Civil Engineering Reference
In-Depth Information
Chapter 14
Materials
David Doran
Consultant, UK
doi: 10.1680/mosd.41448.0225
CONTENTS
14.1 Introduction
225
14.2 Masonry
225
14.3 Metals
229
Materials of suitable strength, stiffness, flexibility, durability and affordability are key to the
realisation of good design. Furthermore, in a world greedily competing for scarce resources, it is
essential that the use of materials is economic and that a high degree of recycling is achieved.
This chapter gives advice on masonry (including ceramics and stone), metals (cast and wrought
iron, steel and aluminium), concrete, timber, glass and polymers. It is hoped that the content
will give a satisfactory grounding for designers to achieve a working knowledge of some of the
most frequently used materials. The chapter gives advice on problems that can occur with the
careless use or inadequate protection of materials. Different types of metal corrosion are listed
and ways to minimise their effect. Concrete, and in particular reinforced concrete, has suffered
from a variety of problems such as carbonation, alkali silica reaction (ASR) and misuse of high
alumina cement (HAC) - these are explained and, where necessary, advice given on elimination
or minimisation of problems. Where appropriate, ranges of mechanical properties are listed.
Additionally advice is given on performance in fire and the protection of materials to resist fire.
14.4 Steel
229
14.5 Aluminium
232
14.6 Concrete
233
14.7 Timber
235
14.8 Polymers
236
14.9 Glass
238
14.10 Conclusions
240
14.11 Acknowledgements
241
14.12 References
241
14.1 Introduction
The aim of this chapter is to provide engineers involved in
structural design with a basic knowledge of those materials
most frequently used in new construction and refurbishment.
The topics covered include masonry (including ceramics and
stone), metals (cast and wrought iron, steel and aluminium),
concrete, timber, polymers and glass.
still exist in Choga Zanbu Zigorat. In the early days, brick-
making was usually a parochial affair with manufacture often
taking place on the construction site. This practice has led to
a wide variety of types of brick the governing factor being the
suitability of the local clay. In early times clay was moulded
into blocks and then allowed to dry in the sun before use. UK
practice distinguishes between bricks and blocks by face size.
A unit smaller than 300 mm × 100 mm is a brick, larger sizes
are blocks.
Bricks for use in structural situations are provided with frogs
(a shaped indent to the top of the brick). These bricks should
be laid frog uppermost with the frog filled with mortar to pro-
vide adequate wall or column strength.
Architects, engineers and bricklayers should be familiar
with the different systems of brick/block bonding to ensure
it is appropriate to the requirements of the construction under
consideration. These include
stretcher
,
header
,
English
,
Flemish
,
garden wall
and
monk
bond. These are illustrated in
Figure 14.1
. In Pakistan
Quetta
bond has been used to increase
resistance to earthquakes.
Mortar (essentially a mixture of cement, sand and water)
used in construction of brickwork should comply with BS
5628-3. If good quality work is required then the use of quality
controlled, ready mix mortar delivered to the site is preferable
to site mixed material. Colouring agents may be added to the
mix to achieve architectural preferences. There is also wide-
spread practice of adding plasticisers and/or retarders to the
mix to control workability and setting times.
Stainless steel or other non-ferrous bed joint reinforcement
may be added in special applications such as gable walls to
houses or perhaps where openings occur in order to supple-
ment other means of support. Several proprietary brands of
reinforcement are available but are usually of welded fabric con-
figuration available in coils. For some structural applications,
14.2 Masonry
14.2.1 Ceramics
14.2.1.1 Introduction
The word ceramics has its origin in
Cerami
, the potters' district
of ancient Athens. In simple terms, ceramics is burnt clay. The
fact that some 3500 year-old masonry structures still exist is tes-
tament to the durability of the material if manufactured and con-
structed to high standards. For the purpose of this section, the key
ceramics are bricks, blocks, tiles, vitrified clay-ware, terracotta
and faience. Although not of ceramic origin, for the sake of com-
pleteness, a note about calcium silicate bricks is also included.
The demolition material from ceramic masonry structures
can be recycled by cleaning off mortar for reuse as brickwork
or crushed to form aggregate for low strength cementitious
materials. A lucrative business exists for the sale of London
stock bricks to be used in refurbishment schemes and in the
repair of existing structures.
Brick masonry walls have exhibited excellent fire resistance
provided that any supporting structure maintains integrity for
the duration of the fire. In the absence of information from UK
Codes further guidance on performance in fire can be gained
from Edgell (1982) and de Vekey (2004).
14.2.1.2 Bricks and blocks
These are probably the earliest unit of industrialised construc-
tion dating back to about 1300 bc. Examples of that construction
