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E. Janowska-Renkas and D. Matyjaszczyk
Fig. 3 Frost resistance of concrete of CEM I 42.5R cement without and with the content of
hydrophilic and hydrophobic nanosilica and superplasticizer
types reached F50 frost resistance level. Only in case of the concrete containing
0.5 wt% of hydrophobic nanosilica (B4) the required level of frost resistance (F50)
could not be reached.
4 Summary and Conclusions
Based on test results obtained it was demonstrated that:
Introduction of nanoadditive to concrete had a beneficial effect on improvement of
their workability and reduction of the air content, depending on the type and quantity
of the nanoadditive used. And thus the air content in the concrete mix was lower in
the presence of M3 hydrophilic nanosilica (0.5%) than with the M4 hydrophobic
nanosilica (1.9%). On the other hand, increase of the nanosilica amount from 0.5 to
1.5% by mass caused a reverse effect demonstrated by higher air content in the mix
containing M10 hydrophilic nanosilica (1.9%) than in case of the mixture with M9
hydrophobic nanosilica (1.6%).
It was demonstrated that introduction of additives to concretes (B2-B14), regardless of their type and quantity, caused the increase of the density in concretes tested
compared to the density of B1 test concrete.
Results of compressive strength tests obtained in the initial period of curing (after
1 day of curing) showed that application of hydrophilic and hydrophobic nanosilica
in the amount of 0.5% by mass caused over twice growth of strength compared to
the test concrete. With the smaller amount of the nanoadditive (0.5% by mass), the
E. Janowska-Renkas and D. Matyjaszczyk
Fig. 3 Frost resistance of concrete of CEM I 42.5R cement without and with the content of
hydrophilic and hydrophobic nanosilica and superplasticizer
types reached F50 frost resistance level. Only in case of the concrete containing
0.5 wt% of hydrophobic nanosilica (B4) the required level of frost resistance (F50)
could not be reached.
4 Summary and Conclusions
Based on test results obtained it was demonstrated that:
Introduction of nanoadditive to concrete had a beneficial effect on improvement of
their workability and reduction of the air content, depending on the type and quantity
of the nanoadditive used. And thus the air content in the concrete mix was lower in
the presence of M3 hydrophilic nanosilica (0.5%) than with the M4 hydrophobic
nanosilica (1.9%). On the other hand, increase of the nanosilica amount from 0.5 to
1.5% by mass caused a reverse effect demonstrated by higher air content in the mix
containing M10 hydrophilic nanosilica (1.9%) than in case of the mixture with M9
hydrophobic nanosilica (1.6%).
It was demonstrated that introduction of additives to concretes (B2-B14), regardless of their type and quantity, caused the increase of the density in concretes tested
compared to the density of B1 test concrete.
Results of compressive strength tests obtained in the initial period of curing (after
1 day of curing) showed that application of hydrophilic and hydrophobic nanosilica
in the amount of 0.5% by mass caused over twice growth of strength compared to
the test concrete. With the smaller amount of the nanoadditive (0.5% by mass), the