Evaluation and optimization of composite thermal insulators from waste materials

الملخص EN

The present work includes a study on the effect of loading rubber waste into cement mortar on the thermal and mechanical properties of a thermal insulator.The experimental work of the study included the preparation of ten models of 35 mm diameter and 5 mm thickness.

Portland cement and natural sand were used as a matrix and rubber waste (extracted from the consumed tires) as a filler was added in weight percentages ( 5% ,10% ,15% ,20% ,25% ,30% ,35% ,40%,45% and 50%).

Water was also used as a binder.Also, the experimental work included conducting a thermal conductivity test using Lee’s Disk method, and a hardness test using the Shore scale.

The theoretical side included extraction of empirical equations, depending on the experimental results.

The thermal conductivity equation was for two variables, temperature and mass fraction.

While the hardness equation was for one variable, mass fraction.

Theoretically determined heat capacity was extracted using the equations of the composites.

Based on the empirical equations of thermal conductivity and hardness and using the technique of multi-objectives genetic algorithm, the optimum values of temperature and mass fraction were extracted, which achieve the best thermal insulation of the mortar.

The results showed a significant decrease in thermal conductivity.

The reduction in thermal conductivity was (90.3%) at 5% and reduced to (95.73%) at 50%.

The specific heat capacity was increasing as the percentage of rubber waste increase.

The results also indicated a decrease in hardness.

The optimal value of thermal insulation was (0.02658 W/m2.ºC ) as a thermal conductivity and (58.07 N/m2) as a hardness, at temperature (50°C) and mass fraction (27.764%) of rubber waste.