Abstract:

This study examined the effects of ground granulated blast furnace slag (GGBFS) content, alkaline solution to binder (Al/Bi) mass ratio, sodium silicate solution to sodium hydroxide solution (SS/SH) mass ratio, and additional water to binder (Aw/Bi) mass ratio on geopolymer paste compressive strength, setting time, and workability. At 23 ± 2 °C, mini-size specimen compression, setting time, and mini-slump tests were conducted. GGBFS and Class F FA were aluminosilicate sources. Combining sodium silicate and sodium hydroxide created the alkaline activator. Workability and setting time were improved by adding water. Based on compressive strength, setting time, and workability tests, the best mix design had 40% GGBFS, 0.5 Al/Bi, 2.0 SS/SH, and 0.15 Aw/Bi. Under optimal mix design, geopolymer paste outperformed Portland cement (OPC) pastes. Next, geopolymer concrete tests using the optimal mix design of geopolymer paste were compared to OPC concrete tests. Also, geopolymer concrete had better properties than OPC concrete. Engineers can save time and labour by using this simple and fast test method to find the best geopolymer concrete mix design. Finally, new mathematical models accurately predicted geopolymer paste properties.