Mechanical properties and microstructure of geopolymer binder based on umeanyar slatestone powder

Abstract

This research focuses on the mechanical and microstructure properties of geopolymer binder with slatestone waste as the base material. This geopolymer binder comes from industrial waste crushing slate in the Umeanyar area. This waste is processed into stone powder (USSP) which contains SiO2 (49%), Al2O3 (11%), CaO (11.2%). This USSP uses a sodium hydroxide (SS) activator with a concentration of 14 M. The proportion of the mixture of precursor and activator (P/A) is 70%: 30%; 75%: 25%; 80%: 20% and alkaline activator Na2SiO3: NaOH (SS/SH) of 1:1; 1.5:1; 2:1, by weight. Samples of specimens were made in the form of a cube with a side of 50 mm and tested at the age of 7 and 28 days. Mechanical properties tested include density and compressive strength based on ASTM-C39. Meanwhile, the microstructural analysis used X-Ray Diffraction (XRD) and Scanning Electronic Microscope-Energy Dispersive X-Ray (SEM-EDX) analysis. The results of the density test were 1.90g/cm3 and 1.85g/cm3 respectively and the compressive strength test results were 7.40 MPa and 12.73 MPa at the age of 7 and 28 days, respectively.