swelling of clay because of lime stabilization 1

WE ARE REMOVING AND REPLACING PARKING LOT PAVEMENT OVER A CLAY SUBGRADE.
THERE IS A NEED FOR LIME STABILIZATION. THE CONTRACTOR WANTS TO CHARGE US FOR REMOVING OF EXCESS OF CLAY RESULTED BY LIME MODIFICATION TO A DEPTH OF 12" USING UP TO 5% CALCIMENT.
HOW TO DETERMINE THE VOLUME OF THE SWOLLEN SUBGRADE?

 

[SirAl]

The recompacted dry density of lime modified clay will be less than that of non-modified clay. To establish the volume difference, have a soils lab perform moisture-density relationship on samples of A)native, and B)native soil mixed with the specified lime amount. Comparing the 2 sets of results, you will be able to estimate the increased volume associated with lime modification.