Behzad Mehdikhani - Standard Research Institute, Technical and Engineering Faculty, Construction and Mineral Department, Karaj, Iran
Behzad Saeedi Razavi - Standard Research Institute, Technical and Engineering Faculty, Construction and Mineral Department, Karaj, Iran
Jamal Ahmadi - Department of Civil, Faculty of Engineering, University of Zanjan, Zanjan, Iran
Ali Goharrokhi - Applied Science Center of Khorasan Razavi Municipalities, Mashhad, Iran

Nanotechnology plays an important role in the current construction industry. It has been observed that several properties of cement-based concrete are affected by different nano materials. In this study, different weight percentages of nano-silica (۰, ۱, ۲, and ۴ wt%) were used to build geopolymer specimens. The mechanical properties of the specimens were then measured, including the compressive and flexural strength. Results demonstrated that increasing the percentage of nano-silica from ۰ to ۴ wt% increases the compressive strength of the specimens from ۵۰.۴ to ۷۵.۲ MPa and the flexural strength from ۱۱.۴ to ۲۶.۲ MPa. Furthermore, it was observed that the ultrasonic pulse velocity was altered by increasing SiO۲ (nano-silica), decreasing the ultrasonic pulse rate from ۷.۰ to ۴.۵ km.s-۱.

Geopolymer concrete, Nano– silica, compressive and flexural strength, ultrasonic pulse velocity