Experimental study of the effects of adding silica nanoparticles on the durability of geopolymer concrete

The advantages of using geopolymer materials instead of cement in concrete are not limited to high durability properties. geopolymer concrete was introduced to mitigate the environmental damages caused by CO2 emissions and the great level of fossil fuels consumption during cement manufacturing. In the present investigation, a number of experimental studies were conducted on slag-based geopolymer concrete. Accordingly, nano-silica particles were used to improve the geopolymer concrete structure's matrix. In the current study, slag-based geopolymer concrete was used with 0-2% polyolefin fibres and 0-8% nano-silica. They were subjected to water absorption and permeability tests to assess their durability. The addition of nano-silica enhanced the whole properties of the slag-based geopolymer concrete. By using the nano-silica, the concrete paste microstructure became denser and more homogeneous, and the pores decreased. The compressive strength and tensile strength of the concrete increased by up to 22% and 14% respectively. On the other hand, in terms of durability, the nano-silica lowered the water absorption and permeability coefficients by up to 24% and 44%, respectively, by filling the pores of the concrete. In the weight loss test, geopolymer concrete achieved superior results (up to 16%) compared to ordinary concrete.