STUDY OF TREATED AND UNTREATED TIRE RUBBER MORTAR

Transcrição

Ana C. Marques (1), Maria L. Marques (2), Jorge L. Akasaki (3), Ana P. M. Trigo (4)
(1) Civil Engineering Department, FEIS/UNESP, Brazil
Abstract ID Number: 283
Author contacts
Authors
E-Mail
Fax
Postal address
Ana C. Marques
cmarquesana@yaho
o.com.br
FEIS – unesp
Maria L. Marques
lidiane_marques@y
ahoo.com.br
FEIS – unesp
Universidade
Estadual
Paulista – Faculdade de
Engenharia de Ilha Solteira
Jorge L. Akasaki
[email protected] 55 (18) 3743- Departamento de Engenharia
esp.br
Civil
1160
Alameda Bahia, 550 – CEP:
15385-000. Ilha Solteira –
S.P. – Brazil
Ana P. M. Trigo
amorenotrigo@yaho
o.com.br
FEIS – unesp
Contact person for the paper: Jorge L. Akasaki
Presenter of the paper during the Conference: Jorge L. Akasaki
1
Total number of pages of the paper (this one excluded):
57
1
Page 0
Ana C. Marques (1), Maria L. Marques (2), Jorge L. Akasaki (3), Ana P. M. Trigo (4)
Abstract
The tire out of use is an abundant material that is not easily biodegradable. Despite of the high
index of retreading, most of them are disposed in inadequately. Another problem also related
with its disposal is the burning of this material that liberates toxic gases and pollutes the
environment.
The objective of this work is to offer a clean alternative of final destination for the tire out of
use. And also show the influence of the rubber's surface treatment with saturated sodium
hydroxide aqueous solution in mechanical properties of mortars that contain this material. The
influence of the treatment was determined by the comparison of mechanical tests' results in
specimens that contained treated and untreated rubber. The analyzed properties were:
compressive strength, tensile strength, modulus of elasticity and water absorption. Most of the
tests were carried through the ages of 7, 28 and 56 days.
The results indicated that the treatment of the rubber's surface influences in some properties
of mortars added with tire rubber particles.
Key words: tire rubber, mechanical properties, mortar, treatment of rubber.
Page 1
1.
INTRODUCTION
The final destiny of tires out of use has became a great problem to Brazil; since 100
million old tires are dispersed in landfills, wastelands, rivers and lakes, according to the
Associação Nacional da Indústria de Pneus (ANIP). Every year, dozens of millions of new
tires are manufactured at the Country. In 2001, they were 45 million (about 15 million
exported and 30 million destined to the internal consumption) [1].
The use of the tire rubber in asphalt concrete, incineration and its reuse in the triturated
form in plastic or rubber products, were alternatives to utilize this material that can cause
damage to the environment.
Another way of taking advantage of the residue, through the civil construction, is the use in
cement kilns, artificial reefs or its incorporation in mortars and concretes.
Some authors, who had adopted the incorporation of the residue in concretes, mortars and
also cement paste, studied several properties of the mixture. The property more frequently
analyzed was the compressive strength. In a general way, when the residue is added in
concretes and mortars there is a decrease in the strength [2]. Similar behavior is observed for
the splitting tensile strength, although there is a less accentuated decrease [3].
In the modulus of elasticity, the addition of tire rubber in mortars provokes a reduction in
the results [4]. This indicates that the material presents a larger capacity to absorb
deformations.
Another property influenced by the addition of tire rubber in the mixture is the water
absorption. According to the literature, the specimens containing tire rubber presents smaller
water absorption than those that doesn’t have the residue [5].
Some authors, aiming at the improvement in the performance of the mechanical properties
of compositions added with tire rubber, have proposed treatments for its surface. In cement
paste tests a superficial treatment of the rubber with a sodium hydroxide saturated aqueous
solution showed that some properties as abrasion resistance and water absorption can be
improved, while another remain practically unaffected. The improvement in the obtained
results is attributed to a larger adhesion among the cement paste and the tire rubber particles
that can be seen by scanning electron microscopy [6].
The objective of this work is to make a comparison among mortars added with tire rubber
particles replacing part of the fine aggregate and to evaluate the influence of its superficial
treatment in some properties of the mortar as: compressive strength, splitting tensile strength,
water absorption and modulus of elasticity.
2.
MATERIALS
The materials used to prepare the mortars were: fine aggregate, cement and tire rubber. As
fine aggregate it was used a fine sand river 2.65 g/cm³ unit weight. The cement used was CPV-ARI PLUS, 3.05g/cm³ unit weight and its physical and chemicals characteristics in
agreement with the Brazilian standards.
The tire rubber, supplied by Borcol Industry of Rubber Ltd. originating from triturated subproducts of automotive industries with 1000µm size and 1,09g/cm³ unit weight. In order to
prepare mortars it was used a composition of: 1:3:0,5 in weight and an amount of 20% in
volume to replace the fine aggregate by rubber. Figure 1 display the residue used in the work.
Page 2
Figure 1: Tire rubber residue
2.
METHODS
2.1
Residue’s treatment
The tire rubber residue was submitted to a treatment with saturated aqueous solution of
sodium hydroxide. The rubber was inserted in the solution for 30 minutes. After the
immersion process, the material was washed until that its pH was 7.
The result of the treatment can be seen in Figures 2 and 3 that shows respectively the
rubber with and without treatment using an electronic microscopy.
Figure 2: Treated rubber
Figure 3: Tire rubber without treatment
Page 3
2.2
Tests procedures
The accomplished tests were compressive strength, splitting tensile strength, modulus of
elasticity and water absorption, all of them according the following Brazilian standards:
- Compressive strength: NBR 7215/96 of ABNT;
- Splitting tensile strength: NBR 7222/94 of ABNT;
- Water absorption: NBR 9778/87 of ABNT;
- Modulus of elasticity: NBR 8522/03 of ABNT.
The tests were carried out for the ages of 7, 28 and 56 days and the specimens were
maintained in humid chamber until the test’s day. The water absorption test was the only test
carried out up to 90 days.
The determination of compressive strength, splitting tensile strength and water absorption
was carried out in cylindrical specimens of (5x10) cm while the modulus of elasticity test
used cylindrical specimens of (10x20)cm.
3.
RESULTS AND DISCUSSION
Figures 4 and 5 present the results obtained from the compressive strength and splitting
tensile strength tests respectively.
Compressive Strength
Compressive strength (MPa)
25
20
15
without treatment
With treatment
10
5
0
0
10
20
30
40
50
60
Time (days)
Figure 4: Compressive strength
In Figure 4 it is observed that the results obtained from the test with mortars with and
without treated rubber were closer in recent ages (19,34 MPa and 18,26 MPa, respectively to
the age of 28 days). In advanced ages the difference among them is higher. In 56 days it can
be seen that mortars with the residue without treatment present better performance than the
added with treated rubber ones (21,38MPa and 17,48MPa, respectively).
Page 4
Tensile Strength
4,5
Tensile Strength (MPa)
4
3,5
3
2,5
Without treatment
With treatment
2
1,5
1
0,5
0
0
10
20
30
40
50
60
Time (days)
Figure 5: Splitting tensile strength
The behavior in compressive strength is observed in splitting tensile strength test (Figure
5). Although the results have also been close in recent ages (3,74MPa for rubber without
treatement and 3,96MPa for treated rubber in 28 days), the rubber treatment provokes a worse
performance in the mortars’ tests for advanced ages (3,66MPa and 4,1MPa, respectively for
rubber without and with treatment in 56 days).
Figure 6 presents the results of water absorption.
Water Absorption
7
Water absorption (%)
6
5
4
Without
treatment
3
With treatment
2
1
0
7
28
56
Time (days)
Figure 6: Water absorption results
Page 5
Through the Figure 6 it can be observed that the treatment has a positive influence for 7
and 28 days. In 56 and 90 days, it can be clearly noticed that, as well as in the previous
properties, the treatment damages the performance of mortars. Since the water absorption of
the specimens constituted with treated rubber is more than 30% higher than the without
treatment ones.
The modulus of elasticity’ results can be seen in Figure 7.
Module of Elasticity
18
Module of Elasticity (GPa)
16
14
12
10
With
treatment
8
Without
treatment
6
4
2
0
0
10
20
30
40
50
60
Time (days)
Figure 7: Modulus of elasticity results
Differently of the observed in the previous tests, in Figure 7 is noticed that the treatment of
the residue doesn't present any influence in modulus of elasticity, since they are almost the
same along the time.
4.
CONCLUSION
Through the obtained results, it is noticed that the treatment of tire rubber doesn't influence
in all of the analyzed properties which is verified in modulus of elasticity results.
In a general way, for advanced ages (56 and 90 days) the treatment of the surface’s tire
rubber was shown prejudicial to the performance of mortars in compressive strength, splitting
tensile strength and water absorption.
For compressive strength and splitting tensile strength tests, the treatment doesn't influence
until the age of 28 days. While in water absorption there is an initial improvement with the
treatment with change in the situation in 56 and 90 days.
Tests in specimens with advanced ages are suggested to confirm the alteration of the
behaviour of the mixture.
Page 6
The increase of the water absorption in specimens with treated rubber can be attributed to
the occlusion. The treatment permit to form empty places in the rubber’s surface, so that its
become rougher. In these interstices it can occur the accumulation of water, increasing the
results of the test.
ACKNOWLEDGEMENTS
The authors thank Holcim Brasil that gave all the cement used in the research, FAPESP for
the financial support, CESP Civil Engineering Laboratory and Borcol Indústria de Borracha
Ltda.
REFERENCES
[1] Revista Fapemig disponível no site www.revista.fapemig.br.
[2] Toutanji, H. A. ‘The Use of Rubber Tire Particles in Concrete to Replace Mineral Aggregates’,
Cement and Concrete Composites. 18 (1996) 135-139.
[3] Bonnet, S. ‘Effet de l’incorporation des granulats caoutchouc sur la résistance à la fissuration des
morties’, XXIEMES Rencontres Universitaires de Genie Civil, 2003, 59-70.
[4] Lia, G., Garricka, G., Eggersb, J., Abadieb, C., Stubblefieldc, M. A. and Panga, S. ‘Waste tire
fiber modified concrete’, Composites: Part B. 35 (2004) 305–312.
[5] Bauer, R. J. F., Tokudome, S. and Gadret, A. D. ‘Estudo de Concreto com Pneu Moído’,
Proceedings of 43º Congresso Brasileiro do Concreto, 2001.
[6] Segre, N., Joekes, I. ‘Use of tire rubber particles as addition to cement paste’, Cement and
Concrete Research 30 (2000) 1421-1425.
Page 7

STUDY OF TREATED AND UNTREATED TIRE RUBBER MORTAR

Transcrição

Documentos relacionados

UB-6200 series

2013 Region III Boys `99 Pool