Exeley Inc.

Nowak, Daria

De Groef, Lies

Moons, Lieve

Mozrzymas, Jerzy W.

MMP-3 deficiency does not influence the length and number of CA1 dendrites of hippocampus of adult mice

Rasmussen, Pernille Darling

 81 
 
Scandinavian Journal of Child and Adolescent Psychiatry and Psychology 
Vol. 6(2):81-82 (2018) DOI 10.21307/sjcapp-2018-013 
 
Editorial  
 
 
 
 
The egg or the hen: Is ADHD the result of attachment problems – or 
do attachment problems arise from ADHD? 
 
Pernille Darling Rasmussen 
 
 
 
 
An 11-year-old boy is referred to assessment in a child 
psychiatric department due to severe symptoms of ADHD. 
It is well recognized that Attention-
Deficit/Hyperactivity Disorder (ADHD) is one of 
the most prevalent child psychiatric disorders. 
What’s more is that an increasing amount of evidence 
points to ADHD as a condition persisting into 
adulthood (1,2). ADHD is further associated with 
significant comorbidity and impaired prognosis (3-5). 
Some studies suggest the subgroup developing 
comorbidity  also displays deviant developmental 
trajectory and poor prognosis (6,7). Importantly, this 
subgroup may represent more than 50 percent of 
diagnosed children (5). Further, longitudinal studies 
have shown age-dependent decline in core symptoms 
(hyperactivity, impulsivity and attention problems) 
whereas the rate of functional ADHD remission is 
no more than 10 % (8). Is it possible that the core 
symptoms of ADHD are not the main problem in 
children and adolescents with ADHD?  
During the child psychiatric assessment of the 11-year-old 
boy, it became clear that he had experienced considerable 
adversity in his life. His mother had been engaging in relations 
with men who behaved violently toward the boy and the mother. 
The boy’s biological father was characterized as “only 
functional when he is under the influence of amphetamine” and 
the contact between the boy and his father had been no more 
than occasional since the boy was three years old. Does the boy 
have ADHD or are his symptoms more likely to be a result 
of insecure attachment?  
One certainly has to consider that this less than 
optimal childhood environment may be explained by 
untreated ADHD-symptoms in the parents. A study 
found that as much as 50 % of parents of children 
with ADHD suffered from ADHD themselves (9). 
As ADHD is associated with impaired prognosis, we 
further need to consider which factors may be 
important in improving our current treatment 
strategies and long-term prognosis. It is of outmost 
relevance to investigate whether our current 
treatment strategies are efficient. Pharmacological 
treatment (the most common treatment strategy for 
ADHD) is primarily targeting the core symptoms of 
ADHD, but does it make a significant difference in 
long-term prognosis? Researchers have attempted to 
determine this by conducting comprehensive 
Cochrane reviews. These reviews have concluded 
that both in terms of pharmacological treatment and 
other general treatment strategies (parental training 
and social training for children), the evidence is not 
sufficiently strong to form the basis of clinical 
guidelines (10-12). Regarding other potentially 
important characteristics of ADHD, it has been 
found that the majority of children (> 80 %) with 
ADHD can be classified as insecurely attached with 
respect to their primary caregiver (13). ADHD and 
insecure attachment representation display shared 
features such as high levels of emotional 
dysregulation in the early years, and problems in peer 
relations in adolescence (14–17). The question is; 
what comes first: ADHD or insecure attachment? 
Some studies suggest that inborn vulnerabilities in 
the child may influence the process of attachment 
formation (18, 19). On the other hand, insecure 
attachment has been linked to increased risk of 
developing ADHD symptoms (20-22). Hence, is the 
persistent low level of functioning in many ADHD 
patients an indication of clinicians putting too much 
emphasis on reducing core symptoms - while other 
factors associated with ADHD may be determinants 
of the long-term prognosis? 
Perhaps in most cases ADHD cannot or should 
not be classified as purely caused by neurobiological 
vulnerabilities or environmental factors. Rather, 
ADHD may need to be considered in the context of 
familial risk and resilience. In this, we need to take 
into account the multiple etiologies including the 
impact of genetics as well as environmental factors - 
both acting across generations. Perhaps we should 
put more focus into perceiving ADHD as a chronic 
condition requiring thorough and continuous 
assessment to address the specific causes of the 
 82 
 
symptomatology in each family. This may facilitate a 
more individualized treatment strategy. 
 
 
References 
 
1.  Polanczyk G, Zeni C, Genro JP, Guimarães AP, Roman T, Hutz 
MH, et al. Association of the adrenergic alpha2A receptor gene with 
methylphenidate improvement of inattentive symptoms in children 
and adolescents with attention-deficit/hyperactivity disorder. Arch 
Gen Psychiatry 2007;64:218–24. 
 
2.  Polanczyk G, Rohde LA. Epidemiology of attention-
deficit/hyperactivity disorder across the lifespan. Curr Opin 
Psychiatry 2007;20:386–92.  
 
3.  Storebø O, Simonsen E. Is ADHD an early stage in the development 
of borderline personality disorder? Nord Psychiatry 2014;68:289–95.  
 
4.  Storebø O, Simonsen E. The Association Between ADHD and 
Antisocial Personality Disorder (ASPD): A Review. J Atten Disord 
2016;20:815–24.  
 
5.  Dalsgaard S, Østergaard SD, Leckman JF, Mortensen PB, Pedersen 
MG. Mortality in children, adolescents, and adults with attention 
deficit hyperactivity disorder: a nationwide cohort study. Lancet 
2015;385:2190–6.  
 
6.  Mannuzza S, Klein RG, Moulton JL. Lifetime criminality among 
boys with attention deficit hyperactivity disorder: A prospective 
follow-up study into adulthood using official arrest records. 
Psychiatry Res 2008;160:237–46.  
 
7.  Mannuzza S, Klein RG, Bessler A, Malloy P, Lapadula M. Adult 
psychiatric status of hyperactive boys grown up. Am J Psychiatry 
1998;155:493–8.  
 
8.  Biederman J, Mick E, Faraone SV. Age-dependent decline of 
symptoms of attention deficit hyperactivity disorder: Impact of 
remission definition and symptom type. Am J Psychiatry 
2000;157:816–8.  
 
9.  Starck M, Grünwald J, Schlarb AA. Occurrence of ADHD in 
parents of ADHD children in a clinical sample. Neuropsychiatr Dis 
Treat 2016;12:581–8.  
 
10.  Storebø OJ, Krogh HB, Ramstad E, Moreira-Maia CR, Holmskov 
M, Skoog M, et al. Methylphenidate for attention-
deficit/hyperactivity disorder in children and adolescents: Cochrane 
systematic review with meta-analyses and trial sequential analyses of 
randomised clinical trials. BMJ 2015;351:h5203.  
 
11.  Storebø OJ, Skoog M, Damm D, Thomsen PH, Simonsen E, Gluud 
C. Social skills training for Attention Deficit Hyperactivity Disorder 
(ADHD) in children aged 5 to 18 years. Cochrane Database Syst Rev 
2011;(12):CD008223.  
 
12.  Zwi M, Jones H, Thorgaard C, York A, Dennis JA. Parent training 
interventions for Attention Deficit Hyperactivity Disorder (ADHD) 
in children aged 5 to 18 years. Cochrane Database Syst Rev 
2011;(12):CD003018.  
 
13.  Storebø OJ, Skoog M, Darling Rasmussen P, Winkel P, Gluud C, 
Pedersen J, et al. Attachment competences in children with ADHD 
during the social-skills training and attachment (SOSTRA) 
randomized clinical trial. J Atten Disord 2014;1087054713520220.  
 
14.  Elicker J, Englund M, Sroufe LA. Predicting peer competence and 
peer relationships in childhood from early parent - child 
relationships. In: Parke RD, Ladd GW (eds.) Family-peer 
relationships: Modes of linkage. Hillsdale, NJ: Lawrence Erlbaum 
Associates, Inc.; 1992. p. 77–106.  
 
15.  Adler LA, Faraone SV., Spencer TJ, Berglund P, Alperin S, Kessler 
RC. The structure of adult ADHD. Int J Methods Psychiatr Res 
2017;26:1–12.  
 
16.  Egeland B, Kalkoske M, Gottesman N, Erickson MF. Preschool 
behavior problems: Stability and factors accounting for change. J 
Child Psychol Psychiatry 1990;31:891–909.  
 
17.  Colvert E, Rutter M, Kreppner J, Beckett C, Castle J, Groothues C, 
et al. Do theory of mind and executive function deficits underlie 
the adverse outcomes associated with profound early deprivation?: 
Findings from the English and Romanian adoptees study. J 
Abnorm Child Psychol 2008;36:1057–68. 
 
18.  Clarke L, Ungerer J, Johnson S, Stiefel I. Attention Deficit 
Hyperactivity Disorder is Associated with Attachment Insecurity. 
Clin Child Psychol Psychiatry 2002;7:179–98.  
 
19.  Finzi-Dottan R, Manor I, Tyano S. ADHD, temperament, and 
parental style as predictors of the child’s attachment patterns. Child 
Psychiatry Hum Dev 2006;37:103–14.  
 
20.  Skovgaard AM, Olsen EM, Houmann TB, Christiansen E, 
Lichtenberg A, Jørgensen T. Markers of mental health problems 
based on public health nurses’ assessments of 0- to 1-year-old 
children: the Copenhagen County Child Cohort 2000. Dan Med 
Bull 2007;169:1006–10. 
 
21.  Roskam I, Stievenart M, Tessier R, Muntean A, Escobar MJ, 
Santelices MP, et al. Another way of thinking about ADHD: The 
predictive role of early attachment deprivation in adolescents’ level 
of symptoms. Soc Psychiatry Psychiatr Epidemiol 2014;49:133–44.  
 
22.  Niederhofer H. Attachment as a component of attention-deficit 
hyperactivity disorder. Psychol Rep 2009;104:645–8.  


The egg or the hen: Is ADHD the result of attachment problems – or do attachment problems arise from ADHD?

Australasian Journal of Neuroscience Volume 28 ● Number 2 ● October 2018 
 3 
Conferences with Benefits 
Linda Nichols 
Editor 
I was so impressed when I was reading the 
abstracts from this year’s annual confer-
ence.  The quality and diversity was really 
impressive and Leigh’s editorial echoed 
many of my own thoughts about how con-
ferences are about so much more than just 
listening to talks and presentations. 
As an academic a major activity for me is 
attending professional conferences both as 
a speaker and as a delegate. The benefits 
are hard to quantify however here are a few 
thoughts from my experience.    
The first benefit that comes to mind is of 
course the opportunity to present, not only 
scientific research to others but also to pre-
sent case studies and/or changes in prac-
tice.   This can often be a really daunting 
undertaking, however anyone who has at-
tended an ANNA conference will know that 
the conference is really supportive of first 
time presenters and it is a great platform to 
share your work in a friendly environment.   
The second area that is often overlooked 
as being important when attending confer-
ences is the opportunity to participate in 
workshops and breakout meetings. Short 
interactive workshops are now a norm at 
most conferences, often over breakfast or 
lunch, these short sessions allow delegates 
to network and learn new skills. These are 
a great opportunity to cover topics that are 
not suited to lengthy courses and when 
attending a conference, it’s always good to 
make the most of these opportunities.  
2018 ANNA Conference Reflections 
Leigh McCarthy 
Conference Convenor 
The ANNA conference was held at the Sheraton 
mirage in the Gold Coast this year, we had over 
100 delegates attend and have received posi-
tive feed back. 
The standard of presentations delivered were 
outstanding and all social functions met every-
one’s expectations. I had the pleasure of net-
working with new and familiar faces. 
Preparation for the 2019 ANNA conference has 
already begun. It was voted to take our meeting 
across the waters to our newly re-opened chap-
ter of New Zealand. 
We will be calling for abstracts soon, so please 
think about presenting. 
Have you nursed a patient that was really inter-
esting or come across a rare diagnosis that you 
want to expand your knowledge on?  
It would be great if you could present this at our 
next conference. All presentations are then en-
couraged to be submitted for publication in the 
AJON.  
If presenting is something you would like to do 
and don’t know where to start you can contact 
myself or our beautiful lifetime member Dr Jen-
nifer Blundell who can help get you started. 
Hope to see lots of neuroscience nurses in New 
Zealand. 
Cheers  
Leigh      DOI: 10.21307/ajon-2017-004 
The final area that I find invaluable for brainstorming, networking and making vital connections are 
social events. Many a collaboration has begun with networking between sessions or during a so-
cial event. Getting to know potential collaborators occurs more naturally in person where genuine 
impressions are made.  So never underestimate a social event, always make the most of confer-
ence workshops and always remember that conferences are an invaluable experience beyond the 
presentations themselves.  
Linda                                     DOI: 10.21307/ajon-2017-003


Editorial

ŹRÓDŁOWSKI, TOMASZ W.

JURKIEWICZ-BADACZ, DANUTA

SROKA-OLEKSIAK, AGNIESZKA

SALAMON, DOMINIKA

BULANDA, MAŁGORZATA

GOSIEWSKI, TOMASZ

Comparison of PCR, Fluorescent in Situ Hybridization and Blood Cultures for Detection of Bacteremia in Children and Adolescents During Antibiotic Therapy

Sharma, Sanjiv

Drane, Michael

PREDIABETES AND THE NEED FOR CARDIOVASCULAR RISK ASSESSMENT IN AVIATION

Ruzicka, Jiri

Urdzikova, Lucia Machova

Kloudova, Anna

Amin, Anubhav G.

Vallova, Jana

Kubinova, Sarka

Schmidt, Meic H.

Jhanwar-Uniyal, Meena

Jendelova, Pavla

Anti-inflammatory compound curcumin and mesenchymal stem cells in the treatment of spinal cord injury in rats

Popova, Elka

Kupenova, Petia

Dopamine D2 receptor blockade differentially affects the light-adapted turtle and frog electroretinogram

Ali, Mohammed

Mohamed, Ahmed

Ahmed, Hussam Elamin

Malviya, Ajay

Atchia, Ismael

The use of ultrasound-guided platelet-rich plasma injections in the treatment of hip osteoarthritis: a systematic review of the literature

GALMAN, Iwona

JASIŃSKI, Radosław

TESTS OF JOINTS IN AAC MASONRY WALLS

Vilela ROCHA, Vanessa

LUDVIG, Péter

1. INTRODUCTION
Carbon nanotubes (CNTs) are hollow tubular chan-
nels, formed by graphene laminated sheets. They can
be classified as single-walled (SWCNTs) when they
have a simple cylindrical layer of graphene or as mul-
tiple-walled (MWCNTs) formed by the joining of two
or more single cylindrical layers.
Due to the extraordinary properties, as a high tensile
strength, the incorporation of the CNTs in civil con-
struction materials has been studied. Recent research
has shown that the incorporation of this nanomaterial
allows improvements in the mechanical properties
of cementitious compounds [1–5]. However, the
hydrophobic nature of CNTs makes the dispersion a
NANOCOMPOSITES PREPARED BY A DISPERSION OF CNTS
ON CEMENT PARTICLES
Vanessa Vilela ROCHA a, Péter LUDVIG b*
aMasters Student in Civil Engineering; Department of Civil Engineering, Federal Centre for Technological Education
of Minas Gerais, Campus II, Av. Amazonas, 7675, Nova Gameleira, Belo Horizonte-MG, Brazil
b Prof.; Department of Civil Engineering, Federal Centre for Technological Education of Minas Gerais,
Campus II, Av. Amazonas, 7675, Nova Gameleira, Belo Horizonte-MG, Brazil
*E-mail address: peter@civil.cefetmg.br
Received: 25.06.2017; Revised: 10.08.2017; Accepted: 19.03.2018
Ab s t r a c t
The hydrophobic behaviour of carbon nanotubes (CNTs) is a main challenge for the incorporation in Portland cement (PC)
composites. In this paper, multi-wallet carbon nanotubes (MWCNTs) at proportions of 0%, 0.05% and 0.10% of cement
weigh, without any surface treatment, were mixed in a non-aqueous isopropanol media and unhydrated PC and were soni-
cated for 2 hours. Thereafter isopropanol was evaporated, water was added to the mixture of cement and carbon nanotubes,
and pastes were prepared and moulded. After 28 days, the cement pastes were subjected to compressive and splitting ten-
sile tests. Results indicated better performance of PC nanocomposites. Incorporation of 0.05 % of CNTs resulted in gains of
approximately 50% in both compressive and splitting tensile strengths. The results suggest that reinforcement due to the
presence of carbon nanotubes and/or the nanomaterial acted as nucleation sites for cement hydration product formation
leading to a matrix densification.
S t r e s z c z en i e
Hydrofobowe zachowanie się nanorurek węglowych (CNT) jest głównym problemem dla ich zastosowania w materiałach
kompozytowych na bazie cementu portlandzkiego (PC). W tym artykule przedstawiono wyniki badań wielowarstwowych
nanorurek węglowych (MWCNT), które w proporcji 0%, 0.05 % i 0.10 % masy cementu, bez żadnej obróbki powierzchniowej,
mieszano w niewodnym medium izopropanolowym i bezwodnym cemencie portlandzkim, i sonikowano przez 2 godziny.
Następnie odparowano izopropanol; do mieszaniny cementu i nanorurek węglowych dodawano wodę; przygotowywano
zaczyny i uformowano próbki. Po upływie 28 dni, zaczyny cementowe poddano badaniom na ściskanie i rozciąganie przez
rozłupanie. Wyniki badań wskazują na lepsze zachowanie nanokompozytów z cementu portlandzkiego. Dodatek w postaci
0.05% CNT przyniósł zysk w przybliżeniu 50% zarówno dla wytrzymałości na ściskanie jak i rozciąganie prze rozłupanie.
Wyniki badań wskazują, że zbrojenie w postaci nanorurek węglowych i/lub nanomateriałów działało jako miejsca zarod-
kowania do tworzenia produktu hydratacji cementu, prowadząc do zagęszczenia matrycy cementowej.
Keywo rd s : Cement paste; Carbon nanotubes; Dispersion; Isopropanol; Mechanical Properties.
2/2018 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 73
A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T
The Si les ian Univers i ty of Technology No. 2/2018
d o i : 1 0 . 2 1 3 0 7 / A C E E - 2 0 1 8 - 0 2 4
V . V . R o c h a , P . L u d v i g
challenge to the cement pastes production. CNTs
tend to agglomerate and form granules in the pres-
ence of water, and those clusters contribute to weak-
ening the PC pastes mechanical properties. A good
dispersion is crucial for the improvement of cement
composites mechanical strength.
According to MELO et al. (2011) [1] there is an opti-
mal range for the incorporation of CNTs in Portland
cement particles. For a given dispersion technique
there is an optimum CNT content and the excess of
nanomaterial lead to granules formation that com-
promise the mechanical performance and durability
of cement pastes. All optimal CNT contents in
cement paste or mortar composites found in the lit-
erature were in the order of 0.01–0.5% in mass with
respect to cement weight [1].
The CNTs can be surface-treated to achieve a better
dispersion, resulting in an increase of the dispersive
properties. According to FILHO and FAGAN (2007)
[6] there is a treatment through noncovalent and
covalent interactions, the so-called functionalization.
The noncovalent interactions are weak bonds with
CNTs, conversely, the covalent interactions are
strong and can cause modifications in the CNTs prop-
erties. Non-covalent functionalization of CNTs can
be achieved by the use of surfactants such as concrete
admixtures [2]. However, the amount of surfactant
necessary to achieve a good dispersion of CNTs may
have negative effects on cement hydration which lim-
its the quantity of CNTs to be incorporated in cement
matrixes [3]. On the other hand, the most common
covalent functionalization involves the use of strong
acids in processes that are not suitable for large scale
production that is needed for the application in
cement based materials [7].
According to PAULA et al. (2014) [4], researchers
have studied two methods of dispersion currently.
The first one involves a previous dispersion in soni-
cating surfactant, allowing covalent interaction
between the materials. The other method is an
attempt to spread the CNTs in the cement or other
grain particles. There are two known methods for this
second way of dispersion: either by the in situ synthe-
sis of the CNTs on ground PC clinker particles [8] or
by suspending the CNTs in a non-aqueous medium,
to avoid hydration of the cement, also with ultrason-
ic frequencies [5].
The in-situ synthesis on clinker produces lower qual-
ity nanotubes, but can be easily upgraded to industri-
al scale. The addition of this nanostructured clinker
resulted in similar effects on the rheology of fresh
paste [4], on the mechanical behaviour [8], and on the
microstructure [9] as the addition of high quality
CNTs.
The research published by MAKAR and CHAN
(2009) [5], using images obtained from a high resolu-
tion electron microscope, indicated good dispersion
of SWCNTs on PC grains, after 2 hours sonication in
non-aqueous isopropanol media. The authors [5] also
observed that the dispersed CNTs in the cement
matrix act as nucleation sites for calcium silicate
hydrate (C-S-H) formation, which is responsible for
the strength and durability of cement pastes, suggest-
ing a good interaction between the C-S-H and CNTs.
Currently, there is no accepted method able to quan-
tify the dispersion of carbon nanotubes in the cement
matrix. An indirect method adopted by some
researchers is the analysis of the mechanical behav-
iour of cementitious composites. Considering this
information and the results obtained by MAKAR
and CHAN (2009) [5], the present paper aims at eval-
uating the mechanical performance of PC pastes with
0%, 0.05% and 0.10% of non-functionalized
MWCNTs in a non-aqueous isopropanol media and
sonication for 2 hours.
2. MATERIALS AND METHODS
2.1. Materials
The nanotubes used were multi-walled type
(MWCNTs), with estimated tube lengths between
5 µm and 30 µm, 99% of external diameter between
10 nm and 50 nm, and purity greater than 93%. CNTs
were produced in the Nanomaterials Laboratory of
the Physics Department of the Federal University of
Minas Gerais (UFMG). Brazilian Type CP-V
Portland cement was used because of the low per-
centage of mineral additions. The isopropanol used
was absolute grade of EMFAL brand.
2.2. CNTs dispersion
The dispersion process began with the mix of CNTs
and approximately 30 ml of isopropanol. The mixture
was shaken and sonicated on ultrasonic apparatus
with 42 Hz frequency for 30 minutes. In sequence,
300 grams of cement was added with further iso-
propanol (approximately 200 ml). The suspension
was mechanically shaken at 500 rpm and sonicated
for additional 2 hours. Fig. 1 illustrates this process.
After 24 hours, the isopropanol was completely evap-
orated, and the dry mixture of cement and CNTs were
used for cement paste preparation.
74 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 2/2018
NANOCOMPOS I T E S P R E PA R ED B Y A D I S P E R S I ON O F CN T S ON C EMEN T PAR T I C L E S
2.3. Cement Paste Preparation
The cement pastes were prepared in a mortar
blender, as described in the Brazilian National
Standard for the determination of consistency of
cement pastes [10]. First the mixing water was placed
in the batch, the CNTs dispersed on cement particles
together with the remaining cement were added sub-
sequently. Tab. 1 describes the proportion of materi-
als used for the production of pastes with and without
CNTs dispersed on unhydrated Portland cement par-
ticles. Three cement paste types were mixed with
water cement ratio of 0.33. The first paste was the
reference, using only cement and water (0% of
CNTs). The second, in addition to cement and water,
contained a proportion of 0.05% carbon nanotubes
with respect to cement weight. The third type incor-
porated 0.10% of carbon nanotubes.
Following the paste preparation, prismatic specimen
with 5 cm of diameter and 10 cm height were mould-
ed and vibrated on a vibrating table for 1 minute. The
moulds were demoulded after 24 hours and bathed in
a tank of lime saturated water until reaching the age
of 28 days. For each type, 8 cylindrical specimens
were moulded: 4 for compressive strength test and 4
for splitting tensile strength test.
2.4. Compressive strength test and splitting tensile
strength test
After 28 days, the test specimens’ surfaces were reg-
ularized for uniform stress distribution in compres-
sive strength test. After that, they were measured and
tested on a universal EMIC brand test equipment
with load cell of 300 kN for compressive strength test
and 20 kN for splitting tensile strength test. The load
increment was 0.20 MPa/sec and 1 mm/min respec-
tively. Fig. 2a and Fig. 2b illustrate the compressive
strength test and splitting tensile strength test setups,
respectively.
C
I
V
I
L
E
N
G
I
N
E
E
R
I
N
G
e
2/2018 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 75
Figure 1.
Mixture of cement, CNTs and isopropanol in the ultrasonic
bath being mechanically agitated
Figure 2.
a) compressive strength test setup; b) splitting tensile
strength test using an apparatus specially developed for the
test
Table 1.
Proportions of materials used to prepare cement pastes with
CNTs dispersed on cement particles
Identification Materials Weight Composition (g)
REF-ISO-P
CP-V Cement 3 000.00
Water 990
0.05%-ISO-P
CP-V Cement 3 000.00
Water 990
CNTs 1.5
0.10%-ISO-P
CP-V Cement 3 000.00
Water 990
CNTs 3
c
a b
V . V . R o c h a , P . L u d v i g
The results of compressive strength test and splitting
tensile strength test were obtained by the following
equations:
fc = compressive strength (MPa);
F = maximum load applied (N);
r = test piece average radius (mm);
ft = splitting tensile strength (MPa);
F = maximum load applied (N);
d = test piece diameter (mm);
h = test piece height (mm).
For analysis, the one with the higher deviation among
the 4 results of the same paste was discarded and the
mean value of the remaining 3 results was consid-
ered.
3. RESULTS AND ANALYSIS
The dispersion process of CNTs on the cement parti-
cles surface using isopropanol resulted in visually
homogenous dispersion. While in suspension, the
CNTs were apparently well dispersed, without forma-
tion of clumps. During the paste preparation no sig-
nificant effect of the CNT addition on paste worka-
bility was noticed.
Tab. 2, Fig. 3 and Fig. 4 describe the results obtained
in the compressive and splitting tensile strength tests.
The presence of CNTs at the cement composites in
both concentrations resulted in a better performance,
when compared to the reference paste. 0.05-ISO-P
paste had 45% higher compressive and 49% higher
tensile strength than the reference. At the same time
the gains for the 0.10-ISO-P paste were 35% and
20%, respectively. For an addition of 0.05% CNTs,
however, the gain was greater than 0.10% in both
compressive and splitting tensile tests.
A difference between the relation of gain in com-
pressive and tensile strength was also observed. For
0.05-ISO-P paste the gain in tensile strength was
slightly higher (49%) than in compressive strength
(45%), meanwhile for 0.10% CNT content the rela-
tion was the opposite: higher compressive strength
gain (35%) than tensile (20%). This phenomenon
may be explained by the CNTs working more like
fibre reinforcement when used in smaller content.
The higher gain in compressive strength for the
0.10-ISO-P paste indicates that the CNTs in this case
have less fibre reinforcement effect, acting rather as
nucleation sites for cement hydration products.
These results may also indicate the existence of a dis-
persion limit of CNTs by this methodology between
0.05 and 0.10% pf CNT content. Despite the visually
76 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 2/2018
Table 2.
Results obtained in the compressive and splitting tensile strength tests
Compressive strength Splitting tensile strength
Identification
Average Standard Strength Average Standard Strength
strength deviation gain strength deviation gain
(MPa) (MPa) (MPa) (MPa)
REF - ISO - P 38.24 6.84 - 2.13 0.18 -
0.05 - ISO - P 55.44 9.27 45% 3.17 0.47 49%
0.10 - ISO - P 51.74 5.91 35% 2.55 0.09 20%
݂ܿ ൌ ிగ௥; (1)
݂ݐ ൌ ଶிగௗ௛ (2) Figure 3.Compressive strength test results
Figure 4.
Splitting tensile strength test results
NANOCOMPOS I T E S P R E PA R ED B Y A D I S P E R S I ON O F CN T S ON C EMEN T PAR T I C L E S
good results using isopropanol, the dispersion of con-
tents higher than 0.05% was less effective, which may
have caused the agglomeration of CNTs and worse
strength performance.
4. CONCLUSIONS
A method for the production of cement pastes based
on the previous dispersion of CNTs on PC particles
was presented in this work. The CNT content with
respect to cement weight was 0.05 and 0.10%. A visu-
ally good dispersion was achieved without using any
surfactant, or covalent functionalization of the nan-
otubes.
The described dispersion method allowed the incor-
poration of MWCNTs in cement matrix, at 0.05% and
0.10% proportion. The addition of CNTs resulted in
improvement of the cement pastes’ mechanical
strength properties. Gains of up to 45% in compres-
sive strength and up to 49% in splitting tensile
strength were observed in the case of 0.05% CNT
content. For higher CNT addition the gains were
lower, but still had better behaviour than the refer-
ence paste without nanotubes.
The better performance of 0.05% than 0.10% CNTs
incorporation may indicate a possible accumulation
of nanomaterial at sites of cement hydration nucle-
ation, compromising the good reaction. This fact cor-
roborates the hypothesis that there is an optimal
range for the incorporation of CNTs, and for the pre-
sent method the ideal range is close to the 0.05%
ratio.
ACKNOWLEDGEMENTS
The authors would like to thank to CAPES, CEFET-
MG, CNPq, CTNano, FAPEMIG and UFMG for the
financial and technical help provided for this work.
REFERENCES
[1] Melo, V. S.; Calixto, J. M. F.; Ladeira, L. O.; Silva, A.
P. (May/June 2011), Macro-and Micro-
Characterization of Mortars Produced with Carbon
Nanotubes, ACI Materials Journal, 108(3), 327–332.
[2] Collins, F.; Lambert, J.; Duan, W. H. (February 2012),
The influences of admixtures on the dispersion, work-
ability, and strength of carbon nanotube – OPC paste
mixtures, Cement & Concrete Composites, 34(2),
201–207.
[3] Liu, Y.; Gao, L.; Sun, J. (2007). Noncovalent
Functionalization of Carbon Nanotubes with Sodium
Lignosulfonate and Subsequent Quantum Dot
Decoration, Journal of Physical Chemistry, 111(3),
1223–1229.
[4] Paula, J. N.d.; Calixto, J. M. F.; Ladeira, L. O.;
Ludvig, P.; Souza, T. C. C.; Rocha, J. M.; Melo, A. A.
V. d. (October 2014), Mechanical and rheological
behavior of oil-well cement slurries produced with
clinker containing carbon nanotubes, Journal of
Petroleum Science and Engineering, 122, 274–279.
[5] Makar, J. M.; Chan, G. W. (June 2009). Growth of
Cement Hydration Products on Single-Walled
Carbon Nanotubes, The American Ceramic Society,
92(6), 1303–1310.
[6] Filho, A. G. d. S.; Fagan, S. B. (2007),
Funcionalização de Nanotubos de Carbono, Química
Nova, 30(7), 1695–1703.
[7] Yu, J.; Grossiord, N.; Koning, C. E.; Loos, J.
(3 March 2007). Controlling the dispersion of multi-
wall carbon nanotubes in aqueous surfactant solution,
Carbon 45(3), 618–623.
[8] Ludvig, P.; Calixto, J. M. F.; Ladeira, L. O.; Gaspar, I.
C. P. (2011), Using converter dust to produce low cost
cementitious composites by in situ carbon nanotube
and nanofiber synthesis, Materials, 4(3), 575–584.
[9] Ludvig, P.; Calixto, J. M. F.; Ladeira, L. O.; Souza, T.
C. C. (June 2017), Analysis of Cementitious
Composites Prepared with Carbon Nanotubes and
Nanofibers Synthesized Directly on Clinker and Silica
Fume, Journal of Materials in Civil Engineering, 29(6),
06017001.
[10] Brazilian Association of Technical Standards, ABNT
NBR NM 43:2003. Portland Cement – Brazilian
National Standard for the determination of consis-
tency of cement pastes. 2003.
C
I
V
I
L
E
N
G
I
N
E
E
R
I
N
G
ce
2/2018 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 77


NANOCOMPOSITES PREPARED BY A DISPERSION OF CNTS ON CEMENT PARTICLES

Not a member yet