Re-use of waste materials to improve mechanical properties of soft soil

This thesis focused on the reuse of waste materials for geotechnical and geo-environmental purposes and the strength development of cement treated soft soils such as peat and clayey soil was studied. The effects of different parameters, such as recycled material content, curing time, curing temperature and the ratio of water to blastfurnace slag cement were investigated. The unconfined compression strength (UCS) and free-free resonance frequency tests were performed to understand the mechanical properties of cemented soil. It was found that a more performant mechanical behaviour of peat and clayey samples was found by adding recycled materials (RM) to the peat and clayey soil. RM composed out of sand, stones, crushed bricks and concrete. Moreover, curing time increases the specimens' ages for all four curing times (28,60, 90 and 120 days) and also increases the UCS of the specimens. The increment on strength was significant from 28 days to 120 days. On the other hand, significant lower results evaluated on clayey soil compared to peat for water/blastfurnace slag cement ratio of 0.9. This might be related to the fact that these clayey mixtures are very difficult to compact. It can be concluded that recycled material showed a good performance in long-term strength development and seemed to be a good material to be concerned in future. Keywords: Recycled Materials, Blastfurnace Slag Cement, Unconfined Compressive Strength, Small-Strain Stiffness