9 Madridge J Nanotechnol Nanosci ISSN: 2638-2075 Volume 1 • Issue 1 • 1000104 Madridge Journal of Nanotechnology & Nanoscience Research Article Open Access Effects of Nano-Silica modified Self-Compacted, High Volume Fly Ash Mortar on Slump Flow and Compressive Strength Veerendrakumar C Khed, Bashar S Mohammed* and Muhd Fadhil Nuruddin Department of Civil and Environmental Engineering, Universiti Technologi Petronas, Seri Iskandar, Perak, Malaysia Article Info *Corresponding author: Bashar S Mohammed Associate professor Department of Civil and Environmental Engineering Universiti Technologi Petronas Seri Iskandar, Perak, Malaysia E-mail: bashar.mohammed@petronas.com.my Received: July 6, 2016 Accepted: July 18, 2016 Published: July 23, 2016 Citation: Khed VC, Mohammad BS, Nuruddin MF. Effects of Nano-Silica modified Self- Compacted, High Volume Fly Ash Mortar on Slump Flow and Compressive Strength. Madridge J Nanotechnol Nanosci. 2016; 1(1): 9-12. doi: 10.18689/mjnn-1000104 Copyright: © 2016 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Published by Madridge Publishers Abstract The purpose of this study is to establish the effects of nanosilica on high volume fly ash self-compacted mortar. The nanosilica was added from zero to 5% in mortar containing 70% fly ash replacement to cement. The flowability of 240 to 260 mm has been maintained by varying the polycarboxylic based super plasticizer. It has been observed that nanosilica had adversely effects the workability. On the other hand, nano- silica mitigated loss of compression strength due to high volume of fly ash replacement. The compressive strength of mortar containing 70% of fly ash replacement to cement and 5% addition of nano-silica has been improved by 94%. Keywords: Nano-silica; Compression strength; Fly ash mortar; Plasticizer. Background The conventional concrete has few disadvantages mainly with its differential compaction, its durability and noise caused by the vibrating instrument. This has encouraged the researchers to develop self-compacting concrete (SCC). In SCC the mortar ingredients play an important part for better performance. Since the mortar is crucial for fluidity thus compacting on its own and it lubricates the coarse aggregate, thus it brings coarse aggregates nearer to each other. In this study the workability and compression strength of self-compacting cement mortar utilizing the binary products such as high volume fly ash and nanosilica had been carried out. Utilizing high volume fly ash (HVFA) as cement replacement in SCC tends to be a possible solution, with reduction in cost of cement, improvement of workability. Although fly ash has a negative effect on the early strength development of concrete. Utilizing Nano Silica (NS) in high volume fly ash can be a possible solution to problem related to the strength loss in SCC, and the early poor strength development of HVFA in SCC due to NS high pozzolanic reaction, filler effect, and activation of fly ash pozzolanic reactivity. Once upon a time, microsilica or silica fume, materialized to be a better pozzolanic cementitious substance, since it is a small in size which has the ability of high packing. In addition, silica fume are non-crystalline in its nature with more specific surface area and thus it reveals a high pozzolanic activity. In various applications, silica fume in partial replacement with cement had improved the hardened properties of cement paste [1-5]. In more recently the nano technology has been introduced in concrete containing nano materials in the form of nonosilica which is available in the market. Nanosilica is high pozzolanic material when compared to silica fume. Nanosilica is ultrafine in size to nanometer (1x10 -9 ).