Alkali-activated binary concrete based on a natural pozzolan: physical, mechanical and microstructural characterization

This article presents the physical, mechanical and microstructural characterization of an alkali-activated binary concrete (AABC) based on a natural pozzolan (NP) of volcanic origin (70%) and granulated blast furnace slag (GBFS) (30%) cured at room temperature (25°C). A solution based on the combination of NaOH and waterglass (Na2SiO3·5H2O) was employed as an alkaline activator. The concrete design was obtained using a modified version of the “absolute volume” method (ACI 211.1). The performance of the AABC was similar and even superior to that of the reference concrete (OPC); e.g., it exhibited a compressive strength of up to 43.4 MPa at 360 days. These results demonstrate that the NP has potential for use in the industrial-scale production of these types of materials in the foreseeable future.