AWAM International Conference on Civil Engineering 2019 (AICCE'19) - Nibong Tebal - Malaysia (2019-08-21)

The permeability and strength of compacted laterite soil-bentonite mixtures for landfill cover application.
The most suitable soil type for landfill cover is the fine-grained soil with high clay content; however, clayey soils are also relatively low in shear strength. The laterite soils, which is regular with the Malaysian construction industry has been the main choice for landfill cover purposes in the country; however, upon investigation, the soils would normally have a permeability coefficient (k) in the order of 10-8 m/s or higher, thus are considered unsuitable for landfill application unless treated to meet the standard. The current study presents properties associated with permeability and shear strength of three laterite soils – LS1, LS2, and LS3 - when treated by mixing with bentonite at 1%, 3%, and 5%. In each case, k was found reduced with increasing bentonite content. However, for LS1, a 5% bentonite treatment was required to decrease k by one order of magnitude, i.e. from 4.7x10-8 m/s to 9.3x10-9 m/s. For LS2, a 3% bentonite content was required to bring down k from 4.26x10-8 m/s to 6.94x10-9 m/s, while for LS3, only 1% bentonite was sufficient to reduce k from 3.25x10-8 m/s to 8.15x10-9 m/s. With the addition of the bentonite, the unconfined compressive strength (UCS) were found weakened to lesser than 200kPa for all samples. Without bentonite, the UCS values for LS1, LS2 and LS3 were respectively 213kPa, 207.84kPa and 156.19kPa
Mrs. Ros Nadiah Rosli, Professor Mohamad Razip Selamat, Dr. Muhd Harris Ramli