Evaluation of Lime Solution in Kneading Water for the Preparation of Roughcast and Plaster Coating

Abstract

AbstractComprehension of the mechanical fixation behaviour of coatings is crucial for a better understanding of the bonding systems, especially at the interface between the mortar and the base. Physical adherence is related, among other things, to the contents of the materials used in the roughcast and plaster, due to the necessary colloidal water penetration into the pores of the substrate, providing mechanical locking of hydrated calcium sulfoaluminate and calcium silicate crystals, according to the principle of active pores. This study proposes to evaluate the influence of the use of a lime solution as a substitution for the kneading water in the preparation of roughcast and plaster, with blends of 0% (reference), 5%, 10%, and 15% in relation to the amount of water used. The experiment included preparing masonry panels 220 × 180 cm2, prepared with concrete blocks and ceramic bricks. Direct tensile bond strength tests were performed, and the results, with a 95% confidence level, showed significant differences for levels from 10% lime blend in the roughcast, in both base types, reaching increments of up to 39% in relation to the reference sample, a behaviour not identified in the plaster samples.KeywordsAdherenceMortarHydrated limeSpatterdash