Creep and shrinkage performance of kenaf bio fibrous concrete composite

Fibrous Concrete Composite (FCC) is a high performance concrete that possesses an improved tensile strength and ductility with restraint to shrinkage and creep under sustained load compared to Plain Concrete (PC). As a result of global quest for sustainable, renewable and green materials to achieve a bio based economy and low carbon foot print environment, the use of fibre to produce fibrous concrete composite has continuously received significant research attention. While several researches have been conducted on metallic and synthetic fibrous concretes, they exhibit several unavoidable drawbacks and bio fibrous concrete has been proved to be a better alternative. This research investigates the creep and shrinkage performance of concrete reinforced with Kenaf bio fibre. After material characterization, concrete reinforced with fibre optimum volume fraction of 0.5% and length of 50 mm was used for the study. The fresh and hardened properties of the concrete were studied under short term quasi static loading. Thereafter, the compressive creep test, uniaxial tensile creep test and flexural creep test at 25% and 35% stress levels at creep loading ages of 7 and 28-day hydration period were conducted. The long term deformation behaviour of the Kenaf Bio Fibrous Concrete Composite (KBFCC) was observed and monitored. Results show that the compressive creep strains of KBFCC is 60.88% greater than the PC, but the deformation behaviour of the specimens shows 33.78% improvement in ductility. Also, uniaxial tensile creep response of fibrous concrete deforms at the rate of 0.00283 mm/day and 0.00702 mm/day at 25% and 35% stress level respectively, but the deformation rate becomes insignificant after 90 days due to the presence of fibre. In addition, the flexural creep test reveals that 0.064 mm/day and 0.073 mm/day deformation rate at 25% stress level of the KBFCC becomes less significant after 40 days of loading. The outcome of the morphology image analysis on the concrete composite shows that Kenaf fibres act as bridges across the cracks, which enhances the load-transfer capacity of the matrix, thus influencing the long term performance of KBFCC. Accordingly, statistical analysis shows that the CEB-FIP creep model is the best fit model for predicting compressive and tensile creep of KBFCC, while EC2 creep and shrinkage models are for predicting flexural creep and shrinkage strain of KBFCC, respectively. A creep and shrinkage prediction model is proposed based on the experimental data for better prediction of KBFCC. Conclusively, KBFCC exhibits appreciable shrinkage, tensile and flexural strength under static short term and long term sustained loads compared to PC.

Creep and shrinkage performance of kenaf bio fibrous concrete composites

Fibrous Concrete Composite (FCC) is a high performance concrete that possesses an improved tensile strength and ductility with restraint to shrinkage and creep under sustained load compared to Plain Concrete (PC). As a result of global quest for sustainable, renewable and green materials to achieve a bio based economy and low carbon foot print environment, the use of fibre to produce fibrous concrete composite has continuously received significant research attention. While several researches have been conducted on metallic and synthetic fibrous concretes, they exhibit several unavoidable drawbacks and bio fibrous concrete has been proved to be a better alternative. This research investigates the creep and shrinkage performance of concrete reinforced with Kenaf bio fibre. After material characterization, concrete reinforced with fibre optimum volume fraction of 0.5% and length of 50 mm was used for the study. The fresh and hardened properties of the concrete were studied under short term quasi static loading. Thereafter, the compressive creep test, uniaxial tensile creep test and flexural creep test at 25% and 35% stress levels at creep loading ages of 7 and 28-day hydration period were conducted. The long term deformation behaviour of the Kenaf Bio Fibrous Concrete Composite (KBFCC) was observed and monitored. Results show that the compressive creep strains of KBFCC is 60.88% greater than the PC, but the deformation behaviour of the specimens shows 33.78% improvement in ductility. Also, uniaxial tensile creep response of fibrous concrete deforms at the rate of 0.00283 mm/day and 0.00702 mm/day at 25% and 35% stress level respectively, but the deformation rate becomes insignificant after 90 days due to the presence of fibre. In addition, the flexural creep test reveals that 0.064 mm/day and 0.073 mm/day deformation rate at 25% stress level of the KBFCC becomes less significant after 40 days of loading. The outcome of the morphology image analysis on the concrete composite shows that Kenaf fibres act as bridges across the cracks, which enhances the load-transfer capacity of the matrix, thus influencing the long term performance of KBFCC. Accordingly, statistical analysis shows that the CEB-FIP creep model is the best fit model for predicting compressive and tensile creep of KBFCC, while EC2 creep and shrinkage models are for predicting flexural creep and shrinkage strain of KBFCC, respectively. A creep and shrinkage prediction model is proposed based on the experimental data for better prediction of KBFCC. Conclusively, KBFCC exhibits appreciable shrinkage, tensile and flexural strength under static short term and long term sustained loads compared to PC

Mechanical and Fresh Properties of Sustainable Kenaf Fibrous Concrete Incorporating Sorghum Husk Ash

This article describes the findings of an experimental investigation on the performance of concrete using Kenaf Fiber (KF) and Sorghum Husk Ash (SHA) (CEM 1). To characterised the SHA (EDS), microstructural studies such as X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF), and Energy-dispersive X-ray spectroscopy were performed. CEM 1 was used with the KBF (length, L = 50 mm) and five volume fractions ranging from 0 to 1.0 percent ( = 0.25 percent ). Following that, five concrete mixtures were cast with 10 percent SHA as a substitute for CEM 1. The samples were cured in water and their characteristics were evaluated in both the fresh and hardened stages. In new concrete, the use of Kenaf fibre and SHA lowered slump values while increased VeBe time. When Kenaf fibre was added to either CEM 1 or SHA concrete mixes, it resulted in a good interaction with high tensile and flexural strengths, as well as increased concrete ductility and crack dispersion. When 0.5 percent Kenaf Fibre was added to dry concrete at the age of 56 days, it resulted in the largest increase in tensile and flexural strengths. The research found that utilising KF and SHA to manufacture sustainable green concrete is both technologically and environmentally viabl

Finite element and finite difference numerical simulation comparison for air pollution emission control to attain cleaner environment

Today, the world major problem is the air pollution because of the rapid growth of industrial areas. The emission of pollutant by factories into the atmosphere is affecting human health and the environment, hence the need for accurate and efficient numerical schemes in modelling this problem is expedient. The purpose of this research is to compare the Finite Element methods (FEMs) and Finite Difference Methods (FDMs) for the simulation of air pollution problem and show the better numerical method out of the two methods. The C program and Matlab software were adopted for the efficient simulation, and result presentation of the two diffusion problem tested. The results show that both numerical models are efficient for solving the problem of diffusion and are suitable for air pollution emission control for a cleaner environment

Analysis And Prediction Of Cost And Time Overrun Of Millennium Development Goals (MDGS) Construction Projects In Nigeria.

The paper focuses on the analysis and forecast of cost and time overrun of MDGs construction projects in Nigeria. Twenty five MDGs construction projects from (2006-2009) were critically investigated and time and cost overrun of the project were studied. The Statistical Package for Social Scientists (SPSS) 19.0 version was used to analyse the variables using Paired t-test and simple regression at 95% confidence limits. The analysis was based on the adaptation of requisition method. The validity test on the efficiency of the model was highlighted using the confidence interval to enhance the application of the models. Mathematical models were developed. The findings shows that there is a significant different between the total contract sum, cost overrun, total contract duration, and time overrun for the MDGS projects. The study suggests acute need for government to engage in proactive strategic planning and approaches to keep construction project cost and time within reasonable limit for the actualization of MDGs policy of development and environmental sustainability.   Keywords: Analysis and Prediction, Cost Overrun, Time Overrun, Millennium Development Goals and Construction Projects

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

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

Potentials of kenaf fibre in bio-composite production: a review

Kenaf plants are blessing to mankind. Its high carbon dioxide (CO2) assimilation rate and ability to clean the air by consuming large quantities of CO2 and also absorbs nitrogen and phosphorous from the soil, which are the main cause of the greenhouse effect has made kenaf significant from the standpoint of environmental friendliness. Today kenaf fibres are envisioned as an alternative medium to replacing conventional materials or synthetic fibres as reinforcement in composites. The low cost, no health risk, low density, high strength and modulus, and availability of kenaf fibres in some countries has made it befitting for use in composites production. This review presents the potential and recent developments of kenaf fibre and its composites. Recommendations for future work are also made