Majed A. A. Aldahdooh was born in Palestine in 1987. He received the B.Sc. degree in civil engineering from the Islamic University of Gaza (IUG), in 2009, the M.Sc.
This study focuses on the measurement of the ultimate flexural and tensile strength of GUSMRC, a ... more This study focuses on the measurement of the ultimate flexural and tensile strength of GUSMRC, a new class of green ultra-high performance fiber reinforced cementitious composites (GUHPFRCCs) in which 75% of the volume contains ultrafine palm oil fuel ash (UPOFA). This green concrete is currently under development at the Universiti Sains Malaysia (GUSMRC). The main objective of this study is to investigate the potential of UPOFA as a partial binder replacement for the ultimate flexural and uniaxial tensile strength of GUSMRC mixtures. Results showed that UPOFA enhances the flexural and uniaxial tensile responses of fresh UHPFRCCs. The highest flexural and uniaxial tensile strength values at the 50% replacement level after 28 days were at 42.38 MPa and 13.35 MPa, respectively, indicating the potential of utilizing UPOFA as an efficient pozzolanic mineral admixture for the production of GUSMRC with superior engineering properties.
This paper presents an ideal experimental design based on the response surface method (RSM) to de... more This paper presents an ideal experimental design based on the response surface method (RSM) to develop a new class of Green Ultra-High Performance Fiber Reinforced Cementitious Composites (GUHPFRCCs), in which 50% of the volume contains ultrafine palm oil fuel ash (UPOFA). This green concrete is currently under development at the Universiti Sains Malaysia (GUSMRC). This could lead to the greater utilization of POFA in concrete and, subsequently, could be useful in protecting the environment by minimizing volume of waste disposed on the wasteland and minimizing emission of greenhouse gases that released during cement production, besides contribute to cost saving which could somehow contribute towards the sustainability of the concrete industry. The results showed that at 90 days the optimum mix was achieved 158.28 MPa, 46.69 MPa and 13.78 MPa of compressive strength, bending tensile strength and direct tensile strength, respectively, with 50% replacement levels of the total binder content by UPOFA, indicating the ability of using UPOFA as an efficient pozzolanic mineral admixture for the production of GUSMRC with promisingly superior engineering properties.
One of the major disadvantages in ultra-high-performance-fiber reinforced concrete (UHP-FRC) is i... more One of the major disadvantages in ultra-high-performance-fiber reinforced concrete (UHP-FRC) is its high ordinary Portland cement (OPC) content, which directly translates into an increase in OPC production. More OPC production results in increased emission of greenhouse gases, as well increased electrical energy consumption and concrete price. This study is aimed at adjusting the binder content (OPC and silica fume (SF) contents) of UHP-FRC using the response surface method. The present investigation shows that, for a given water/binder and superplasticizer/OPC, the compressive strength is independent of the binder content, whereas the flow depends on the binder content. Increasing the binder content does not enhance the strength compared with the required design strength because the capillary porosity increases with increasing OPC content; however, the workability increases. The final result is the production of a UHP-FRC with an OPC content of 720.49 kg/m3, an SF content of 214.25 kg/m3, a compressive strength of 181.41 MPa, a direct tensile strength of 12.49 MPa, a bending tensile strength of 30.31 MPa, and a flow of 167 mm.
This paper describes an application of the acoustic emission signal features in the structure hea... more This paper describes an application of the acoustic emission signal features in the structure health monitoring (SHM) fields. The most popular applications of acoustic emission signal in SHM are specified on crack monitoring, quantifying the degree of damage and crack classification. In this study, the acoustic emission signal is applied to classify the types of cracks (flexural or shear cracks) of several types of RC beams subjected to four-point bending. Generally, the two common methods used in crack classification are the AE parameter analysis-based method and the signal-based method. The aim of this study is to classify the crack types of RC beams with varying thicknesses based on the fracture mechanism of the RC beams and the acoustic emission signal features. As a result, the ratio of shear cracks at the failure stage becomes 17.10%, 14.50% and 12.05% of the AE hits for the 20 cm, 25 cm and 30 cm beam thickness, respectively. These results coincided with the visual observation results according to crack modes. The results of the present application can be utilized in health monitoring of vital concrete structures such as bridges, and any RC member subjected to bending load. Which in term is used for prioritization of repair and retrofitting processes for these structures.
The aim of this study is to investigate the ability of the Acoustic emission (AE) in order to tes... more The aim of this study is to investigate the ability of the Acoustic emission (AE) in order to test the effect of beam thickness on the damage mechanism of the RC beams under four-point bending. The results showed that as the level of damage increased, the values of all AE parameters increased except for average frequency; moreover, all AE parameters increased with increasing beam thickness, including the average frequency. Thus, it has been established in this work that AE can be effectively used in monitoring the behavior of RC beams with variable thickness.
This study focuses on the measurement of the ultimate flexural and tensile strength of GUSMRC, a ... more This study focuses on the measurement of the ultimate flexural and tensile strength of GUSMRC, a new class of green ultra-high performance fiber reinforced cementitious composites (GUHPFRCCs) in which 75% of the volume contains ultrafine palm oil fuel ash (UPOFA). This green concrete is currently under development at the Universiti Sains Malaysia (GUSMRC). The main objective of this study is to investigate the potential of UPOFA as a partial binder replacement for the ultimate flexural and uniaxial tensile strength of GUSMRC mixtures. Results showed that UPOFA enhances the flexural and uniaxial tensile responses of fresh UHPFRCCs. The highest flexural and uniaxial tensile strength values at the 50% replacement level after 28 days were at 42.38 MPa and 13.35 MPa, respectively, indicating the potential of utilizing UPOFA as an efficient pozzolanic mineral admixture for the production of GUSMRC with superior engineering properties.
This paper presents an ideal experimental design based on the response surface method (RSM) to de... more This paper presents an ideal experimental design based on the response surface method (RSM) to develop a new class of Green Ultra-High Performance Fiber Reinforced Cementitious Composites (GUHPFRCCs), in which 50% of the volume contains ultrafine palm oil fuel ash (UPOFA). This green concrete is currently under development at the Universiti Sains Malaysia (GUSMRC). This could lead to the greater utilization of POFA in concrete and, subsequently, could be useful in protecting the environment by minimizing volume of waste disposed on the wasteland and minimizing emission of greenhouse gases that released during cement production, besides contribute to cost saving which could somehow contribute towards the sustainability of the concrete industry. The results showed that at 90 days the optimum mix was achieved 158.28 MPa, 46.69 MPa and 13.78 MPa of compressive strength, bending tensile strength and direct tensile strength, respectively, with 50% replacement levels of the total binder content by UPOFA, indicating the ability of using UPOFA as an efficient pozzolanic mineral admixture for the production of GUSMRC with promisingly superior engineering properties.
One of the major disadvantages in ultra-high-performance-fiber reinforced concrete (UHP-FRC) is i... more One of the major disadvantages in ultra-high-performance-fiber reinforced concrete (UHP-FRC) is its high ordinary Portland cement (OPC) content, which directly translates into an increase in OPC production. More OPC production results in increased emission of greenhouse gases, as well increased electrical energy consumption and concrete price. This study is aimed at adjusting the binder content (OPC and silica fume (SF) contents) of UHP-FRC using the response surface method. The present investigation shows that, for a given water/binder and superplasticizer/OPC, the compressive strength is independent of the binder content, whereas the flow depends on the binder content. Increasing the binder content does not enhance the strength compared with the required design strength because the capillary porosity increases with increasing OPC content; however, the workability increases. The final result is the production of a UHP-FRC with an OPC content of 720.49 kg/m3, an SF content of 214.25 kg/m3, a compressive strength of 181.41 MPa, a direct tensile strength of 12.49 MPa, a bending tensile strength of 30.31 MPa, and a flow of 167 mm.
This paper describes an application of the acoustic emission signal features in the structure hea... more This paper describes an application of the acoustic emission signal features in the structure health monitoring (SHM) fields. The most popular applications of acoustic emission signal in SHM are specified on crack monitoring, quantifying the degree of damage and crack classification. In this study, the acoustic emission signal is applied to classify the types of cracks (flexural or shear cracks) of several types of RC beams subjected to four-point bending. Generally, the two common methods used in crack classification are the AE parameter analysis-based method and the signal-based method. The aim of this study is to classify the crack types of RC beams with varying thicknesses based on the fracture mechanism of the RC beams and the acoustic emission signal features. As a result, the ratio of shear cracks at the failure stage becomes 17.10%, 14.50% and 12.05% of the AE hits for the 20 cm, 25 cm and 30 cm beam thickness, respectively. These results coincided with the visual observation results according to crack modes. The results of the present application can be utilized in health monitoring of vital concrete structures such as bridges, and any RC member subjected to bending load. Which in term is used for prioritization of repair and retrofitting processes for these structures.
The aim of this study is to investigate the ability of the Acoustic emission (AE) in order to tes... more The aim of this study is to investigate the ability of the Acoustic emission (AE) in order to test the effect of beam thickness on the damage mechanism of the RC beams under four-point bending. The results showed that as the level of damage increased, the values of all AE parameters increased except for average frequency; moreover, all AE parameters increased with increasing beam thickness, including the average frequency. Thus, it has been established in this work that AE can be effectively used in monitoring the behavior of RC beams with variable thickness.
Uploads