| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 256147 | Construction and Building Materials | 2016 | 14 Pages |
•Effect of different sizes of nano-SiO2 particles on HPC properties was investigated.•By decreasing w/b ratio, coarser nano-SiO2 improved mechanical properties of HPC more than finer type.•Finer nano-SiO2 showed higher pozzolanic activity than coarser nanoparticles.•Probability of nano-SiO2 agglomeration was increased by using finer type.•Coarser type of nano-SiO2 led to a finer pore structure compared to finer particles.
The aim of this study was to evaluate the effects of applying low replacement ratios (0.75% and 1.50% of the binder weight) of nano-SiO2 particles with different specific surface areas (200 and 380 m2/g) on the properties of high-performance concrete (HPC). Mechanical (compressive and splitting tensile strengths), electrical resistivity, non-destructive (ultrasonic pulse velocity), and microstructural (mercury intrusion porosimetry, X-ray diffraction, and scanning electron microscopy) tests were conducted to investigate the macroscopic and microscopic effects of nano-SiO2 particles on HPC characteristics.The results indicated that the performance of nano-SiO2 particles significantly depended on their specific surface areas and the water to binder (w/b) ratio of the mixtures. By decreasing the HPC w/b ratio from 0.35 to 0.25, nano-SiO2 particles with lower specific surface area performed better than finer one (higher specific surface area). Microstructural investigations demonstrated that the decrease in efficiency of nano-SiO2 particles with higher specific surface area at lower w/b ratio correlates to the formation of nanoparticles agglomerates, particularly at the higher replacement ratio of nanosilica (1.5%). However, the influence on the compressive and splitting tensile strengths and electrical resistivity varied due to differences in performance of nano-SiO2 particles affected the mechanical and durability properties.
