Effect of Nano-Silica Particles on the Fresh Properties of UHPC

Abstract:

Nanotechnology is being used in UHPC for achieving more dense structural packing and better physical and mechanical properties. In this paper, nanosilica particles (0-1wt %) by cement were incorporated in cement pastes and mortars with water-binder ratio of 0.2, and their effect on fresh properties was addressed. The fresh properties of mixtures were investigated by spread, rheology and cohesiveness. In addition, effect of nanosilica on cement hydration was also investigated. The results show that significant increase of yield stress, viscosity and cohesiveness is observed with nanosilica above 0.005 wt% by cement, but nanosilica with content below 0.005% presents an improvement of workability especially with content of 0.002%. Moreover, the addition of nanosilica in cement pastes obviously accelerates the early cement hydration rate, but does not increase the cumulative heat evolution.

• Periodical: Key Engineering Materials (Volumes 629-630)
• Pages: 91-95
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.629-630.91
• Online since: October 2014
• Authors: Qian Qian Zhang*, Jian Zhong Liu, Wei Lin
• Keywords: Cohesiveness, Fresh Properties, Hydration, Nanosilica, Rheology, UHPC

References

[1] Q. Ye, Z.N. Zhang, D.Y. Kong, et al, Influence of nano-SiO2 addition on properties of hardened cement paste as compared with silica fume, Constr Build Mater. 21(2007) 539-545.

DOI: 10.1016/j.conbuildmat.2005.09.001

[2] M. Collepardi, J.J. Ogoumah Olagot, U Skarp, R Troli, Influence of amorphous colloidal silica on the properties of self-compacting concretes, In: Proceedingsof the international conference in concrete constructions-innovations anddevelopments in concrete materials and constructions, Scotland, 2002, pp.473-483.

[3] L. Senff, J.A. Labrincha, V.M. Ferreira, et al, Effect of nano-silica on rheology and fresh properties of cement pastes and mortars, Constr Build Mater. 23(2009) 2487-2491.

DOI: 10.1016/j.conbuildmat.2009.02.005

[4] D.A. Williams, A.W. Saak, H.M. Jennings, The influence of mixing on the rheology of fresh cement paste, Cem Concr Res. 29(1999)1491-1496.

DOI: 10.1016/s0008-8846(99)00124-6

[5] W.W.S. Fung, A.K.H. Kwan, Role of water film thickness in rheology of CSF mortar, Cem Concr Compos. 32(2010), pp.255-264.

DOI: 10.1016/j.cemconcomp.2010.01.005

[6] De Larrard F, Concrete mixture proportioning: a scientific approach, CRC Press, (1999).

[7] J.J. Thomas, A new approach to modeling the nucleation and growth kinetics of tricalcium silicate hydration, J. Am. Ceram. Soc. 90(2007) 3282-3288.

DOI: 10.1111/j.1551-2916.2007.01858.x