Research into the use of marble waste as mineral filler in soil pigment-based paints and as an active pigment in waterborne paints

Abstract

Producing paint using waste and soil is an efficient way of contributing to sustainable development and reducing costs in the finishing and protection of buildings. Although there are numerous studies related to paints of natural land base, there remain certain technical limitations to be overcome. Moreover, no research has been found in the literature on the use of marble waste as an active or inert pigment in the production of paint, although this waste has several pertinent properties and basic constituents. Thus, the aim of this study was to evaluate whether the use of untreated marble waste as an active pigment in building paint enables a product to be developed which meets specifications and whether the performance of soil pigment-based paints can be improved by incorporating marble waste as a mineral filler. The only preparation for using the waste and the soils as pigments was to sieve them to remove coarser impurities. The samples were formulated based on mix planning using the simplex network and consisted of: marble waste pigment (MWP), soil pigment (SP) and polyvinyl acetate resin (PVA). The amount of water varied according to the ideal viscosity range for paint application. The formulas were analyzed for hiding power (HP), abrasion resistance (AR), microbiological attack and resistance to weathering. The results showed that, for paints produced with MWP as the only pigment, the performance set out in ABNT NBR 15079:2011 was achieved above a percentage of 30% resin in solution. Furthermore, the addition of MWP to SP-based paints provided a film with higher HP and, together with the increased resin content, increased the AR of the samples. Five formulas met both HP and AR performance specifications. The percentages in the mixture were as follows: 0.3 PVA and 0.7 MWP; and 0.4 PVA and 0.6 MWP, with MWP as the sole pigment; 0.25 PVA, 0.175 YSP (yellow soil pigment) and 0.575 MWP; and 0.35 PVA, 0.175 YSP and 0.475 MWP, of YSP and MWP; and 0.25 PVA, 0.175 RSP (red soil pigment) and 0.575 MWP, of RSP and MWP. The weatherability test showed that MWP addition to the paint formula contributed to increased paint durability and improved photolytic stability. Thus, the results indicate that marble waste, as an active pigment or mineral filler, is a promising alternative for producing building paint.