UTILIZATION OF SCRAP TIRES IN THE PRODUCTION OF BUILDING MATERIALS TO CIVIL CONSTRUCTION

Transcription

1 UTILIZATION OF SCRAP TIRES IN THE PRODUCTION OF BUILDING MATERIALS TO CIVIL CONSTRUCTION RODRIGUES JORGE, Mara Regina Pagliuso (1), FERREIRA, Osny Pellegrino (2) and CLARO NETO, Salvador (3) (1) D. Pedro II Colleges São José do Rio Preto SP Brazil (2) Laboratory of Civil Construction Engineering College of São Carlos Universidade de São Paulo Brazil (3) Grupo de Química Analítica e Tecnologia de Polímeros - Instituto de Química de São Carlos Universidade de São Paulo Brazil Abstract The increase in levels of environmental pollution and generating residue is intrinsically related to the contemporary life style, because there has been a growth in the consumption of goods and services. To solve this problem, researches have been developed according to the 3Rs: Reduction, Reutilization, and Recycling. This paper aims to develop a minimization technology of the impact caused by the environmental passive, generated by the scrap tires associated to support development. The tires have a singular physical structure with great resistance and durability, even in the final of their useful life, being inadequate to deposition in sanitary land-fillings because they do not allow compaction, becoming favorable to the creation of disease vectors, besides offering great fire risks, with serious environmental impact. The developed technology uses the rubber residue of the scrap tires at the composition of low cost products to be used in the civil construction. Mechanical process is used to divide the tire rubber into fractions to the attainment of granulometric levels that allow the study of different rubber/bonding agent ratio, that are pressed afterwards at several temperature levels. The bonding agent used was the polyurethane resin derived from the castor oil (Ricinus communis) that is a renewed resource, which also presents physical and chemical stabilities, and strong bonding strength. The obtained composite was tested in compressive and tensile strengths, and had determined its modulus of elasticity, showing satisfactory results to the application at the civil construction as rubber pavements and filling sandwich wall materials. Keywords : Tire, Rubber, Recycling, Residues, Polyurethane Resin 1. INTRODUCTION In order to confront the damages caused by the environmental impacts derived from solid residues, resulting from their final inadequate disposition, several forms of minimization have been adopted in the whole world, such as recycling and reusing of materials. These measures 472

2 aim at the amplification of the useful cycle of life, minimizing the extraction of natural resources and maximizing the useful life of the sanitary land- fillings. It is verified in Brazil that, while the utilization of some solid residues developed in the last decades, other materials, such as the scrap tires and other derivatives from rubber, continue being inadequately disposed in the environment. Inside this context, the question of the abandoned or inadequately disposed scrap tires requires special attention; because beyond these materials constitute an environmental passive; they cause serious hazards to the environment and to the public health. There are several impacts the tires can cause to the environment. When burned in the open air, they liberate sulphurdioxide in atmosphere, contributing to air pollution. To each burned tire, around 10 liters of oil are liberated in the soil, which percolate until they reach the water table, contaminating this subsoil water. When disposed in sanitary land-fillings, the tires, due to their low compressibility, reduce the useful life of these fillings [1]. Having the materials that compound the structure of the tires a difficult composition, their final disposition becomes more complex. The actual challenge to mitigate the environmental damage caused by these residues in Brazil and in the world consists in applying the technolo gical alternatives of utilization, reutilization and recycling for scrap tires. Therefore, this report presents an additional technological alternative to the utilization of this residue by using the rubber of scrap tires in covering plates used in civil construction, analyzing the best dose of compounds of rubber polyurethane resin derived from castor oil, creating solutions and contributing to the reduction of this environmental passive. 2. MATERIALS AND METHOD The method consisted in analyzing the optimum ratio to the composition of rubber residue derived from scrap tires with agglomerative of vegetal origin polyurethane resin derived from the castor oil. 2.1.Tire residue The tire residue used was acquired from the private company, in the following granulometric sizes, as shown in picture 1 : P5-mesh 5 P10-mesh 10 P20-mesh 20 P30-mesh 30 Figure 1 Tire residue. 2.2 Polyurethane resin Polyurethane resin derived from castor oil, developed since 1983 by the Laboratório de Química Analítica e Tecnológica de Polímeros (LQATP) do Instituto de Química (IQ-USP). This resin has the advantage of being a material obtained from a natural and renewable resource. On the other hand, the polyurethane resin derived from the petrochemical industry 473

3 which has the raw material to their production in the compounds derived from petroleum, that is an exhaustible resource, besides the former can be prejudicial to health, in case of being submitted to fire. The polyurethane is always mentioned as an example of material that combines high mechanical resistance with elevated rate of extending before the rupture (% of extention). This combination of basic properties of polyurethanes conducts to the combination of enormous resistances to the impact and abrasion, besides excellent resistance to the most organic liquids, in form of oils and fluids. The use of this resin is interesting because it will be utilizing a causing residue of environmental impact in the production of a compound with potential industrial utilization. The picture 2 and 3 shows the Ricinus communis plant, and and the polyurethane resin derived from castor oil. Prepolymer Polyol Figure 2 and 3 - Castor oil plant (Ricinus communis)andpolyurethane resin derived from castor oil. The table 1 shows the % retained in the meshes. Table1 Granulometric Composition of Rubber Rubber Utilized Granulometry % Retained in the Meshes 4,8 2,4 1,2 0,6 0,3 0,15 P05 0,0 57,5 98,9 99,7 99,8 99,9 P10 0,0 0,0 68,3 99,4 99,6 99,9 P20 0,0 0,0 2,7 59,4 87,4 97,6 P30 0,0 0,0 0,0 1,7 54,6 90,6 The Ruthfuchs method was used because it was the best method to obtain the percentagens of rubber. The percentage of rubber in the different meshs was obtained by the Ruthfuchs method, represented in the charts 1 below: 474

4 Chart 1 Results of graduated mixtures (Ruthfuchs Method) to zone 3. Fifteen percent (15%) of polyurethane resin was used in the composite, at the approximated temperature of 100 C, to agglomerate the rubber. 2.3 Molds A device to heat the composite with a temperature variation until 300 C and molds to mold the bodies of test to the necessary analysis were developed. (Mold for cylindrical specimen test and for strips with rectangular section). Figure 4 - Molds for the cylindrical specimen compression test 475

5 Figures 5 and 6 Mold for the specimen traction test. Figures 7 and 8 Mold and Prototype of floor covering plate. 2.4 Tests of axial compression and axial traction The tests were done according to [2] for compression and [3] for traction in the Laboratório de Química Analítica e Tecnologia de Polímeros (LQATP) do Instituto de Química (IQ-USP). Pictures 9 and 10 Specimen test deformed by axial compression and broken by axial traction 476

6 2.5 Action compression test Results The relation between Tension σ (MPa) and Deformation ε (%) is represented in the chart below: Chart 2 Compression test zone Axial Traction test Results The relation between Tension σ (MPa) and Deformation ε (%) is represented in the chart 5 below: Chart 3 Traction test zone

7 2.7 Elasticity module Graphic determination Tan θ = E = σ / ε (1) Table 2- Elasticity module COMPOSITE Rubber/Resin Tension σ (MPa) Deformation ε (%) Elasticity module E (MPa) compression properties 2, ,6 traction prope rties 0, , Hardness test For the hardness test a durometer Wultest was utilized, with the end of test to the shore A scale, model MP-2. The tests of hardness in the samples rubber/ resin were done at ambient temperature, folowing the procedure described by the standard [4] for rubber property durometer hardness. Table 3 Durometer hardness Composite Hardness (Shore A scale) Tire 73 Rubber/Resin z Density and Specific Gravity (Relative Density) of Plastics by Displacement. This test was done according to the [5]. Because it is a material that does not absorb water, its density was obtained through mass and volume of the bodies of test. The mass was achieved in a scale with precision of 0,001 g and the volume, through measurements with caliper rule with precision of 0,01 mm. In this manner, the density was plainly obtained by quotient of the division of the mass (g) by the volume (cm 3 ). ρ = m / v (2) Table 4 Density and specific gravity Composite Density ρ (g / cm 3 ) Rubber/Resin z3 1,16 Tire 1,17 3. ANALYSIS OF THE RESULTS Resistance to Axial Compression and Traction The tests achieved according to the standards [2] and [3] permit evaluate the axial compression and axial traction performances of the composite material (rubber- polyurethane resin), comparing with the sample removed directly from a tire in use. The initial results, limiting the ratio of polyurethane resin in 15% (in mass) relatively to the triturated rubber, indicate a low capacity of the composite to resist to high tensions of compression or traction, with their rupture occurring after deformations around 50% of the 478

8 initial dimensions of the bodies of test. Deformation and Extension Module Both the axial compression deforming module and the axial traction deforming module presented biggest values in the case of the composite rubber/polyurethane resin when compared with the values of a tire in use, having small extensions to the first material as a consequence, when its rupture has occurred. Hardness and Density The result of Shore hardness rate, obtained for the composite rubber/polyurethane resin, is not substantially different from the sample removed from a tire in use, which can be explained in consequence of the former being constituted of fragments of rubber, which has not suffered any type of alterations of their properties, it has just suffered successive grind process and granulometric selection in specific meshes. 4. CONCLUSION The general performance, as the mechanics properties of the composite rubber/polyurethane resin derived from castor oil, was satisfactory in those preliminary tests. We intend to go ahead with this study in order to investigate the most important limits that interfere in rubber adherence with the resin utilized. Different ratios of polyurethane resin comparing with rubber must be investigated to evaluate the consequences in the physics and mechanics properties of the resultant composite. In addition of heating, other surfacing treatments can be necessary to improve the link in the interface of the rubber particle with the polyurethane resin, so improving the mechanic performance of the composite. It is also suggested the achievement of studies to verify the abrasion performance, important trait for the use of this new material in the covering surfaces (floor and walls) in buildings. Although the research is still in an initial phase, the results obtained indicate a high potential for the utilization of this composite rubber/polyurethane resin derived from vegetal oil, in several applications in the civil construction, representing a practicable alternative to the reutilization of rubber coming from the grind process of scrap tires. Important questions, of high environmental interest, could be satisfied with the utilization of this recent composite material, but alternatives to their use in different construction sectors will still be proposed. REFERENCES [1] Cimino, M. A., Baldochi, V. M. Z. 'Minimização de Resíduos Sólidos Urbanos - Alternativas Tecnológicas para Pneumáticos Inservíveis'. Unisanta, Ufscar, [2] ASTM D695M.. Standard Test Method for Compressive Properties of Rigid Plastics. [3] ASTM D638M. Standard Test Method for Tensile Properties of Plastics. [4] ASTM D for rubber property Durometer Hardness. [5] ASTM D792 Density and Specific Gravity (Relative Density) of Plastics by Displacement 479