Abstract
This paper aims at investigating a rapid and environmentally friendly soil stabilization method to significantly increase the strength of carbonated reactive magnesia (MgO)-treated soil by exposing it to substantial quantities of CO2. Soil specimens treated with 10, 15 and 20% reactive MgO were subjected to accelerated carbonation tests for 1.5, 3, 4.5, 6, and 12 hr. Later, tests of specimen weight, permeability, unconfined compressive strength and pH value were performed on soil specimens after carbonation. The results can be summarized as follows: the weight of carbonated soils increases with dosage and carbonation time (especially 3 hr); the permeability coefficient increases with the increase of porosity and the decrease of dosage of reactive MgO and it decreases first and then increases with the carbonation time; the strength of carbonated soils increases with dosage, and increases quickly with carbonation time in first 3 hours, then keeps stable. The strength reaches or exceeds the strength of cement-stabilized soils for 28 days with the same dosage; the pH value first increases and then decreases generally with reactive MgO content increasing, and a critical carbonation time (about 3 hr) exists in terms of the varying trend.
