9. Laboratory testing
This chapter outlines the testing of clays for civil engineering purposes in the laboratory. The laboratory may range from a large permanent establishment to a small temporary facility set up on site. Field tests (or in situ tests), which are carried out on clay while it is still in the ground, are covered in Section 7.6.
Field tests and laboratory tests are not alternative options, but are complementary. Each has its advantages and limitations. Some of the advantages of laboratory tests can be summarized as follows:
specific soil properties can be measured;
the choice of material for testing can be controlled;
control of test conditions can be exercised, and changes in conditions can be simulated;
a relatively high degree of accuracy of measurements is possible;
parameters can be derived within an acceptable timescale;
tests can be performed on undisturbed, re-constituted or remoulded clay.
Data obtained from laboratory tests provide a closer understanding of the properties and behaviour of clays as engineering materials. This can lead to a reduction in uncertainties in the analysis of earthworks; more economic design; construction in difficult conditions which would otherwise not be feasible; and increased economy in the use of clay as a construction material.
The laboratory tests outlined in this document are thosethat are commonly recognized throughout the world as being appropriate for geotechnical purposes. The procedures can be conveniently divided into three categories:
classification tests—to establish the type of clay and the engineering category to which it belongs;
Figures & Tables
Clay Materials Used in Construction
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.