Nanocomposites and nanomaterials

An overview on the effects of nanomaterials on the properties of alkali-activated materials
Sikora P. 1,2, Firdous R.1, Djobo Y.J.N.1,3, Krivenko P.4, Sanytsky M.5, Kropyvnytska T.5, Stephan D.1
1 Building Materials and Construction Chemistry, Technische Universität Berlin, Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
E-mail: pawel.sikora@zut.edu.pl
2 Faculty of Civil Engineering and Architecture, West Pomeranian University of Technology, Szczecin, Al. Piastow 50, 70-311 Szczecin, Poland
3 Local Materials Promotion Authority/MIPROMALO/MINRESI, 2396, Nkolbikok, Yaoundé, Cameroon
4 Scientific Research Institute for Binders and Materials, Kiev National University of Civil Engineering and Architecture, Vozdukhoflotskyi prospect, 31, Kiev 03680, Ukraine
5 Department of Building Production, Lviv Polytechnic National University
S. Bandera str., 12, Lviv 79013, Ukraine  

Alkali-activated materials (AAM) are recognized as potential alternatives to ordinary Portland cement (OPC) in order to limit CO2 emissions as well as for their beneficial properties for some special applications. Similarly to OPC the properties of AAM like strength, elasticity, hardness, durability, and workability vary depending on their composition. In addition, in thrive of producing sustainable construction material, high amounts of waste materials and supplementary cementitious materials (SCMs) are included in AAMs. As a result, these composites might suffer from low strength development as well as compromised durability. Therefore, in recent years nanomaterials (NMs) such as nanosilica, nanoclay, carbon nanotubes etc. were proposed as a solution to tackle these challenges. Depending on the type of NMs used they exhibit various effects including: (i) the filler effect, (ii) the seeding effect and/or (iii) the pozzolanic effect. These effects can accelerate the early strength development as well as refine the microstructure and improve the durability of AAMs. 
This work discusses the current development status of nanomodified-AAMs in terms of raw materials, activators, additives, mechanical and physical properties, curing mechanisms, hydration products, and environmental impacts.
Acknowledgement: The project is supported by the Polish National Academy for Academic Exchange within project No. PPN/BEK/2018/1/00078.