SWANSEA UNIVERSITY
EG-112 Introduction to Civil Engineering Materials
Professor Chenfeng Li
c.f.li@swansea.ac.uk
Faculty of Science and Engineering
Swansea University
Course Walk Through
❑ Reference: Construction Materials Their Nature
and Behaviour, 5th Edition, Marios Soutsos and Peter
Domone, CRC Press.
❑ Content
❖ Introduction
❖ Concrete
❖ Metals and Alloys
❖ Timber
❖ Masonry: Brickwork, Blockwork and
Stonework
❖ Bituminous Materials
❖ Glass
❖ Polymers
❖ Fibre Composites
2
Course Walk Through
❑ Canvas -> EG-112: lecture note, lecture and lab
recordings, quiz exercise, assignment, lab report,
announcement, and feedback……
❑ Lecture class: timetabled on-campus delivery; prerecorded lectures available on Canvas.
❑ Lab practice:
❖ In personal attendance in concrete and structural
labs.
❖ Video recordings available on Canvas
❑ Assessment: lab report 1 (10%), lab report 2 (10%),
Canvas test 1 (40%), Canvas test 2 (40%)
❑ Office hours: announced on Canvas.
❑ Offline communication: email and Canvas
announcement.
3
Concrete – Content
❑ Introduction
❑ Concrete Mix and Workability Testing
❑ Portland Cements
❑ Admixtures
❑ Additions
❑ Aggregates for Concrete
❑ Properties of Fresh Concrete
❑ Early Age Properties of Concrete
❑ Deformation of Concrete
❑ Strength and Failure of Concrete
❑ Non-Destructive Testing of Hardened Concrete
❑ Durability of Concrete
❑ Recycling of Concrete
4
Concrete – Aggregates
❑ HCP suffers from several drawbacks: high dimensional
changes, low modulus, high creep and shrinkage, and
cost. These disadvantages are overcome by adding
aggregates to the cement paste, thus producing
concrete. The objective is to use as much aggregate
as possible (about 65–80% of the total concrete cheap strong
sand= fine addregate
volume).
❑ Aggregates can be thought of as being inert fillers.
Size requirements:
❖ The largest possible aggregate size consistent with
the mixing, handling and placing requirements of
fresh concrete should be used.
❖ A continuous range of particle sizes from fine sand
up to coarse stones is desirable; this minimises the
void content of the aggregate mixture and therefore
the amount of HCP required, and helps the fresh
concrete to flow more easily.
5
Concrete – Aggregates
?
❑ Three general types of aggregates: primary, secondary, recycled.
industry Primary aggregates form by far the greatest proportion of those used.
They can either be obtained from natural sources, such as gravel deposits
and crushed rocks, or be specifically manufactured.
❑ Based on the density, aggregates can be divided into three groups.
Normal-density aggregates. Many different natural materials are used
for making concrete, including gravels, basalt, granite, limestone and
sandstone. All of the above rock types have relative densities of
approximately 2.55–2.75, and therefore all produce concretes with similar
densities, in the range 2250–2450 kg/m3. Lightweight aggregates are
used to produce lower density concretes, which are advantageous in
reducing the self-weight of structures and also have better thermal
insulation than normal-weight concrete. Where concrete
of high density is required, for example, in radiation
shielding, heavyweight aggregates can be used.
These may be from high-density ores such as barytes
and haematite, or manufactured, such as steel shot.
6
Concrete – Aggregates
❑ Aggregates are often classified as uncrushed with most particles
rounded or irregular and crushed with all particles sharp and angular.
More rounded particles will pack more efficiently and will therefore have a
lower voids content.
7
Concrete – Aggregates
❑ Based on the particle size, aggregates can be divided into two groups:
fine and course aggregates. The size threshold is 4mm, 5mm, 6mm or 8
mm depending on the country. In Europe, the size is described by
designation d/D, where d is the smallest nominal particle size and D the
nominal largest, such as: 0/4 is a fine aggregate with a maximum particle
of 4 mm (with the ‘0’ indicating a near zero lower size limit); 4/20 is a
coarse aggregate with a minimum particle size of 4mm and a maximum
particle size of 20mm. not %
use in lab report
❑ The distribution of particle sizes is also important both for classification
and for determining the optimum combination for a particular mix. To
determine this, a sieve analysis is carried out. In European practice, sieve
sizes ranges from 0.063 to 63mm, each sieve having approximately twice
the aperture size of the previous one, i.e. in the geometric progression
0.063, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32 and 63mm.
Some countries also use supplementary sizes in the
coarse aggregate range, e.g. 10, 20 and 37.5 (40)mm
in the UK.
8
Concrete – Aggregates
❑ Sieve analysis: the analysis starts with drying and weighing a
representative sample of the aggregate, and then passing this through a
stack or nest of the sieves, starting with that of the largest aperture. The
weights of aggregate retained on each sieve are then measured. These
are converted first to percentage retained and then to cumulative, i.e.
total, percent passing, which are then plotted against the sieve size to
give a grading curve or particle-size distribution.
cut
❑ Grading of aggregates (BS EN 12620)
9
Concrete – Aggregates
❑ During the process of mix design, the individual subdivisions or fractions
of aggregates are combined in proportions to give a suitable overall
grading for good concrete consistence and stability. Examples for
maximum coarse aggregates sizes of 10, 20 and 40mm are shown below
Overall aggregate grading
affect
❑ It is important that aggregates are clean and free from
impurities that would affect the fresh or hardened
properties of the concrete.
10
Concrete – Aggregates
absorb water?
rock
property
❑ All aggregates contain pores, which can absorb and hold water. Moisture
conditions (1) or (2) will absorb some of the mix water in mixed fresh
concrete, condition (4) will contribute water, and condition (3), saturated
surface dry, is most desirable for use in concrete mix.
add water, wait
(1) Completely dry,
all pores empty
(2) Air dry,
water
partially saturated
(3) Fully saturated
but surface dry
w2=wet aggragate
(4) Wet, inside
outside
excess water
w1=one
Absorption (% by weight) = 100(w2 - w1)/w1, where w1 is weight of a
sample of aggregate in the completely (oven) dry state and w2 is the
weight in the saturated surface dry state. The absorption is related to the
porosity of the aggregate particles. Most normal weight aggregates have
absorptions in the range 1–3%. It is necessary to allow
for the aggregate moisturecondition when calculating
the amount of water to be added during concrete mixing.
If the aggregate is drier than saturated surface dry, extra
water must be added. If it is wetter, then less mix water
is required.
11
Concrete – Aggregates
❑ Normal-weight aggregates are generally considerably stronger than the
HCP and therefore do not have a major influence on the strength of most
concretes. However, in high-strength concrete (with compressive
strengths in excess of, say, 80Mpa) careful aggregate selection is
important.
❑ The surface texture of the aggregate has a greater influence on the
flexural strength than on the compressive strength of the concrete,
probably because a rougher texture results in better adhesion to the HCP.
This adhesion is also greatly affected by the cleanliness of the surface –
which must therefore not be contaminated by mud, clay or other similar
crack between attracted layer
materials.
❑ The interface or transition zone between the aggregate surface and the
HCP has a major influence on the properties of concrete, particularly its
strength.
12
Concrete – Aggregates
❑ Manufacturing of aggregates
https://www.youtube.com/watch?v=cTwidiB15I8
13
Concrete – Content
❑ Introduction
❑ Concrete Mix and Workability Testing
❑ Portland Cements
❑ Admixtures
❑ Additions
❑ Aggregates for Concrete
pure water
❑ Properties of Fresh Concrete
❑ Early Age Properties of Concrete
❑ Deformation of Concrete
❑ Strength and Failure of Concrete
❑ Non-Destructive Testing of Hardened Concrete
❑ Durability of Concrete
❑ Recycling of Concrete
14
Concrete – Properties of Fresh Concrete
❑ The behaviour and treatment of the concrete during the period before
setting and during the first few days of hardening have a significant effect
on its long-term performance. The aim of practices is to produce a
homogeneous structure with minimum air voids as efficiently as
possible; it is also necessary to ensure that the concrete is stable
and achieves its full, mature properties.
❑ Fluidity. The concrete must be capable of being handled and flow into the
formwork and around any reinforcement, with the assistance of whatever
equipment is available.
❑ Compactability. All, or nearly all, of the air entrapped during mixing and
handling should be capable of being removed by the compacting system
being used, such as poker vibrators.
❑ Stability or cohesiveness. The concrete should remain
as a homogeneous uniform mass throughout. For
example, the mortar should not be so fluid that flows out
of or segregates from the coarse aggregate.
water, rock uniformly
seperate, located
15
Concrete – Properties of Fresh Concrete
❑ Fluidity and compactability, have
traditionally been combined into the
compact, need to be flow
general property called workability. But this has now been replaced by
the term consistence in some current standards. The definition of
workability / consistence is by no means straightforward:
x definetion
❖ ‘That property of freshly mixed concrete or mortar which determines
the ease and homogeneity with which it can be mixed, placed,
consolidated and finished’ (ACI, 1990)
❖ ‘That property determining the effort required to manipulate a freshly
mixed quantity of concrete with minimum loss of homogeneity’ (ASTM,
1993).
❑ By an increased water content, higher consistence concrete can be
reached, while a lower strength and/or durability will result if no other
changes to the mix are made. The use of plasticisers increase workability
and superplasticisers has therefore been a key factor
in the trend towards the use of higher-consistence
concrete in recent years.
16
Concrete – Properties of Fresh Concrete
❑ Rigorous measurement of the flow behaviour of any fluid is normally
carried out in a rheometer or viscometer. There is general agreement
that the behaviour of fresh paste, mortar and concrete all approximate
reasonably closely to the Bingham model. stress, flow
Flow only starts when the applied
shear stress reaches a yield
stress (𝜏_𝑦) sufficient to overcome
the interparticle interference
effects, and at higher stresses
the shear rate varies approximately
linearly with shear stress, whose
slope is the plastic viscosity (𝜇).
❑ A large number of simple but arbitrary tests have been
used over many years. These all measure only one
value, and are called single-point tests, e.g. slump flow
test, compacting factor test, flow table test, V-funnel test
etc. Details of these have been covered in the lab
description of “concrete mix and workability test”.
17
Concrete – Properties of Fresh Concrete
❑ Despite their limitations, single-point tests, particularly the slump test, the
flow table and slump-flow tests, are popular and in regular use, both for
specification and for compliance testing of the concrete after production.
❑ Lower values of yield stress (𝜏𝑦 ) and plastic viscosity (𝜇) indicate a more
flowable mix. Some of the more important effects of variation of mix
proportions and constituents on 𝜏𝑦 and 𝜇.
mainly
18
Concrete – Properties of Fresh Concrete
=workability
❑ The consistence of concrete continually decreases after it’s mixed.
Solutions:
❖ Absorption of water by the aggregate can be avoided by ensuring that
saturated aggregate is used, for example by spraying aggregate
stockpiles with water and keeping them covered in hot/dry weather.
❖ Evaporation of mix water can be reduced by keeping the concrete
covered during transport and handling as far as possible.
❖ The rate of loss of consistence can be reduced by continued
agitation of the concrete, for example, in a ready-mix truck, or
modified by admixtures, particularly retarders.
❖ Hot weather, the initial concrete temperature can be reduced by
cooling the constituents before mixing (adding
ice to the mix water is a common practice), and the
concrete can be transported in cooled or insulated
trucks.
19
undergroung to support building
Deep Foundation Construction and Defects
Mattressing
Inclusions
Channeling
bleeding
Segregation
not enough cemant
20
Deep Foundation Construction and Defects
Mattressing
Inclusions
Channelling
Segregation
21
Rheology of Fresh Concrete

Bingham Model:  =  + 0
0: yield stress
: viscotiy
Slope: 
0

0
Bingham model is widely accepted for cement-based
material: grout, paste, mortar and concrete.
1. Shear stress VS shear rate;
2. Properties: yield stress and viscosity.
22
Workability Tests
Space scale index
Slump flow test
Output: spread diameter
Time scale index
V-funnel test
Output: discharge time
23
Digital Twin of Workability Tests
𝜏0 = 40 𝑃𝑎
𝜇 = 100 𝑃𝑎 ∙ 𝑠
Digital twin of slump flow test
40
discharge time
Digital twin of V-funnel test
0 120 Pa
0 140 Pa
0 160 Pa
0 180 Pa
0 200 Pa
0 220 Pa
0 240 Pa
0 260 Pa
0 280 Pa
0 300 Pa
10
0 20 Pa
0 40 Pa
11 viscosity
0 60 Pa
20
0 80 Pa
0 100 Pa
10 yield stress
tn (s)
30
 100 Pas
 90 Pas
 80 Pas
 70 Pas
 60 Pas
 50 Pas
 40 Pas
 30 Pas
 20 Pas
 10 Pas
0
0.4
0.5
0.6
0.7
D (m)
0.8
diammiter
0.9
1.0
24
Workability to Rheology Conversion
40
0 120 Pa
0 140 Pa
0 160 Pa
0 180 Pa
0 200 Pa
0 220 Pa
0 240 Pa
0 260 Pa
0 280 Pa
0 300 Pa
10
0 20 Pa
0 40 Pa
0 60 Pa
20
D = 0.57 m
0 80 Pa
0 100 Pa
tn (s)
30
 100 Pas
 90 Pas
 80 Pas
 70 Pas
 60 Pas
 50 Pas
 40 Pas
 30 Pas
 20 Pas
 10 Pas
Slump flow test
0
0.4
0.5
0.6
0.7
D (m)
0.8
0.9
1.0
tn =12 s
Workability to Rheology Conversion
V-funnel test
25
Case Study - Diaphragm Wall
6m
Real Joints
6.1 m
1m
Geometry
Simplified Joints
26
Case Study - Diaphragm Wall
Cone outflow test
Slump flow test
property of concrete varied
800
S50
S40
Diameter (mm)
700
600
500
400
300
0
5
10
15
20
25
Flow Time (s)
Summary of Tests
On-site tests
27
Case Study - Diaphragm Wall
9 representative concretes
Concrete Mixes
CM1
CM2
CM3
CM4
CM5
CM6
CM7
CM8
CM9
Flow Time (s)
4
3.7
4.2
6
6.3
8.7
11.2
2
4
Diameter (mm)
470
520
630
400
550
550
480
500
750
Concrete Mixes
CM1
CM2
CM3
CM4
CM5
CM6
CM7
CM8
CM9
Viscosity (Pa·s)
120
120
160
120
200
240
250
60
160
Yield Stress (Pa)
200
110
60
350
80
80
150
130
40
28
Case Study - Diaphragm Wall
not consistence
9 Representative concretes in
middle section
9 Representative concretes on
surface
29
Case Study – Bored Pile
concrete flow
not work
Pile design && concrete placement
30
Case Study – Bored Pile
have reference, books ?
concrete flow
Velocity field
Flow History
31
Bored pile investigation
32
Bored pile investigation
33
Other Examples of Computer Simulation
34