Geotechnical properties of cement treated sediment: influence of the organic matter and cement contents

Abstract

Organic matter (OM) is reported to affect some of the soil properties and hydration processes in case of cementbased treatment. This paper presents investigations on the influence of organic matter on the geotechnical properties of cement-based solidified sediment with naturally high OM content (7%). Moreover, this sediment was treated to provide two other OM content materials: 2 and 5%. Grain size distribution, Atterberg limits, one dimensional compression and microstructure analyses were performed on raw sediment and on sediments treated with 2, 5 and 10% cement. The geotechnical properties appear to be affected by both cement and OM contents. Investigations show an increase in grain size distribution with increasing cement contents. Furthermore, an increase in the OM content is believed to produce an increase in the Atterberg limits of the sediment before and after cement addition. With the same cement content, the developed preconsolidation pressure of treated sediments decreases when the OM content increases. After a 28 days curing period, the preconsolidation pressure σ′<i>_p</i> of sediments with OM contents of 2, 5 or 7% reaches 160, 60 and 50kPa, respectively, for a 5% cement treatment and 400, 310 and 210kPa for a 10% cement treatment. Finally, for all OM contents, the compression index <i>C_c</i> increases with increasing cement content. It reaches its maximal value for 5% cement treatment and tends to decrease over. Compared with raw sediment, the compression of cement-treated sediments is characterized by faster primary consolidation.