A study on the delamination of external wall tiles for high-rise buildings

Abstract

Over the past thirty years, tile finishes have been recognized as one of the most popular and important external wall decoration materials due to its capacity of resisting adverse weather, durability and aesthetic performance. There are obvious benefits of using wall tile finishes, yet there had been many incidents of tiles falling from high-rise buildings in the recent years that caused injuries and damages to people and properties. Hence, raising out the question on whether the performance of existing external wall tile system meets the stated quality and safety criteria. To aid designers and maintenance surveyors in understanding the potential causes and failure modes of external wall tile system, a study on the basis of previous experimental results was undertaken. A full-scale laboratory test was conducted over a year in which the effects of environmental and cyclic influence on the performance among different interface of external multi-layer wall tile system had been investigated. Previous experiments comprised mainly two parts, namely static load test, and artificial weathering test. Standard sizing wall panels fixed with various specifications were tested under static load applying towards the surface of wall panels, the effects of deformation on different interface were studied. Concrete cubic specimens were later placed under artificial weathering cycles that simulated the temperature and moisture conditions in summer and winter of Hong Kong and tested destructively by shear bond strength methods. Although flexural cracks were found in the first stage experiments, the 16 testable wall panels were not failed under current wind loading practice in Hong Kong. The subsequent weathering cycling tests had demonstrated that the shear bond strength of external wall finishes may be affected. In the basis of the experimental results, the possible failure load has further been studies by means of Monte Carlo simulation. The possible failure load and the corresponding variance were complied. The simulations indicated that the expected failure load between the tile and the render background, and the render background and the substrate decreased in 100 weathering cycle.

Date of Award	15 Feb 2007
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Siu Ming LO (Supervisor)