Evaluación técnica, económica y ambiental del reemplazo de refuerzo de acero por fibras PET recicladas en losas apoyadas sobre terreno.
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Date
2025
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Universidad de Concepción
Abstract
La industria de la construcción representa uno de los sectores más intensivos en el uso de recursos, con alta demanda de materiales como el hormigón y el acero, cuyos procesos productivos generan elevados impactos ambientales. La producción de cemento representa cerca del 8 % de las emisiones globales de CO₂, mientras que el acero requiere alta energía y presenta una fuerte dependencia de importación en países como Chile. En paralelo, la acumulación de residuos plásticos, especialmente PET, ha motivado su valorización como insumo en nuevos materiales. En este contexto, el uso de fibras recicladas de PET en hormigón aparece como una alternativa prometedora en términos técnicos, ambientales y económicos.
Este trabajo tiene como objetivo evaluar la factibilidad técnica, económica y ambiental de usar PET reciclado como refuerzo en el hormigón, con énfasis en su viabilidad como sustituto del acero en losas apoyadas sobre terreno. Se analiza su efecto en la resistencia mecánica, el control de fisuración y el comportamiento postfisura, considerando su aplicación en elementos de baja exigencia estructural.
La metodología incluyó una revisión bibliográfica del estado del arte, un análisis estadístico de resultados experimentales, y la evaluación de criterios normativos aplicables. Se desarrolló un diseño comparativo de losas con malla de acero y con fibras R-PET, seguido de un análisis económico y ambiental con enfoque de ciclo de vida adaptado al contexto chileno.
Los resultados indican que, en promedio, con una dosificación del 1 % en volumen y fibras de entre 30 y 50 mm de longitud, se logra un buen equilibrio de propiedades en el hormigón, manteniendo su resistencia a compresión y trabajabilidad, y permitiendo mejorar la resistencia a flexión, el control de fisuración y la tenacidad. Sin embargo, para reemplazar una malla de uso convencional en losas apoyadas sobre terreno, se determinó que una dosificación de solo 0,24 % en volumen sería suficiente. Aunque este volumen es inferior a lo estimado como óptimo, resultaría adecuada para aportar resistencia postfisura y control de agrietamiento en aplicaciones de baja exigencia estructural, donde el hormigón ya cumple por sí solo con la resistencia base requerida.
El diseño con fibras PET mostró una reducción de hasta un 24 % en el costo por metro cuadrado de superficie de losa, así como una disminución de aproximadamente un 12 % en las emisiones de CO₂e por unidad de superficie, en comparación con el uso de refuerzo con malla electrosoldada.
Se concluye que las fibras recicladas de PET constituyen una alternativa viable para sustituir parcialmente el acero en losas apoyadas, especialmente en aplicaciones de baja exigencia. Esta solución permite valorizar residuos plásticos, reducir costos y avanzar hacia una construcción más sostenible.
The construction industry is one of the most resource-intensive sectors, with high demand for materials such as concrete and steel, whose production processes generate significant environmental impacts. Cement production accounts for approximately 8% of global CO₂ emissions, while steel requires high energy input and presents strong import dependency in countries like Chile. In parallel, the accumulation of plastic waste—particularly PET—has driven its valorization as a raw material in the development of new construction products. In this context, the use of recycled PET fibers in concrete emerges as a promising alternative from technical, environmental, and economic perspectives. This study aims to assess the technical, economic, and environmental feasibility of using recycled PET as reinforcement in concrete, with emphasis on its viability as a substitute for steel in ground supported slabs. Its effects on mechanical strength, crack control, and post-cracking behavior are analyzed, considering its application in elements with low structural demands. The methodology included a state-of-the-art literature review, a statistical analysis of experimental results, and an evaluation of relevant design standards. A comparative slab design was developed using welded wire mesh and R-PET fibers, followed by an economic and environmental life cycle analysis adapted to the Chilean context. The results indicate that, on average, a dosage of 1% by volume with fiber lengths between 30 and 50 mm achieves a good balance of concrete properties, maintaining compressive strength and workability while improving flexural strength, crack control, and toughness. However, to replace conventional mesh in ground-supported slabs, a dosage of only 0.24% by volume was found to be sufficient. Although this volume is lower than the optimal dosage estimated in the literature, it would still be adequate to provide post-cracking resistance and crack control in low-demand structural applications, where concrete alone already meets the basic strength requirements. The PET fiber-reinforced slab design showed a reduction of up to 24% in cost per square meter of slab surface, as well as an approximate 12% decrease in CO₂e emissions per unit area, compared to slabs reinforced with welded wire mesh. It is concluded that recycled PET fibers are a viable alternative to partially replace steel in ground supported slabs, particularly in low-demand applications. This solution allows for the valorization of plastic waste, cost reduction, and progress toward more sustainable construction practices.
The construction industry is one of the most resource-intensive sectors, with high demand for materials such as concrete and steel, whose production processes generate significant environmental impacts. Cement production accounts for approximately 8% of global CO₂ emissions, while steel requires high energy input and presents strong import dependency in countries like Chile. In parallel, the accumulation of plastic waste—particularly PET—has driven its valorization as a raw material in the development of new construction products. In this context, the use of recycled PET fibers in concrete emerges as a promising alternative from technical, environmental, and economic perspectives. This study aims to assess the technical, economic, and environmental feasibility of using recycled PET as reinforcement in concrete, with emphasis on its viability as a substitute for steel in ground supported slabs. Its effects on mechanical strength, crack control, and post-cracking behavior are analyzed, considering its application in elements with low structural demands. The methodology included a state-of-the-art literature review, a statistical analysis of experimental results, and an evaluation of relevant design standards. A comparative slab design was developed using welded wire mesh and R-PET fibers, followed by an economic and environmental life cycle analysis adapted to the Chilean context. The results indicate that, on average, a dosage of 1% by volume with fiber lengths between 30 and 50 mm achieves a good balance of concrete properties, maintaining compressive strength and workability while improving flexural strength, crack control, and toughness. However, to replace conventional mesh in ground-supported slabs, a dosage of only 0.24% by volume was found to be sufficient. Although this volume is lower than the optimal dosage estimated in the literature, it would still be adequate to provide post-cracking resistance and crack control in low-demand structural applications, where concrete alone already meets the basic strength requirements. The PET fiber-reinforced slab design showed a reduction of up to 24% in cost per square meter of slab surface, as well as an approximate 12% decrease in CO₂e emissions per unit area, compared to slabs reinforced with welded wire mesh. It is concluded that recycled PET fibers are a viable alternative to partially replace steel in ground supported slabs, particularly in low-demand applications. This solution allows for the valorization of plastic waste, cost reduction, and progress toward more sustainable construction practices.
Description
Tesis presentada para optar al título de Ingeniero Civil Mecánico
Keywords
Materiales Análisis, Aprovechamiento de desechos, Reciclaje, Plásticos en la construcción