Geosynthetic Clay Liners (GCLs) are an innovative construction material that has been developed over the last two and a half decades. As of recent times, various types of GCLs are used as composite contaminant barriers or as structural waterproofing in the construction industry. A factory controlled prehydration with cation exchange resisting polymer prior to installation is most desirable in hostile geochemical environments. This research investigated the need to retard the moisture loss in hostile thermal environments. The cffect of drying on the flexibility of the clay mat has been demonstrated in this thesis. When exposed to various thermal environments, the moisture content of the GCL can fall to such levels where it can become brittle at the stage of rolling out the liner prior to installation. A suitable improvement needed to be made in the manufacturing process to retard the moisture loss within the prehydrated GCL. With this in mind, the drying characteristic of clays has been revisited and a mathematical model to predict moisture change has been developed and is presented in this thesis. The development of the mathematical model has accounted for the factors controlling the moisture movement within the bentonite clay core for a range of temperature (20 - 40 'C) and relative humidity level (15 - 70%) for two different clay mats. Strong correlations between aforesaid parameter and drying characteristics were observed and are discussed in detail. The laboratory controlled drying observation were complemented and compared with 'on site' observation. The research contribution from the study includes: the establishment of an appropriate drying model; the laboratory evidence to show a strong correlation between the modified Brinell Hardness and the flexural stiffness for the clay mat; the laboratory information on the ductile to brittle transition of the clay mat during drying; the development of a quality control tester to assess the level of moisture in the GCL after manufacture as well as at the point of installation of the liner.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:532885 |
| Date | January 2008 |
| Creators | Loh, Eric Wooi Kee |
| Publisher | University of East London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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