FRP sheets contribution in common repair techniques of concrete structures with emphasis on concrete columns

The history of composites dates back to few thousand years ago. Actually, natural fibrous composites were used by ancient Egyptians to build small houses. Numerous studies have revealed that Fibre Reinforced Polymer (FRP) is a convenient material for repair and strengthening of concrete structures compared to the traditional materials. Since the presentation of fibre reinforced polymer (FRP) in the concrete structures, the need for practice codes containing FRP in field of strengthening and repair has emerged. Many parts of structures are usually replaced simply, instead of repair due to the lack of knowledge about the techniques of repair. Hence, in this review, advantages and disadvantages of FRP repair, different types of FRP repair systems, repair stages and principles of repair theory for concrete structures with FRP are reviewed. In addition, modern repair techniques are reviewed in detail for different damaged levels of concrete structures. Recent developments in the field of repair with FRP have highlighted the need for assessment of repaired concrete columns. Thus, in one part of this review, the authors emphasise different damaged concrete column repaired with CFRP. Finally, the recent needs for further researches in field of repair with FRP are discussed

Effect of halloysite nanoclay on mechanical properties, thermal behavior and microstructure of cement mortars.

Many studies have targeted the application of clay in cement composites and declared some enhancement on the properties of concrete. However there is little knowledge on nanoclays and their effect on the mechanical properties and durability of cement composites. Halloysite nanoclay is one of the subcategories of nanoclay that has been undeservedly ignored in the production of cement composites. Chemically, the outer surface of the halloysite nanotubes has properties similar to SiO2 while the inner cylinder core is related to Al2O3 which together may improve the cement matrix. In this study the mechanical properties, flowability, thermal behavior and durability of mortars containing 1, 2, 3% halloysite nanoclay were studied. Compressive strength and gas permeability of samples with 3% and 2% nanoclay were improved up to 24% and 56%, respectively. SEM, XRD, DSC tests were carried out to investigate the microstructure and chemical composition change in samples with halloysite nanoclay

FRP Sheets Contribution in Common Repair Techniques of Concrete Structures with Emphasis on Concrete Columns

The history of composites dates back to few thousand years ago. Actually, natural fibrous composites were used by ancient Egyptians to build small houses. Numerous studies have revealed that Fibre Reinforced Polymer (FRP) is a convenient material for repair and strengthening of concrete structures compared to the traditional materials. Since the presentation of fibre reinforced polymer (FRP) in the concrete structures, the need for practice codes containing FRP in field of strengthening and repair has emerged. Many parts of structures are usually replaced simply, instead of repair due to the lack of knowledge about the techniques of repair. Hence, in this review, advantages and disadvantages of FRP repair, different types of FRP repair systems, repair stages and principles of repair theory for concrete structures with FRP are reviewed. In addition, modern repair techniques are reviewed in detail for different damaged levels of concrete structures. Recent developments in the field of repair with FRP have highlighted the need for assessment of repaired concrete columns. Thus, in one part of this review, the authors emphasise different damaged concrete column repaired with CFRP. Finally, the recent needs for further researches in field of repair with FRP are discussed

Experimental study of externally prestressed segmental beam under torsion

Externally prestressed segmental (EPS) concrete beams are widely used in the construction of bridge structures today. The EPS concept has become an attractive tool for rehabilitation and strengthening of existing bridges which have insufficient strength and/or excessive deflection and cracking. EPS bridges are affected by combined stresses (bending, shear, normal, and torsion) at the joint interface between the segments. This paper presents an experimental investigation of the structural behaviour of EPS bridge beams under combined stresses, i.e. bending, shear and torsional stresses. An experimental study of two different external tendon layouts, two types of joint between segments and different levels of torsional force applied at different load eccentricities was conducted. It was concluded that torsion reduced the vertical load and vertical deflection at the onset point of nonlinearity as well as at a failure load. Furthermore, the opening between segments was the reason behind the nonlinear behaviour of EPS beams. Torsion did not only alter the value of the failure load, tendon strain and deflection of the beams but it also altered the failure mechanism. Furthermore, due to the shear key, there was a difference between the onset points of nonlinearity load for the different tendon layouts and joint types

Characterization of high strength mortars with nano Titania at elevated temperatures.

This study focused on the chemical composition, microstructural changes and residual mechanical properties of high strength mortars with presence of 1%, 2% and 3% nano Titania at elevated temperatures. XRD, SEM and gas permeability tests were conducted to investigate the chemical composition and microstructural changes of mortars after being exposed to elevated temperatures up to 1000 °C. The residual compressive strength, energy absorption per unit volume and relative elastic modulus were also obtained. Addition of nano Titania increased residual compressive strength up to 14% and enhanced elastic modulus and energy absorption of mortars at temperatures up to 600 °C

Externally prestressed monolithic and segmental concrete beams under torsion: A comparative finite element study.

Externally Prestressed segmental beams are widely used in the construction of bridge structures today. These beams have many attractive advantages for rehabilitation and strengthening of existing structures as well. However, segmental beams experience significant effect under combined stresses at the joint interfaces between segments. This paper presents a finite element study on the effect of torsion on the structural behavior of both external prestressed monolithic and segmental concrete beams. Geometric and material nonlinearities were included in the study. The results show significant difference in the behavior of monolithic and segmental beams under torsion

Development of a Reflective Practice Guideline (C-E-R-M-I-N) for Nursing Students in the Malay Language

Reflective practice is an integral aspect of nursing education and professional development. However, there is a lack of reflective practice guidelines available in Malay that Malaysian nursing students can effectively utilise. This study aimed to address the gap by developing a reflective practice guideline specifically tailored for nursing students in the Malay language to enhance their learning experience. This study's method involved reviewing existing reflective learning models, adapting the terminologies into the Malay language, and selecting appropriate words for each stage of reflection. To ensure face validity, a discussion was held with subject matter experts, who provided valuable insights and recommendations for further refinement of the guideline. The developed reflective practice guideline was named C-E-R-M-I-N, which stands for C-cerita (describe), E-emosi (emotion), R-rasional (rationale), M-mengambil iktibar/inisiatif (drawing lessons/initiative), and N-nomborkan mengikut prioriti (number according to priority). The C-E-R-M-I-N reflective practice guideline is designed to benefit nursing students, particularly those who use Malay as their main communication language. C-E-R-M-I-N provides a framework in their native language that eases comprehension and memory. Future work on the guideline could focus on its impact on nursing students' reflective skills, critical thinking skills, and overall professional growth

Fundamentals of Entrepreneurship (ETR300) : Grandma's Recipe / Mohd Ridzuan Mohatar [et al.]

After a short discussion being made, the name GRANDMA'S RECIPE is the most suitable name for our company. We prefer this name because this name bring to nostalgic of old time where we always remembered our parents dish. The word "grandma" to remind us of grandma recipes that are hereditary favourites. We believe that if we can supply high quality cake to our customers, we can preserved and commercialised our local traditional cak

Microstructural characterization of fly ash particulate reinforced AA6063 aluminium alloy for aerospace applications

Aluminium-fly ash (FA) particulate reinforced composites (AA6063-FA) have been used in automotive and aerospace industries because of their low density and good mechanical properties. Three different weight fraction of FA: 2%, 4% and 6% are added to AA6063 alloy using compocasting method. The effect of FA particulates on microstructure, density and compression strength of AA6063- FA composites are investigated. Field Emission Scanning Electron Microscope (FESEM) micrographs reveal that the FA particulates are uniformly distributed in AA6063 alloy. The results also show that density, compression strength and microstructure of the AA6063-FA composites are significantly influenced by the FA amount. The increase in the weight fraction of FA will improve the microstructure and enhance the compression strength. The density of AA6063-FA composites decreases as the incorporation of FA increases

The influence of fly ash on the microstructure and mechanical properties AA6063 alloy using compocasting technique

Fly ash (FA) has collected attention as a possible reinforcement material for aluminium matrix composites (AMCs) to improve the properties and decrease the production cost. In this study, AA6063 alloy was reinforced with FA particles by compocasting technique. The experiments were conducted by varying weight percentage of FA (0 to 12 wt.% in steps of 2%). The FA particles were incorporated into semisolid state of AA6063 alloy melt. The microstructure of aluminum-FA particulate composite (AA6063-FA) prepared with the homogenous distribution of FA was analyzed using X-ray Diffraction (XRD), Energy Dispersive X-ray spectroscopy analysis, Variable pressure scanning electron microscope (VPSEM) and Field emission scanning microscope (FESEM). The mechanical and thermal properties of the composites were determined with a tensile, compressive and thermal expansion tests. The experimental results indicated that the microstructure, mechanical and thermal properties of AA6063-FA composites were observably affected by increasing FA content. The fracture surface was observed to be different in the failure mechanism