Effect of different high surface area silicas on the rheology of cement paste

[ES] Efecto de diferentes sílices de alta área superficial sobre la reología de pastas de cemento. Este tra¬bajo estudia el efecto de la nanosílice (NS) sobre la reología de pastas de cemento por comparación con sílices de alta área superficial: humo de sílice (SF) y pirosílice (PS). Las pastas fueron fabricadas con diferentes rela¬ciones agua-material cementante y sustituciones sólidas de sílice. Fueron ejecutados ensayos de demanda de agua, tiempo de fraguado y reología. Se encontró que la NS y SF disminuyen la viscosidad plástica, mientras que la PS la aumenta. Solo la PS tuvo efecto sobre el límite elástico. La NS presentó mayor disminución de la viscosidad, independientemente de su alta demanda de agua. Se concluyó que el comportamiento de las pastas con NS y SF es gobernado por el efecto de ¿rodamiento¿ de la sílice, por su grado de aglomeración y por su impacto en la fracción de sólidos. El comportamiento de las pastas con PS es gobernado por su capacidad de absorber agua.[EN] This work studies the effect of nanosilica (NS) on the rheology of cement paste by comparing it with two high specific surface area silicas: silica fume (SF) and pyrogenic silica (PS). Portland cement pastes were produced with different water-to-cementing material ratios and different solid substitutions of cement by silica. Water demand, setting time, and rheology tests were performed. Results showed that NS and SF decreased plastic viscosity, while PS increased it. Only PS was found to have an effect on yield stress. NS showed the most decreasing effect on viscosity, regardless of its higher water demand. It was concluded that the behavior of pastes containing NS and SF is governed by the "ball-bearing" effect from silica particles, by their agglomeration degree, and their impact on the solid volume fraction. The behavior of pastes containing PS is governed by its ability to absorb a portion of the mixing water.Tobón, J.; Mendoza, O.; Restrepo, O.; Borrachero Rosado, MV.; Paya Bernabeu, JJ. (2020). Effect of different high surface area silicas on the rheology of cement paste. Materiales de Construcción. 70(340):1-9. https://doi.org/10.3989/mc.2020.15719S19703401. Kwan, A.K.H.; Li, Y. (2013) Effects of fly ash microsphere on rheology, adhesiveness and strength of mortar. Constr. Build. Mater. 42, 137-145.2. Jal, P.K.; Sudarshan, M.; Saha, A.; Patel, S.; Mishra, B.K. (2004) Synthesis and characterization of nanosilica prepared by precipitation method. Coll. Surf. A Physicochem. Eng. Asp. 240 [1-3], 173-178.3. El Sokkary, T. M.; Assal, H. H.; Kandeel, A. M. (2004) Effect of silica fume or granulated slag on sulphate attack of ordinary portland and alumina cement blend. Ceram. Int. 30 [2], 133-138.4. Gutsch, A.; Krämer, M.; Michael, G.; Mühlenweg, H.; Pridöhl, M.; Zimmermann, G. (2002) Gas-Phase production of nanoparticles. KONA Powder Part. J. 20, 24-37.5. Singh, L.P.; Karade, S.R.; Bhattacharyya, S.K.; Yousuf, M.M.; Ahalawat, S. (2013) Beneficial role of nanosilica in cement based materials - A review. Constr. Build. Mater. 47, 1069-1077.6. Björnström, J.; Martinelli, A.; Börjesson, L.; Panas, I.; (2004) Accelerating effects of colloidal nano-silica for beneficial calcium-silicate-hydrate formation in cement. Chem. Phys. Lett. 392 [1-3], 242-248.7. Mendoza Reales, O.A.; Silva, E.C.C.M.; Paiva, M.D.M.; M.; Duda, P.; Toledo Filho, R.D. (2017) The role of surface area and compacity of nanoparticles on the rheology of cement paste 25.3. ACI Symp. Pub. 320, 25.1-25.14. https://www.concrete.org/publications/internationalconcreteabstractsportal/m/details/id/51701063.8. Tobón, J. I.; Mendoza Reales, O.; Retrepo, O.J.; Borrachero, M.V. (2018) Effect of pyrogenic silica and nanosilica on Portland cement matrices. J. Mater. Civ. Eng. 30 [10], 1-10.9. Mehdipour, I.; Khayat, K.H. (2018) Understanding the role of particle packing characteristics in rheo-physical properties of cementitious suspensions: A literature review. Constr. Build. Mater. 161, 340-353.10. Boukendakdji, O.; Kadri, E.H.; Kenai, S. (2012) Effects of granulated blast furnace slag and superplasticizer type on the fresh properties and compressive strength of selfcompacting concrete. Cem. Concr. Compos. 34 [4], 583-590.11. Park, C.K.; Noh, M.H.; Park, T.H. (2005) Rheological properties of cementitious materials containing mineral admixtures. Cem. Concr. Res. 35 [5], 842-849.12. Deng, H.; Li, H. (2018) Assessment of self-sensing capability of carbon black engineered cementitious composites. Constr. Build. Mater. 173, 1-9.13. Mendoza-Reales, O.A.; Arias Jaramillo, Y.P.; Ochoa Botero, J.C.; Delgado, C.A.; Quintero, J.H.; Toledo Filho, R.D. (2018) Influence of MWCNT/surfactant dispersions on the rheology of Portland cement pastes. Cem. Concr. Res. 107, 101-109.14. Quercia, G.; Hüsken, G.; Brouwers, H.J.H. (2012) Water demand of amorphous nano silica and its impact on the workability of cement paste. Cem. Concr. Res. 42 [2], 344-357.15. Norhasri, M.S.M.; Hamidah, M.S.; Fadzil, A.M. (2017) Applications of using nano material in concrete: A review. Constr. Build. Mater. 133, 91-97.16. Bowen, P. (2002). Particle size distribution measurement from millimeters to nanometers and from rods to platelets. J. Dispers. Sci. Technol. 23 [5], 631-662.17. Staiger, M.; Bowen, P.; Ketterer, J.; Bohonek, J. (2002) Particle size distribution measurement and assessment of agglomeration of commercial nanosized ceramic particles. J. Dispers. Sci. Technol. 23 [5], 619-630.18. Hidalgo, A.; Petit, S.; Domingo, C.; Alonso, C.; Andrade, C. (2007) Microstructural characterization of leaching effects in cement pastes due to neutralisation of their alkaline nature. Part I: Portland cement pastes. Cem. Concr. Res. 37 [1], 63-70.19. 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Effect of Pyrogenic Silica and Nanosilica on Portland Cement Matrices

[EN] In this work, the effect of pyrogenic silica and nanosilica on the properties of portland cement matrices is compared. Two chemically and mineralogically similar mineral additions (amorphous silica) with different particle size and specific surface area were used to prepare pastes and mortars with different solids substitutions of cement by silica. These samples were used to measure water and superplasticizer demand, setting time, hydration kinetics, water absorption by capillary suction, and compressive strength. It was found that specific surface area, rather than particle size, played a crucial role in the amount of water and superplasticizer necessary to obtain a desired workability in pastes and mortars. Such water and superplasticizer demands had a delaying effect on the setting time and hydration kinetics of pastes. Nevertheless, compressive strength results at different curing ages of mortars were found to have a direct correlation with the porous structure of the matrix, rather than with the specific surface area of the silica particles. It was concluded that regardless of its higher specific surface area and greater effect on the fresh state properties of pastes, pyrogenic silica was less efficient than nanosilica to increase the compressive strength of mortars, being considered a less efficient pozzolanic material.Tobón, J.; Mendoza-Reales, O.; Restrepo, O.; Borrachero Rosado, MV.; Paya Bernabeu, JJ. (2018). Effect of Pyrogenic Silica and Nanosilica on Portland Cement Matrices. Journal of Materials in Civil Engineering. 30:1-10. https://doi.org/10.1061/(asce)mt.1943-5533.0002482S1103

Mineralogical evolution of Portland cement blended with silica nanoparticles and its effect on mechanical strength

Mineralogical analysis on pastes of Spanish Portland cement Type I, blended with nanosilica was carried out by conventional and high-resolution thermogravimetric analysis (TG-HRTG) and X-ray diffraction (XRD) in order to determine the quantity of the different mineralogical phases obtained during the hydration process. Simultaneously, mortars with the same materials and replacement ratio were made in order to assess their compressive strength for up to 28 days of curing time. In this paper, the rate and quantity of each one of the main constituent phases of the cement during its hydration process (CSH, portlandite, stratlingite, etc.) were determined. A correlation between the quantity of CSH and the development of compressive strength was established. Additionally, the pozzolanic activity of nanosilica was evaluated by quantifying the fixation of calcium hydroxide and its impact on the development of the compressive strength. © 2012 Elsevier Ltd. All rights reserved.The authors express their thanks to Cementos Argos S.A. and to COLCIENCIAS (Project 20201007768) of Colombia for their financial support in the execution of this research.Tobón, JI.; Paya Bernabeu, JJ.; Borrachero Rosado, MV.; Restrepo Baena, OJ. (2012). Mineralogical evolution of Portland cement blended with silica nanoparticles and its effect on mechanical strength. Construction and Building Materials. 36:736-742. https://doi.org/10.1016/j.conbuildmat.2012.06.043S7367423