In this study

reactive magnesia (MgO) is used as a binder to carbonate and stabilise silty clay. The changes of unconfined compressive strength

soil pH

carbonation products

and microstructure of the silty clay carbonated and stabilized by reactive MgO are studied at different carbonation time and initial water contents through the experiments of unconfined compression

pH

X-ray diffraction

mercury intrusion porosimetry and scanning electron microscope

respectively. The micromodel of carbonation reaction of silty clay is proposed according to the intrinsic relationships between the strength of carbonated soil and contents of carbonation products as well as the cumulative pore volume. The results show that with the increase of the carbonation time or the decrease of the initial water content of carbonated samples

the carbonation products increase

and the strength of reactive MgO stabilized soil gradually increases with the decrease of cumulative pore volume. Moreover

the pH values of reactive MgO-stabilized soil decreased with the increase of the carbonation time

whereas the initial water contents show no obvious changes. Finally

the micromodel of carbonation reaction of silty clay is established

and the highest strength of reactive MgO-stabilized silty clay is determined after about 6 hours of carbonation.