Gypsum Composites with Modified Waste Expanded Polystyrene

Abstract

The construction and demolition waste recycling into secondary raw materials is vital to achieving a sustainable and circular building life cycle. Expanded polystyrene (EPS) is one of the materials whose recycling rate should be increased. EPS boards can be shredded and used as aggregate of lightweight cement composites resulting in a material with combined properties subjected from EPS and mineral binder. To reduce the open structure of shredded EPS particles, proper treatment could improve EPS performance. The heat treatment of the aggregates can reduce the volume and increase their density. In this paper, EPS aggregates were heat-treated at 120 and 130 °C, and heat-modified EPS aggregates with a bulk density of 40 and 100 kg/m3 were incorporated as filler material in gypsum composites. The composites’ density, compressive strength, thermal conductivity, and sound absorption were characterized. Results indicate that a composite with a compressive strength from 15 to 136 kPa and a material density ranging from 48 to 194 kg/m3 can be obtained. Thermal conductivity was achieved from 0.0390 to 0.0604 W/(mK). Following the ISO 10534-2 standard, the noise reduction coefficient was determined and showed promising results at 600 to 800 Hz, reaching a sound absorption coefficient of 0.88.

Additive Manufacturing of Lightweight Gypsum and Expanded Polystyrene Granulate Composite

“…As aggregate, recycled EPS beads with a particle size of up to 5 mm were used (GoGridas, Jaunolaine, Latvia). For the specific particle size distribution range of the used EPS beads, see the authors' previous research paper [10], Figure 1, EPS10. A citric acid-based setting retarder, Gips Retard (TKK, Srpenica, Slovenia), was used to slow down the setting time.…”

“…Some studies have researched the printability of lightweight aggregate concrete using aggregates such as expanded clay [3], expanded glass granulate [4], lightweight ceramsite sand [5,6] expanded perlite aggregate [7], and expanded thermoplastic microspheres [8]. During the last decade, research on the development of lightweight gypsum composites as a more environmentally friendly alternative to lightweight cement-based materials has been emerging [9][10][11], extending the relatively limited gypsum application possibilities. The use of lightweight gypsum composites offers possibilities to create building elements with reduced dead load, improved thermal and acoustic insulation properties, and enhanced fire resistance which contributes to the longer lifespan of constructions [9].…”

Enhancing Sustainability in Construction: Investigating the Thermal Advantages of Fly Ash-Coated Expanded Polystyrene Lightweight Concrete

“…The air pockets in the concrete might cause a lightweight concrete with EPS beads to have a much lower thermal conductivity than denser concrete that does not have these beads. The alteration of the EPS aggregates somewhat affects the thermal conductivity of the overall material [24]. This trend shows that adding EPS beads lowers the overall density.…”

Utilization of Waste-Expanded Thermoplastic as a Sustainable Filler for Cement-Based Composites for Greener Construction

“…Expanded thermoplastic materials are characterized by their soft matrixes filled with a high number of closed air pores. So, because of their small mechanical strength in the range of tens (in relation to the maximum of hundreds of kPa [60,61]), EPS beads represent a very fragile material that is susceptible to easy failure under loading in a hardened composite matrix [8,62]. However, even with the full volumetric replacement of the natural aggregate with a fraction of EPS beads at 2/4 mm, it was still possible to achieve mortars with 20 MPa of compressive strength.…”