Effects of the curing methods on the process of plastic shrinkage of self compacting concrete in Vietnam

Journal of Science and Technology in Civil Engineering NUCE 2018. 12 (5): 39–50

EFFECTS OF THE CURING METHODS ON THE PROCESS
OF PLASTIC SHRINKAGE OF SELF-COMPACTING
CONCRETE IN VIETNAM
Nguyen Hung Cuonga,∗, Luu Van Thuca , Tran Hong Haia , Pham Nguyen Van Phuonga
a

Faculty of Construction Economics and Management, National University of Civil Engineering,
55 Giai Phong road, Hai Ba Trung district, Hanoi, Vietnam
Article history:
Received 09 May 2018, Revised 06 August 2018, Accepted 24 August 2018

Abstract
This paper presents the experimental results of researching on plastic shrinkage (plastic deformation) and the
effect of curing methods on the process of plastic shrinkage at the early stages when self-compacting concrete
(SCC) starts setting and develops the strength. The experiments were carried out in two typical climatic conditions in Vietnam which are humid and dry. The experiments were conducted with two typical water/powder
ratios of 0.3 and 0.35 and four cases of curing methods which are nylon membrane, watering, no-curing and
soaking in water (the standard condition). Besides, the influences of plastic shrinkage at the early stages on
strength development and occurrence of surface cracking of SCC were also investigated. The conclusions were
drawn about the plastic deformation process and the curing method that might minimize plastic shrinkage of
SCC, control surface cracking early, and ensure the quality and strength of SCC in the hot and humid climatic
condition of Vietnam.
Keywords: plastic shrinkage; self-compacting concrete; hot and humid climate; hardening process.
/>
c 2018 National University of Civil Engineering

1. Introduction
Plastic shrinkage is a common physical process that takes place in the early stage when concrete
starts setting and hardening, especially for members with large exposed surfaces. Plastic shrinkage
process is also an important physical process that causes cracks in the early stage and directly affects

the development of concrete strength. According to [1], when the evaporation rate of water on the surface of the newly poured concrete is quicker than that of the excess water from the cement hydration,
the concrete surface will shrink. Due to the restraint of concrete under drying surfaces, tensile stress
develops in weak areas, which forms cracks. According to [2, 3], plastic shrinkage process occurs
because the water drainage out of the pore system causing negative pressure leads to the change of
cement volume while the concrete is not strong enough to resist the tensile stress induced by plastic
shrinkage.
According to [3, 4], physical processes occur immediately after concrete placement, which include: dehydration (evaporation), plastic deformation (plastic shrinkage), displacement and change of
water and vapor pressure in concrete, stress formation inside, cracking, capillary, pores in concrete.
These processes are interrelated, interdependent, and decisive to the initial structural formation of
concrete as well as to the physical-mechanical properties of concrete.
∗

Corresponding author. E-mail address: (Cuong, N. H.)

39


Cuong, N. H. et al. / Journal of Science and Technology in Civil Engineering

According to [5], when concrete is in a flexible state, the dehydration facilitates shrinkage deformation. In this state, the deformation does not lead to the formation of cracking concrete structures,
whereas the movement of aggregate particles makes concrete solid, porosity and pore size within concrete smaller. At the same time, the excessive water in concrete evaporates, which reduces the risk of
forming pores and capillary voids in concrete. According to [6], if the water evaporation of concrete
at the early stage of hardening is from 30% to 35% of the total, it will not adversely affect the structure and quality of concrete. If the dehydration happens quickly and massively, it will promote plastic
deformation to reach the maximum value quickly and to develop continuously during the subsequent
stages of concrete (solid phase). As a result, cracks in concrete members will be created.
According to [7], with remarkable advantages in terms of workability, quality and strength, selfcompacting concrete (SCC) has been widely used in the construction industry around the world and
applied in super high rise building projects in Vietnam. Due to being more effective in terms of
technology and economics, SCC is predicted as an indispensable trend in concrete construction in
Vietnam [8]. SCC is basically not much different from traditional concrete. However, the characteristics of less coarse aggregate content, powder increase (using fly ash and blast furnace) and specially
the use of more additives (in particular superplasticizers) make the hydration and hardening processes

of SCC much different from traditional concrete [4, 7].
According to [4], the self-compacting property of SCC is obtained by using fine fillers and low
water/powder ratio, minimizing coarse aggregate content and adding high superplasticizers. According to [9], the important factor affecting the processes of hydration and formation of cement structure
of SCC is the amount of water available in the mixture and the bond type of water with the solid phase
and new substances formed during the hydration. According to [10], the presence of fly ash improves
the microstructure of concrete, making it denser. Nevertheless, it also makes the microstructure grow
slower. Unresponsive fly ash particles contribute to the microstructure development of the cement
because it acts as super-fine aggregate in the cement paste.
There have been many studies relating to plastic shrinkage of SCC. According to [11], fillers do
not have much significant influence on autogenous shrinkage of SCC. Effect of additives on plastic
shrinkage is studied in [12]. Its finding shows that additives can reduce the risk of cracking due to
plastic shrinkage if shrinkage reducing additives or paraffin oil-based curing agent are used. Another
research points out that curing time is important in limiting plastic shrinkage at early ages, and the
total long-term shrinkage of cured concrete has higher than that of uncured concrete [13]. According
to [14], the cracking age depends on the water/powder ratio; fly ash and limestone powder increase
the cracking age of concrete; the shrinkage rate is greater when concrete is exposed to dry conditions;
and the longer curing time leads to a shorter cracking age. However, these studies were conducted
at climatic conditions different from that of Vietnam or in laboratories with temperature-humidity
conditions controlled.
Vietnam has a hot and humid climate. The means of relative humidity and temperature are normally high. The periods of sun and rain are cyclical and long. Many long hot cycles often happen
in the summer season for the North and Central, and in the rainy season for the South. During that
cycles, solar radiation can reach 500 kcal/m2 .hour to 900 kcal/m2 .hour, daytime temperatures can be
35◦ C to 50◦ C, and humidity can be low about 40% to 65%. Winter in the North and Central basically
has a dry climate with dry monsoon. The average temperature is normally low, about 15◦ C to 30◦ C.
The relative humidity is low, often from 40% to 65%. These characteristics speed up the process of
water evaporation. Additionally, the variations of temperature and humidity in the day are high, about
10◦ C to 15◦ C and 45% to 50% respectively [3, 15]. These adverse weather conditions may have great
40

tionplastic
and the
thedeformation
occurrence and
of early
early
cracks is
is also
also
analyzed.
Finally,
the
paper proposes
proposes
the occurrence
of early
cracksFinally,
is also the
analyzed.
Finally, the
tion
and
occurrence
of
cracks
analyzed.
paper
ive
curing
method

to
minimize
plastic
deformation
of
SCC
and
toanalyzed.
ensure
the
quality
ic
and
the
occurrence
of
cracks
isplastic
also
analyzed.
Finally,
the
paper
prop
plastic
deformation
and the
occurrence
of early
cracks

isand
alsoto
Finally,
the
pa
the
most
effective
curing
method
to
minimize
deformation
of SCC
and to
ens
ticdeformation
deformation
andto
the
occurrence
of early
early
cracks
is
also
analyzed.
Finally,
the
paper

propo
ve
curing
method
minimize
plastic
deformation
of
SCC
ensure
the
quality
most
effective
curing
method
to
minimize
plastic
deformation
of SCC
SCC and
and
to ensure
ensure
theensu
qu
SCCand
in the
the

Vietnamses
hot
and
humidtoclimate.
climate.
the
most
effective
curing
method
minimize
plastic
of SCC
and to
strength
of SCC
in the
Vietnamses
hot and
humiddeformation
climate.
most
effective
curing
method
to
minimize
plastic
deformation
of

to
the
qua
SCC
in
Vietnamses
hot
and
humid
strength
in
Vietnamses
hot
and
humid
climate.
and of
strength
ofthe
SCC
inN.the
Vietnamses
hotandand
humid
climate.
strength
ofSCC
SCCprocess
in
the

Vietnamses
and
humid
climate.
Cuong,
H. et al. / hot
Journal
of Science
Technology
in Civil Engineering
nd
experiment
2.
Materials
and
experiment
process
d experiment process
aterials
and
process
2. Materials
and
experiment
process
impacts
on the
water
evaporation
as well as the formation of internal structure of SCC.

Materials
andexperiment
experiment
processprocess
nd experiment
equipment
2.1
Materials
and
experiment
equipment
Currently,
there are no experimental studies on the plastic deformation process at the early hardnd experiment
equipment
Materials
and
experiment
2.1 Materials
and
equipment
Materials
and
experiment
equipment
ening
stages
of
SCCexperiment
inequipment
the hot humid

climate of cement
Vietnam. The
paperof
aims
i) to investigate
the plastic
used in the
experiments
include:
portland
PC40
Vincem
But
Son;
yellow
Materials
used
in
the
experiments
include:
portland
cement
PC40
ofyellow
Vincem B
used
in
the
experiments

include:
portland
cement
PC40
of
Vincem
But
Son;
deformation process in the early hardening stages of SCC and ii) to examine the effect of curing
Materials
used
in
the
experiments
include:
portland
cement
PC40
of
Vincem
But
Son;
ye
Materials
used
in
the
experiments
include:
portland

cement
PC40
of
Vincem
Bu
Materials
used
inmix
the
experiments
cement
PC40
of
Vincem
But
River
with
theRed
modulus
size
ofthe
2.76;
crushed
stone
with
the
maximum
diameter
of yell
sand

from
River
with
modulus
size
of 2.76;
crushed
stone
the
maximu
methods
and
design
on the
plastic
deformation
process.
The
correlation
between
thewith
plastic
de- Son;
River
with
the
modulus
size
of
2.76;

crushed
stone
with
the
maximum
diameter
of
3 the modulus
3crushed
from
Red
River
with
the
size
ofPha
stone
with
thethermal
maximum
diamete
sand
from
Red
River
with
size
2.76;
crushed
stone

with
the
maximum
dspecific
from
Red
River
with
the modulus
modulus
stone
with
the
maximum
diamete
gravity
of
2.67g/m
; offlyearly
ash
of
Lai
thermal
power
with
thethe
type
of
F with
formation

and
the
occurrence
cracks
is2.76;
also
analyzed.
Finally,
the
paper
proposes
most
10mm
and
the
specific
of
2.67g/m
;offly
ash
ofpower
Pha
Lai
power
3gravity
specific
gravity
of
2.67g/m
;

fly
ash
thermal
with
the
type
of
Fwith
3of Pha Lai
3
m
the
specific
gravity
2.67g/m
;2.67g/m
fly ash ;of
Lai
thermal
power
with
thethe
type
effective
curing
method
toof
minimize
plastic
deformation

of
SCC
and
tomodified
ensure
andon
strength
10mm
andASTM
theBiFi-HV298
specific
gravity
ofBiFi-HV298
fly
ash
of
Pha the
Laiquality
thermal
power
mm
and
the
specific
gravity
of
2.67g/m
Pha
Lai
thermal

power
with
the
type
M and
C618
standard;
superplasticizer
based
on
polymer
with
following
C618
standard;
superplasticizer
based
modified
poo
M
C618
standard;
BiFi-HV298
superplasticizer
based
on
modified
polymer
with
the

of
SCC
in
the
Vietnamese
hot
and
humid
climate.
wing
ASTM
C618
standard;
BiFi-HV298
based
on
modified
polymer
with
following
ASTM
BiFi-HV298
superplasticizer
based
onCuLminal
modified
poly
ASTM
C618
standard;

BiFi-HV298
based
on
modified
polymer
with
yowing
of specific
1.05
equivalent
toC618
the
Gstandard;
type following
ASTM
C-494
standard;
and
gravity
of
1.05G
equivalent
tosuperplasticizer
theASTM
G type
following
ASTM
C-494
standard;
of

1.05
equivalent
to
the
type
following
C-494
standard;
and
CuLminal
ific
gravity
of
1.05
equivalent
to
type
ASTM
C-494
standard;
and CuLm
CuLm
specific
gravity
of
1.05
equivalent
to
thefollowing
G (Fig.1).

type
following
ASTM
C-494 standard;
a
gravity
of
1.05modifying
equivalent
to the Gmodifying
ASTM
C-494
standard;
and
0cific
type
as 2.viscosity
admixture
(VMA)
with
MHPC400
type
as viscosity
admixture
(VMA)
(Fig.1).
Materialsmodifying
and
experiment
process

type
as
viscosity
admixture
(VMA)
(Fig.1).
type
modifying
admixtureadmixture
(VMA) (Fig.1).
(Fig.1).
with MHPC400
type as viscosity
modifying
(VMA) (Fig.1).
hMHPC400
MHPC400
type as
as viscosity
viscosity
modifying
riments were
conducted
with
two
water/powder
ratios
which
are 0.3ratios
and which

0.35. The
The
experiments
were
conducted
with
two
water/powder
are 0.3
2.1.
Materials
and experiment
equipment
riments
were
conducted
with
two
water/powder
ratios
which
are
0.3
and
0.35.
The
The
experiments
were
conducted

with
two
water/powder
ratios
which
are
0.3
and
0.35.
The
experiments
were
conducted
water/powder
ratios
which
are
0.3
and
0.35.
The
experiments
were
conducted
with
two
water/powder
ratios
which
are

0.3
ed inmix
the designs
experiments
are
chosen
based
onare
practical
experience
in Japan
andyellow
Europe
used
in
the
experiments
chosen
based
practical
in
JapaT
Materials
usedare
in the
experiments
include:
portland
cement
PC40on

of Vincem
But experience
Son;
ed
in
the
experiments
chosen
based
on
practical
experience
in
Japan
and
Europe
designs
used
inSociety
the
experiments
onand
practical
experience
in
and
Eur
designs
used
in

the
experiments
are
chosen
based
practical
experience
in Japan
Japan
and
Eu
mixJapan
designs
used
inthe
the
experiments
are
chosen
based
onEuropean
practical
experience
inofJapa
sand
from
Red
River
the
modulus

size of
crushed
stone
with
the
maximum
diameter
of
by
the
ofwith
Civil
Engineers
(JSCE)
the
Federation
recommended
by
Japan
Society
of2.76;
Civil
Engineers
(JSCE)
and
the
European
by
the
Japan

Society
of
Civil
Engineers
(JSCE)
and
the
European
Federation
of
3
ommended
by the
the the
Japan
Society
(JSCE)
and
the
European
Federation
mmended
Japan
Society
Civil
Engineers
(JSCE)
and
thewith
European

recommended
by
the
Japan
Society
Engineers
(JSCE)
and
the ofEuropean
F
10by
mm
and
specific
gravity
ofof
2.67
g/m
;of
fly Civil
ash of of
Pha
Lai thermal
power
the
type
FFederatio
ciations
Representing
producers

and
applicators
specialist
building
products
for
National
Associations
Representing
producers
and
applicators
of
specialist
buildin
iations
Representing
producers
and applicators
ofand
specialist
building
products
for
following
ASTM
C618
standard;
BiFi-HV298
superplasticizer

based
on modified
polymer
with theproducts
ional
Associations
Representing
applicators
of
specialist
building
onal
Associations
Representing
producers
and used
applicators
of
specialist
building
products
National
Associations
Representing
applicators
of
specialist
building
ARC).
The

theory
of
absolute
volume
isproducers
also
to C-494
determine
the
mix
designs
asthe
Concrete
(EFNARC).
The
theory
of
absolute
volume
is
also
used
to
determine
specific
gravity
of
1.05
equivalent
to

the
G
type
following
ASTM
standard;
and
CuLminal
with
ARC).
The theory
of absolute
isabsolute
also used
to determine
the mix
designs
as
creteConcrete
(EFNARC).
The
theory
ofvolume
absolute
volume
isvolume
also
used
to
determine

the
mix
designs
crete
(EFNARC).
The
theory
of
used
to
determine
the
mix
design
(EFNARC).
The
theory
of
is
also
used
to
determine
the m
. shown
MHPC400
type as viscosity modifying admixture (VMA) (Fig. 1).
in
Tab.1.
.

wnininshown
Tab.1.in Tab.1.
wn
Tab.1.

(a) Cement
ement Cement
a)
a) Cement
Cement
ement a)a)Cement

(d) Crushed stone

Fly ash
(c) Yellowc)
sand
b) Fly ashb)(b)Fly
sand
b)Fly
Flyash
ash c) Yellow
c)
Yellow
Fly
ash
Yellow
ashb)
c)sand
Yellowc)sand

sand
Yellow
b) Fly ashb)
c) Yellow

(e) Super-plasticizer

(f) VMA

Crushed
stone stone
e) Super-plasticizer
Super-plasticizer
hed d)
stone
e) Super-plasticizer
d)
Crushed
stone
e)Super-plasticizer
Super-plasticizer f) VMA f)f)VMA
VM
Crushed
e)
VMA f)f)VM
d) stone
Crushed
e)
hedd)
stone

e) Super-plasticizer
f)
VMA
Figure 1. Materials used in the experiments
Figure 1.
1. Figure
Materials
used
in
the
experiments
Figure 1. Materials
used in1.
experiments
1.the
Materials
used
theexperiments
experiments
Figure
Materials
used
in
the
experiments
Figure
Materials
used
ininthe
Figure

1.
Materials
used
in
the
experiments
The experiments
were1.
conducted
withdesign
two water/powder
ratiosexperiments
which are 0.3 and 0.35. The mix
Table
The
mix
used
in the
Table
mix1.design
used
inmix
the
Table
1.design
The
mix
design
used
the

experiments
Table
The
used
in the
experiments
Table
1.
The
design
used
ininthe
experiments
designs
used1.inThe
the
experiments
aremix
chosen
based
onexperiments
practical
experience
in Japan
and Europe recTable
1.
The
mix
design
used

in
the
experiments
ommended by the Japan
Society of Civil
(JSCE) and
the European SuperFederation of National
Cement
FlyEngineers
Stone
Cement
Fly
Stone
Super-Stone
Cement
Fly
Stone
SuperCement
Fly
Stone
SuperMix
design
Sand
VMA
Cement
Fly
SuperAssociations
Representing
producers
and

applicators
of
specialist
building
products
for Concrete
(EFgnMix design
Sand
VMA
Water Wa
Mix
design PC40
Sand
V
Sand
VMA
Wa
Cement
Fly
Stone
Superash
(0.5x1)
plasticizer
Sand
VM
ash volume
(0.5x1)
plasticizer
PC40
ash

(0.5x1)
plasticizer
ash
(0.5x1)
plasticizer
NARC).PC40
The theory ofPC40
absolute
is also used
to determine
the mix (0.5x1)
designs
as VMA
shown
in Table
1.
gn
Sand
Water
PC40
ash
plasticizer
PC40
ash
plasticizer (g)
(kg)
(kg) (0.5x1)
(kg)
(kg)
(g)

41
(kg)
(kg)
(kg)
(kg)
(kg) (kg
(kg)
(kg)
(kg)
(kg)(g) (g) (g)
(g)
(kg)
(kg)
(kg)
(kg) (g) (kg)
(g)
(k(
(kg)
(g
(kg)
(kg)
(kg)
(kg)
(g)
(g)
(kg)
Water/Powder=0.3
30.69
10.2
53.9

50.82
388.2
12.0
12.
er=0.3 Water/Powder=0.3
30.69
10.2 30.69
53.9
50.82
12.0 388.2
12.27 121
30.69
10.2 53.9
53.9388.250.82
50.82
388.2
Water/Powder=0.3
30.69
10.2
53.9
50.82
388.2
12.0
10.2
er=0.3
30.69
10.2
53.9
50.82
388.2 259.2

12.0
12.27 12.
Water/Powder
=0.35
27.6
9.45
53.9
50.82
12.0


Cuong, N. H. et al. / Journal of Science and Technology in Civil Engineering

Table 1. The mix design used in the experiments

Mix design
Water/Powder = 0.3
Water/Powder = 0.35

Cement
PC40
(kg)

Fly
ash
(kg)

30.69
27.6

10.2
9.45

(kg)

Stone
(0.5 × 1)
(kg)

Superplasticizer
(g)

53.9
53.9

50.82
50.82

388.2
259.2

Sand

VMA

Water

(g)

(kg)

12.0
12.0

12.27
12.99

The specimen size is 10 × 10 × 30 cm. The longest side (30 cm) is used to measure plastic deformation of SCC specimens.
2.2. Experiment conditions
The experiments were conducted in January and February in Vinh Tuy ward, Hai Ba Trung district, Hanoi, with the climatic conditions of the North of Vietnam.
2.3. Experiment process
After weighing in accordance with the mix design, the aggregates were added to the mixer and
mixed following the defined process and corresponding time in Table 2 and Fig. 2. The plastic deformation was measured by using two strain gauges with the graduation of 0.002 mm. These gauges were
placed at the both ends of the specimens. At each end, there was a 0.5 mm-thin steel plate with the
size of 9.5 cm × 9.5 cm. These plates were attached to the concrete by welding (Fig. 3). The steel plate
were embedded in the measurement form before placing concrete to make sure that its outer surface
is beyond the outer edge of the specimen. The tip of the probe is placed in contact with the outside
of the plate and adjusted to the center. When the concrete shrinks or expands, the steel plate moves
along with the movement of the probe. The measurement was done once per hour during the first 7
hours to 8 hours, and measured again at the 22nd to 24th hours since the time of concrete placement
to investigate plastic deformation at longer intervals.
Table 2. Concrete mixing process of the experiment

Step
1
2
3
4
5
6

Content
Adding 50% (water + additives) + 100% stone
Adding gradually (cement + powder), and mixing the materials evenly
Adding remaining materials (sand + water + additives), and mixing all
materials evenly
Stopping and waiting
Mixing again
Discharging the mixture

Time
1 minute
1.5 minutes
5 minutes
5 minutes
5 minutes

3. Experimental results
The experiments were conducted with two different mix designs and in two typical climate conditions which are humid condition and dry condition. Three experiments were carried out, including:
42


4

4

5

5

4 Stopping
and waiting
and waiting
Stopping
andStopping
waiting
5 5 Mixing
Mixing
again
Mixing
again
Mixing againagain

6

6

6 Discharging
Discharging
the the
mixture
6 Discharging
Discharging
mixture
the mixture
the mixture

5 minutes
5 minutes
5 minutes

5 5minutes
minutes
5 minutes
5 minutes

Cuong, N. H. et al. / Journal of Science and Technology in Civil Engineering

(a) Adding aggregates
(b) Adding additives
Mixing
(d) Discharging plastic
Adding
b) Adding
plastic
a) Adding
b) Adding
additives
c)(c)Mixing
d) Discharging
plasticplastic
a) aggregates
Adding
aggregates
b) Adding
additivesc) Mixing
c) Mixingd) Discharging
d)
Discharging
a)aggregates
Adding

aggregates
b) additives
Adding
additives
c) Mixing
d)
Discharging
concrete
concrete
concrete plastic
concrete
concrete
measured by using two strain gauges with the graduation of 0.002mm. These gauges were placed at
the both ends of the specimens. At each end, there was a 0.5mm-thin steel plate with the size of
9.5x9.5cm. These plates were attached to the concrete by welding (Fig.2). The steel plate were
embedded in the measurement form before placing concrete to make sure that its outer surface is
beyond the outer edge of the specimen. The tip of the probe is placed in contact with the outside of
Spreading
plastic
(f) Curing
(g) Removing the form
(h) Installing
gauges and
e)
Spreading
plastic
h) Installing
gauges
e) Spreading
plastic

h)
gauges
e) (e)
Spreading
plastic
h) Installing
Installing
gauges
the
plate
and adjusted
to the center. When the concrete shrinks or expands, the
plate
moves
along
e) Spreading
plastic
h) steel
Installing
gauges
concrete into the
measuring plastic
concrete
into
the
f) Curing
g) Removing
the the
form
andand

measuring
plastic
concrete
into
the
f)
Curing
g)
Removing
form
measuring
plastic
concrete
into
the
f)
Curing
g)
Removing
the
form
and
measuring
plastic
with into
themeasurement
movement
of the probe.
The measurement
was done once

per hourand
during
the first plastic
7÷8 hours,
concrete
the
f) Curing
g) Removing
the form
measuring
form
deformation
measurement
form
deformation
measurement
form
deformation
measurement
deformation
and measured
at the 22nd -24th hours since the time of concrete placementdeformation
to investigate
plastic
measurement
form againform
Figure
2.
The
mixing

process
and
the
measurement
of
plastic
deformation
of
SCC
specimens
Figure
3. The
process
and the
measurement
of plastic
deformation
of SCC
specimens
Figure
3.mixing
The
mixing
process
andand
thethe
measurement
ofofplastic
deformation
of

specimens
Figure
The
mixing
process
measurement
plastic
deformation
of SCC
specimens
deformation
at3.longer
intervals.
Figure 3. The mixing process and the measurement of plastic deformation of SCC specimens
. Experimental
results
3. Experimental
results
3. Experimental
results

Experimental results

The experiments
were were
conducted
with with
two
different
mixmix

designs
andand
in two
typical
climate
The The
experiments
conducted
two
in
typical
climate
experiments
were
conducted
with
twodifferent
different
mixdesigns
designs
and
in two
typical
climate
The
experiments
were
conducted
with
two

different
mix
designs
and
in
two
typical
climate
onditions
which
are
humid
condition
and
dry
condition.
Three
experiments
were
carried
out,
conditions
which
are are
humid
condition
carried
out,
conditions
which

humid
conditionand
anddry
drycondition.
condition.Three
Three experiments
experiments were carried
out,
ncluding:
Experiment
1
with
the
water/power
ratio
of
0.35
in
humid
condition;
Experiment
2
with
onditions
which
are
humid
condition
and
dry

condition.
Three
experiments
were
carried
out,
including:
Experiment
1
with
the
water/power
ratio
of
0.35
in
humid
condition;
Experiment
2
with
including: Experiment 1 with the water/power ratio of 0.35 in humid condition; Experiment 2 with
he water/power
ratio 1of
0.3ofin
humid
condition;
Experiment
3 with
the water/power

ratio
0.35
in in
ncluding:
Experiment
with
ratio
of 0.35
in humid
Experiment
2 of
with
the water/power
ratio
0.3
in humid
condition;
Experiment
33condition;
with
ratio
of
0.35
the water/power
ratiothe
ofwater/power
0.3
in humid
condition;
Experiment

withthe
thewater/power
water/power
ratio
of
0.35
in
ry water/power
condition.
Three
curing
werewere
carried
out for 3each
experiment
to examine
effect
of of
he
ratio Three
of
0.3
inmethods
humid
condition;
Experiment
with
theexperiment
water/power
ofthe

0.35
ineffect
dry condition.
curing
methods
carried
examine
the
effect
dry condition.
Three
curing
methods
were
carriedout
outfor
foreach
each
experiment to
toratio
examine
the
of
uring
method
on plastic
deformation
of
at the
early

hardening
stages,
curing
method
on plastic
deformation
process
of
stages,
including:
no
ry
condition.
Three
curing
wereprocess
carried
outSCC
for
each
to
examine
the including:
effect
of nono
curing
method
on methods
plastic
deformation

process
ofSCC
SCCatexperiment
atthe
theearly
earlyhardening
hardening
stages,
including:
uringcuring
- KBD- KBD
(free evaporation
of water
under
the influence
of the
natural
environment);
watering
- (free
evaporation
of
water
under
the
influence
of
the
natural
environment);

watering
uring method
on- plastic
deformation
process
of SCC
early hardening
stages,
including: watering
no
curing
KBD (free
evaporation
of water
under at
thethe
influence
of the natural
environment);
N (watering the specimens every one hour), nylon membrane - BNL (dry curing method, covering
TN
(watering
the
specimens
every
one
hour),
nylon
membrane
BNL

(dry
curing
method,
covering
TN (free
(watering
the specimens
every
onethe
hour),
nylon of
membrane
- BNL
(dry curing watering
method, covering
uring - KBD
evaporation
of water
under
influence
the natural
environment);
he specimen surfaces by nylon to minimize the water evaporation). At the same time, the plastic
the
specimen
surfaces
by
nylon
to
minimize

the
water
evaporation).
At
the
same
time,
the
plastic
specimen
surfaces
nylon
to minimize
the water
At the
same
the plastic
N (watering
the
specimens
every
one
hour),
nylon
- evaporation).
BNL (dry
method,
covering
oncrete
ofthe

mixing
batches
wasby
also
collected
for membrane
making
specimens
thatcuring
were
used
fortime,
compression
concrete
of mixing
was
also
collected
forfor
making
specimens
that
were
used
compression
concrete
of mixing
batches
was
also

collected
makingand
specimens
that
were
used
for
compression
he
surfaces
by batches
nylon
to
minimize
the
water
evaporation).
At the
same
time,
thefor
plastic
est specimen
in order
to determine
the
effect
the
curing
method

plastic
shrinkage
on
the
strength
1 -to
Measurement
platform;
2of
- Soffit
of
the
formwork;
33-- Steel
plates;
4 -4Concrete
specimen;
1- Measurement
platform;
2soffit
of
the
formwork;
steel
plates;
concrete
specimen;
5-strength
test test
in

order
determine
the
effect
of
the
curing
method
and
plastic
shrinkage
on
the
strength
inSCC.
order
to determine
the5 effect
ofmaking
the 6curing
method
andwere
plastic
shrinkage
on the
oncrete
of mixing
batches
was also collected
for

specimens
that
used
for
compression
Strain
gauges;
Nylon
membrane
evelopment
of
strain
gauges;
6nylon
membrane
development
of SCC.
development
of SCC.
st inThe
order
to determine
the effect
of3. the
curing
method deformation
and plastic
shrinkage
on the
strength to a

Figure
Measurement
of plastic
of SCC
concrete
were mixed
according
to
the process
stated
in Section
2.3, then
discharged
Figure
2. Measurement
of
plastic
deformation
of
SCC
The
concrete
were
mixed
according
to
the
process
stated
in

Section
2.3,
then
discharged to
to a
evelopment
of SCC.
The concrete
mixed according
to the process
stated
Section
2.3, then
discharged
ucket, and poured
into the were
measurement
form. Every
one hour,
theindata
of plastic
shrinkage
were a
Table
2. Concrete mixing
process
ofone
the
experiment
bucket,

and and
poured
intointo
the the
measurement
form.
Every
one
hour,
the
of
shrinkage were
were
bucket,
poured
form.
Every
hour,
thedata
data
of plastic
plastic
shrinkage
ecorded
until
the were
22nd
hour
after
themeasurement

concrete
placement.
The
experiment
results
were
recorded
in
The
concrete
mixed
to
the
process
stated
in
Section
2.3,
then
discharged
to
a
ndthendaccording
Experiment
1
with
water/power
ratio
of
0.35

in
humid
condition;
Experiment
2
with
the
warecorded
untiluntil
the the
22 22hour
after
thethe
concrete
placement.
The
experiment
results
were
recordedinin
recorded
hour
after
concrete
placement.
The
experiment
results
were
recorded

he
table
form,
and
were
analyzed
and
presented
in
graph
diagrams.
Step into
Content
Time
ter/power
ratio
ofwere
0.3
in
humid condition;
Experiment
3 with
the data
water/power
ratioshrinkage
of 0.35
inwere
dry
ucket,the
and

poured
measurement
form.
Every
one
hour,
the
of plastic
table
form,
andthe
analyzed
and
presented
inin
graph
diagrams.
the
table
form,
and
were
analyzed
and
presented
graph
diagrams.
nd
condition.
Three

curing
methods
were carried
out for each
to examine
effect
of curingin
.1. Experiment
ecorded
until
the
hour
after50%
the(water
concrete
placement.
Theexperiment
experiment
results the
were
recorded
1 1:22
Adding
+ additives)
+the
100%
stone
1 no
minute
3.1. Experiment

1:
method
on
plastic
deformation
process
of
SCC
at
early
hardening
stages,
including:
curing
3.1.
Experiment
1:was conducted
he table
form,
and were analyzed
and presented
inthgraph
diagrams.
The
1st
experiment
on 20
January
2018.
The

weather
was
humid,
-The
KBD
(free
evaporation
of
water
under
the
influence
of
the
natural
environment);
watering
- drizzling,
TNdrizzling,
th
Adding gradually
(cementon
+ powder),
and mixing
the weather was humid,
th
1st
experiment
was
conducted

20
January
2018.
The
2
1.5
minutes
The
1st
experiment
was
conducted
on
20
January
2018.
The
weather
was
humid,
og and cool
with
gentle
windy.
The
concrete
after
mixing
with
the

water/power
ratio
of
0.35
was
(watering
the specimens
every
one hour), nylon membrane - BNL (dry curing method, covering thedrizzling,
materials
evenly
1. Experiment
1: with
and
cool
gentle
windy.
The
concrete
after
mixing
with
the
water/power
ratio
of 0.35
0.35
was
fog
and

cool
with
gentle
windy.
The
concrete
after
mixing
with
the
water/power
ratio
of
was
ouredfog
into
the
measurement
form
at
10:15am
and
since
1:15pm
the
concrete
began
to
shrink.
specimen surfaces by nylon to minimize the

water evaporation). At the same time, the plastic concrete The
th
remaining
materials
(sand
+2018.
water+
additives),
poured
into
themeasured
measurement
form
at 10:15am
and
since
1:15pm
the
concrete
began
to shrink.
shrink.
The
1st
experiment
was
on
2010:15am
January
weather

was
humid,
drizzling,
lasticThe
deformation
from
the
gauges
was
converted
to
the
unit
type
of
millimeter
per one
poured
theAdding
measurement
form
at
and
sinceThe
1:15pm
theand
concrete
began
to
The

of mixing
wasconducted
also collected
for
making
specimens
that
were
used
for compression
test in
3 intobatches
5 minutes
mixing
all
materials
evenly
plastic
deformation
measured
from
theshown
gauges
was
totothe
type
per one
one
meter
incool

concrete
length.
The
results
were
in
Fig.4.
og and
with
gentle
windy.
Theof
concrete
after
mixing
with
the water/power
ratioof
ofmillimeter
0.35 wasper
plastic
from
the
gauges
wasconverted
converted
the
unitstrength
type
ofdevelopment

millimeter
order
todeformation
determine
themeasured
effect
the
curing
method
and
plastic
shrinkage
onunit
the
inSCC.
length.
The
were
shown
of
4concrete
Stopping
and
waiting
minutes
in concrete
length.
The
results
were

shown
inFig.4.
Fig.4.the concrete began to 5shrink.
ouredmeter
intometer
the
measurement
form
atresults
10:15am
and
sincein1:15pm
The

lastic deformation
measured
the gauges was converted to the unit type of millimeter
per one
5
Mixingfrom
again
5 minutes
43
meter in concrete
The results the
were
shown in Fig.4.
6 length.Discharging
mixture

Cuong, N. H. et al. / Journal of Science and Technology in Civil Engineering

The concrete were mixed according to the process stated in Section 2.3, then discharged to a
bucket, and poured into the measurement form. Every one hour, the data of plastic shrinkage were
recorded until the 22nd hour after the concrete placement. The experiment results were recorded in
the table form, and were analyzed and presented in graph diagrams.
3.1. Experiment 1
The 1st experiment was conducted on 20th January 2018. The weather was humid, drizzling, fog
and cool with gentle windy. The concrete after mixing with the water/power ratio of 0.35 was poured
into the measurement form at 10:15 AM and since 1:15 PM the concrete began to shrink. The plastic
deformation measured from the gauges was converted to the unit type of millimeter per one meter in
concrete length. The results were shown in Fig. 4.
Shrinkage Deformation
(mm/m)
0.00
0
2
4
-0.20

Time
(h)

6

8

10

12

14

16

18

Humidity
100

Temp
29.0

20

28.0

90

27.0

80
70

26.0

-0.40

60

25.0

50

-0.60

24.0

-0.80

40

23.0

30

22.0

-1.00

20
Temperature

21.0

-1.20
No-Curing

wrapping by nylon memberance

Humidity

10

20.0

Watering

8

(a) Shrinkage deformation

9

10

11

12

13

14

15

16

17

0
18
(h)

(b) Weather conditions

Figure 4. Plastic deformation of SCC specimens for different curing method – Experiment 1

The results show that with the three curing methods, plastic deformation of SCC took place mainly
in the first 4 hours to 5 hours after the concrete was mixed. This deformation process then continued
but at a slower rate; and it seems to be negligible. Therefore, the plastic deformation process might
be considered to finish within the first 4 hours to 5 hours (Fig. 4). Plastic shrinkage occurred in the
specimens in the cases of using nylon membrane and watering were not much different. This could be
explained that the humid and cool conditions produce a humid temperature environment which slows
the rate of water evaporation down and limits plastic deformation.
Samples cured with nylon membrane method were the smallest in plastic deformation, while
those cured with watering method appear as the second smallest in plastic deformation. The largest
deformation occurred in the no-curing specimens. At 5:15 PM, four hours passed from the beginning
of plastic shrinkage, the deformation in the case of nylon membrane was 0.29 mm/m, while that in
the case of watering and no-curing were 0.38 mm/m and 0.88 mm/m, respectively (Fig. 4). These
values indicated that the nylon membrane method provided the best humid temperature conditions for
the water evaporation at the early stages, better than natural humid conditions. As a result, with the
climatic conditions and mix design of the 1st experiment, the curing method of nylon membrane is
the most effective in reducing plastic deformation at the early hardening stages of SCC.
3.2. Experiment 2
The 2nd experiment was conducted on 21st January 2018. The weather was humid, drizzling, fog
and cool with gentle windy. The concrete after mixing with the water/power ratio of 0.3 was poured
44

Cuong, N. H. et al. / Journal of Science and Technology in Civil Engineering

into the measurement form at 10:30 AM. Two hours later, at 12:30 PM, the concrete began to shrink.
The results were shown in Fig. 5.
The results show that with the three curing methods, plastic deformation of SCC took place mainly
in the first 5 hours to 6 hours after the concrete was mixed. Therefore, with the water/powder ratio of
0.3, the plastic deformation process might be considered to be finished within the first 5 hours to 6
hours (Fig. 5), later than that with the water/powder ratio of 0.35. Similar to the previous experiment,
samples cured with nylon membrane method were the smallest in plastic deformation, while those
cured with watering method appear as the second smallest. The largest plastic deformation occurred
in the non-curing specimens. At 5:30 PM, five hours after the concrete started to contract, the plastic
deformation of the specimens cured by nylon membrane was 0.23 mm/m while that cured by watering
was 0.66 mm/m. The largest deformation of 1.11 mm/m was happened at the no-curing specimens
(Fig. 5). Therefore, with the climatic conditions and mix design of the 2nd experiment, the curing
method of nylon membrane is still the most effective in reducing plastic deformation at the early
hardening stages of SCC. There was an obvious trend that the higher the water/powder ratio of SCC
is, the longer the plastic deformation process takes.
Shrinkage Deformation
(mm/m)

0

0

2

4

6

8

10

12

14

16

18

20

Time
(h)

Humidity

Temp

22

-0.2
-0.4

-0.6
-0.8

-1
-1.2

31.0

90

30.0

80

29.0

70

28.0

60

27.0

50

26.0

40

25.0

30

24.0

-1.4

23.0

-1.6

22.0

No-Curing

Watering

wrapping by nylon memberance

20
Temperature
8

9

10

(a) Shrinkage deformation

11

12

13

14

Humidity
15

16

10

17

0
18
(h)

(b) Weather conditions

Figure 5. Plastic deformation of SCC specimens for different curing method – Experiment 2

Shrinkage Deformation
(mm/m)
0
2
4
6
0

8

10

12

14

16

18

Time
(h)
20
22

-0.5
-1
-1.5
-2
-2.5
-3
No-Curing

wrapping by nylon memberance

Humidity
90

Temp
35.0
33.0
31.0
29.0
27.0
25.0
23.0
21.0
19.0
17.0
15.0

Watering

80

70
60
50
40
30
20

Temperature
Humidity

10

0

8

9

10

11

12

13

14

15

16

17

18
(h)

(a) Shrinkage deformation

(b) Weather conditions

Figure 6. Plastic deformation of SCC specimens for different curing methods – Experiment 3

45

non-curing specimens. At 5:30pm, six hours after the concrete started to contract, the plastic
deformation
of theAtspecimens
cured
by after
nylonthe
membrane
1.45mm/m
while
of the
non-curing
specimens.
5:30pm, six
hours
concrete was
started
to contract,
the that
plastic
deformation
the by
specimens
by nylon The
membrane
was 1.45mm/m
while that
the
specimensofcured

watering cured
was 2.00mm/m.
largest deformation
of 2.45mm/m
wasof
accounted
Cuong,
N.
H.
et
al.
/
Journal
of
Science
and
Technology
in
Civil
Engineering
specimens
by watering
was (Fig.6).
2.00mm/m.
The largest
of humid
2.45mm/m
was accounted
for thecured
no-curing

specimens
Therefore,
underdeformation
thermal and
conditions
and the mix
rd
for the
no-curing
(Fig.6).
underofthermal
and humid isconditions
and the
mix in
design
of the specimens
3 experiment,
theTherefore,
curing method
nylon membrane
still the most
effective
3.3.
Experiment
3
rd
design
of the plastic
3 experiment,
method

nylonthe
membrane
is still the
most effective
in
th of after
reducing
deformation
atcuring
the early
hardening
SCC.
non-curing
Atthe
5:30pm,
six
hours
concrete
the plastic
The 3rdspecimens.
experiment
was
conducted
on
04
Februarystages
2018. of
The
weatherstarted
was dryto

andcontract,
light sunshine
non-curing
specimens.
At
5:30pm,
six
hours
after
the
concrete
started
to
contract,
the
plastic
reducing
plastic
deformation
at
the
early
hardening
stages
of
SCC.
deformation
of theThe
specimens
cured

by with
nylon
membrane
was of
1.45mm/m
whileinto
that
the
withThe
gentle
windy.
concrete
after
mixing
the
water/power
ratio
0.35
was
poured
the of and
of watering
three
experiments
showed
that
despite
differences
in
climatic

conditions
deformation
ofresults
the specimens
cured
by nylon
membrane
was
1.45mm/m
while that
of
the
specimens
cured
by
was
2.00mm/m.
The
largest
deformation
of
2.45mm/m
was
accounted
measurement
form
at 10:30
AM. At showed
11:30 AM,
thedespite

concretedifferences
began to shrink.
The results
are shownand
The
results
of
three
experiments
that
climatic
conditions
specimens
cured
watering
was (Fig.6).
2.00mm/m.
The
largest
deformation
ofin
2.45mm/m
was
accounted
concrete
mixby
designs,
curing
by nylonTherefore,
membrane

is the
most effective
method
to
minimize
plastic
forinthe
no-curing
specimens
under
thermal
and
humid
conditions
and the
mix
Fig.
6.
concrete
mix
designs,
curing
by
nylon
membrane
is
the
most
effective
method

to
minimize
plastic
for
the
no-curing
specimens
(Fig.6).
Therefore,
under
thermal
and
humid
conditions
and
the
mix
rd
deformation
in
the
early
hardening
stages.
Due
to
the
ability
to
limit

plastic
deformation,
curing
by
design
of
the
3
experiment,
the
curing
method
of
nylon
membrane
is
still
the
most
effective
in
With rd
all three curing cases, the plastic deformations of SCC took place mainly in the first 6 hours
design
of thein
3theexperiment,
theatcuring
method
of nylon
membrane

is stilldeformation,
the most effective
in
deformation
early
hardening
stages.
Due
to
the
ability
to
limit
plastic
curing
by
st
nd
reducing
plastic
deformation
the
early
hardening
stages
of
SCC.
using
membrane
also controls

surface
when
to curing
by 1watering
to plastic
7nylon
hoursdeformation
after the concrete
was
mixed,
longercracking
than
thatof
inSCC.
thecompared
humid conditions
of the
and 2 or nonreducing
at the
early
hardening
stages
using nylon
membrane
also
controls
surface
cracking
when
compared

to
curing
by
watering
or nonexperiments.
Therefore,
under
dry conditions,
theother
plastic
deformation
was the
considered
to becured
finished
curing
(Fig.7).
In of
addition,
different
from
two
methods,
specimens
by nylon
The
results
three
experiments
showed

that curing
despite
differences
in
climatic
conditions
and
The
results
of
three
experiments
showed
that curing
despite
differences
climatic
conditions
and
curing
(Fig.7).
In
addition,
different
from
two
other
methods,
the in
specimens

cured
by nylon
within
6
hours
to
7
hours
after
concrete
placement.
The
plastic
deformation
process
still
continued
concrete
mix
designs,
curing
by
nylon
membrane
is
the
most
effective
method
to

minimize
plastic
membrane
did not curing
show any
white efflorescence
on
surface.
Therefore,
it might
consider that
curing
concrete
mix
designs,
by
nylon
membrane
theplastic
most
effective
to minimize
plastic
membrane
did
not
show
any white
efflorescence
onisto

surface.
Therefore,
itmethod
might
consider
that
curing
after
that
but
at
a
slower
rate
(Fig.
6).
The
smallest
deformation
happened
in
the
case
of
deformation
in
the
early
hardening
stages.

Due
the
ability
to
limit
plastic
deformation,
curing
by nyloninmembrane
also helps in
controlling
efflorescence
on
concrete
surface. curing by by
deformation
early
hardening
stages.
Due
towhite
the
ability
to limit
plastic
deformation,
by nylon
membrane
also
helps

controlling
white
efflorescence
on concrete
curing
bythe
nylon
membrane
the second
was
watering.
The
largest
plastic
deformation
occurredor nonusing
nylon
membrane
alsoinwhile
controls
surface
cracking
when
compared
to surface.
curing
by watering
using nylon membrane also controls surface cracking when compared to curing by watering or nonin the
non-curing
specimens.

At 5:30
hours
after
the concrete
tospecimens
contract,
the
plastic
curing
(Fig.7).
Inbeing
addition,
different
from
two
other
curing
methods,
cured
byplastic
nylon
Although
smaller
thanPM,
thesix
plastic
deformation
instarted
thethecase
of no-curing,

curingAlthough
(Fig.7). Inbeing
addition,
different
other
curing methods,
specimens
cured byplastic
nylon
smaller
thanfrom
the two
plastic
deformation
in thethecase
of no-curing,
membrane
didof
not
any white
on
surface.
itthat
might
deformation
theshow
specimens
cured efflorescence
byby
nylon

membrane
was
1.45Therefore,
mm/mthan
while
that when
of consider
the specimens
deformation
curing
watering
was
much
larger
curingthat
by curing
nylon
membrane
did
nothappened
showwhen
anywhen
white
efflorescence
on
surface.
Therefore,
itthat
might
consider

curing
deformation
happened
curing
watering
was
much
larger
than
when
curingthat
by
nylon
by cured
nylonby
membrane
also2.00
helps
inby
controlling
white
efflorescence
on
concrete
surface.
watering
was
mm/m.
The
largest

deformation
of
2.45
mm/m
was
accounted
for
the
membrane.
According
to in
[2,12],
in hot
weather
conditions
solar radiation,
watering
by nylon
membrane
also helps
controlling
white
efflorescence
onwith
concrete
surface.
membrane.
According
to (Fig.
[2,12],

in hot
weather
conditions
with
highhigh
solar
watering
no-curing
specimens
6). Therefore,
under
thermal
and humid
conditions
andradiation,
the
mix
design
of plastic
Although
being
smaller
than
the
plastic
deformation
in
the
case
of

no-curing,
method
not
effective
even
it result
canthe
result
in reduction
ofconcrete
the the
concrete
quality.
Many
research
results
rdis effective
Although
being
smaller
than
deformation
the
case
of no-curing,
plastic
method
is 3not
even
it can

inplastic
reduction
of the
quality.
Many
research
results
the
experiment,
the curing
membrane
still in
most
effective
reducing
plastic
deformation
happened
when method
curing of
bynylon
watering
was is
much
larger
than
thatinwhen
curing
by nylon
deformation

happened
when
curing
bystages
watering
was
much
largerof
than
curing
by
nylon
that
under
the
effect
of periodic
watering,
the
temperature
ofthat
water
is much
lower
than
deformation
at the
early
hardening
of SCC.

showshow
that
under
the
effect
of
periodic
watering,
the temperature
water
iswhen
much
lower
than
the the
membrane.
According
to
[2,12],
in
hot
weather
conditions
with
high
solar
radiation,
watering
membrane.
According

to
[2,12],
in
hot
weather
conditions
with
high
solar
radiation,
watering
temperature
ofeffective
the
heated
surface,
which
leads
to
a continuous
heat
pulse
with
the research
deviation
The
of three
experiments
showed
that

differences
in
climatic
conditions
and contemperature
ofresults
the
heated
surface,
which
leads
to
adespite
continuous
pulse
with
the
deviation
up results
toup to
method
not
it result
can result
in
reduction
of
the heat
concrete
quality.

Many
method
is notiseffective
eveneven
it can
in reduction
of the
concrete
quality.
Many
research
results
cretethat
mixThis
designs,
byadversely
nylon
membrane
is the
most
effective
method
to minimize
plastic
defor- of the
30÷50C.
problem
might
adversely
affect

the
structure
physical-mechanical
properties
of
show
under
thecuring
effect
of
periodic
watering,
the
temperature
of water
is much
lower
30÷50C.
problem
might
affect
the
structure
and and
physical-mechanical
properties
show
that This
under
the effect

of periodic
watering,
the
temperature
of water
is much
lower
thanthan
the
mation
in
the
early
hardening
stages.
Due
to
the
ability
to
limit
plastic
deformation,
curing
by
using
of heated
the heated
surface,
which

a continuous
the deviation
up to
SCC. of the
SCC.temperature
temperature
surface,
which
leadsleads
to a to
continuous
heat heat
pulsepulse
withwith
the deviation
up to
nylon membrane
also controls
surface
cracking
when
to curing
by watering or non-curing
30÷50C.
problem
might
adversely
affect
thecompared
structure

physical-mechanical
properties
30÷50C.
This This
problem
might
adversely
affect
the structure
and and
physical-mechanical
properties
of of
Generally,
curing
by
nylon
membrane
is
the
most
effective
method
to ensure
the
quality
of
(Fig.
7).
In

addition,
different
from
two
other
curing
methods,
the
specimens
cured
by the
nylon
memGenerally,
curing
by
nylon
membrane
is
the
most
effective
method
to
ensure
quality
of
SCC.
SCC.
brane
did

not
show
any
white
efflorescence
on
surface.
Therefore,
it
might
consider
that
curing
by
surface.
SCCSCC
surface.
Generally,
curing
by nylon
membrane
is most
the most
effective
method
to ensure
the quality
Generally,
curing
byhelps

nylon
is the
effective
method
to ensure
the quality
of of
nylon
membrane
also
in membrane
controlling
white
efflorescence
on concrete
surface.
surface.
SCC
surface.
a) SCC
b)
a)
b)
a)

a)

c)
c)

c)
c)

(a) No-curing

b)

b)

d)
d)

d)
d)

(b) Wrapping by nylon membrane

(c)Figure
WhiteFigure
efflorescence-cured
bycracking
watering
(d)curing
Watering
7: Surface
cracking
and white
efflorescence
in the
cases

7: Surface
and white
efflorescence
in
the
curing
cases

Figure
7:b)Surface
cracking
and
white
efflorescence
inefflorescence-cured
theefflorescence-cured
curing cases by watering;
a) No
curing;
Wrapping
by nylon
membrane;
c) White
a)–No
– curing;
by
nylon
membrane;
c) White
Figure

7.Wrapping
Surfacecracking
cracking
and
efflorescence
in the curing
Figure
7:b)Surface
and
white
efflorescence
in
the cases
curing cases by watering;
d)white
Watering
d)
Watering
a) No – curing; b) Wrapping by nylon membrane; c) White efflorescence-cured by watering;
4. The
effect
conditions
andplastic
curing
plastic
deformation
of SCC
a)ofNoclimatic
– being
curing;

b)conditions
Wrapping
by
nylon
membrane;
c)on
White
efflorescence-cured
by SCC
watering;
4. The
effect
of
climatic
and
curing
methods
the
plastic
deformation
of
Although
smaller
than the
deformation
inon
thethe
case
of no-curing,
plastic deformation

d)methods
Watering

d)and
Watering
To
assess
the
effect
of by
climatic
conditions
curing
methods
the
deformation
of of
happened
when
curing
watering
was
muchand
larger
than
that methods
whenon
curing
by nylon
membrane.

To of
assess
the
effect
of
climatic
conditions
curing
on plastic
the
plastic
deformation
4.
The
effect
climatic
conditions
and
curing
methods
on
the
plastic
deformation
of
SCC
SCC,SCC,
the results
of plastic
deformation

of experiments
conducted
in the
humid
condition
and
results
of plastic
deformation
of
experiments
conducted
in hot,
the deformation
hot,
humid
condition
4. Thethe
effect
ofthe
climatic
conditions
and
curing
methods
on the plastic
of
SCC and
dry condition
with

same
water/powder
ratio
of
0.35
are
compared.Equipment,
mixing
process,
To
assess
the
effect
of
climatic
conditions
and
curing
methods
on
the
plastic
deformation
of
46 of 0.35 are compared.Equipment, mixing process,
dry condition with the same water/powder ratio
To
assess
the
effect

of
climatic
conditions
and
curing
methods
on
the
plastic
deformation
SCC, the results of plastic deformation of experiments conducted in the hot, humid condition and of
SCC, the with
resultstheofsame
plastic
deformationratio
of experiments
in the hot, humid
dry condition
water/powder
of 0.35 are conducted
compared.Equipment,
mixingcondition
process, and
dry condition with the same water/powder ratio of 0.35 are compared.Equipment, mixing process,


Cuong, N. H. et al. / Journal of Science and Technology in Civil Engineering

According to [2, 12], in hot weather conditions with high solar radiation, watering method is not
effective even it can result in reduction of the concrete quality. Many research results show that under

the effect of periodic watering, the temperature of water is much lower than the temperature of the
heated surface, which leads to a continuous heat pulse with the deviation up to 30◦C to 50◦C. This
problem might adversely affect the structure and physical-mechanical properties of SCC.
Generally, curing by nylon membrane is the most effective method to ensure the quality of SCC
surface.
4. The effect of climatic conditions and curing methods on the plastic deformation of SCC
To assess the effect of climatic conditions and curing methods on the plastic deformation of SCC,
the results of plastic deformation of experiments conducted in the hot, humid condition and dry condition with the same water/powder ratio of 0.35 are compared. Equipment, mixing process, manpower
and materials were the same. Concrete was mixed, poured into the mold at 10:30 AM. The measurement was carried out during twenty-two hours since the concrete began to contract.
Experimental results as shown in Fig. 8 indicate that under dry condition, the plastic shrinkage
took place after one hour, while under humid condition, it occurred after three hours. It demonstrates
that plastic shrinkage occurred much sooner under dry condition than under humid condition. The
reason is that humid condition allows the rate of water evaporation to be slower, so that concrete has
a good temperature-humidity environment to continue hydrating. Therefore, the process of plastic
shrinkage happens later. The value of plastic deformation of SCC under dry condition is much larger
than that under humid condition. At the 22nd hour (Fig. 8) with the same method of curing by nylon
membrane, the plastic deformation was 1.53 mm/m under dry condition while only 0.42 mm/m under
humid condition. This might be explained that under dry condition, the dehydration takes place with
high speed and volume, which causes plastic deformation to start early with high value.
Plastic Shrinkage
(mm/m)
0 1 2
0.00

3

4

5

6

7

8

9

Time
(h)
10 11 12 13 14 15 16 17 18 19 20 21 22 23

-0.50
-1.00
-1.50
-2.00
-2.50
-3.00
Humid-0.35-KBD
Dry-0.35-KBD

Humid-0.35-BNL
Dry-0.35-BNL

Humid-0.35-TN
Dry-0.35-TN

Figure 8. Plastic deformation of SCC with different climatic conditions and curing methods

5. The effect of mix design and curing methods on the plastic deformation and compressive

strength of SCC
The results as shown in Fig. 9 indicate that in the case of watering (TN) or no curing (KBD), the
plastic deformation of the specimen created with 0.3 water/powder ratio was greater than that of the
47


Cuong, N. H. et al. / Journal of Science and Technology in Civil Engineering

specimen created with 0.35 water/powder ratio. Conversely, as curing by nylon membrane, the plastic
deformation occurred with the case of 0.35 water/powder ratio was larger. However, the difference was
not significantly higher. As a general trend, SCC with the higher ratio of water/power tends to produce
smaller plastic deformation. This trend might be caused by the greater water/powder ratio the smaller
amount of powder (cement and fly ash), that means the amount of aggregate in the mixture is bigger.
Therefore, the amount of binding paste remains smaller, which leads to smaller plastic deformation.
Obviously, in the mixture of aggregates and cement paste, plastic deformation only occurs where the
cement paste is distributed.
Plastic Shrinkage
(mm/m)
0 1 2 3
0.00

Time
(h)
4

5

6

7

8

9

10 11 12 13 14 15 16 17 18 19 20 21 22

-0.20
-0.40
-0.60
-0.80
-1.00

-1.20
-1.40
-1.60
Humid-0.35-KBD

Humid-0.35-BNL

Humid-0.35-TN

Humid-0.3-KBD

Humid-0.3-BNL

Humid-0.3-TN

Figure 9. Plastic deformation of SCC with different mix designs

From the strength development curves of SCC with the both cases of water/powder (N/B) ratio of
0.35 and 0.3, it can be seen that the samples cured by nylon membrane have the highest compressive
strength (the dashed line in Fig. 10). At the 28th day of age, for the ratio of 0.35, the strength of SCC
in the cases of nylon membrane, watering and no-curing were 536.0 daN/cm2 , 480.0 daN/cm2 and
474.0 daN/cm2 , respectively. Those values reach about 100.75%, 90.22% and 89.10% respectively of
strength of the samples that were cured under the standard condition. For the water/powder ratio of 0.3,
strength of the samples cured by the above three curing methods were 630.0 daN/cm2 , 584.0 daN/cm2
and 537.0 daN/cm2 respectively, which reach 101.2%, 93.82%, 86.27% respectively of the strength
of SCC cured under the standard condition.
Under the same test conditions, a correlation can be observed that the greater the plastic deformation, the lower the compressive strength. As shown in Fig. 9, under humid condition and the
water/powder ratio of 0.35, the smallest plastic deformation was recorded in SCC specimens that are
cured by nylon membrane (solid line with dots). They also provided the best value of compressive
strengths (the dashed line as seen in Fig. 10). This correlation is also true for samples which are cured
by other methods and under dry condition.
Generally, the method of curing by nylon membrane not only ensures the quality of concrete surface by minimizing surface cracking and white efflorescence, but also provides the best compressive
strength which exceeds the standard curing method (see Fig. 10). This demonstrates that the process
of hardening and developing strength of SCC takes place in the best condition when SCC members
are cured by nylon membrane.

48


Cuong, N. H. et al. / Journal of Science and Technology in Civil Engineering
(daN/cm2)
600.0

(daN/cm2)
700.0

N/B=0.35- Humid conditions

N/B=0.3- Humid conditions

600.0

500.0

500.0

400.0

400.0

300.0
300.0

200.0
Humid-0.35-KBD
Humid-0.35-BNL

100.0

200.0

Humid-0.35-TN
Humid-0.35-TC

Humid-0.3-KBD
Humid-0.3-BNL

100.0

0.0

Humid-0.3-TN
Humid-0.3-TC

0.0

0

5

10

15

20

25

(day)
30

0

(a) The water/powder ratio of 0.35

5

10

15

20

25

(day)
30

(b) The water/powder ratio of 0.30

Figure 10. Strength development of SCC with different curing methods under humid conditions

6. Conclusions
From the experimental results, the paper draws the conclusions as follows:
Under two climatic conditions, humid and dry, curing by nylon membrane is the most effective
method in minimizing plastic deformation of SCC in the early hardening stage. With the reduction of
plastic shrinkage, nylon membrane also controls surface cracking and white efflorescence better than
watering and no-curing methods. Accordingly, in order to obtain the best quality of concrete surface,
nylon membrane should be chosen. It is also suitable for use in construction sites.
Under dry conditions, the plastic deformation of SCC specimens occurs earlier greater than humid conditions. The period of plastic deformation occurring is from four to five hours under humid
conditions and from six to seven hours under dry conditions. Under the same climatic conditions, the
higher the water/powder ratio, the smaller the plastic shrinkage tend to be.
The curing method of nylon membrane provides the highest results of compression strength,
which is greater than the compression strength of SCC cured under the standard condition. This
shows that nylon membrane can control the water evaporation of SCC and minimize plastic shrinkage along with the creation of an ideal temperature-humidity environment for forming the structure
and developing the strength of SCC. Besides, a correlation can be observed that the larger the plastic
deformation of SCC, the lower the compressive strength.

References
[1] Huong, N. T. T. (2013). Causes of crack and measures to limit the crack for concrete and reinforced
concrete of works used seaside protection. Journal of Water Resource & Environmental Engineering,
(42):69–74.
[2] ACI committee (2008). ACI 224R-01, Control of Cracking in Concrete Structures.
[3] Dich, N. T. (2000). Concrete work in hot and humid climate conditions. Construction Publishing House,
Hanoi.
[4] Hai, T. H., Thuc, L. V. (2017). Research on the theoretical bases of the hardening of self - compacting
concrete. Journal of Structural Engineering and Construction Technology, (25):49–62.
[5] Khoa, H. N., Vu, N. T. (2015). Curing monolithic concrete by membrane in the climate condition of
Quang Nam - Da Nang region. Journal of Structural Engineering and Construction Technology, (17):
30–42.
[6] Khoa, H. N., Cuong, N. H. (2011). Specification of effective methods to well-maintain concrete in hotand-humid climate. Journal of Science and Technology in Civil Engineering (STCE)-NUCE, 5(1):33–39.

49


Cuong, N. H. et al. / Journal of Science and Technology in Civil Engineering

[7] Khoa, H. N. (2015). Influence of self-compacting concrete mortars workability on the quality of concrete.
Viet Nam Journal of Construction, 4:93–95.
[8] Khoa, H. N. (2015). The effect of the storage time on the workability of self - compacting concrete. Viet
Nam Journal of Construction, 1:89–91.
[9] ACI committee (2008). ACI 308R-01, Guide to Curing concrete.
[10] Boel, V. (2006). Microstructure of self-compacting concrete in relation with gas permeability and durability aspects. Doctoral Thesis, Magnel Laboratory for Concrete Research, Ghent University, Belgium.
¨ Aggoun,
[11] Craeye, B., De Schutter, G., Desmet, B., Vantomme, J., Heirman, G., Vandewalle, L., Cizer, O.,
S., Kadri, E. H. (2010). Effect of mineral filler type on autogenous shrinkage of self-compacting concrete.
Cement and Concrete Research, 40(6):908–913.
[12] Loser, R., Leemann, A. (2009). Shrinkage and restrained shrinkage cracking of self-compacting concrete

compared to conventionally vibrated concrete. Materials and Structures, 42(1):71–82.
[13] Oliveira, M. J., Ribeiro, A. B., Branco, F. G. (2015). Curing effect in the shrinkage of a lower strength
self-compacting concrete. Construction and Building Materials, 93:1206–1215.
[14] Tongaroonsri, S., Tangtermsirikul, S. (2009). Effect of mineral admixtures and curing periods on shrinkage and cracking age under restrained condition. Construction and Building Materials, 23(2):1050–1056.
[15] Khoa, H. N., Hai, T. H. (2013). Slump loss of mixed concrete under climatic conditions during storage
process prior to pouring into formwork systems. Journal of Science and Technology in Civil Engineering
(STCE)-NUCE, 7(3):29–39.

50