This study is an attempt to partially replace Ordinary Portland cement (OPC) in concrete with palm oil fuel ash (POFA) and eggshell powder (ESP). The mix proportions of POFA and ESP were varied at 10% of cement replacement and compared with OPC concrete as control specimen. The fineness of POFA is characterized by passing through 300 μm sieve and ESP by passing through 75 μm sieve. Compressive strength testing was conducted on concrete specimens to determine the optimum mix proportion of POFA and ESP. Generally the compressive strength of OPC concrete is higher compared to POFA-ESP concrete. Based on the results of POFA-ESP concrete overall, it shows that the optimum mix proportion of concrete is 6%POFA:4% ESP achieved compressive strength of 38.60 N/mm 2 at 28 days. The compressive strength of OPC concrete for the same period was 42.37 N/mm 2 . Higher water demand in concrete is needed due to low fineness of POFA that contributing to low compressive strength of POFA-ESP concrete. However, the compressive strength and workability of the POFA-ESP concrete were within the ranges typically encountered in regular concrete mixtures indicating the viability of this replacement procedure for structural and non-structural applications.

Peat is a well-known problematic soil associated with poor engineering properties. Its replacement with an expensive competent foundation material is practiced for road embankment construction which is costly and causes greenhouse gas emissions. Therefore, this paper investigated the effectiveness of a byproduct from a metal industry (silica fume) to stabilize peat along with ordinary Portland cement (OPC) through a series of experimental tests. After peat-indexed characterization, a number of standard compaction and mechanical tests were performed on the stabilized and parent peat. For this purpose, nine designated mixes were prepared possessing various combinations of silica fume (SF) and 10–20% OPC. Unconfined compressive strength (UCS) and California Bearing Ratio (CBR) tests were carried out after 7, 14, and 28 days of curing to assess strength enhancement and binder effectiveness, and the microstructural evolution induced by the binders was examined with scanning electron microscopy (SEM). The analysis revealed a substantial improvement in mechanical properties with the incorporation of SF and OPC, ultimately meeting the minimum strength requirement for highway construction (i.e., 345 kPa). A peak UCS of 1063.94 kPa was recorded at 20% SF, and an unsoaked CBR value of 42.95 was observed using 15% SF and 15% OPC after 28 days of curing. Furthermore, the increasing percentage of hydraulic binders exhibited brittle, collapsible failure, while the microstructural study revealed the formation of a dense matrix with a refined pore structure in the treated peat. Finally, a significant statistical analysis was carried out by correlating the test parameters. In this way, rather than stockpiling and dumping, an industrial byproduct was implemented in peat stabilization in an eco-friendly manner.

Composite concrete consists of two elements cast at different times which are the concrete base and concrete topping. To achieve composite action, interface shear strength must be sufficient to resist the sliding motion between the two concrete surfaces in contact. The interface shear strength is mainly depended on concrete cohesion, friction and dowel action. A total of 36 “push-off” tests were performed to study the interface shear strength and to assess the influence of surface texture and steel reinforcement crossing the interface. Three different concrete base surfaces are prepared which include smooth or “left as-cast”, roughened by wire-brushing in the transverse direction and steel reinforcement projecting from the concrete base. Eurocode 2 provides design equations for determining the interface shear strength with different surface textures and also the one where projecting steel reinforcement crosses the interface. The experimental results show that the transverse roughened surface produced the highest interface shear strength of 1.89 N/mm2 (σn = 0 N/mm2), 4.69 N/mm2 (σn = 0.5 N/mm2), 5.97 N/mm2 (σn = 1.0 N/mm2) and 6.42 N/mm2 (σn = 1.5 N/mm2) compared with the other surface textures. This proves that the increase in the degree of roughness contributes to higher concrete cohesion and friction coefficient. However, for the surface with projecting steel reinforcement, the failure is not sudden as experienced by the surface without one. This is due to the contribution of the clamping stress from the dowel action of the steel reinforcements. Meanwhile, for specimens without any projecting steel reinforcements, the interface shear strength depended solely on friction and concrete cohesion of the surface textures. The interface shear strength of surface with and without the projecting steel reinforcement can be predicted using the Mohr-Coulomb failure envelope. This paper also proposed design expressions for concrete-to-concrete bond on surfaces provided with and without projecting steel reinforcement that can be adopted in Eurocode 2.

Sustainable construction is a rapidly increasing research area. Investigators of all backgrounds are using industrial and agro wastes to replace Portland cement in concrete to reduce greenhouse emissions and the corresponding decline in general health. Many types of wastes have been used as cement replacements in concrete including: fly ash, slag and rice husk ash in addition to others. This study investigates the possibility of producing a sustainable approach to construction through the partial replacement of concrete using biofillers. This will be achieved by studying the physical and mechanical properties of two widely available biological wastes in Malaysia; eggshell and palm oil fuel ash (POFA). The mechanical properties tests that were studied and compared are the compression, tensile and flexural tests.

This paper presents the development and verification of a three-dimensional (3D) numerical modelling to predict the thermal performance of reinforced concrete encased wide-flanged steel (RCEWFS) column. The numerical model was developed using finite element software, ABAQUS. Then, the verified model was used to determine the suitable value for heat transfer conductance, time step and mesh size that provide the most reliable prediction against the experimental results. The parametric studies were also conducted to study the effect of rising time of fire exposure, section size, and flange width of I-section on the thermal performance of the RCEWFS column. From this study, it can be concluded that the predictions by the 3D numerical model are reliable and accurate. The study on the contour of the model shows that the thermal behaviour of concrete is non-linear