소성된 항만 준설토의 포졸란 반응성 분석

Abstract

Large amount of dredged sea soil is produced in southeast seashore region in Republic of Korea during harbor maintenance. Disposal of dredged sea soil has become more difficult due to the enforcement in the environmental regulation such as London Protocol. To address this problem, a company, called Sindaeyang, has developed a process to remove hazardous chemicals and organic compounds from dredged sea soil. Dredged sea soil which experienced such cleaning process can be safely disposed and be also utilized as materials for land reclamation. However, if the size of the dredged sea soil is in the range of silt or clay, it cannot be used as reclamation material because land settlement will eventually occur. A new recycling method needs to be developed, and in this research, the pozzolanic activity of dredged sea soil was investigated to evaluate its possible application as a pozzolanic material. Dredged sea soils from three different sources(N harbor outer port, N harbor inner port, and J harbor) were investigated using particle size distribution(PSD), X-ray fluorescence(XRF), X-ray diffraction(XRD), and thermogravimetry/differential thermal analysis(TG/DTA) to understand its chemical and mineralogical characteristics and also to find proper temperature for heat treatment. Pozzolanic activities of cement paste with 10% replacement of various heat treated dredged sea soil were evaluated using XRD and TG/DTA by monitoring the reduction in the amount of calcium hydroxide. Compressive strength were also measured to correlate with the results from XRD and TG/DTA. According to the results, the optimum temperature for heat treatment was at 500℃ for 1 hour. It was also found that heat-treated dredged sea soil showed decrease in the amount of calcium hydroxide. In addition, incorporation of heat treated dredged sea soil increase both 28 and 56 day compressive strength of mortar specimen. Among heat treated dredged sea soil, dredged sea soil from J harbor showed highest pozzolanic activity mostly because of its smaller particle size.