Abstract

Peat normally has high organic matter content and is generally associated with high compressibility and high magnitude and rates of creep. It may also be associated with poor strength characteristics and a risk of large deformation. The main specifications in the peat nature are the presence of acidic or less commonly alkaline media, combined with a high level of ground water. One of the most common methods for improving peat is by cement columns by adopting the dry mixing method. This paper presents the results of the effects of peat nature on cementation and pozzolanic reactions over time by treating peats with ordinary Portland cement (cement) and blast furnace slag (slag). Samples of peat were prepared by mixing specific amounts of cement and also cement and slag (cement-slag). Unconfined compressive strength (UCS) of the stabilized samples was evaluated after curing for 15, 45 and 90 days in different pH media. The results indicated that, acidic media (pH = 3 and 5) has negative effect on the cementation and pozzolanic reactions, whereas alkaline media (pH = 10 and 12) improves the strength of the mixtures. It showed that, the aggressive media has less negative effect on treated peat with cement-slag as slag decreases the permeability of the mixture. Furthermore, the strength of treated peat in an acidic media was found to be less compared with others due to its physico-chemical characteristics.

Key words: Peat nature, cementation, pozzolanic reactions, dry mixing method.