Durability characteristics of normal-and medium-strength one-part geopolymer concrete

The study is an experimental investigation on durability properties of normal- and medium-strength one-part geopolymer concrete designed for a targeted compressive strength of 30 MPa and 50 MPa, respectively. The properties were studied in terms of compressive strength, sulfate resistance, chloride resistance, bulk density, volume of permeable voids, sorptivity, water penetration depth, initial surface absorption and microstructural studies. Results showed that approximately 90% of the targeted compressive strength was achieved in initial 7 days. The strength loss in normal-and medium-strength onepart GPC was 7% and 5%, respectively, after immersion of concrete in 5% MgSO₄ solution for 180 days. The measured values of permeable voids, chloride penetration depth, sorptivity, initial surface absorption, water penetration depth decreased in medium-strength one-part GPC relative to normal-strength one-part GPC. The microstructure of the concretes was studied using SEM, EDS, FITR and XRD which confirmed polymerization reaction with formation of three-dimensional aluminosilicate network of C-(N)-A-S-H gel.