Assessment on the Potential of Volcano Ash as Artificial Lightweight Aggregates using Geopolymerisation Method

Following the Yogyakarta earthquake on May 27th, 2006, the subsequent eruption of a volcano mud has been closely observed and analyzed by the geological community. The volcano mud, known as LUSI (LUlumpur, SI-Sidoarjo), began erupting near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia. LUSI offers a unique opportunity to study the genesis and development of a volcano mud. This paper summarizes the current knowledge about the potential of volcano ash as a raw material in geopolymer and as artificial aggregate. Previous experimental study shows that the volcano ash has a good performance when 5 and 10 OPC was replaced by volcano ash mixture. Volcano ash mixed with fly ash in certain composition has a potential to become a binder in geopolymer concrete. An effort to convert the volcano ash to artificial aggregate also shows good potential due to their specific gravity and water absorptions, and characterization of this material. The characterization of this material have been done through X-ray Fluorescence (XRF), X-ray Diffraction (XRD), Scanning Electron Micrograph (SEM), and Fourier Transform Infrared Spectroscopy (FTIR), and then compared to other materials. Sintered volcano ash showed good performance in terms of strength as a cement replacement material with OPC and fly ash. Volcano ash also showed good performance for porosity. This material has a potential as a raw material due to high compounds of SiO2 and Al2O3 in producing geopolymer composites, and as new artificial aggregate to be used in concrete application