Optimal Mixture Design of Mix-Wasted Tile Aggregates for Reducing Pavement Surface Temperature

The heat generated from dark-colored asphalt pavement contributes to the rise in surface temperature and results in the formation of an environmental problem known as urban heat island. In this paper, an approach was developed to optimize the mixture design of experiment (DOE) for the mixed type of crushed waste tile aggregates in developing cool-pavement coating materials that could reduce the surface temperature of pavement. Furthermore, the mean temperature difference, Delta T, was determined by comparing the 16 runs of the suggested design model with the conventional asphalt model. Three types of wasted tile aggregates were used in this study: full body porcelain (FBP), monoporosa or ceramic glaze (MP), and porcelain glaze (PG). A linear model was formed as a function of mixed-tile fraction, and the ANOVA analysis showed that the special cubic term used for this model is significant. The diagnostics of the model were validated using box-cox plot and normal plot of residuals. Finally, the model was optimized to predict the optimum mixture of different types of tiles to produce the highest value of Delta T by proposing two solutions from the design mix. Accordingly, the values of Delta T obtained are 4.9 and 3.1 degrees C, respectively, as per the first and second solution using 100% of FBP and MP. In conclusion, the optimum mixture DOE is reliable and can be used to optimize the composition of the proposed mixed type of tile aggregates for obtaining higher values of Delta T, which is necessary for developing the coating materials. (C) 2014 American Society of Civil Engineers.