Unconfined compressive strength of compacted marine clay treated with magnesium chloride

Abstract

Inadequate characteristics of marine clay often lead to engineered structures being damaged. There is a need to perform soil improvement prior to any construction activity. This study intends to ascertain marine clay strength from samples obtained from the West-Coast Expressway (WCE) project; the samples are planned to be strengthened using magnesium chloride (MgCl2). Specifically, the determination of the compressive strength of magnesium chloride-treated marine clay is a key objective of the study. The testing process comprises lab assessment to ascertain the Unconfirmed Compressive Strength (UCS) to treated and untreated marine clay samples. Laboratory tests confirmed that, typically, marine clay treated with MgCl2 had enhanced strength. The UCS test indicated that an addition of 6% MgCl2 to marine clay led the strength peaking at 137\u2005kPa.In contrast, the addition of MgCl2 upwards of 4% led to a decrease in strength. Marine clay treated with 6% MgCl2 recorded an increase in UCS to 137\u2005kPa and 110\u2005kPa at seven and three days of curing, respectively. Subsequently, at fourteen and eighteen days, the strength values were 132\u2005kPa and 125\u2005kPa, respectively. It indicates that, typically, there is an increase in strength till the seventh day of curing and, subsequently, strength values begin to decrease. The change in strength can be attributed to the formation of cementation products that lead to soil particles getting bound together, and they occupy the free space between clay particles and MgCl2. With an increase in positive surcharge, soil particles begin to repel, thereby leading to reduced soil strength.