Keupayaan pengurangan kebisingan konkrit berliang menggunakan cangkerang kelapa sawit sebagai gantian agregat bagi pembinaan penghalang kebisingan lebuh raya

Abstract

Porous concrete is generally applied in noise barrier porous medium. Currently standard porous concrete has relatively low noise reduction and this will cause noise annoyance to resident and road users. This study aims to increase the noise reduction of noise barrier surface by replacing the natural aggregate with oil palm shell (OPS). The OPS is selected due high porosity characteristic and abundantly available. The objectives of the study are to determine the density, porosity, compressive strength and noise reduction capability of specimens and to evaluate the relationship between percentage of oil palm shell as aggregate replacement with strength and noise reduction capability. Specimens with mixture proportion of 25%, 50%, 75% and 100% aggregate replacement were carried out with specimen of porous concrete without OPS replacement as control specimen. The results showed porosity content significantly escalated with the increase of OPS while the density become lesser. Consequently, compressive strength decreased as the content of OPS increased, due to escalated porosity. Except 75% OPS and 100% OPS, however the values obtained were still within the typical range (2–28 N/mm2). OPS replacement showed better noise reduction coefficient but there is no clear relationship between noise reduction and percentage of OPS replacement. In respect with the compressive strength limit for noise barrier porous surface (2 N/mm2), the highest noise reduction is given by the 25% OPS replacement with compressive strength of 3.07 N/mm2. This could be due to the microstructure of OPS which increased the entrapped air inside the porous concrete. Thus, porous concrete with 25% OPS replacement can be potentially applied in porous medium of noise barrier.