Sound absorption for concrete containing polyethylene terephthalate waste

Plastic solid waste generation increases every year with the current consumption habit prevalent in society nowadays. The improper disposal of plastic has been a major concern to the environment as it is not easily degradable. The issue of environmental pollution caused by polyethene terephthalates (PET) has been extensively discussed and the best solution proposed is recycling. Fibre Concrete (FC) was a composite material resulting from the addition of fibres to ordinary concrete. The objective of this research was to determine the acoustic absorption coefficient of concrete containing 0%, 0.5%, 1.0%, 1.5%, 2.0% of PET fibre compared to normal concrete. In this study, straight and irregular recycled PET fibres were used. The fibres were simply cut from PET plastic bottles. The length and width of recycling PET fibre were fixed at 25 mm and 5 mm respectively. The chosen percentages were 0.5%, 1.0%, 1.5% and 2.0% of fiber. A water-cement ratio of 0.45 was acceptable for all ranges. The tests that were conduct include the slump test, compression test, and impedance tube test. The specimens were tested on day 7 and day 28 after the concrete is mixed. The end of this research results for the compressive strength of normal concrete after 28 days of curing was 48.2 MPa while concrete with 0.5% PET, 1.0 % PET, 1.5% PET and 2.0% PET recorded a compressive strength of 50.9 MPa, 49.8 MPa, 47.9 MPa and 46.6 MPa respectively. The result of the impedance test received at age 28 days was 0.13 for normal concrete and 0.16, 0.14, 0.16 MPa, and 0.14 for 0.5% PET, 1.0 % PET, 1.5% PET and 2.0% PET respectively. In conclusion, the aspect ratio of the fibres to the concrete must be correlated to avoid reducing durability. In conclusion, the addition of 0.5% PET recycled fibre into concrete showed the best value in terms of strength and 0.16 for the sound absorption coefficient

Properties of Palm Oil Fuel Ash (POFA) Geopolymer Mortar Cured at Ambient Temperature

Geopolymer material needs high temperature curing to produce good microstructure, high strength, and durable product. However, curing at ambient temperature is more preferable and practical in application for cast in situ geopolymer. In order to allow curing at ambient temperature, the geopolymer is mixed with mineral additives that has high calcium content such as slag, Ordinary Portland Cement (OPC) and high calcium fly ash. In this study, the Ordinary Portland Cement (OPC) was added in the Palm Oil Fuel Ash (POFA) geopolymer mortar to induce setting and hardening at ambient temperature. Setting time, compressive strength and porosity of the POFA geopolymer mortar were measured. The OPC was added into the geopolymer at dosages of 0%, 20%, 25%, 30%, 35%, and 40%. The alkaline activator used was a combination of NaOH (16M) and sodium silicate with a ratio of 2.5 by mass. The POFA geopolymer mortar were cast and cured at ambient temperature. Results show that addition of 35% OPC increased the setting time by 99.44%, increased the compressive strength of mortar by 95.46% and decreased the porosity by 5.27% at 28 days. It can be concluded that inclusion of the OPC could improve the setting and final strength of the geopolymer material