Kenaf fibrous concrete: mechanical properties with different fiber volume fraction

Kenaf fiber comes from Kenaf plant which grows thrivingly in hot and humid temperature. The origin of Kenaf comes from a few different countries that have similar characteristics such as Africa, China, and India. Kenaf or its scientific name, hibiscus cannabinus is a beneficial crop where the seeds and stems can be used in various industries such as medicine, paper production and composite material. Kenaf core and bast fiber can reach up to 3 meters long and this is an essential reason to corporate Kenaf with other composite material like polymer and concrete. This paper indicates the investigation of finding an optimum value of Kenaf Fibrous Concrete with fiber volume of 0%, 0.5%, 0.75%, 1% and 1.5% in the mix proportions. The mechanical properties of fresh and hardened samples were tested during 7th and 28th day of curing in water. Compressive strength, splitting tensile and flexural strength tests were executed in accordance of BSEN 12390-3:2009, ASTM C496M-06 and BSEN 12390-5:2009 respectively, with different volume fractions in finding an optimum value of Kenaf Fibrous Concrete. The result shows that kenaf fiber has the hydrophilic characteristic that influences more water absorption in the mix proportions. The capability of this fiber improves the tensile strength and ductility because of the inclusion of fiber. However, it decreases the concrete compressive strength

Evaluation of the effective mechanical properties of concrete composites using industrial waste carpet fiber

Synthetic waste fibers are cheap and popular materials used in the concrete, and they may positively affect the properties of cementitious composites because of their superior properties. This research proposes the utilization of waste carpet fiber and palm oil fuel ash (POFA) to develop the physical, mechanical and microstructural properties of concrete. Carpet fiber of 20 mm length and six volume fractions of 0, 0.25, 0.5, 0.75, 1.0 and 1.25% were used with ordinary Portland cement (OPC). Another six mixes were made that replaced OPC with 20% POFA. The combination of carpet fiber and POFA decreased the slump values and increased the VeBe time of fresh concrete. Likewise, the addition of carpet fiber, either into OPC or POFA concrete, did not improve the compressive strength. However, the positive interaction between the carpet fiber and POFA lead to higher tensile and flexural strengths. Despite lower strength development, an increment in the post-failure compressive strength of concrete composite was observed in all mixes. A significant enhancement was also observed in impact resistance of the concrete composite containing carpet fiber, as compared to that of plain concrete. Microstructure of concrete was examined by using scanning electron microscope. It is revealed that carpet fibers act as bridges across the cracks, which improve the load-transfer capacity of the matrix. The study showed that the utilization of waste carpet fiber and POFA in the production of concrete is feasible from both technical and environmental points of view

Performance of carbon fibre reinforced polymer plate bonding system under various environmental conditions

The use of Carbon Fiber Reinforced Polymer (CFRP) as strengthening material for reinforced concrete and steel has been a focused of many researched around the world. Superior properties of the CFRP plate including lightweight, high tensile strength, and corrosion resistance make it a favorable material in strengthening of existing structures. The CFRP strengthening technique has been known to enhance the structural performance of the strengthened member. However, one of the main drawbacks is the long-term durability of the CFRP bonding system against various environmental conditions. This study evaluates the durability performance of the CFRP plate bonding system exposed to different environments. Experimental work was conducted in which the CFRP plate, adhesive coupons, and CFRP double lap shear samples were prepared and subjected to either continuous or wet-dry cycles in different exposures including plain water, salt water, acidic solution, and outdoor. The exposed samples were tested at different ages. The study found that the CFRP plate was quite durable and the change on the properties was negligible. However, the results indicated that exposure to different environments had affected the adhesive strength properties significantly with exposure to salt water was found to have the most degradation effect on the adhesive

Development of students’ knowledge-behavioural changes in relation to sustainability through a case study

The purpose of this study is to develop students’ knowledge and behavioural changes in relation to sustainability through a case study. Cooperative Problem-Based Learning (CPBL) was used as a teaching and learning approach among the first year chemical engineering students. A case study was designed to create a learning environment where students involved in the ‘Waste to Wealth’ Campus Contest. A quantitative method was conducted. Data for the research were gathered through administrated a survey instrument at the beginning and end of semester. Structure of Observed Learning Outcomes (SOLO) taxonomy and Precaution Adoption Process Model (PAPM) of changing individual behaviour were used to measure the levels of students’ knowledge and behavioural changes, respectively. The findings showed that CPBL significantly developed students’ knowledge, and behavioural changes towards instilling the awareness of sustainable development

An evaluation of the interfacial bond strength of kenaf fibrous concrete and plain concrete composite

The deterioration of concrete structures is a matter of critical concern as it threatens the durability and strength of concrete structures. Kenaf fibrous concrete composite (KFCC) can be used with advantage in new structures such as precast elements, as well as the strengthening, repair and rehabilitation of old structures to improve their durability properties. These structures are composite components, with parts as Plain concrete (PC) and others as KFCC. This study, therefore, investigated the interfacial bonding behaviour between KFCC and PC. Shear, tensile and compressive tests were carried out to measure the bond strength in shear, direct tension and compression respectively for PC to PC, PC to KFCC and KFCC to KFCC interface. Three different types of concrete grade (25, 35, and 45 MPa) were produced for the KFCC and one type of concrete grade (35 MPa) for the substrate PC. The outcome of the test showed that KFCC had an excellent interlock with the surface of the PC substrate, and thus, gives bond strength greater than the strength of PC. New concrete with the highest concrete grade of 45 MPa ensued in high compressive, tensile and shear bond strength

Compressive creep of kenaf bio-fibrous concrete composite under one dimensional stressing

The experiment was designed to investigate the creep of concrete specimens under one dimensional compressive principal stress. The equipment for producing the stress and the gauges for measuring the strai ns are described. T he results of the experimental study illustrated the effects o f the inclusion of Kenaf fibre and age at loading on creep signature of the concrete. Creep tests were performed in the drying ro om with 50±4% relative humidity . Kenaf fibres were used at 50mm fibre length and volume fractions of 0.5% by volume of mix. Results available for specimens subjected to 25 and 35% of the strength in compression were presented. The final discussion compared the effect of Kenaf fibre inclusion and age a t loading of specimens subjected to compressive creep at two different stress levels. Low modulus fibrous concrete such as Kenaf bio - fibrous concrete composite demonstrated somewhat greater creep strains than the plain concrete, but the deformation behavio ur shows improvement in ductility

Visual Simultaneous Localization and Mapping Using Direct-Based Method for Unmanned Aerial Vehicle (UAV)

The Direct Sparse Odometry (DSO) technique is a new form of visual odometry that makes use of a direct and sparse structure to achieve precision. In this project, the objective is to apply the DSO algorithm on the Unmanned Aerial Vehicle (UAV) application. The main studies in this project are focusing on the experimentation for DSO algorithm parameter setting. Another objective is to evaluate the parameter and performance of DSO algorithm. The data evaluation was based on three different environments in the university campus. In this project, the Realsense D435i camera was applied to the RDDRONE-FMUK66 with interface of the Raspberry Pi 3 B+ model to capture the data. This project managed to analyze suitable point values on the active points and gradient parameter setting. The same parameter configuration which concerns on point density and keyframe management have been experimented in the three environment. From this project it is concluded that DSO on UAV can be improved in order to gain a stable data processing to be applied in the algorithm

Behaviour of pultuded GFRP composites under tensile and compressive loading

Glass fibre reinforced polyester (GFRP) pultruded composite consists of polyester resin (thermosetting polymer) as a matrix and glass fibre as reinforcement. It is manufactured through a continuous pultrusion process to form structural sections. During the manufacturing process, the form(s) of continuous glass fibres are pulled from one end of the line into a resin bath that contains liquid polyester resin, curing agent (initiator), and other ingredients. The fibre-resin is then passed through in the heated die for curing to form a hard, solid and continuous structural section. Since 1990s, the use of the glass fibre reinforced polymeric composites in the construction industry has grown very rapidly especially in developed countries. The applications of the composite material are mainly in building structures, bridges, offshore structures, etc. The development of the material in the construction industry in Malaysia is still at its infancy. In local current applications, the use of the material is only visible in marine and aircraft technology, and chemical industries where fabrication process are employed mainly by close- and open moulded techniques. But, in the construction industry, the pultrusion technique is normally employed to fabricate structural components. The material has been used for secondary structures such as water tanks, light poles, platform gratings, beams, cladding and piping