Alkaline activation synthesis by graphite/calcite mortar and the effect of experimental conditions on compressive strength

Abstract

The construction industry is an application area that has continuity all over the world and requires cheap, durable, and environmentally friendly materials. Synthesis with alkali activation includes materials that have come to the fore in the construction industry in recent years. In this study using alkali activation method, a graphite/calcite mortar was prepared by optimizing the experimental conditions and its properties were investigated. The effects of Na2SiO3/NaOH mass ratio, NaOH solution concentration, and graphite content variables on structure and compressive strength in alkaline activation synthesis were investigated. It was determined that the samples reached a compressive strength of 21 MPa at the end of 28 days when the Na2SiO3/NaOH ratio was 2 and the NaOH concentration was 10 M. In the continuation of the optimized experimental conditions, the effect of the amount of graphite on the compressive strength was examined between 5 and 100% (w/w). Structural properties of the samples were investigated by X-ray diffraction and Fourier transform infrared spectroscopy, and their morphological properties were investigated by scanning electron microscopy. It was determined that C–S–H gel was formed and samples with heterogeneous morphology were synthesized.