Although lime-treated soil has been widely used in the road construction with many application experiences
the determination of the optimum water content in the parameters control of construction still needs to be deeply discussed. In this paper
the method to determine the optimum water content of lime-treated expansive soil in the road engineering is analyzed; and a new method
different from the corresponding testing standards and technical specifications for the ministry of communications
is presented; and it is illustrated that the optimum water content in the lime-treated soil should be 3% larger than the one determined by the compaction test.