Research on effects of the cement and magnesium oxide contents on some characteristics of stabilized dredging soil in Ca Mau province

Abstract

Using a mixture of cement combined with additives including (fly ash, blast furnace slag and magnesium oxide) to harden dredged silt as a substitute for sand is necessary in construction areas where sand resources are scarce nature. In the study, the mixtures (cement + fly ash + ground blast furnance slag + magnesium oxide) were used to harden mud in brackish and salt water areas in Ca Mau province of the Mekong Delta. The experimental results show that when hardening dredged sludge with content of 6% Cement combined with a mixture of ground blast furnace slag, fly ash and MgO, the viscosity, internal friction angle, adhesive force and compressive strength of the mixture sludge solidification will improve. The higher the ratio of MgO content, the lower the viscosity; the greater the internal friction angle, adhesive force and compressive strength of the hardened sludge. However, in order to balance the design requirements of the sludge after hardening, it was found that: With the rate of 4% fly ash, 2% ground blast furnace slag and 0.5% MgO, the design requirements were met, the quality of the dredging soil after hardening meets the requirements according to TCVN 8217:2009, equivalent to the hard plastic state (0.25 < IL < 0.5, Ctc = 32÷57 kPa and  = 11 ÷ 18°). With such hardening mud quality, it will meet the requirement of replacing sand for embankment, embankment and other works in Ca Mau in particular, and the whole Mekong Delta in general.