An Evaluation of the Compressive Strength of Nanosilicate Hollow Crete Blocks

Abstract

The need for significant infrastructure development in Nigeria; the high demand for cement; the challenges associated with the disposal of agricultural waste; and—most significantly—the emission of CO2 associated with cement production and use, which has a negative impact on the environment, have created opportunities for research in the construction sector. The urgent need for researchers to explore substitute materials that may sustainably replace cement in the construction sector has also been prompted by the necessity to manage Nigeria’s natural resources. This paper investigates the properties of hollow blocks produced by replacing cement with nanosilica produced from rice husk waste at 1%, 2%, 3%, 4%, and 5% in order to assess the impact on the hollow block’s strength. The hollow blocks have four mixes: cement-to-sand ratios of 1:4, 1:6, 1:8, and 1:10 for different curing durations (1, 3, 7, 14, 28, and 56 days by spraying water). The results from the findings showed that the nanosilica produced from rice husk ash and used in this study are a good reactive pozzolana with particle sizes in the range of 1–49 nm, with majority of the particles within 1–7 nm. Hollow blocks produced at 1, 2, 3, 4, and 5% replacement by weight of cement (nanosilica-crete) proved stronger than hollow blocks produced at 0% cement replacement (conventional sandcrete), with an optimal nanosilica percentage replacement of 3% by weight of cement.

Keywords

• nanosilica
• nanosilica-crete
• cement
• rice husk ash
• compressive strength