Modification effects of colloidal nanoSiO2 on cement hydration and its gel property
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Citations
An investigation on the influence of nano silica morphology on the characteristics of cement composites
Utilization of waste marble powder in cement-based materials by incorporating nano silica
Nano-Modified Fly Ash Concrete: A Repair Option for Concrete Pavements
Effect of nano-silica on chemical and volume shrinkage of cement-based composites
References
Nanotechnology in concrete – A review
Microstructure of cement mortar with nano-particles
Influence of nano-SiO2 addition on properties of hardened cement paste as compared with silica fume
Characteristics of cement mortar with nano-SiO2 particles
The nanogranular nature of C–S–H
Related Papers (5)
Influence of nano-SiO2 addition on properties of hardened cement paste as compared with silica fume
Frequently Asked Questions (16)
Q2. What is the effect of CNS on the NEW content of cement paste?
As the pozzolanic reaction is a water-intake process other than that from CH [32], the decrease in NEW content can be due to gel structure modification.
Q3. What is the effect of the cement hydration on the mechanical properties of cementitious materials?
Modification caused by the cement hydration of small particles can be reflected by their effect on the mechanical properties of cementitious materials.
Q4. What is the effect of CNS on the nanoscale mechanical properties of cement paste?
To determine the effect of CNS on the nanoscale mechanical properties of cement paste, a statistical nanoindentation technique was applied, through which the intrinsic gel modifying effect of CNS can be shown.
Q5. What is the effect of CNS on the cement hydration process?
Although CNS can accelerate cement hydration to a great extent in the early age, the later hydration of cement is hindered; (3) NEW content measurement is not suitable for monitoring the hydration process of CNS-added paste, which in the later age will gradually decrease due to the effect of CNS on the gel structure; (4) A reduction in low-stiffness C–S–H gel and an increase in high-stiffness C–S–H gel can be the result of CNS addition.
Q6. Why has nanotechnology been introduced to cement and concrete research?
Nanotechnology has been introduced to cement and concrete research because it can achieve a stronger and more durable concrete [1,2].
Q7. What is the hydration acceleration effect of CNS?
The hydrate morphology evolution of CNS-added cement pastes indicates that the hydration acceleration effect of CNS is achieved by its high pozzolanic activity in the very early age, which generates C–S–H gel and then acts as nucleation sites to accelerate cement hydration.
Q8. What is the effect of CNS addition on the NEW content of cement paste?
During the polymerization process (Eq. (3)), combined water in silicate chains can be released, resulting in a decrease of NEW content of the paste [30].
Q9. What is the effect of nanoSiO2 on cement?
Jo et al. [6] reported that 6% nanoSiO2 can improve the compressive strength of concrete by 152% and 142% at 7 and 28 days, respectively; Li [7] found that 5% nanoSiO2 can improve compressive strength by 17.5% at 28 day; Gaitero et al. [9] revealed reduced calcium leaching of nanoSiO2-added cement pastes.
Q10. Why is the hydration rate higher in cement paste?
It demonstrates that CNS accelerates cement hydration at a higher rate and this can be due to the higher amount of nucleation sites, which results in a greater amount of nucleus formation [27].
Q11. What is the reason for the lower compressive strength of 5% CNS-added mortar?
The lower compressive strength of 5% CNS-added mortar compared to the control at 84 days can be due to the hindrance of cement hydration as described in Section 3.2.4.
Q12. What is the effect of CNS on the electrical conductivity of cement?
It is shown in Fig. 8 that the addition of CNS introduces a higher rate of increase in pH and electrical conductivity in the early age (effects of CNS on pH and electrical conductivity were negligible), meaning a quicker dissolution of cement particles.
Q13. What is the hydration acceleration mechanism of CNS-added paste?
The hydration acceleration mechanism revealed by the SEM images can be verified by comparing the morphology evolution of CNS-added cement paste and of C–S–H seeded C3S paste, as shown in Ref. [12], the latter of which shows a faster formation of new hydrates but no prior step of nucleus formation.
Q14. How much strength can be improved by adding CNS?
It is shown in Fig. 6 that CNS has a more pronounced enhancing effect in the early age: for the 5% CNS mix, compressive strength can be improved by as much as 16% and 45% at 3 and 7 days, respectively.
Q15. What is the effect of CNS on the cement paste?
Effects of nano-SiO2 on the cement hydration process, as well as its influence on the gel structure and nanoscale mechanical properties of cement paste were studied.
Q16. How was the surface of the samples cleaned?
In the final step, the polished samples were ultrasonically cleaned in water for 1 min using a bath sonicator to remove polishing debris from the sample surface.