The influence of blast furnace slag content on the mechanical and durability properties of raw perlite-based geopolymer mortars

In this work, 21 different raw perlite-(RP)-based geopolymer mortars (RPGMs) were manufactured. Blast furnace slag (BFS) was replaced by RP in 7 different proportions with respect to the CaO/SiO2 oxide ratio of RP and BFS mixture in the RPGMs. Sodium hydroxide (NaOH= 5, 10, and 15M) was used as alkaline medium for geopolymer synthesis in the RPGMs. The ultrasound pulse velocity (U-pv), flexural strength (f(fs)) and compressive strength (f(cs)), water absorption, and acid and sulfate durability of the RPGMs are investigated. The test results revealed that the BFS improved the mechanical properties of RPGMs for the low and medium alkaline medium of 5M and 10M, respectively. On the other hand, BFS had negative effect on the mechanical properties of RPGMs produced at a high alkaline medium of 15M. Moreover, the BFS improved the acid and sulfate durability of the RPGMs.