The special properties of high liquid limit soil and red clay of Zhucheng highway are revealed through laboratory test. Based on the characters of high liquid limit soil

the modified experiments are completed by adding lime to the high liquid limit soil; and the change laws of the physical and mechanical properties and strength are studied. The results show that

after being improved by lime

the high liquid limit soil can be used as subgrade filling of expressway as its liquid limit and plastic index being reduced

the dilatability decreased and the value of CBR increased remarkably. In addition

the corresponding contents on the high liquid limit soil and the red clay that are not rigorous in “Specifications for Design of Highway Subgrades”

are discussed so as to contribute to the rational use of high liquid limit soil and the red clay and the renewal or amendment of the corresponding technical specification.