Performance of Rubberized Concrete-filled Hollow Steel Column under Monotonic and Cyclic Loadings

Concrete-filled hollow steel (CFHS) has become more popular due to its advantages and benefits compared to reinforced concrete. This paper presents the experimental investigation on the performance of rubberized pozzolanic concrete-filled hollow steel column (RuPCFHS) under monotonic and cyclic lateral load in comparison to bare hollow steel column and normal concrete-filled hollow steel column (NCFHS). The test parameters included the type of concrete infill and the level of axial load. Modified rubberized pozzolanic concrete with comparable compressive strength to that of normal concrete was used. Two types of axial load conditions: no axial load and 20% axial load were considered in the testing. The test results indicate that the performance of the columns improved when concrete infill was introduced in the hollow steel. The application of axial loading also increased the capacity of the column specimens. RuPCFHS behaved with comparable performance with NCFHS in both monotonic and cyclic testing. RuPCFHS recorded the highest increment in the energy dissipation capability when 20% axial load was applied to the column when compared to the other specimens. The comparable performance indicated the possibility of RuPC as an infill material of CFHS and RuPCFHS as a structural component

A review on self-compacting concrete incorporating palm oil fuel ash as a cement replacement

Palm oil fuel ash (POFA) is a waste materials dumped into an open field of a palm oil industry and thus, caused environmental contamination and health threat problems. The problems can be lessened by making use of POFA as cement replacement materials. A lot of researchers have conducted a research to study the use of POFA as cement replacement in the production of normal and high strength self-compacting concrete (SCC). However, a strong review on the use of POFA to replace part of cement in the production of SCC is yet to be established. In this paper, physical, chemical properties, morphology of POFA, fresh, hardened and durability properties of SCC incorporating POFA were reviewed. The information presented has shown that sufficient data have been obtained from the review of different articles to give confidence in the general behavior of SCC incorporating POFA

Microstructure and compressive strength of self-compacting concrete incorporating palm oil fuel ash exposed to elevated temperatures

Palm oil fuel ash (POFA) has been extensively used to substitute cement in the production of self-compacting concrete (SCC) to lessen its production cost, health hazard, energy consumption problems and environmental pollution caused during the production of cement. Nevertheless, the impact of elevated temperatures on self-compacting concrete produced with POFA (POFA-SCC) has not been studied extensively. When designing the fire resistance of concrete at elevated temperatures, its compressive strength is of primary interest. This research endeavor is carried out to study the impact of elevated temperatures on the microstructure and compressive strength of SCC produced from POFA with 15% replacement level by weight of cement. The 28 days compressive strength of SCC samples was determined using concrete cubes. Subsequently, the SCC samples were subjected to elevated temperatures which varying from 200 to 1000 °C at an intermission of 200 °C utilizing an automatic regulated electric furnace for duration of 120 min after reaching the requisite temperatures. After heating, mass losses and compressive strength were evaluated. The microstructures of SCC were also examined by scanning electron microscope and X-ray diffraction analysis. Results revealed that there was an incessant loss in mass of the cubes with upsurge in temperature. There was an upsurge in the values of compressive strength at 400 °C whereas it fluctuated sharply at the range of 400–600 °C, 600–800 °C and 800–1000 °C for the two mixes. The results of the microstructures showed the transformation of calcium silicate hydrate (C-S-H) into distinctive phases. The outcome of this research will be applicable in high fire resistance structures and also help to minimize the waste from palm oil factory