Toughness properties of steel-polypropylene fibre reinforced concrete under elevated temperature

Application of fibres in concrete which is also known as fibre reinforced concrete (FRC) has been found to improve the energy absorption or toughness of the material. However, only little information on FRC toughness is found when it is exposed to high temperature such as under prolonged heat or fire. The main objective of the study is to evaluate the toughness behaviour of FRC by experimentation when exposed to elevated temperature. The fibre used in the experimental work is steel (ST) or polypropylene (PP), and also the combination of both fibres. The fibre dosage varied between the ST and PP summarised as (100-0), (75-25), (50-50), (25-75) and (0-100). Meanwhile, the total volume fraction, Vf is fixed at 1.5% and they are exposed to elevated temperature at the following degree; room temperature (27 C), 200 C, and 400 C. The research shows that the addition of fibres in concrete enhanced the FRC toughness, however, it reduces as the exposure temperature increases

State of the art on pre-tensioning steel straps confinement: literature review

This paper presents the state-of-the-art of the current research development on pre-tensioning steel straps confinement. Critical review was conducted based on careful selection of references to provide in-depth overview in the development of this confining technique. The paper was started with highlighting the features of such confining technique, then an extensive description of the connection clip systems was presented. The experimental and numerical investigations performed on steel-strapped concrete structures were discussed at length in the paper. The potential usage of pre-tensioning steel straps confinement in increasing the bond properties of confined concrete and as a repairing technique of damaged concrete were also covered in this paper

State of the art on pre-tensioning steel straps confinement: literature review

This paper presents the state-of-the-art of the current research development on pre-tensioning steel straps confinement. Critical review was conducted based on careful selection of references to provide in-depth overview in the development of this confining technique. The paper was started with highlighting the features of such confining technique, then an extensive description of the connection clip systems was presented. The experimental and numerical investigations performed on steel-strapped concrete structures were discussed at length in the paper. The potential usage of pre-tensioning steel straps confinement in increasing the bond properties of confined concrete and as a repairing technique of damaged concrete were also covered in this paper

Mechanical and shrinkage properties of hybrid steel and polypropylene fibre reinforced concrete composite

An experimental study had been carried out to investigate the mechanical properties, expansion and shrinkage of fibre reinforced concrete composite (FRC). However, instead of using single type fibre of either steel (SF) or polypropylene (PPF), this study also combined the two types in one mix.The mechanical properties investigated in this study include compressive strength, splitting tensile strength and flexural strength. Three different FRC mix proportions and one normal concrete (control) were casted which includes (a) 75% SF, (b) 75% SF + 25% PPF, (c) 25% PPF, and (d) 0% fibre for control (PC). Meanwhile, the volume fraction, Vf for the FRC was fixed at 1.5% and the concrete strength was designed to achieve grade C60 at 28 days. The results show that the use of fibres in concrete decreased the workability of concrete. In addition, concrete mix with both SF and PPF produced the highest splitting tensile and flexural strengths by an increase of 75.9% and 86.5%, respectively as compared with the control. Furthermore, expansion and shrinkage of FRC was found to be less than the control. It can be concluded that the combined SF and PPF in concrete gives the most appropriate combination as regards to the highest flexural and splitting tensile strengths, and also reduced the shrinkage strain

Effects of the partial replacements of Oil Palm Boiler Clinker (OPBC) on the density and compressive strength of concrete

Purpose: Oil Palm Boiler Clinker (OPBC) is a promising waste material that can be deployed toward sustainable development. Researchers have been looking into the potential of industrial waste and by-products to provide an alternative to natural stone aggregates in concrete production. This study aims to determine an OPBC concrete mix eligible for lightweight reinforced precast concrete products according to BS EN 13369:2013. Design/methodology/approach: The concrete mix design is determined via the trial mix method, where percentages of OPBC are varied as partial replacements in the control mix. Raw OPBC is collected from a local palm oil mill in Johor, Malaysia and is processed to be implemented in the concrete mix. Three 100mm cube samples of nine OPBC mixes and one control mix are tested and weighed on day 1, day 7, and day 28 to determine their cube compressive strength and density to BS EN 12390-3:2009. The mix that fulfils the requirements is the mix with 90% coarse clinker and 90% fine clinker, cured by the method of air curing, which achieved a cube compressive strength of 38.66N/mm2 and density of 1920kg/m3. Findings: In conclusion, the results show that OPBC concrete is a green alternative to standard concrete that does not differ significantly in terms of strength while offering a density reduction of as much as 16%. Originality/value: This paper is original Paper type: Research pape

The chemical properties of seaweed for modify concrete

Seaweed is one of the natural sources usually use in industrial food, cosmetic, pharmaceutical and fertiliser. A natural polymer material such as seaweed is found to have excellent bonding mechanism and also the critical factor to achieve sustainability. Malaysia is also rich with seaweed species like Eucheuma Cottonii. The future study was carried out seaweed species from Malaysia especially seaweed from Sabah. This research aimed to investigate the relationship of a few chemical properties namely physical properties, metal element content, microstructure image and chemical component of seaweed type of Eucheuma Cottonii for modifying concrete. This research is mainly base on experimental works. That powdered seaweed from Eucheuma Cottonii was analysis using Energy Dispersive X-Ray (EDX), Scanning Electron Analysis (SEM) and Fourier Transform Infra-Red (FT-IR). All the procedure of the laboratory work complies with the specified and relevant standard. The research had shown that Euchema Cottonii powder content suitable for metal and component to bind together with concrete. Concrete with seaweed powder is alternative to become green construction material for sustainable concrete

Ultimate shear capacity and failure of shear key connection in precast concrete construction

This paper presents the experimental results on the strength of shear key connection in precast concrete construction. The use of shear key is to connect two separate precast components to increase the shear resistivity of the joint surfaces. The proposed shear key shape in this study comprises of triangular, composite rectangular, semi - circle and trapezoidal. In addition, the trapezoidal shape is made up with 3 different key’s angles. All specimens are tested using the “push - off” method to obtain the ultimate shear capacity of which is due to the failure of the connection. From the analysis, stiffness, elastic and plastic behaviour, and the mode of failure is discussed to determine the most effective shape of the proposed shear key. From the findings, semi - circle shear key produced the highest shear capacity at 62.9 kN compared to that of the other shapes. Meanwhile, the trapezoidal shape at an angle of 45° produced the highest shear capacity at 44.1 kN. Together in the aspect of stiffness,the 45° trapezoidal shapes produced the highest resistance towards slip at 166.7 kN/mm. Failure mode are mostly due to shear, sliding and diagonal tension crack. Large slip of 7.35 mm is recorded from the triangular shape. The large slip is maybe due to sliding since the angle of the key faces to the shear plane is 45° which indicates to less interlocking compared with the other shapes they form an angle of 90° with the shear plane

Review on maintenance issues toward building maintenance management best practices

Buildings deteriorate gradually over time due to several reasons, including unattended defects, neglected damage, and natural causes. Hence, maintenance activities are required to impede the deterioration process to ensure the continuous function of the buildings. Maintenance is a systematic process to safeguard features and resources operated at optimum levels to achieve building standards and performance. Nevertheless, previous studies have shown that maintenance practices in Malaysia were not implemented efficiently and performed far below maintenance best practices. Hence, this study aimed to explore the building maintenance practice issues in Malaysia. A systematic literature review (SLR) was conducted to examine the issues or factors that affect building maintenance practice. The review included articles on issues affecting building maintenance practice and recommendations to minimize the issues. The maintenance practice issues were categorized into planning, management, staff, competency, technology, and technical capabilities. Besides, the study proposed recommendations from the literature for future studies aligning with the ISO 41001 guidelines. Finally, a conceptual framework was proposed toward building maintenance management best practices at the end of the study

Optimization of steel fibre reinforced concrete as concrete topping in composite slab construction

Steel fibre can act as an alternative to replace the conventional prefabricated welded wire mesh (PWWM). It serves as a secondary reinforcement in concrete topping of the precast composite slab construction. Hence, an in-depth study on the performance was conducted to prove the notion. The study was essential due to the differences of behaviours between steel fibre in the compression and the flexural zone of the composite slab. In fact, there was no sufficient knowledge of compression mechanism of steel fibre reinforced concrete (SFRC) due to the lack of study in this area. The main objectives of this study were to investigate the structural performance of composite slab where SFRC was applied in the concrete topping and to develop an analytical model to predict the shear strength of the composite slab by validating the model with the experimental results. Aspect ratio and volume fraction were emphasised in selecting the most suitable type of steel fibre in this study. The experimental results showed that SFRC concrete topping improved the ultimate load and failure mechanism. The results also suggested that the ideal types of steel fibre to be applied in the concrete topping are SF60 and SF33 with optimum volume fraction between 0.75% and 1.00%. Furthermore, it was proven that the SFRC concrete topping has improved the shear capacity of the composite slab by 17%. The performance of the proposed analytical model in predicting the ultimate shear capacity of the composite slab with SFRC concrete topping was considered good due to its strong correlation with the experimental data. This suggested that steel fibre was suitable to replace PWWM as secondary reinforcement in concrete topping in precast composite slab construction. The proposed analytical model can also be used to predict the shear capacity of the composite slab with SFRC concrete topping