Soon Poh Yap

Torsional and cracking characteristics of steel fiber-reinforced oil palm shell lightweight concrete

The study presents the investigations of the torsional behavior and crack resistance of a sustainable lightweight oil palm shell (OPS) concrete. In the comparison between the OPS concrete (OPSC) and normal weight concrete (NWC), the torsional failure of the NWC was sudden and brittle, while the OPSC exhibited post-cracking behavior. The second part of the study examines the effect of steel fibers of 0.25–1.00% in the OPSC to produce OPS fiber-reinforced concrete (OPSFRC). Improved mechanical properties and reduced brittleness were reported in the OPSFRC mixes. The addition of 1% steel fibers in the OPSC-100 mix produced the highest compressive and flexural strengths of 47 MPa and 8.2 MPa, respectively. The steel fibers up to 1% enhanced the ultimate torque, torsional toughness, and twist at failure of the OPSFRC specimens by 60%, 1000%, and 550%, respectively. The addition of steel fibers significantly improved the crack resistance of the OPSFRC specimens.

The effect of aspect ratio and volume fraction on mechanical properties of steel fibre-reinforced oil palm shell concrete

AbstractThe utilization of oil palm shell (OPS) as a replacement for conventional coarse aggregate produces a greener structural lightweight aggregate concrete (LWAC). Steel fibres enhance the mechanical properties of LWAC including OPS concrete (OPSC). This paper reports on the influence of the aspect ratio (l/d) and volume fraction (Vf) of hooked end steel fibres in oil palm shell fibre-reinforced concrete (OPSFRC). The fresh and hardened concrete properties, including ultrasonic pulse velocity (UPV) and post-failure compressive strength (PFCS) of ten mixes with three each for l/d (55, 65 and 80) and Vf (0.25%, 0.5% and 0.75%) are investigated. The mix with an l/d of 65 produced the highest values of slump, density, and compressive strength. The enhancement in the splitting tensile strength of 83% compared to the control mix was obtained for the mix with the highest l/d. Generally, the increase in Vf from 0.25% to 0.75% improved the mechanical properties. The UPV results indicated that all OPSFRC and PF...

Ductility behaviours of oil palm shell steel fibre-reinforced concrete beams under flexural loading

Abstract In the effort of developing sustainable concrete, studies on the replacement of conventional coarse aggregates with local waste material are increasing. The new oil palm shell fibre-reinforced concrete (OPSFRC) utilises Malaysia’s waste material and is emerging as a promising sustainable concrete attributed to its lightweight and enhanced concrete properties. In this study, the flexural behaviours of OPSC and OPSFRC beams (with steel fibres .25, .50, .75 and 1.00% by volume) were investigated. The results show that the addition of steel fibres improved both the mechanical properties and moment capacities of OPSFRC specimens. However, the OPSFRC exhibited reduced deflection at failure of about 30–40% relative to the OPSC beams. Meanwhile, the steel fibres significantly improved the failure load to ultimate load ratios of OPSFRC to .65–.80 compared to the ratio of .19 as in OPSC. In addition, different approaches to compute the ductility ratios of OPSFRC beams are also conducted and compared.

Chloride Binding Ability and Anti-corrosion Properties of Supersulfated Cement in Seawater/Sand Mixing Concrete

In this study, we aim to shift attention to ability of chloride binding of supersulfated cement and its use for formulating sea water/sand mixing concrete. To formulate SSC cement, slag as main component is activated by high alkaline of C-H and the following reaction with SO4 2−. Material analysis (XRD, SEM/EDX) showed that effectively low-Ca-ettringite products were formed abundantly at early age and others chloride binding products such as Friedel’s salt, hydrotalcite in their turn were resulted at later age in high Cl− solution. Notable high ratios of bound Cl− on total Cl− indicate eventually capacity of hydrated cement matrix in neutralizing chloride content in seawater. As an addition, very low Cl− permeability of mortar specimen could be taken into account. By monitoring the corrosive state of embedded steel bar ϕ8 mm (inside mortar prism 40 × 40 × 160 mm, with seawater exposure condition), we observe no major deterioration due to such natural anti-corrosion phenomenon.