The invention discloses an
expansive soil improver which comprises the following components in percentage by weight: 0.1-10% of propyl diammonium N,N'-bis(octyldimethyl)-2-hydroxy-1,3-dichloride, 1-10% of
potassium chloride, 0.01-10% of cationic
polyacrylamide, 1-10% of water glass and the balance of water. The
expansive soil improver can well inhibit the expansion potential of the
expansive soil. The improved soil sample has the advantages of lower specific area, lower total pore size and higher average pore size. The plastic limit is enhanced, the
plasticity index, expansibility and 50KPa
free expansion rate are lowered, and the expansion property of the soil sample is improved. The shrinkage limit is enhanced, the transversal
reduction ratio, vertical
reduction ratio and
volumetric shrinkage are lowered, and the shrinkage potential of the soil sample is fixed. The
shear strength is enhanced, the CBR is increased, the strength of the soil sample is enhanced, and various indexes can satisfy the
engineering construction requirements. The
electron microscope spectrum of the soil sample indicates that the soil sample has obvious grain agglomeration and obvious fixing effect. The improver has favorable permeability, is simple for construction, and does not influence the people and environment in the construction process and after improvement.