Structural use of polymer composites using unsaturated polyester resins based on recycled poly(ethylene terephthalate).

摘要

Recycled poly(ethylene terephthalate), PET, mainly recovered from plastic beverage bottles, can be used to produce unsaturated polyester resins. Polymer concrete (PC) and polymer mortar (PM) made with these resins have been investigated for their potential use in structural applications. An initial evaluation consisted of determining the various properties of the neat resins and the PC materials. Various resins, made with different formulations and with different percentages of recycled PET in their alkyd portion, were used in this evaluation. Properties investigated included mechanical properties, effect of level of PET, quality control, and relationships between neat resins and PC mechanical properties. Based on this initial evaluation, two resins were selected to produce PC and PM for a more extended evaluation. The extended evaluation included durability properties (such as chemical resistance and water absorption), dimensional stability (such as shrinkage, thermal expansion, and creep), and time and temperature dependent properties (such as age and temperature effects on PC mechanical properties and thermal cycling of thin PM overlays on portland cement concrete slabs). Potential construction and structural applications of the PC and PM materials were also discussed. The properties and behavior of PC and PM using resins based on recycled PET are comparable to those obtained from PC and PM materials made from virgin resins. Resins using recycled PET offer the possibility of a lower source cost of materials for making useful PC and PM products. Also, the recycling of PET in PC and PM would help alleviate an environmental problem and save energy.; The structural behavior in shear and flexure for the steel-reinforced PC was extensively analyzed. Analysis included load-deflection and moment-curvature responses, modes of failure, cracking patterns and variation of strains and neutral axis depth with loads. The effect of the shear span-to-depth ratio, reinforcement ratio, compressive and flexural strength, and steel fibers was investigated with the shear beams while the effect of reinforcement ratio was investigated with the flexure beams. This study is not only important from the standpoint that resins based on recycled plastics were used, but also because very few investigations have been done in this area with steel-reinforced PC using virgin resins. Two approaches were then used to predict the shear and flexural strength of reinforced PC. The conventional approach, used for reinforced portland cement concrete, was first tried to determine if this theory can be extended to reinforced PC. A new procedure, based on structural behavior and statistical analysis, was then recommended for the efficient design of reinforced PC members subject to shear and flexure.