The investigation of some mechanical and physical properties of geopolimer concrete produced by using volcanic tuff

In this study, some mechanical and physical properties and the availability of geopolymer concrete production of volcanic tuff obtained from Nevsehir Region were investigated. Geopolymer concrete was produced in two different groups; the first group was activated by silica module (Ms) 0.8 and 0.6 and the second group was activated by using 10, 12, 14 and 16 molarities of NaOH. For both groups, during the production phase of the sample, three different cure temperatures and two different alkali liquid / binder (w/ b) ratio were used. Then, samples having a maximum compressive strength for both groups were determined and for these two samples, the effect of different amounts of nano-silica (1%, 2, 3), micro silica (1%, 3, 5) and styrene butadiene (SB) latex (5, 10, 15%) were investigated. The compressive strength, freeze-thaw (FT) resistance, microstructure, water absorption and density properties of geopolymer concrete specimens obtained by adding various additives were investigated. Experimental results show that geopolymer concrete activated with NaOH has higher compressive strength values than similar ones activated using Ms. The optimum curing temperature values for the first and second group of samples were determined as 105 ° C and 90 ° C, respectively. For samples in both groups, a decrease in the w / b ratio of 0.6 to 0.5 causes a decrease in compressive strength. Additionally, it has been observed that the maximum compressive strength value in the samples for each group was provided by the use of micro silica additive. At the end of the 300 FT cycles, the highest compressive strength losses occurring in the specimens were observed in pure samples of both two groups. Scanning Electron Microscopy (SEM) analysis and the water absorption test results showed that the addition of micro silica helped to formation of the more compact microstructure. Keywords: Geopolymer concrete, volcanif tuff, compressive strength, freze-thaw resistance, alkali activator