Influence of thermal condition on the shrinkage and bond strength of polymer-modified ceramic tile adhesive

For the better application of large-sized ceramic tiles, an innovative in-situ monitoring method using the stain gauge was developed to measure the deformation of ceramic tile adhesive (CTA) under different influencing variables, including curing conditions, thickness, and locations of CTA. Furthermore, the correlation between the deformation and the measured bond strength was studied. At last, the mechanism leading to the debonding of ceramic tiles under the different variables was analyzed. It is found that applied thickness, the locations and the curing condition of CTA can significantly affect the deformation of CTA and the following bond strength. Specifically, the increased thickness of CTA leads to a higher shrinkage and a lower bond strength. Compared to the sample with the CTA`s thickness of 12 mm, the shrinkage of the sample with CTA`s thickness of 5 mm was decreased by around 20% and the 28 d bond strength was increased by at least 34%. Besides, a decreased shrinkage and increased bond strength were observed along with the diagonal direction to the center of the tile. Compared to the shrinkage measured at the edge position, the shrinkage at the center position was decreased by more than 16% and the 28 d bond strength was increased by at least 12%. Compared to the condition with a constant temperature, the cyclical variation of temperature causes a huge fluctuation in the measured deformation of the applied adhesive, and leads to a significantly decreased bond strength. The applied CTA with a decreased thickness is more sensitive to the varied curing temperature.