INFLUENCE OF THE INTERACTION BETWEEN NANOSILICA AND A SHRINKAGE-REDUCING ADDITIVE ON THE MECHANICAL BEHAVIOR OF PORTLAND CEMENT PASTES
The process of urban verticalization has intensified the demand for high-performance cementitious materials capable of offering high strength and durability. In this context, nanosilica (NS) stands out for its ability to densify the cementitious matrix and improve mechanical properties. However, its incorporation can increase autogenous shrinkage, compromising long-term performance. As an alternative, shrinkage-reducing admixtures (SRA) have been used to mitigate this effect, although they may negatively impact mechanical strength. Given this, this study investigates the interaction between NS and SRA in Portland cement pastes, evaluating their effects on consistency and compressive strength. Six mixtures were produced, with and without 1% cement replacement by NS, and with 0%, 1%, and 2% SRA content, while maintaining a constant water-to-binder ratio (0.35) and slump (110±10 mm). Compressive strength tests were conducted at 2, 7, and 28 days, with results analyzed using ANOVA and Duncan’s test. The results indicated that NS promoted a significant increase in strength at all ages, while ARR did not alter the consistency of the pastes. In mixtures without NS, a 1% ARR content showed a tendency to increase strength at early ages, while 2% produced no significant effects. On the other hand, the combination of NS and ARR resulted in a reduction in strength at all ages analyzed. It is concluded that, although NS contributes to strength gain, its combination with ARR may compromise mechanical performance, possibly due to delayed hydration and microstructural changes. Nevertheless, the potential of ARR in mitigating shrinkage suggests the need for further investigations focused on durability.
INFLUENCE OF THE INTERACTION BETWEEN NANOSILICA AND A SHRINKAGE-REDUCING ADDITIVE ON THE MECHANICAL BEHAVIOR OF PORTLAND CEMENT PASTES
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DOI: https://doi.org/10.22533/at.ed.1317632627032
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Palavras-chave: Nanosilica; Shrinkage-reducing additive; Cement pastes; Compressive strength; Cementitious materials.
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Keywords: Nanosilica; Shrinkage-reducing additive; Cement pastes; Compressive strength; Cementitious materials.
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Abstract:
The process of urban verticalization has intensified the demand for high-performance cementitious materials capable of offering high strength and durability. In this context, nanosilica (NS) stands out for its ability to densify the cementitious matrix and improve mechanical properties. However, its incorporation can increase autogenous shrinkage, compromising long-term performance. As an alternative, shrinkage-reducing admixtures (SRA) have been used to mitigate this effect, although they may negatively impact mechanical strength. Given this, this study investigates the interaction between NS and SRA in Portland cement pastes, evaluating their effects on consistency and compressive strength. Six mixtures were produced, with and without 1% cement replacement by NS, and with 0%, 1%, and 2% SRA content, while maintaining a constant water-to-binder ratio (0.35) and slump (110±10 mm). Compressive strength tests were conducted at 2, 7, and 28 days, with results analyzed using ANOVA and Duncan’s test. The results indicated that NS promoted a significant increase in strength at all ages, while ARR did not alter the consistency of the pastes. In mixtures without NS, a 1% ARR content showed a tendency to increase strength at early ages, while 2% produced no significant effects. On the other hand, the combination of NS and ARR resulted in a reduction in strength at all ages analyzed. It is concluded that, although NS contributes to strength gain, its combination with ARR may compromise mechanical performance, possibly due to delayed hydration and microstructural changes. Nevertheless, the potential of ARR in mitigating shrinkage suggests the need for further investigations focused on durability.
- Larissa da Silva Marques
- Fernando da Silva Souza
- Yuri Sotero Bomfim Fraga
- Vitória Régia Araújo Ribeiro
- PEDRO FILIPE DE LUNA CUNHA
