Loss of Cementitious Elements on Lime Stabilised Soil Samples
Soil stabilisation with lime is used in many countries in the construction of road bases and sub-bases and for the treatment of subgrade soils. Studies have shown that the performance of stabilised soil layers can be affected by certain undesirable (deleterious) chemical reactions probably occurring on lime-treated soil. Carbonation is one of them. Carbonation referred to here has reference to the reaction that occurs between free lime and atmospheric carbon dioxide. Also called lime carbonation, the reaction referred to above of lime with carbon dioxide forms calcium carbonate instead of the cementitious CAHs and CSHs. The paper examines the existence of carbonation on two soil samples (sample one and two) treated with lime by conducting an Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), X-RD, SEM, EDS/EDX tests. The UCS of the soil decreases sharply at lime content of 6% for sample one while weak bonding due to the loss of cementitious element of the soil samples impacted on the CBR of the soil due to soil voids not so-closely tight, with EDS/EDX micro images showing the existence of the pores within the soil particles indicating the change in microstructure due to loss of cementitious element in soil (carbonation).
Keywords - Carbonation, Microstructural analysis, CBR Penetration, UCS, X-RD, SEM, EDS/EDX.