![]() One is between the render and the backing concrete substrate (render–concrete interface), and the other is between the wall tile and the tile adhesive or render (tile–render interface). As a preliminary study, we have prepared ten (10) Experimental setup – shear test The workmanship issue can be rest assured. The test specimens including the application of tile finishes are prepared by qualified and skilled workers who are experienced trainers of the Construction Industry Training Authority (CITA), Hong Kong. The laboratory is air-conditioned and the room temperature is kept at 24 ☌. The laboratory tests are conducted in the Heavy Structure Testing Laboratory of the City University of Hong Kong, Hong Kong. About 80% of the rain falls between May and September Experimental setup – accelerated ageing process The annual rainfall ranges from around 1300 mm to more than 3000 mm. The minimum and maximum average temperature per month ranges from 5 to 25 ☌ and from 22 to 36 ☌, respectively in 1990–2002. Summer is hot and humid with afternoon temperatures often exceed 31 ☌elsius (☌). Simpson and Horrbin discussed various weathering factors, including temperature, humidity, wind, sunshine, and air pressure, that affect the performance of tiles.īriffett argued that rain Weather of Hong KongĮxternal wall finishes in Hong Kong are exposed to severe weathering impacts as Hong Kong’s climate is sub-tropical, tending towards temperate for nearly half the year. ![]() For example, Wallis contended that the mosaic tiles could become unglued due to the polluted environment and harsh tropical weather. , environmental effects are believed to be one of the major causes. ![]() The causes of external wall tile delamination has been comprehensively reviewed in the Ref. After a certain number of ageing cycles, the blocks are tested on their remaining shear strength. It can be considered as an artificial accelerated ageing process on tiled sample blocks. Weathering conditions are simulated by heating, cooling and watering. Therefore, this paper attempts to study by laboratory experiments the weathering effects on the shear strength of external wall tiling system. Worse still, most of the studies, , concern tensile strength of adhesive instead of shear strength between different components. However, there are very few laboratory studies on the relationships between them. Weathering effect is commonly recognized as one of the main causes of external wall tile defect. ![]() It is the right time we studied the ageing process of the tiling system to prepare for a large number of aged buildings with external wall tiles. There have already been numerous casualties and injuries caused by failures of external wall finishes in the past decade. However, the ageing process of the tiling system has seldom been studied and it renders maintenance scheduling highly difficult. More than 30% of them are aged over 20 years old. It is very commonly used in high-rise residential buildings in Hong Kong as it is found that over 75% of the external wall finishes of existing residential buildings is tile finishes in high-rise residential buildings in Hong Kong. Tile finishes have been commonly used in external walls of buildings since the 1970s. ![]()
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