Performance evaluation of nanoclay-modified waterborne coatings for mechanical and durability properties of cement mortar

Waterborne coatings are widely adopted as a sustainable material in the construction industry, primarily due to their low volatile organic compound content. However, their insufficient barrier and durability properties limit their application on concrete substrates. To overcome this limitation, nanoclay, which is characterized by its high aspect ratio, reinforcing properties, corrosion resistance, and impermeability, is utilized as a functional additive in waterborne coatings. This experimental study investigates the effect of nano-kaolin (nanoclay) and nano-zeolite (nano-additive), incorporated at 2–5% by weight of cement, on the performance of waterborne coatings applied to the mortar substrates. Mortar cube specimens were prepared with a cement to M sand ratio of 1:2 with a nano-modified coating formulation. The developed specimens were evaluated using compressive strength tests, water absorption assessments, and acid resistance tests. The results indicate that nano-additive incorporation significantly enhances the barrier properties of waterborne coatings by reducing water absorption and improving resistance to acidic environments while maintaining adequate compressive strength in the mortar substrate. This study demonstrates the potential for enhancing the durability of concrete with waterborne nanoclay-modified coatings as an effective and sustainable solution.