Application of nano-silica (nS) in concrete mixtures

Concrete is the most common used material for construction and their design consumes almost the total cement production in the world. The use of large quantities of cement produces increasing CO2 emissions, and as a consequence the green house effect. A method to reduce the cement content in concrete mixes is the use of silica fines. One of the silica fines with high potential as cement replacement and as concrete additive is nano-silica (nS). However, the commercial nS is synthesized in a rather complex way, resulting in high purity and complex processes that make them non-feasible for the construction industry. Furthermore, the application of nS and its effect in concrete is not fully understood yet. In a recent research project a new nano-silica [1-4] is produced from olivine. This nS, as well as commercially available nS, will be applied and tested. In addition, a mix design tool used for self compacting concrete (SCC) [5] [6] will be modified to take into account particles in the size range of 10 to 50 nm. This paper aims to present the state of the art of nS application in concrete, focusing on the nS properties to render it suitable to be applicable in concrete. It includes the nS production process, their addition effect and their application in concrete. Also an overview of the experimental setup and further research is presented