2018 Volume 74 Issue 1 Pages 21-34
In Japan, dehydrated cake discharged from crushed stone quarry is still disposed. To make it possible to recycle a large amount of dehydrated cake, we focused on a high temperature heating production method for recycling construction waste as concrete aggregates, we have been produced coarse aggregates for concrete by using dehydrated cake discharged from crushed stone quarry and investigated their performances. However, to produce dehydrated cake coarse aggregates, we had decided appropriate heating conditions, i.e., temperature and time of dehydrated cake granulated materials through high temperature heating test with different heating conditions. By the trial and error method, since the kinds of dehydrated cake differ depending on the kinds of crushed stone, working efficiency to produce dehydrated cake coarse aggregates decreases.
To improve the working efficiency, the objective of this study is to develop an estimation model of heat melting temperature (temperature keeping time: 30 min) of dehydrated cake discharged from crushed stone quarry based on its chemical composition by x-ray fluorescence analysis (XRF). First of all, several kinds of dehydrated cake discharged from crushed stone quarry in the Tohoku region were used and the range of heating temperature and heating time to produce dehydrated cake granulated materials were indicated through high temperature heating test. Next, the performances of melted granulated materials were evaluated and strength properties of concrete using the melted ones was measured. As a result, it was clear that the melted granulated materials can be used as coarse aggregates for concrete. Finally, based on the above results, estimation model of heat melting temperature of dehydrated cake discharged from crushed stone quarry was developed by using neural network back propagation. It was found that the estimated all results were good agreement with the measurement ones.
