Caracterización física y mecánica de morteros de cemento Portland fabricados con adición de partículas de poliestireno expandido (EPS)

Abstract

Caracterización física y mecánica de morteros de cemento Portland fabricados con adición de partículas de poliestireno expandido (EPS) Physical and mechanical characterization of Portland cement mortars made with expanded polystyrene particles addition (EPS) RESUMENEl objetivo de este estudio es evaluar la influencia de la adición de distintos tipos y dosificaciones de poliestireno expandido, tanto comerciales como procedentes de reciclado, sobre las características físicas y mecánicas de morteros de cemento Portland. Las variables estudiadas fueron: consistencia, aire ocluido, densidad aparente, resistencias mecánicas, porosidad, absorción de agua y absorción acústica. Los morteros también se han caracterizado por microscopia electrónica de barrido. Con objeto de mejorar la trabajabilidad de los morteros se ha empleado aditivos aireante, retenedor de agua y fluidificante. Los resultados muestran que al aumentar la cantidad de poliestireno expandido la trabajabilidad y las resistencias mecánicas disminuyen. El empleo de aditivos mejora la trabajabilidad y la porosidad, permitiendo fabricar morteros con altos contenidos de residuo, con propiedades mecánicas adecuadas para su empleo como morteros de albañilería, revoco y enlucido.Palabras clave: morteros, cemento, propiedades físicas y mecánicas, poliestireno expandido (EPS), residuo. SUMMARYOn this work the influence of the addition of different types (commercial and recycled) and contents of expanded polystyrene on the physical and mechanical properties of Portland cement mortars has been studied. Variables studied are: workability, air content, bulk density, mechanical strength, porosity, water absorption and sound absorption. Mixtures have been also characterized by scanning electron microscopy. Airentraining agents, water retainer and superplasticizer additives have been used in order to improve the workability of mortars. The results show that the workability and mechanical strength decreases with increasing content of expanded polystyrene. Additives improve the workability and porosity, allowing manufacture mortars with high levels of recycled material that show mechanical properties suitable for use as masonry mortars, stucco and plaster.

Lightweight cement-based materials

“…Giurich and Pique ´ [18] added that vibration is not effective in reducing cavities in low-consistency, high-cohesive mixtures, only leading to an increase in segregation. Sri Ravindrarajah and Tuck [6] recommend the usage of plasticizers in mixtures with low water-to-cement ratio in order to reduce the number of cavities, in agreement with other authors [2,7]. Airentraining agents can also be used to improve the workability of EPS concrete; however, the arising reduction of mechanical strength must be considered.…”

“…Madandoust et al [13] showed that, for a given EPS content, reducing the waterto-cement ratio reduces consistency, due to a decrease in the cement paste viscosity. Garcı ´a-Alcocel and Ferra ´ndiz-Mas [2] reported that for the same EPS content and water-to-cement ratio, consistency of mixtures made with spherical EPS beads is higher than that of mixtures made with crushed recycled EPS. This is because the former has a lower surface area than the latter, thus reducing the surface area to which cement paste adheres and increasing the free cement paste responsible for the mixture flow.…”

“…Compared to other lightweight aggregates, EPS stands out for being highly porous (95%À98% of its volume is void space) but at the same time hydrophobic [2]. The latter property makes EPS different from other lightweight aggregates, as it has almost zero absorption of the concrete mixing water [3].…”

“…The consistency of EPS lightweight concrete generally decreases with an increase in the EPS content [2,5,7,12,18]. This phenomenon is mainly attributed to a lower weight of the mix itself, as weight is the driving force that causes slump.…”

Thermal insulating plasters and their hygric properties

“…Less attention was paid to plasters, especially to the improvement of their thermal properties. The utilization of expanded polystyrene [4] or polyurethane foam [5] in Portland cement plasters belongs to the subjects of such research. Other studied materials are gypsum mortars with polyamide powder [6] or with cork [7].…”