Amorphous nano-silica (nS) particles (0โ2.5wt%) by cement were incorporated in cement pastes and mortars, and their effect on the fresh state behaviour was analysed. Rheological tests showed that after 75min from the mixing start, the mortar having 2.5wt% nS shows insufficient flowability to allow i
Experimental study of the effect of addition of nano-silica on the behaviour of cement mortars Mounir
โ Scribed by Ltifi; Achraf Guefrech; Pierre Mounanga; Abdelhafid Khelidj
- Publisher
- Elsevier
- Year
- 2011
- Tongue
- English
- Weight
- 889 KB
- Volume
- 10
- Category
- Article
- ISSN
- 1877-7058
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โฆ Synopsis
The properties of cement mortars with nano-SiO 2 were experimentally studied. The amorphous or glassy silica, which is the major component of a pozzolan, reacts with calcium hydroxide formed from calcium silicate hydration. The rate of the pozzolanic reaction is proportional to the amount of surface area available for reaction. Therefore, it is plausible to add nano-SiO 2 particles in order to make highperformance concrete. In the aim to study the effects of the addition of nanoparticles on the behavior of pastes and cement mortars, nano-particles of silica amorphous were incorporated at a rate of 3 and 10% by weight of cement. The compressive strengths of different mortars increase with the increasing of the amount of nano-SiO 2 . The influence of nano-SiO2 on consistency and setting time are different. Nano-SiO2 makes cement paste thicker and accelerates the cement hydration process.
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The effect of three fillers (ground limestone, dolomite and basalt) on the strength of cement mortars was studied on 1:2.75 mixes having a w/c ratio of 0.70. The filler content ranged from i0 to 40% of the cement weight and their fineness (specific surface) from 1,150 to 11,200 sq.cm per g. Results
Cement mortars containing 0, i0 and 30 percent silica fume were prepared at water/cement + silica fume ratios of 0.45 and 0.60. Compressive strength, Ca(OH) 2 and non-evaporable water contents and pore-size distribution were monitored up to 180 days. Silica fume reacts with most of the Ca(OH) 2 for