Use of Expanded Polystyrene (EPS) Integrated with Steel Fibres as Coarse Aggregate Replacement in Concrete

McManus, Brendan (2022) Use of Expanded Polystyrene (EPS) Integrated with Steel Fibres as Coarse Aggregate Replacement in Concrete. [USQ Project]

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The versatility and durability of concrete make it the most extensively used construction material around the world. The high density of concrete, however, means that the self-weight of concrete members and foundation systems often restricts the design options available. As such, the development of light weight concrete offers the potential to expand the limits of concrete as a construction material.

Expanded Polystyrene (EPS) is a low-density material that is increasingly being used as a replacement for conventional aggregates to produce lightweight concrete. The addition of EPS, though, has been shown to compromise the beneficial mechanical properties of concrete. Previous research has demonstrated a decrease in the compressive, tensile and flexural strength of concrete containing EPS. These losses have proven to be substantially greater than the desired reduction in density achieved.

This study investigates a potential way of restoring the lost mechanical properties of EPS concrete through the addition of steel fibres connected to individual EPS beads as replacement coarse aggregate. The physical combination of fibres and beads provides a basic model to test and analyse results, with the aim to develop into a commercial product that can be added to a concrete mix at a specified dosing rate. A configuration of one bead to one fibre was adopted at a replacement percentage of 20% of coarse aggregate for this study.

The combined EPS and steel fibre aggregate was compared to concrete containing only conventional aggregate as well as control samples of concrete consisting of the same replacement percentage of EPS, steel fibres and plasticiser in various combinations. Test cylinders and a beam were cast from each batch with the cylinders used for analysis of density, compressive strength, tensile strength and segregation of materials. Each beam was subjected to a four-point bending test to determine the modulus of rupture and observe the flexural behaviour of the beam after fracture.

The results demonstrate that compressive strength and flexural strength is reduced in concrete containing the experimental combined steel fibre and EPS bead aggregate. The tensile strength results, however, indicate improved tensile strength in concrete with the combined aggregate. Density analysis of the samples shows an increase in segregation of materials occurring in the mix with the combined aggregate, although further analysis of EPS distribution suggests that this is a result of denser material migrating to the lower region of the concrete mix rather than an uneven distribution of the EPS beads and steel fibre aggregate within the mix.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Current – Faculty of Health, Engineering and Sciences - School of Engineering (1 Jan 2022 -)
Supervisors: Lokuge, Weena
Qualification: Bachelor of Engineering (Honours) (Civil)
Date Deposited: 19 Jun 2023 02:11
Last Modified: 20 Jun 2023 01:06
Uncontrolled Keywords: Expanded Polystyrene (EPS); concrete; conventional aggregates

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