Timothy Zhi Hong Ting

The rapid urbanization and industrialization of a country have created pressure on climate change. Industrial waste is a hazardous by-product produced by indust

Awareness of sustainability in construction has led to the utilization of waste material such as oil palm shell (OPS) in concrete production. The feasibility of OPS as alternative aggregates in concrete has been widely studied at the material level. Meanwhile, nonlinear concrete material properties are not taken into account in the conventional concrete wall design equations, resulting in underestimation of lightweight concrete’s wall axial capacity. Against these sustainability and technical contexts, this research investigated the buckling behavior of OPS-based lightweight self-compacting concrete (LWSCC) wall. Failure mode, load-deflection responses, and ultimate strength were assessed experimentally. Numerical models have been developed and validated against experimental results. Parametric studies were conducted to study the influence of parameters like slenderness ratio, eccentricity, compressive strength, and elastic modulus. The results showed that the axial strength of concrete wall was very much dependent on these parameters. A generalized semi-empirical design equation, based on equivalent concrete stress block and modified by mathematical regression, has been proposed. The ratio of average calculated results to test results of the proposed equation, when compared to ACI 318, AS 3600, and Eurocode 2 equations, are respectively improved from 0.36, 0.31, and 0.42 to 0.97. This research demonstrates that OPS-based LWSCC concrete can be used for structural axial components and that the equation developed can serve a good guideline for its design, which could encourage automation and promote sustainability in the construction industry.

As concrete wall panel is gaining popularity in precast construction industry, better insight into its behaviour is of paramount importance. Considerable research has been carried out on concrete wall under axial loading. Most of the published literatures have proposed design equations for wall design purpose. In this aspect, the paper is aimed to review the design equations of one-way concrete wall. The limitations of existing design equations are subsequently identified.

The application of organic lightweight aggregates (LWA) such as rice husk, coconut shell and oil palm shell in concrete are gaining popularity. However, organic substances are generally flammable under elevated temperature. As such, it is important to understand the strength performance of concrete with organic LWA under elevated temperature. To this end, this paper presents the compressive strength and mass loss of lightweight self-compacting concrete (LWSCC) when exposed to elevated temperature. In the research, comparison was made between the LWSCC samples of the control mix and mix with 40% of fly ash replacement. The compressive strengths of these mixes at 28-day were 31.35 MPa and 22.77 MPa respectively while at 90-day age, they were 33.27 MPa and 25.04 MPa respectively. Compressive strength of LWSCC samples were studied experimentally under different temperature of 26°C (room temperature), 100°C, 200°C and 300°C respectively. The experimental results showed that there is significant reduction in concrete compressive strength within the temperature range of 100°C-200°C. When temperature was increased to 300°C, the concrete experienced strength reduction of nearly 84% and 79% at 28-day and 90-day age respectively for control mix. When 40% fly ash is incorporated, the concrete experienced strength reduction of nearly 72% and 66% at 28-day and 90-day age respectively.

This paper presents the results of an experimental research on the fresh concrete properties, density, compressive and tensile strength of lightweight self-compacting concrete (LWSCC) incorporating oil palm shell (OPS) as coarse aggregates. Three aspects of fresh concrete properties including passing ability, filling ability and segregation resistance of the mixtures have been investigated experimentally and tests were carried out in accordance with the procedures stated in European Federation of National Associations Representing for Concrete (EFNARC) guidelines. LWSCC with OPS as aggregates fulfils the fresh concrete properties requirements of the EFNARC guidelines. In this study, the compressive and tensile strengths have also been compared with granite based self-compacting concrete (SCC). It is observed that OPS based SCC achieved comparable compressive strength with granite based SCC. This research provides basic framework to develop mix design of lightweight selfcompacting concrete by using OPS as aggregates. Other properties such as durability and fire resistance of the developed concrete are not considered in the present study and are recommended for future research. The experimental studies show that LWSCC, with the use of OPS as full replacement to normal weight aggregates (NWA), is potentially a sustainable alternative construction material. Its use also provides a cleaner and more beneficial solution in OPS disposal for oil palm industry. This research demonstrated that OPS can be successfully used to develop lightweight self-compacting concrete. This research will benefit the oil palm industry and the environment as a whole.