The Effect of the Synergistic Application of Waste Granite Powder and Linen Fibers on the Adhesive Properties of Ecological Epoxy Coatings

The coating was obtained by combining epoxy resin, granite powder (a waste material), and linen fibers (a renewable material). The first part of the paper describes all the ingredients and the method of preparing the concrete substrate. Afterwards, the way of modifying the coating is presented. The effect of two additives was analyzed: granite powder in amounts ranging from 0 to 50% (variable in 10% increments) in relation to the weight of the resin, and flax fibers in amounts ranging from 0 to 1.5% (varying in 0.5% increments) in relation to the weight of the resin. The reference sample was prepared without the addition of powders and fibers. The study focused on obtaining the highest possible pull-off strength. The greatest increase in strength was achieved with the addition of 1.5% of linen fibers and 30% of granite powder. In this case, the pull-off strength was equal to 3.09 MPa (σ = 0.17 MPa), which is 0.46 MPa (17.5%) better than the result obtained for the reference sample. Nine out of twenty-three modified coatings achieved a greater strength than the reference coating. The second part of the article presents a cost-economic analysis, and shows that the addition of granite powder significantly reduces the cost of the coating, and also that the fibers have a negligible effect on the total cost of the coating.