Study the Effect of Nano SiO2 Prepared from Rice Husk Ash on Compressive Strength of Reactive Powder Concrete

Nano-SiO2 was extracted successfully from rice husk ash. The obtained SiO2 powders exhibited a monoclinic crystal system, mesoporous structure, and a large specific surface area of 258.3 m2/g, with particle sizes ranging from 10 to 15 nm. Incorporating Nano-SiO2 derived from rice husk ash significantly enhances the compressive strength of reactive powder concrete with varying contents of SiO2 (3%, 6%, 9%, and 12% of cement weight) and different water-to-cement ratios (0.23, 0.25, 0.35, and 0.48). Notably, when the Nano-SiO2 content was 9%, the compressive strength of the concrete reached the highest values across all the researched water-to-cement ratios. Specifically, at a water-to-cement ratio of 0.25 and a Nano-SiO2 content of 9%, the compressive strength peaked at 112.5 MPa. Furthermore, at a water-to-cement ratio of 0.48 and the same Nano-SiO2 content, the impact on the mixture was most pronounced, with a compressive strength increase of 33.5%.