Soil stabilisation with cement or lime is used in many countries in the construction of road bases and sub-bases and for the treatment of subgrade soils. Recent studies have shown that the performance of stabilised layers can be affected by carbonation which inhibits the formation of cementitious products in soil-cement and soil-lime reactions.
This paper examines the evidence for carbonation in road trials constructed
in a hot, arid area in Botswana and describes the laboratory study that followed using a clayey sand (a poor quality calcrete) from Botswana to investigate the effect of different curing conditions on soil-cement and soil-lime mixtures. Humidity, temperature and carbon dioxide in the environment were varied and the affect on strength and properties of the stabilised soils were assessed by the unconfined compressive strength and plasticity tests. Different curing periods were examined and the extent of carbonation was identified by the use of phenolphthalein indicator.
PTRC. Proc of Seminar H, PTRC Transport and Planning Summer Annual Meeting, University of Bath, 7-11 September 1987. TRL - Crowthorne, UK. pp. 22