Bloating Mechanism for Artificial Light Weight Aggregate of Surface Modification with Coal ash

Abstract

We manufacture artificial lightweight aggregates (ALWAs) using bottom-ash as the primary raw material. We coat the ALWA surfaces with low-melting point materials in order to enable them to bloat, which is essential to reduce the bulk density of the aggregate. Then, we sinter the prepared aggregates at 1000, 1100, and 1200℃ using either the direct or two-step firing schedules. Finally, we evaluate the properties of the fired samples through analyzing their bulk density, water absorption, and microstructure. The surface-modified samples result in a reduction of their bulk density by 0.3 ~ 0.4 g/㎤ regardless of the firing method used. Based on these results, we conclude that this approach could provide a viable method for the mass-production of ALWAs from industrial waste such as bottom-ash.