High-performance, marble-like plaster coatings

Conventional plaster coatings based on lime wash, cement paints, and resins offer decorative look with varying degree of water proofing. However, thes e coating surfaces usually undergo weather-induced deteriorations due to ch emical and physical changes that lead to chipping, peeling off, and develop ment of shrinkage cracks. To overcome these problems, a composite formulati on, which contains more than 80% marble powder as inorganic graded filler w ith small amount of hydraulic components, has been developed. The uniform a pplication of these composite pastes on masonry-plastered surfaces, result in a marble-like surface after the hardened coat is polished. The Mohs hard ness of the developed, hardened, and polished coating surface was found to be >5. The coating was observed to retain dimensional stability and hardnes s when exposed to elevated temperature conditions (similar to 60 degrees C) over long periods. After 2 years of exposure to various weather conditions , the external wall plasters did not shown any sign of deterioration. The m ineralogy and morphology of the coating surfaces have been found to be comp arable to that of an eggshell. (C) 2000 Elsevier Science Ltd. All rights re served.