Nano-Silica Modified Recycled Aggregate Concrete: Mechanical Properties and Microstructure

Author: Khaleel H. Younis1
1Erbil Polytechnic University (EPU), Erbil, Iraq

Abstract:  Sustainability of concrete could be enhanced by incorporating recycled aggregate in the production of concrete. The aim of this study is to assess the effect of using nano-silica (nanoparticles of SiO2) to improve the performance of recycled aggregate concrete (RAC) containing recycled aggregate (RA) derived from processing construction and demolition waste of concrete buildings. In this study, compressive strength of concrete and the microstructure of RA and RAC with and without nanoparticles of SiO2 were examined. Nine mixes: one control mix with natural aggregate without nanoparticles, two mixes with RA at 50% and 100% contents (without nano-silica) and three mixes for each content of RA with nano-silica content of 0.4, 0.8 and 1.2% (by mass of cement) were investigated. The results showed that nanoparticles of silica can improve the compressive strength and modify the microstructure of RAC.

Keywords: Nanoparticles SiO2, Compressive Strength, Recycled Aggregate, SEM

Download the PDF Document from here.

doi: 10.23918/eajse.v3i3p167

Berndt, M. L. (2009). Properties of sustainable concrete containing fly ash, slag and recycled
concrete aggregate. Construction and Building Materials, 23(7), 2606-2613.
BS EN 12390-3 (2009). Testing hardened concrete Part 3: Compressive strength of test specimens.
British Standard Institution, London, UK.
IQS No. 45/1984. “Iraqi Specification for Cement”.
Katz, A. (2004). Treatments for the improvement of recycled aggregate. Journal of Materials in
Civil Engineering. 16(6), 597-603.
Said, A.M., Zeidan, M.S., Bassuoni, M.T., & Tian, Y. (2012). Properties of concrete incorporating
nano-silica. Construction and Building Materials, 36, 838-844.
Sanchez, F., & Sobolev, K. (2010). Nanotechnology in concrete–a review. Construction and
Building Materials, 24(11), 2060-2071.
Shaikh, F.U.A., Odoh, H., & Than, A. B. (2014). Effect of nano silica on properties of concretes
containing recycled coarse aggregates. Proceedings of the Institution of Civil Engineers

Construction Materials, 168(2), 68-76.
Tam, V.W. (2008). On the effectiveness in implementing a waste-management-plan method in
construction. Waste Management, 28(6), 1072-1080.
Tam, V.W., Gao, X.F., & Tam, C.M. (2005). Microstructural analysis of recycled aggregate concrete
produced from two-stage mixing approach. Cement and Concrete Research, 35(6), 1195-
Younis, K. H., & Pilakoutas, K. (2013). Strength prediction model and methods for improving
recycled aggregate concrete. Construction and Building Materials, 49, 688-701.