The Effect of HDPE Plastic Fibres on Concrete Performance

: HDPE (high-density polyethene) plastic waste is stronger, harder, and more resistant to 11 high temperatures than other plastics. Using it as an additive in a concrete mixture is one solution 12 to reduce this type of waste. We examined how HDPE-type plastics can be used as an additive 13 material in the manufacture of concrete to improve its hardness, tensile strength and compressive 14 strength. Using 156 samples, we aimed to identify the effect of HDPE plastic fibres on concrete of 15 three qualities; B0, f'c10 MPa (low quality), and f'c25 MPa (medium and high quality). We added 16 four compositions (2.5%, 5%, 10% and 20% by weight of cement) of HDPE plastic fibre to each 17 quality of cement, with HDPE plastic fibre sizes of 1 x 1 cm, 0.5 x 2 cm or 0.25 x 4 cm. We found that 18 the addition of 5% HDPE plastic fibre with a 0.5 x 2 cm cross-sectional shape to the f'c10 MPa 19 concrete gives the best result, with increased tensile and compressive strength of the concrete. workability can be measured by testing the value of slump, which is identical to the concrete mixture plasticity. To examine the appropriate mixes of HDPE fibres as an addition to concrete for non- structural applications, this study conducted several trials to observe the effects of HDPE sizes on normal concrete, low quality concrete and high quality concrete.

As the scope of this study was non-structural applications, the cement used for this examination 101 was cement type 1, which is intended for walls, pavement, sidewalks and other precast products.

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The HDPE plastic materials were collected from the disposal at Samarinda landfills, as part of 170 the plan to reduce non-sustainable waste that can contaminate the waterways and aquifers. We then 171 rinsed them to ensure they were ready for the cutting process. As shown in Figure 2, to ensure visual 172 similarity among the HDPE plastic fibres, we selected plastic materials with a thickness of 0.05 mm 173 and cut them to a size of 1 x 1 cm, 0.5 x 2 cm, and 0.25 x 4 cm. The reason for this was to give them 174 the same surface area of 1 cm 2 . As the interaction between the fibres and cement affects the reinforced 175 concrete mixes, the same surface area was assumed to give a similar bonding effect in the process.

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We also tested the density of the concrete mass after the addition of HDPE fibres. We found that 309 concrete added to HDPE fibres decreased in weight compared to normal concrete, as shown in figure   As seen in Figure 6, which shows the inner layers of each destroyed sample, concrete containing 332 HDPE fibres seems more permeable and not fully solid. This study shows that the greater the amount 333 of fibre added to concrete, the more layers of concrete are porous. Thus, the addition of fibres will be 334 beneficial for reducing the weight of the concrete.    were flexed during casting, so plastic is not optimal for accepting external forces.

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This study identified several findings, which are discussed below.  Figure 1 shows that the addition of HDPE fibres to concrete affects the properties of the concrete.

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One of the properties that changes due to the addition of HDPE is the slump value, which is essential 433 for concrete workability. It also affects the quality of the concrete, due to the reduced slump value, as

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We conclude that the use of HDPE plastic fibres as a concrete additive material is able to increase 504 the strength of concrete in the composition with the addition of 5% HDPE for all fibre sizes. Of the 505 three concrete qualities examined, the f'c10 MPa concrete quality was the best quality to interact with 506 added HDPE plastic fibre material. We found that added HDPE plastic should only be used on low-507 quality concrete, aiming for non-structural concrete works.

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In the cases where the concrete containing HDPE plastic fibres is for the manufacture of wall 509 panels from precast concrete (f'c10 MPa), the addition should only be around 5-10%. For future 510 research, further investigations are needed to determine the effects of more than 20% HDPE and other 511 varying plastic addition into concrete, including to thermal insulation. This study has contributed to 512 the understanding of the optimal composition of HDPE plastic fibres in concrete. These findings will 513 add to the development of lightweight concrete for the green construction sector, especially for non-514 structural concrete applications. Furthermore, the use of HDPE fibres could also lead to a more 515 sustainable approach to reducing plastic waste.

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Nurdiana; draft preparation, visualisation, administration process, and the editing process.

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Conflicts of Interest: The authors declare no conflicts of interest associated with this publication and there has 520 been no significant financial support for this work that could have influenced its outcome.