12. Specialized applications
12.1.1. Scope of chapter
This chapter essentially covers the specialized uses of clay in construction not included in the more routine applications covered in other chapters. There is a very wide range of such specialized applications, so none can be treated in great depth in this book. In addition, some of the applications, especially in the areas of environmental engineering, are undergoing rapid development. Readers interested in particular applications should therefore consult the appropriate references given and be prepared to search for more recent publications.
The applications discussed in this chapter may be divided into two main categories, though there is some overlap between the two. The first category includes the use of clay slurries in drilling, piling, diaphragm wall construction and tunnelling. In most cases the slurry is used as a construction expedient to provide fluid pressure, support soil particles in suspension to prevent sedimentation, and to act as a medium of transport for excavated material. In some cases the slurry may be left in place to form an impermeable barrier; in such cases the clay slurry may be mixed with natural soil and/or cement to achieve a semi-solid final state. Clay or clay/cement slurries may also be used as grouts to seal permeable natural ground for either short- or long-term purposes.
The other principal category includes uses where plastic solid clay is employed to form impermeable barriers or waterproof layers, most commonly in the construction of engineered landfill facilities or for the containment of hazardous solids or liquids. In these cases the applications are making use of the low hydraulic conductivity of clays, which is maintained even when the material is deformed, due to the clay’s ability to strain plastically without cracking. A traditional form of such material is ‘puddle clay’, widely used in the past for lining canals and forming the core of earth embankment dams.
Figures & Tables
Concluding the trilogy on geological materials in construction by specially convened Geological Society working parties, this authoritative volume reviews many uses of clays, ranginf from simple fills to manufactured products. Comprehensive and international coverage is achieved by an expert team, including geologists, engineers and architects, who met over six years to produce the book. Packed with information prepared for a wide readership, this unique handbook is also copiously illustrated. The volume is dedicated to the memory of Professor Sir Alec Skempton.
Various definitions of ‘clay’ are explored. Clay mineralogy is described, plust the geological formation of clay deposits and their fundamental materials properties. World and British clay deposits are reviewed. New compositional data are provided for clay informations throughout the British stratigraphic column. Investigate techniques and interpretation are considered, ranging from site exploration to laboratory asessment of composition and engineering performance.
Major civil engineering applications are addressed, including earthworks, earthmoving and specialized roles utilizing clays. Traditional earthen building is included and shown to dominate construction in places. Clay-based construction materials are detailed, including bricks, ceramics and cements. The volume also includes a comprehensive glossary.