Mechanical, durability and damping properties for optimum rubberised concrete performance

• Main Author: Senin, Mohamad Syamir
• Format: Thesis
• Language: English; English; English
• Published: 2022
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://eprints.uthm.edu.my/8436/1/24p%20MOHAMAD%20SYAMIR%20SENIN.pdf; http://eprints.uthm.edu.my/8436/2/MOHAMAD%20SYAMIR%20SENIN%20COPYRIGHT%20DECLARATION.pdf; http://eprints.uthm.edu.my/8436/3/MOHAMAD%20SYAMIR%20SENIN%20WATERMARK.pdf; http://eprints.uthm.edu.my/8436/

Waste tyres pose significant health and environmental concerns if there are not recycled or appropriately discarded. Partial replacement of natural aggregate with waste tyres in the concrete mixture has been proven to be more economical and sustainable. Many researchers have study on mechanical and durability properties of rubberised concrete. However, there are lack of study on damping properties of rubberised concrete. Previous study has shown that incorporating rubber in concrete mix caused significant reduction on mechanical and durability properties of rubberised concrete and thus discourage its commercialisation. Large rubber particle and high percentage of rubber replacement causes substantial reduction on mechanical and durability properties of rubberised concrete. The goal of this research is to investigate the mechanical, durability and damping properties by using small rubber particles, namely rubber ash and rubber crumb, to partially replace sand in concrete at low percentage namely 3%, 5%, 7% and 9%. The material properties of sand, rubber ash and rubber crumb, namely: (1) bulk density; (2) specific gravity; (3) particle size distribution; (4) morphology; and (5) chemical composition, are determined by using five different tests. Further eight tests were conducted to determine the engineering properties of the concrete mix with rubber ash or rubber crumb, namely: (1) workability; (2) bulk density; (3) compressive strength; (4) flexural strength; (5) splitting tensile strength; (6) modulus of elasticity; (7) water absorption; and (8) water permeability. Damping properties of the concrete mix with rubber ash or rubber crumb, namely: (1) frequency; (2) mode shape; and (3) damping ratios, are determined by using impact hammer test. The mechanical, durability and damping properties of rubber ash concrete and rubber crumb concrete are compared with the control concrete. The results show that the rubber ash and rubber crumb are suitable to partially replace sand in the concrete mix. Both the mechanical, durability and damping properties have improved by up to 15%. This study found that the optimum content for rubber ash to replace sand in concrete mix is found to be at 5%, whilst the rubber crumb is at 3% for achieving improved engineering properties. The optimised rubber ash or rubber crumb to replace sand in concrete mix are 3% and 9%, respectively, for achieving improved damping properties. The experimental results of damping properties for rubber ash concrete and rubber crumb concrete are validated by computational modelling, and thus the damping properties of any rubberised concrete structure within the range of this study can be determine by computational modelling. The results of this study indicate the huge potential of the waste rubber to be recycled and used to partially replace sand in concrete mix, and hence reduce dumped tyre waste as well as reduce the use of natural resources (sand).