Potential of LUSI Mud as geopolymer material for artificial lightweight aggregate

Abstract

The abundant amount of LUSI (LU-Lumpur, SI-Sidoarjo) mud that began erupting near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia need to convert onto useful and valuable alternatives. Geopolymer becomes an attractive research due to improving the concrete properties, increased durability, improved performance, lower cost and preserves the environment. Geopolymer is a term used to describe inorganic polymers based on aluminosilicates that can be produced by synthesizing pozzolanic compounds or aluminosilicate source materials with highly alkaline solutions. The high demand for lightweight aggregate in concrete encourages this research to explore new material of LUSI mud to be used as artificial lightweight aggregate with excellent properties and performance in concrete application. This study will focus on utilizing the LUSI mud as an artificial lightweight geopolymer aggregate (ALGA) to be used in lightweight concrete. Sintering method has been choosen in this study due to better properties produced and commercial priority. Production processes include design, mixing of LUSI mud and alkaline activator (sodium hydroxide, NaOH + sodium silicate, Na2SiO3), pelletizing and sintering process. There are three parameters that influence aggregate produced, i) sintering temperature; ii) NaOH molarity; iii) LUSI mud/alkaline activator ratio and Na2SiO3/NaOH ratio. The characterization of LUSI mud and properties of ALGA have been done by using Particle Size Analyzer (PSA), X-Ray Flourescence (XRF), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR). The results showed that the sintering temperature of 950 °C, NaOH molarity of 12M, LUSI mud/alkaline activator ratio of 1.7 and Na2SiO3/NaOH ratio of 0.4 gives the optimum Aggregate Impact Value (AIV) of 15.42% with low density of 1100 kg/m3 and water absorption (4.7%).