natfiber - Natural Fiber Reinforced Concrete Ben Davis...

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1 1 Natural Fiber Reinforced Concrete Ben Davis CEE8813 Dr. Kurtis 4/2/2007 2 Overview • Fiber reinforced concrete • Types of natural fibers • History of natural FRC • Wood pulp fiber composition and processing • Wood pulp FRC – Fresh properties – Mechanical properties – Durability • Future research and conclusions
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2 3 Fiber Reinforced Concrete Factors controlling performance of composites – Physical properties of reinforcement and matrix – Strength of bond between reinforcement and matrix Characteristics of fiber reinforced systems – Fibers distributed through given cross section, reinforcement bars only placed where required – Fibers are short and closely spaced, reinforcing bars are continuous – Small reinforcement ratio when compared to reinforcement bars Concrete of Area ent Reinforcem of Area Ratio ent Reinforcem = (PCA, 2006) 4 Fiber Reinforced Concrete • Advantages – Easily placed • Cast • Sprayed • Less labor intensive than placing rebar – Can be made into thin sheets or irregular shapes – Used when placing rebar is difficult • Disadvantages – Efficiency factors as low as .4 2-D (spray placement method), or .25 3-D placement (casting method) – Not highly effective in improving compressive strength (PCA, 1991)
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3 5 Natural Carbon Asbestos Polymeric Glass Steel Fiber Type - - .076-.464 0.96 40-160 Akwata 1.5-1.9 36-51 3.7-4.64 1.02-1.04 4-8 Jute - 51-73 4.79-5.8 1.5 2-16 Bamboo 10-25 17-29 2.76-3.77 1.12-1.15 4-16 Coir (Coconut) 3-5 41-82 1.89-3.77 - <8 Sisal - 44-131 1.45-5.8 1.5 .8-4.7 Wood cellulose .5-1.5 260-380 33.4-55.1 1.9 .3-.35 2-3 29-500 23.8-28.4 2.6-3.4 .0008-1.2 2.5-3.6 525 9-17 1.44 .4-.47 Amarid 10-50 80-170 1.45-2.5 1.38 .4-3 Polyester 3-80 29-435 .725-25 0.96 1-40 Polyethylene 8 80-110 0.5 0.9 20-160 Polypropylene 3.6-4.8 360-500 10.44-11.6 2.5-2.7 .4-.5 3 300 23.2 7.8 .4-13 Stainless 3.5 50-250 29 7.8 4-40 High Tensile Strain at Failure, % Tensile Strength, ksi E, ksi x1000 Specific Gravity Diameter, .001 in. 3.6 26 .716 - 17 Elephant Grass Comparison of Fiber Types and Properties ( PCA, 1991) 6 Types of Natural Fibers Sisal (Castro, 1981) From AgaveSisalana in Mexico Durability problems caused by chemical decomposition in alkaline environment Coir (Balaguru, 1985) Coconut husks Very durable to natural weathering Increases modulus of rupture of concrete (MOR) Bamboo (Ghavami 2005; Rodrigues, 2006) E is very similar to that of concrete Susceptible to volume changes in water Increases ultimate tensile strength and MOR Jute (Balaguru, 1985) Grow in India, Bangladesh, China, and Thailand Increases tensile, flexural and compressive strengths, as well as flexural toughness Akwara(Balaguru, 1985) Abundant in Nigeria No dimensional changes due to variations in water Alkali resistant No changes in flexural or compressive strengths Impact strength 5 to 16 times greater than unreinforced cement matrix Elephant Grass (Balaguru, 1985)
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natfiber - Natural Fiber Reinforced Concrete Ben Davis...

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