Characterization of marine clay under microstructure examination as a potential pozzolana

Abstract

Globally, marine clay is found in coastal areas. It is often regarded as a profitless material because it affects building foundations, dredging and replacing it with a more suitable material before construction is therefore inevitable. However, the dumping of this marine clay after excavation has become a major problem in most countries like Singapore where dumping of clay is prohibited. Thus, the quest towards determining its potential use for sustainability. In that regards, this paper seek to investigate the characterization of two marine clay samples under microstructure examination through particle size analysis (PSA), X-ray fluorescence (XRF), thermo gravimetric and differential thermal analysis (TGA/DTA) and X-ray diffraction (XRD) to study the microstructural features of the marine clay under magnification in an attempt to examine its potential use as a pozzolana. Characterization is a very important stage in order to know the characteristics of a material before the initiation of any necessary modification. From the microstructure analysis, the PSA revealed that the particles are in micro size with less than 35% of the materials retained when wet sieved on 45 μm sieve. The XRF showed the chemical compositions of the marine clay with dominance of aluminum oxide (Al2O3), silica oxide (SiO2) and ferric oxide (Fe2O3). These three oxides made up over 70% of the chemical constituents in both samples. From TGA/DTA, maximum weight loss occurred at the temperature range 400–650 °C and the percentage of kaolinite was determine to be 42.7% and 45.1% for S1 and S2 respectively. From the XRD, the structural pattern and crystal orientation of marine clay gave rise to a diffraction pattern showing a high intensity of quartz and kaolinite indicating yet again that the marine clay belongs to the kaolinite group with basic composition of aluminosilicate, hence can be used as a potential pozzolana.