Influence of nanosilica on mechanical properties, sorptivity, and microstructure of lightweight concrete

Mohamed Abd Elrahman, Sang Yeop Chung, Pawel Sikora, Teresa Rucinska, Dietmar Stephan

Research output: Contribution to journalArticlepeer-review


This study presents the results of an experimental investigation of the effects of nanosilica (NS) on the strength development, transport properties, thermal conductivity, air-void, and pore characteristics of lightweight aggregate concrete (LWAC), with an oven-dry density <1000 kg/m3. Four types of concrete mixtures, containing 0 wt.%, 1 wt.%, 2 wt.%, and 4 wt.% of NS were prepared. The development of flexural and compressive strengths was determined for up to 90 days of curing. In addition, transport properties and microstructural properties were determined, with the use of RapidAir, mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM) techniques. The experimental results showed that NS has remarkable effects on the mechanical and transport properties of LWACs, even in small dosages. A significant improvement in strength and a reduction of transport properties, in specimens with an increased NS content, was observed. However, the positive effects of NS were more pronounced when a higher amount was incorporated into the mixtures (>1 wt.%). NS contributed to compaction of the LWAC matrix and a modification of the air-void system, by increasing the amount of solid content and refining the fine pore structure, which translated to a noticeable improvement in mechanical and transport properties. On the other hand, NS decreased the consistency, while increasing the viscosity of the fresh mixture. An increment of superplasticizer (SP), along with a decrement of stabilizer (ST) dosages, are thus required.

Original languageEnglish
Article number3078
Issue number19
Publication statusPublished - 2019 Oct 1

Bibliographical note

Funding Information:
Acknowledgments: We acknowledge support by the German Research Foundation and the Open Access Publication Fund of TU Berlin. P.S. is supported by the Foundation for Polish Science (FNP). Additionally, we would like to thank Christian Lehmann from TU Berlin for supporting this research with SEM measurements.

Funding Information:
Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 841592.

Publisher Copyright:
© 2019 by the authors.

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics


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