A Study on Natural Rain Surface Erosion of Different Walling Materials in Tropics

This study presents most common phenomena observed on wall facades due to excessive rain in tropical climatic condition in Sri Lanka. The objective of this study is to understand the effect surface decay of walling materials. The most common walling materials such as brick, cement block, earth cement blocks and novel walling materials mud concrete block, geopolymer blocks were subjected to this study. Faade covering materials such as rough cement plaster and cement slurry plaster were studied. Intrinsic material properties were studied prior to natural rain erosion quantification. Basic engineering properties of water absorption, capillary action, surface roughness, compressive strength was studied. Material properties such as water absorption, surface roughness were studied. Ten years of rain was simulated to measure natural surface decay. The results show that, stronger materials and less surface rough materials are resistant to surface decay. Plastering is recommended to protect walling materials reduce the surface decay. Comparatively stronger walling materials are less prone to natural rain decay. Cement plasters and cement slurry plaster covering is the most suitable materials for heavy rain. Cement slurry plaster is the most suitable walling covering for rain drop bouncing areas in outdoor walls in Sri Lanka.