Amorphous Aluminosilicates as a Structure-Forming Additive in Cementitious Systems

Логанина, В. И.; Zhegera, K. V.; Fediuk, Roman; Timokhin, Roman; Zayakhanov, M. E.; Liseitsev, Yuriy

doi:10.1061/(asce)mt.1943-5533.0002995

Cited by 11 publications

(3 citation statements)

References 18 publications

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“…The study of autogenous shrinkage of cement paste is very important for a better understanding of that of mortar and concrete. Another limitation of the existing studies is that most of them are only about one type of supplementary material and the water-binder ratio of mixtures concerned in different studies always varies [12][13][14][15][16][17][18][19][20]. Therefore, it is hard to compare the effects of different supplementary materials on autogenous shrinkage based on the available results from the literature.…”

Section: Introductionmentioning

confidence: 99%

Effect of Supplementary Materials on the Autogenous Shrinkage of Cement Paste

Huang

2020

Materials

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In recent years more and more attention has been given to autogenous shrinkage due to the increasing use of high-performance concrete, which always contains supplementary materials. With the addition of supplementary materials—e.g., fly ash and blast furnace slag—internal relative humidity, chemical shrinkage and mechanical properties of cement paste will be affected. These properties significantly influence the autogenous shrinkage of cement paste. In this study, three supplementary materials—i.e., silica fume, fly ash and blast furnace slag—are investigated. Measurements of final setting time, internal relative humidity, chemical shrinkage, compressive strength and autogenous deformation of the cement pastes with and without supplementary materials are presented. Two water-binder ratios, 0.3 and 0.4, are considered. The effects of different supplementary materials on autogenous shrinkage of cement paste are discussed.

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Section: Introductionmentioning

confidence: 99%

Effect of Supplementary Materials on the Autogenous Shrinkage of Cement Paste

Huang

2020

Materials

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“…Note the presence of quartz particles in the mineralogy of metakaolin and fly ash. This can harm the activation process of the binders, since a high degree of amorphism is required for the material to be activated correctly [34,35]. Amorphous bands are observed in these two binders, especially in the range of 20 • to 30 • and 40 • to 50 • for metakaolin and in the range of 20 • to 35 • for fly ash.…”

Section: Resultsmentioning

confidence: 99%

Alkaline Activation of Binders: A Comparative Study

Alves,

Marvila,

Linhares Júnior

et al. 2024

Materials

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Binders formulated with activated alkali materials to replace Portland cement, which has high polluting potential due to CO2 emissions in its manufacture, have increasingly been developed. The objective of this study is to evaluate the main properties of activated alkali materials (AAM) produced by blast furnace slag, fly ash, and metakaolin. Initially, binders were characterized by their chemical, mineralogical and granulometric composition. Later, specimens were produced, with molarity variation between 4.00 and 5.50, using the binders involved in the research. In preparing the activating solution, sodium hydroxide and silicate were used. The evaluated properties of AAM were consistency, viscosity, water absorption, density, compressive strength (7 days of cure), calorimetry, mineralogical analysis by X-ray diffraction, and morphological analysis by scanning electron microscopy. The results of evaluation in the fresh state demonstrate that metakaolin has the lowest workability indices of the studied AAM. The results observed in the hardened state indicate that the metakaolin activation process is optimized with normal cure and molarity of 4.0 and 4.5 mol/L, obtaining compressive strength results after 7 days of curing of approximately 30 MPa. The fly ash activation process is the least intense among the evaluated binders. This can be seen from the absence of phases formed in the XRD in the compositions containing fly ash as binder. Unlike blast furnace slag and metakaolin, the formation of sodalite, faujasite or tobermorite is not observed. Finally, the blast furnace slag displays more intense reactivity during thermal curing, obtaining compressive strength results after 7 days of curing of around 25 MPa. This is because the material’s reaction kinetics are low but can be increased in an alkaline environment, and by the effect of temperature. From these results, it is concluded that each precursor has its own activation mechanism, observed by the techniques used in this research. From the results obtained in this study, it is expected that the alkaline activation process of the types of binders evaluated herein will become a viable alternative for replacing Portland cement, thus contributing to cement technology and other cementitious materials.

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“…In [15,16], to intensify the process of lime hardening, it is proposed to add additives based on natural and synthetic zeolites to the formulation of lime compositions. The authors found that with the introduction of an additive based on synthetic zeolite in an amount of 10% by weight of lime, an increase in strength by 94.25% is observed compared to the control sample.…”

Section: Introductionmentioning

confidence: 99%