonation processes to, e.g., modify composition and microstructure of cementbased materials [11][12][13] and to improve material properties using CO2 curing [14][15][16] . The techniques have also important applications in CO2 capture and storage [1] , carbonation of hazardous water materials [17][18][19] and treatment of recycled concrete [20][21][22] .…”

Section: Introductionmentioning

confidence: 99%

Experimental and statistical study on the irregularity of carbonation depth of cement mortar under supercritical condition

Liu

et al. 2018

Construction and Building Materials

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The heterogeneity of a cement-based material results in a random spatial distribution of carbonation depth. Currently, there is a lack of both experimental and numerical investigations aiming at a statistical understanding of this important phenomenon. This paper presents both experimental and numerical supercritical carbonation test results of cement mortar blocks. The carbonation depths are measured along the carbonation boundary by the proposed rapid image processing technique, which are then statistically studied by calculating, e.g., their probability density and power spectral density (PSD). The results indicate that the distribution of the carbonation depth can be approximately represented by a lognormal distribution function and the PSD has quantitative correlation with some of the statistic parameters used in the simulations. In particular, the effects of the autocorrelation lengths and the coefficient of variation of porosity, which are used to define the random porosity field, on the irregularity of carbonation depth are analyzed numerically in details and validated by experimental results. The study has shown that using a random field of porosity with due consideration of spatial correlation and variance, the irregularity of carbonation depth can be realistically captured by the numerical model. The numerical results confirm that lognormal distributions represent the random nature of carbonation depth well and the average and variance of the irregular carbonation depth increase with the increase of carbonation time, autocorrelation length and coefficient of variation of porosity. The study also offers a potential method to numerically calibrate some of the statistic parameters required by a numerical carbonation model through comparing the PSD with that from experimental tests. Overall the methodology adopted in the paper can provide a foundation for future investigations on probability analysis of carbonation depth and other similar work based on multi-scale and-physics modelling.

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Einfluss der Nachbehandlung auf das Karbonatisierungsverhalten von Beton aus klinkerarmen Zementen

Cited by 8 publications

References 18 publications

Performance based durability design, carbonation part 1 – Benchmarking of European present design rules

Performance based durability design, carbonation part 1 – Benchmarking of European present design rules

Performance‐based durability design, carbonation part 2 – Classification of concrete

Experimental and statistical study on the irregularity of carbonation depth of cement mortar under supercritical condition

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