Thermophysical characteristics of eco?friendly mortars containing recycled PET as partial sand replacement in dry and wet conditions

摘要

Plastic has become one of the most widely manufactured materials in the world and a key part of daily life. However, a large amount of plastic waste must be recycled to protect the environment. One of the ways of recycling is to use this waste as a substitute for raw material. This study aims to provide a thermophysical characterization of an eco-friendly mortar. This material is characterized by the partial replacement of sand with recycled PET. The sand was partially substituted (5, 10, 15, and 20%) by recycled PET with a water/cement ratio of 0.5. Thermophysical properties, which are thermal conductivity, volumetric specific heat, and thermal diffusivity, were measured experimentally in the dry and wet (water-saturated) state. These properties were determined as a function of the percentage of recycled PET using a Hot Disk analyzer. The workability, density, ultrasonic pulse velocity, and compressive strength of the samples were also evaluated. Experimental results revealed that with the addition of recycled PET, workability increased to a maximum value of 370 mm. The density of the mortar decreased by approximately 6.76% in the dry state and 4.28% in the wet state for a substitution rate of 20%. Thermophysical parameters also decreased linearly when 20% PET was added to the cement mortar: 46.81% for thermal conductivity with a minimum value of 0.693 W/mK, 26.80% for specific volumetric heat, and 27.34% for thermal diffusivity. A very good correlation (R-2 = 0.9847) was shown between compressive strength and ultrasonic pulse velocity, both decreasing with increasing percentages of recycled PET. The use of recycled PET as a partial replacement of sand affects the thermophysical properties of the cement mortar due to its porosity compared to the control mortar, thus highlighting the potential use of these mortars as energy-efficient and environmentally friendly construction materials. In addition, this is an ecological and sustainable practice as it conserves natural resources.[GRAPHICS].