Mohamed Belbachir

Resistance of Polymer (PET) - Mortar Composites to Aggressive Solutions

This paper describes an innovative use of plastic bottle waste as cement-substitution within composite materials for preventing chemical attacks or repairing various reinforced concrete structures. Various weight fractions of cement varying from 2.5% to 7.5% were substituted by the same weight of polyethylene terephthalate (PET). The specimens were tested in flexure and compressive strength and for chemical resistance to acid, basic solutions at 5% and for chloride ion permeability. From this study, it was found that the PET-modified mortars exposed to aggressive environments showed better resistance to chemical attack and higher resistance to chloride ion penetration than unmodified one without substantially affecting the mechanical strength in tap water. The addition of PET to the modified mortars, means reducing the penetration of aggressive agents. So, the mass loss of composites exposed to hydrochloric and acetic acid solutions is lower than those of unmodified mortar. The basic solutions are harmless for composite materials. The formations which appear such as different calcium salts were determined by X-ray diffraction and FT-IR.

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

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.