Surface modification of alkali-activated materials regarding durability

Technical University of Ostrava, Faculty of Civil Engineering, Department of Building Materials and Diagnostics of Structures, 708 00 17. listopadu 2172/15, Czech Republic

^* Corresponding author: adela.brazdova@vsb.cz

Abstract

This paper deals with the possibility of applying a surface modification coating to hybrid alkali-activated materials based on granulated blast-furnace slag activated with disodium metasilicate anhydrous with partial replacement of silica fly ash and cement by-pass dust in the amounts of 15% and 15%. The selected coatings (epoxy and synthetic) were applied in two series - the first, deposited in the water after demolding, and the second, wrapped in foil. The strength of the materials, the thickness of the coating and the effect of scaling resistance were monitored in the experiment. The compressive strength of this mixture was around 68 MPa and the flexural strength was around 6.5 MPa after 28 days of curing. For the tensile strengths of the prepared composites, slightly higher strengths were obtained for the samples deposited in the plastic foil, with the strengths of both series being around 2.4 MPa. For the scaling resistance, the lowest weight losses were achieved for the specimens coated with synthetic coating, which is valid for both deposition methods.