Plastic Waste Particles in Mortar Composites: Sulfate Resistance and Thermal Coefficients

Abstract

Plastic industry produces large amounts of waste polyethylene terephthalate (WPET), what causes environmental problems. An investigation was carried out on the effect of sulfate attack on the durability of composites produced with WPET. An attempt was also made to determine the thermal coefficients as well as the dynamic elastic moduli. Experiments were accomplished on limestone sand and cement mortars where the blended Portland cement was partially replaced by various volume fractions of WPET particles. The test solutions used to supply the sulfate ions and cations were 5% sodium sulfate solution and 5% magnesium sulfate solution. Tap water was used as the reference solution. Mass changes, compressive and flexion strengths measured on specimens were used to assess the changes in the mechanical properties of composites exposed to sulfate attack at different times. X-ray diffraction, FT-IR spectroscopy, scanning electron microscope (SEM/EDS) and differential scanning calorimetry were used to evaluate the microstructural nature of the sulfate attack. The test results showed that the presence of WPET had a beneficial effect in the control of the strength loss due to sodium and magnesium sulfate attacks and gave better insulation properties. This study insures that reusing TWPET particles as cement substitutes in mortar gives a good approach to sulfate durability, insulation, mechanical properties and solves some of the solid waste problems posed by plastics. Therefore, WPET-mortar composites are often presented as the materials of the future because of their potential for innovation and the advantages they offer. In fact, using WPETs as cement substitutes reduces the energy consumption. These composites address problems related to environmental pollution by CO2 emissions, and are used to repair various reinforced concrete structures.

Impact Resistance and Sodium Sulphate Attack Testing of Concrete Incorporating Mixed Types of Recycled Plastic Waste

“…After that, the specimens experienced comparable behaviour and gained more mass due to composition of higher quantities of gypsum, ettringite or other sulphate minerals that filled the pores. Mass gain as a result of the formation of the previously mentioned corrosion products has been reported by Benosman et al [12]. Moreover, the control mix continued to follow the same behaviour until the end of the test.…”

“…This indicates that the loss in both compressive and splitting tensile strengths was higher in MRPC mixes compared to the control. Among limited studies, Benosman et al [12] studied the compressive and flexural strengths of concrete composites contained PET recycled plastic after exposure to 180 days sodium sulphate attack. The findings showed an increase in compressive strength for mixes with higher plastic content although all values were less than the control mix.…”

Prediction models of mechanical properties for pet-mortar composite in sodium sulphateaggressive mediums

“…The composites containing waste PET particles were produced in accordance with the results of the works of Benosman et al [12]. A massic ratio of 3 between sand (S) and cement (C) was respected.…”

Evaluación del comportamiento a compresión y propiedades físicas de morteros de cemento reforzados con fibras recicladas PET

“…La ausencia de productos de hidratación del cemento en la interface pastafibras plásticas también se debe considerar para la reducción en la resistencia a compresión y el módulo elástico [30]. Otros estudios concluyen que la reducción de la resistencia a compresión y del módulo elástico de los materiales cementantes se debe al bajo módulo elástico de las partículas PET (módulo de elasticidad en el orden de 2900 MPa) [31], y que la reducción en el módulo de elasticidad de los compuestos cementantes está relacionada con el incremento de la dosificación de partículas PET [32,33]. Lo anterior se atribuye a la alta capacidad deformable de las partículas o fibras PET que disminuye la capacidad de carga y la rigidez axial del compuesto cementante.…”