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1. Introduction

Clay, noun. Old English Cladg. A stiff viscous earth. (Blackies Compact Etymological Dictionary. Blackie & Son, London and Glasgow. 1946. War Economy Standard)

Clay: The original Indo-European word was 'gloi-" "gli-' from which came "glue' and 'gluten'. In Germanic this became 'klai-; and the Old English 'claeg" became Modern English "clay'. From the same source came "clammy' and the northern England dialect "claggy' all of which describe a similar sticky consistency. (Oxford English Dictionary and Ayto's Dictionary of Word Origins, Bloomsbury, 1999)

Clay." from Old Greek yRia, y2oia "'glue" 72ivfl "slime, mucus "" y2oidq "'anything sticky" 'from L-E. base *glei-, *gli- 'to glue, paste stick together. (Klein E. A comprehensive etymological dictionary of the English language. Elsevier, Amsterdam, 1967; Skeat W. An etymological dictionary of the English language. Oxford University Press, 1961; Mann S.E. An Indo-European comparative dictionary. Buske Verlag, Hamburg, 1987)

1.1. Clay

Definitions of clay are given in Section 1.2. The uses of clay are ubiquitous and diverse. On a world scale, clay is

of major economic significance, touching virtually every aspect of our everyday lives, from medicines to cosmetics and from paper to cups and saucers. It is very difficult to over-estimate its use and importance. The treatment of clay in this book is therefore wide ranging to reflect this situation.

The occurrence of clay is also ubiquitous and diverse (see Text Box below) and, with its various mineral species, properties and behavioural characteristics, the industrial applications of clay are thus manifold and complex. As well as their traditional major uses for brickmaking, pottery and porcelain manufacture, refractories and the fulling of cloth, clays are now used for refining edible oils, fats and hydrocarbon oils, in oil well drilling and synthetic moulding sands, in the manufacture of emulsi- fied products in paper and, as noted in Chapters 13, 14 and 15, many hundreds of other uses, including medicine, cosmetics and, on a larger scale, as fillers, as well as many uses in geotechnical engineering e.g. for grouts, membranes etc.

In foundation engineering, clay often provides poor foundation support, and can be responsible for slope instability. It finds extensive use as a construction material in embankments and in water-controlling structures as an impermeable barrier and in many other specialist ways (see Chapters 10, 11 and 12).

Given the worldwide distribution and variability of clay deposits, the production of an authoritative text, which is the aim of the Working Party, on all aspects of

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2 INTRODUCTION

clay, was considered a most daunting task. The original brief from the Engineering Group committee, the parent committee of the Working Party, was that the Working Party report, viz. this book, should exclude the engineering aspects of clay in situ (i.e. not consider it as a foundation material) but that other engineering aspects, or example use in embankments or in specialized engineering applications, should be considered.

In addition to this particular omission conceming the in situ use of clay, the Working Party decided that in order to retain depth of discussion it should concentrate only on the principal construction and industrial applications of clay with the omission of other specialist non- engineering uses, and in order to limit the scope of this current publication to a sensible size.

1.2. Definitions of clay

The term 'clay' has no genetic significance. It is used for material that is the product of in situ alteration, e.g. by weathering, hydrothermal action or, alternatively, deposited as a sediment during an erosional cycle or developed in situ as an authigenic clay deposit. 'Clay' can be used as a rock term and also can be used as a particle size term in mechanical analysis of sedimentary rocks or soils. As a rock term, it is difficult to define precisely because of the wide variety of materials that have been called clays. A universal implication of the term 'clay' conveys that it is a natural, earthy, fine-grained material that develops plasticity when mixed with a limited amount of water. By 'plasticity', it is meant that within a certain range of moisture content the material will deform under the application of pressure, the deformed shape being retained when the deforming force is removed. Chemical analysis of clay minerals shows them essentially to comprise silica, alumina and water in variable combinations, frequently with appreciable quantities of iron, alkalis and alkaline earths.

A difficulty is that some material called 'clay' does not meet all the above descriptors. A glance at any comprehensive dictionary will show that clay has a plethora of definitions, scientific and colloquial, often steeped in history and clearly demonstrating that the definition of the word 'clay' depends on the context in which it is being used. The reasons for this situation undoubtedly lie in the many and diverse industries in which clay is used, each having developed, over the years, a definition appropriate to its requirements. A summary of the definitions of clay and clay minerals, presented in the joint report of the Association Intemationale pour l'etude des Argiles (AIPEA) Nomenclature Committee and the Clay Miner- als Society (CMS) Nomenclature Committee is given in Section 1.2.1; civil engineering definitions of clay in British practice are given in Section 1.2.2 and international civil engineering soil classification by particle size distribution (grading) is given in Section 1.2.3.

Examples of common, non-specific dictionary definitions are given in the Text Box on p. 3.

There are many geological dictionaries which seek to define clay. These are typically in general accord with the Working Party views. An example is given in the Text Box on p. 4, together with closely related terms defined in the same dictionary. These related terms are also in general accord with their use in this book.

It is necessary to state, however, that within the following chapters, where the term clay is used in a general sense as a material, it implies any fine-grained, natural, earthy, argillaceous material. This includes clays, shales and argillites of the geologists, and soils as defined by geologists, engineers and agronomists, provided such material is argillaceous (i.e. it contains clay minerals).

Any specific definition of the term clay that depends on the context, in which it is being used, is given within the chapter related to that definition. This is because, as is clear from the above dictionary definitions, the term clay is imprecise and variously defined. Description of clays is discussed in more detail in Chapters 4 and 8. The term clay mineral is described in the second Text Box on p. 4.

1.2.1. Definitions of clay and clay minerals by the AIPEA Nomenclature and CMS Nomenclature Committees

The definitions of clay and clay minerals in the Joint Report of the AIPEA Nomenclature and CMS Nomencla- ture Committees should be read in full for the complete expression of their views (Guggenheim & Martin 1995), together with the subsequent Discussions on this Report (Moore 1996; Guggenheim & Martin 1996). The following summarises some of the salient points and demon- strates the difficulties in making a precise definition of clay.

'Clay' Definition The term 'clay' refers to a naturally occurring material composed primarily of fine-grained minerals, which is generally plastic at appropriate water contents and will harden when dried or fired. Although clay usually contains phyllosilicates, it may contain other materials that impart plasticity and harden when dried or fired. Associated phases in clay may include materials that do not impart plasticity and organic matter."

In the Discussion to the Definition, the Committees make the point that, 'The 'naturally occurring' requirement of clay excludes synthetics and that based on the standard definition of mineral, clays are primarily inorganic materials excluding peat, muck, some soils, etc. that contain large quantities of organic materials. Associated phases, such as organic phases, may be present. 'Plasticity' refers to the ability of the material to be moulded to any shape. The plastic properties do not require quantifi- cation to apply the term 'clay' to a material. The fine- grained' aspect cannot be quantified, because a specific particle size is not a property that is universally accepted by all disciplines. They say that,for example, most geologists and soil scientists use particle size less than 2 izm, sedimentologists use 4/um, and colloid chemists use 1 I~m for clay-particle size.'



iiii i i!i i lipidic! i'! �84

INTRODUCTION

N O ~ S D ~ C ~ " : ~ i : ~ * :: " :'::": :::: ~' :": :~: :~: ~: :,t :~: :~ : ~ , . . ,.

;~ :.': ~: t : : . , ~:, ::.: a l ~ ~ :: : : : ; : . : :~: : , , : ; ~ :::: ::~ ~:: :~::: ~ ; : ~ : ~ : ~ :. :~7:~ ~ . : :.':~, ~ ~:~, ,:~: :';~ :~:~.~: ::.~:::~: z: ::9 : :~ ~ ~:::~::::~ ~:~ :::~

They also say that 'Plasticity is a property that is greatly affected by the chemical composition of the material For example, some species of chlorite and mica can remain non-plastic upon grinding macroscopic flakes even where more than 70% of the material is less than 2 lure esd (equivalent spherical diameter). In contrast, other chlorites and micas become plastic upon grinding macroscopic flakes where 3% of the material is less than 2 lure esd' and that, 'Plasticity may be affected also by the aggregate nature of the particles in the materiaL'

In the Discussion on the Report, surface effects, grain- size effects, practical considerations and other issues are discussed in some detail, to which the reader is referred. In this discussion, Moore (1996) urges the Committees to state clearly that they are aware that clay is used in three different ways in their discipline: as a size term, as a rock term and as a mineral term. 'Users who do not clearly separate these meanings provide one o f o u r most consistent sources of confusion. Each of these uses has utility or each would not have survived'.

Clay mineral Definition: 'The term "'clay mineral" refers to phyllosilicate minerals and to minerals which impart plasticity to clay and which harden upon drying or firing.'

In the Discussion, the Committees say that, 'Currently, minerals known to produce the property of plasticity are phyllosilicates. Because minerals are not defined based on their crystallite size, appropriate phyllosilicates of any grain size may be considered "clay minerals ". Like- wise, clay minerals are not restricted, by definition, to phyllosilicates. '

They go on to say that minerals that are non- phyllosilicates, which impart plasticity to a clay and harden upon drying or firing, are also 'clay minerals'. They quote as example,' i f an oxy-hydroxide mineral in a clay shows plasticity and hardens upon drying or firing, it may be properly referred to as a "clay mineral'. Thus a clay is not required to be predominantly composed of



4 INTRODUCTION

i ~ ~ de~ved~o~ ~hemical uetion ::::~ the secreti~h~ Oforganis~:: :i ~ a s e ~ediment such ~ sand~, ~ , i ! i

l, adj~ :: (of ~herat grains) ~a~Orted and : as i ~edi~ient~ ~bOt: were: deriv~ ,:~om P ~ i i::i

i : ~ e r a ! S ~:~: discussed in d e ~ ! in: C ~ ~'i ~ iliil

phyllosilicates. Minerals that do not impart plasticity to clay and non-crystalline phases (regardless if they impart plasticity or not) are either 'associated minerals' or "associated phases ' respectively '.

The Committees make the important point that their definition of clay mineral departs from previous definitions (e.g. Bailey 1980) where clay minerals were equated to phyllosilicates. They say that the current definition broadens the scope of possible minerals defined as clay minerals.

For an exhaustive account of the history of definition of clays up to 1963, the reader is referred to Mackenzie

(1963), and for the more recent developments, Weaver (1989).

1.2.2. Civil engineering definitions of clay in British practice

When used in the mechanical analysis of soils following British civil engineering practice, clay is defined as material of particle size less than 0.002 mm (BS 5930:1999, Code of Practice for Site Investigations). However, some clay mineral particles may be larger than this. BS 5930 defines silt by mechanical analysis as between 0.002



INTRODUCTION 5

and 0.06 mm. Clay is thus defined without reference to mineralogical composition.

A practical example of the way in which the term clay is used in context for civil engineering practice, and therefore of importance to this book, is the way that BS 5930:1999, handles the term. It recommends that soils are divided into two classes: fine soils and coarse soils. It sug- gests that as a first appraisal of the engineering properties, the soil's nature and composition are described visually, assisted by a few simple hand tests. "Soils that stick together when wet and can be rolled into a thread that supports the soil's own weight (i.e. have cohesion and plasticity), contain sufficient silt and~or clay in them to be described as fine soils. Soils that do not exhibit these properties behave and are described as coarse soils ".

The actual soil name 'is based on particle size distribution o f the coarse fraction and~or the plasticity o f the fine

fraction as determined by the Atterberg Limits. These characteristics are used because they can be measured readily with reasonable precision and estimated with sufficient accuracy for descriptive purposes '. It is suggested that where a soil (omitting any boulders or cobbles, i.e. particles greater than 60 mm in size) contains about 35% or more of fine material it is described as a fine soil ( 'clay' or 'silt', dependent on its plasticity). The Code goes further and says that 'the effects of clay mineralogy and organic content are significant. Fine soil should be described either as 'silt' or 'clay', depending on the plastic properties; these terms are to be mutually exclu- sive so that terms such as 'silty CLAY' are unnecessary and not to be used'.

It should be noted that many geologists call all bedrock material 'rocks', even if their behaviour is 'soil-like' (cf. the Eocene 'London Clay'), whereas engineers tend to call bedrock clays 'engineering soils'. Clay rocks (e.g. a strong mudstone) which ring to the hammer would be called a rock by engineers. Current civil engineering thinking on the term 'cohesion' and the divisions between 'soil' and 'rock' are discussed in Chapter 4.

1.2.3. International Civil Engineering Soil Classification by particle size distribution (grading)

Figure 1.1 shows some of the most used soil classifica- tions by particle size distribution ('grading') by various countries, determined by their national standardization institutes. An important point in this figure is that the boundary between sand and silt is 0.06 mm in European countries and 0.075 mm in the USA and Japan. These numbers have been used since the beginning of the stan- dards in each country and both values are in use around the world to identify the boundary between sand and silt, which can be defined differently in different countries.

The current ISO Standard 14688:1996 placed the boundary at 0.06 mm. Japan has recently proposed that ISO should reflect the two values 0.06 and 0.075 mm.

1.3. Some British clay production statistics

In 2000 it was reported that clays represent only 4% (approximately 15 million tonnes, Quarry Managers Journal 2000) of the minerals quarried annually in the UK, but this greatly understates the quantity of clay materials actually excavated per annum. Statistics of production (see the Text Box on p. 7) are generally collected for clay materials extracted and transported away from a quarry for a specific purpose, say, manufacture of paper, ceramics, cement, bricks, tiles, pipes, sanitary ware and other clayware and take no account of large volumes of clay materials excavated during the course of civil engineering projects and reused within the construction site.

For example, also in 2000, a comprehensive survey of waste generated by construction and demolition showed that this activity creates 24 million tonnes of soil (uncon- solidated material) and 15 million tonnes of mixed soils and demolition waste requiring disposal (Environment Agency 2000).

The quantities of clay materials excavated and reused internally during construction must be many times greater but no national statistics are recorded. It has proved very elusive to obtain the actual quantities of clay worked in heavy civil engineering; no statistics have been found but from the Working Party members' experience, it was considered, as a rough approximation, that some 15 km of new major highway in the UK required the handling of some 3 million cubic metres of clay material, i.e. for the approximately 100 km of new major highway in the UK per year, in very round figures, some 20 million cubic metres of clay material is handled, the highest total being in England. Similarly, the Working Party estimated some 10 million cubic metres of clay material was handled in all other engineering construction per year.

1.4. Geographical and stratigraphical distribution

Clays are widely distributed both geographically (i.e. across the surface of the Earth) and stratigraphically (i.e. over geological time). The outcrops of the main formations containing clay material in Great Britain are shown in Figure 1.2; similar maps could be prepared for all countries that have been geologically surveyed. Maps of this kind show both the areal extent and the outcrop of the clay formations at the present time. Chapters 5 and 6 contain maps from elsewhere.

The stratigraphical positions of the main clay formations in Great Britain are shown in Figure 1.3; again, similar stratigraphical columns could be prepared for other countries. The column shows the geological periods during which the main clay formations were deposited. See also discussion in Chapters 5 and 6.



Co~oids

0.001 0.005

Clays

INTRODUCTION

USA ASTM:D422-63(90) (Uniform soil classification)

0.075 0.425 2.0 4.75 19 75

Fine I Medium [ Coarse Fine I Coarse Silt

Sand Gravel

0.002 0.02

l__ (Clays) ] (Silt)

Fine Particles I

0.005 0.05

USA ASTM: D653-90 (Standard terms)

0.075 4.75

Sand

300

Cobble Boulder

76.2 305

t Gravel [ Cobble Boulder

I

USA ASTM:D3282-93 (AASHTOM 145) (Soil classification for road construction)

0.075 0.425 2.0 75

Silt-Clay Fine Coarse

Sand Gravel Boulder

Clays

UK BS5930:1999

0.002 0.006 0.02 0.06 0.2 0.6 2.0 6.0 20 60 200

Fine I Med. ICoarse nelMed ICoarse Fine ]Med. Come Cobble

Silt Sand Gravel Boulder

Clays

GERMANY DIN 4022 1987

0.002 0.006 0.02 0.06 0.2 0.6 2.0 6.0 20 60

Fine ] Med. ] Coarse Fine I Med. [ Coarse Fine Med. Coarse Cobble

Silt Sand Gravel

200

Boulder

SWEDEN 1981

0.0006 0.002 0.006 0.02 0.06 0.2 0.6 2.0

Fine] Fine Med. ] Coarse Fine Med. I Coarse Clays Silt Sand

6.0 20 60 200

Fine Med. Coarse Small [ large

n

Gravel Cobble

Small Large

Boulder

Clays

ISO/DIS 14688 1996

0.002 0.006 0.02 0.06 0.2 0.6 2.0 6.0 20 60 200

Fine [ Med. [ Coarse Fine [ Med. I Coarse Fine I Med. ]Coarse Cobble

Silt Sand Gravel Boulder

0.006

Clays Med. Coarse

JAPAN JGS 0051 2000

0.075 0.26 0.85 2.0 4.75 19 75 300

Fine Med. Coarse Fine Med. ] Coarse Coarse Rock Large Rock

m

(Cobble) (Boulder) Sand Gravel

FIG. 1.1. Soil classification by particle size (mm) in various countries.



INTRODUCTION "]

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1.5. TheWorking Party

The Clay Working Party was convened by the Engineer- ing Group of the Geological Society to produce a Report to be published as a book. The published book is now the third of a trilogy produced by the Working Parties on Construction Materials. Together the three books cover the complete range of particle sizes of natural geological materials (geomaterials) used in civil engineering construction. The two previous books are:

Aggregates: sand, gravel and rock aggregates for construction purposes Collis & Fox (eds), 1st edn (1985); Smith & Collis (eds), 2nd edn (1993), reprinted in 1998; and Smith, M.R. & Collis, L. (eds) 3rd edn. revised by Fookes, Lay, Sims, Smith & West (2001). Aggregates: sand, gravel and rock aggregates for construction purposes. Geological Society, London, Special Publications, 17. 'Stone: building stone, rock fill and armourstone in construction' Smith, M.R. (ed.) 1999. Stone: building stone, rock fill and armourstone in construction. Geological Society, London, Special Publications, 16.

This trilogy is part of a series of Working Party Reports on engineering geology topics produced over the last four decades by the Engineering Group of the Geological Society.

The clay book is intended to be practical, authoritative and informative and to be of use to a wide spectrum of readers in the UK, Europe and around the world, from a diversity of backgrounds and employments.

Each member of the Working Party is knowledgeable in some aspects of clay and it is hoped that their combined expertise covers the full spectrum of clay from its geology and mineralogy to geological, chemical and engineering properties, investigation, testing, its practical use in construction and as commercial products.

Members were largely from industry, together with some from academia, and included geologists, engineering geologists, industrial geologists, geotechnical engineers, laboratory specialists and industrial chemists.

To achieve the maximum possible breadth and balance in the report, advice and constructive criticism were can- vassed from a range of individual specialists, professional institutions, learned societies, industrial associations and research bodies.



8 INTRODUCTION

FIG. 1.2. Map of the UK showing major clay-rich solid-geology formations (more detailed UK maps are included in Chapter 6).

Thus it should be clear that the concepts and techniques described in the report are drawn from a wide scientific spectrum in which the Working Party sought advice from beyond the confines of the committee. The report links

diverse fields in a common theme and as such will inevi- tably be used by persons of widely different vocational backgrounds. Consequently, basic material which is included in one section might be considered by an expert



INTRODUCTION 9

FIG. 1.3. Stratigraphical distribution of the principal British structural clays (ages after Gradstein & Ogg 1996).

in that particular field to be oversimplified. However, it is thought that this approach is justified in order to serve a wide readership and it is hoped that elementary facts might assume a new significance when presented in relation to the central theme. To help this, text boxes have been used to discuss a topic or part of a topic in specialist detail, or to give a simple basic background on some aspects of the subject where the text has assumed some prior knowledge.

As part of the extension of the work of the Working Party and its specialist corresponding members, a consul- tative seminar, ' Clay materials used in construction', was held on 19 April 2000, in Manchester, at Geoscience 2000, the major biennial conference of the Geological Society. In this, the preliminary drafts of chapters in summary form were made available as preprints. The chapters were then presented during the session and wide-ranging discussion, for each chapter, held with the audience. This



10 INTRODUCTION

ii!i~ii!i~ii!i~iiii!iiii!~iiii

authoritative, up,to.date :~d eXtensively @ported by:data: ~ d eollat ~!~[l!!be minimise fi and necessary specialist terms wi!L~ defim

~op~:~Uustrationsi many Of which :wi!t!~eiOriginal, and:: ::.good ~ 6 : : ~#i[llbe collective responsibili~ ::f6~:: ~e whole repo~ii!~$oug dra~g~author or co, author o f one, or more ~. chapters, all members wil

praet~eat~ of applications. There will bel aa endeavour to identify likely: directions of 1 ptei~it : ~ e developments. Based principally on UK experience and practicei the CW]

of the subject throughout Europe and worldwide,

cons~etion will be fully assessed, including a range of direct applications, plus other igi~ ~ t i a l raw material.

uses ofc!ay ~i~ i:i processes in which ii :/!il

procedure produced valuable feedback for the Working Party and many ideas and suggestions developed at this meeting were included in the Terms of Reference (see the above Text Box).

1.5.1. The report

Based on the objectives outlined above, it was decided to structure the book round its sequence of chapters. The chapters have been subdivided into three main thematic groups: Geology, 2 to 6; Investigation, 7 to 9, and Application, 10 to 15 (see Text Box on p. 11).

The Geology chapters begin with fundamental scientific aspects, composition, formation and alteration of clays, and continues with discussions of their basic properties and reviews of clay deposits around the world as well as in Britain. This approach was designed to set the scene for the following Investigation chapters evaluating clays, their exploration, composition, textural analysis and their testing. This book is completed by the practical Application chapters concerning clays in earthworks and engineering situations, in buildings and in industrial use, principally bricks, ceramics and cement and related products.

It was considered that extensive appendices would be required to provide mineralogical and property data,

detailed information on deposits around the world, test methods and a glossary. The intention was that, with the appendices, repetitive information, factual information and details which would hinder the flow of the text but were otherwise necessary in an authoritative book, would be included.

Each chapter is thoroughly cross-referenced to the other chapters, as appropriate, and contains detailed references for further reading.

Attention is drawn to the implications of the use of such terms as 'weathering' and 'weathered clay' throughout the text. Near surface clay is usually in a weathered condi- tion. This weathering changes the characteristics of the material and most sources of clay around the world are weathered to a lesser or great extent. Therefore the form and influence of the weathering on the characteristics of the material must be taken into consideration in its evaluation and use. Often, reported test properties are those of the fresh material, whereas the material as deliv- ered may be weathered to some extent and have different properties. Users and specifiers must be aware of this. See further discussion on weathering in Chapter 4.

The four Appendices (plus a glossary), together with parts of the text, have been assembled mainly from data of which the Working Party have no first-hand knowledge of the provenance or the reliability, although every effort has



INTRODUCTION 11

Strueture:,~Of thei::boo~repo~ B r i e f n o t e s : o n s c o p e o f : c t l a p t e r

T e ~ s ofimf~eneer scope:::!of report; ~fmifions; ;:~tiStics;d~s~bufiort of clays in t ~ e and space; outlier:of Chapters.

a n d ~ a l

m ~ d t e ~ t e ~ i :::: ;i:~;:

C ta~ ~::"ehe~e~~mposifion, and: atomiC: s~e:mre~!:ofelay ~e~als~i Non e~ay! min~a] !Phasesi Swellirig and iOn.eXch~ge~ fl~ids ai~d goses::present;:: ere:; Mode.:: o f ~ t i o n ~ . : O f e l a y ~ a l s and !their al terafio~: ~ tetation:::to their i~ar t::;:Diagenes~si :ithifieafiO~: and: l o ~ i a ~ , me~m6~hi~m,,

pa!ar h!~ !!arid ~l~ie;~S:~iaffe~i~g'{ehy~:.ii! :i::~ i~! iii i~i: ~:::i: :::~ i~i i: ;i: :i:i i::~ i!

:! !!'i:i:~:!.: ~:~�84

been made to check the authenticity of the data sources. The quality of analyses and reliability of the information will vary considerably around the world and therefore data assembled in the appendices (as well as chapters) should only be used with considerable caution and it must not be assumed that similar clays from different locations

will have similar properties: they may or may not. Instead, reliance should be placed on comprehensive sampling, testing and quality control at the original location.

Appendix A calls for a special comment. It includes new and valuable clay mineral analyses of over one hundred clay samples spanning the stratigraphic



12 INTRODUCTION

succession of the British Isles, collected, or provided, by members of the Working Party, during the period of its work. The samples were divided into two sub-samples: the whole clay, and the fraction less than 0.002 mm particle size. These were analysed by automated X-ray powder diffraction methods at the laboratories of the Macaulay Land Use Research Institute, Scotland, all at the same time by the same method and the results analysed by the same person (Dr Stephen Hillier). These studies provided a self-consistent set of results for the mineralogical composition of the clays, both the clay minerals present and non-clay-minerals. The samples were also analysed by X-ray fluorescence at the laboratories of Watts Blake Bearne and Company in Germany. This study provided information on the major elements and supplemented the results obtained by the X-ray diffraction method.

This appendix is considered a most important piece of work: it is the first comprehensive analytical study of this kind carried out in Britain. It follows the pioneering work of Perrin (1971) in the 1960s, and gives an authoritative conspectus of the mineralogical composition of British clays using modern methods of analysis. The results should be valuable in both the academic study of the origin and nature of clays and in the application of clay mineralogy to practical uses.

It is hoped that this book provides a fitting third member to the geomaterials trilogy. Improving and/or updating comments for possible further editions are welcome.

References

ASTM : D422-63 (90), STM for particle size analysis of soils. ASTM : D653-96, Standard Terminology relating to soil, rock and

contained fluids. ASTM : D2487-93, Classification of Soils for Engineering

Purposes (Unified Soil Classification System). ASTM : D3282-93, Standard Classification of soils and soil

aggregate mixtures for highway construction purposes. BAILEY, S. W. 1980. Summary of recommendations of AIPEA

Nomenclature Committee. Clays & Clay Minerals, 28, 73-78. BRITISH GEOLOGICAL SURVEY 1996. United Kingdom Minerals

Yearbook 1995, Keyworth. BRITISH GEOLOGICAL SURVEY 1988. United Kingdom Minerals

Yearbook 1988, Keyworth. BRITISH GEOLOGICAL SURVEY 2001. United Kingdom Minerals

Yearbook 2000, Keyworth. BRITISH STANDARD BS 5930, 1999. Code of Practice for Site

Investigations. British Standardst Institution, London. CASSELL CONCISE DICTIONARY, Revised. 1998. Cassell. COLLOCOTT, T. C. & DOBSON, A. B. (eds) 1975. Chambers

Dictionary of Science and Technology. Vol. 2. Chambers, Edinburgh.

DIN 1987. Classification and Description of soil and rock. DIN 4022, Part 1 Swedish Geotechnical Society : 1981 : Soil Classification and Identification. Laboratory Committee of Swedish Geotechnical Society.

ENVIRONMENT AGENCY 2000. Construction and Demolition Waste Survey, R&D Report P402, Swindon.

GUGGENHEIM, S. & MARTIN, R. T. 1995. Definition of clay and clay mineral: Joint Report of the AIPEA Nomenclature and CMS Nomenclature Committees. Clay and Clay Minerals, 43 (2), 255-256.

GUGGENHEIM, S. & MARTIN, R. T. 1996. Reply to the comment by D.M. Moore on: Definition of clay and clay mineral: Joint Report of the AIPEA Nomenclature and CMS Nomenclature Committees. Clay and Clay Minerals, 44 (5), 713-715.

G~a.DSTErN, F. M. & OGG, J. G. 1996. A Phanerozoic time scale. Episodes, 19 (l&2).

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Documents

egsp 021 001 0001 · pottery and porcelain manufacture, refractories and the fulling of cloth, clays are now used for refining edible oils, fats and hydrocarbon oils, in oil well