CEE 3020 Exam 2_S09

CEE 3020 Exam 2_S09 - Name Mm CE 3020 Construction...

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Unformatted text preview: Name Mm CE 3020 - Construction Materials Spring 2009 -—EXAM #2 Honor Code Having read the Georgia Institute of Technologz Academic Honor Code, I understand and accept my responsibility as a member of the Georgia Tech Community to uphold the Honor Code at all times. In addition, I understand my options fiir reporting honor violations as detailed in the code. (your Slgnature Slgmfies compllance With the Georgia Tech honor code) POLYMERIC MATERIALS: 1. Which of the following is a factor that does NOT affect th (a) Degree of cross-linking (b) Temperature (c) Percent crystallinity (d Strain rate (e) Condensation The consistency and mechanical properties of a polymer change drastically at the :1 rm 5 I j:- T “D PL - temperature. 3. Thermoplastics e - ' .- 't a form of localized cracking perpendicular to the applied stress known as “Grazing.” or FALSE) e properties of polymeric materials: to) e? 2. ass (3)__ _. 4. Two mechanisms by which polymer chains are formed are: ‘ . s a. Viscous growth - ' (5) Linear addition c. Algebraic subtraction d. Cross-linking Ce? Polymeric condensation (4) h and __Q_ 5. What atomic property of carbon makes it an ideal backbone for a polymeric chain? Name 6. List two important differences between thermoplastic and thermosets: a. ' 2/?” land'ch a f i from 2 {1206' ‘k His 0 Le? . . r 512/35 cw not: . 0- 77101710 Pia/5mg m2 UM!” av” branded, peg/:1ng Mamas)me W cryg—(xflmfl 7. Most polymeric materials exhibit a comparatively low melting point (less than 300° C) (fin; or False) (7)_ __ 8-9. Identify the three mechanical models for viscous behavior shown below: J (a) (12)wa .1 (c) Q:- Mad C gar 4H"! Mdcfd} for str '11 versus infi'i'm ffl‘flgows clfl-S‘Vlb FRPs: 11. Name three types of fibers commonly used in FRP materials: a. M g b. cmle 0. £61; [0W _/Amm€c7( Name 12. State two advantages and two disadvantages of composite materials: <2? ' C?) (a) Advantage: in f a: M; mfia (b)Advantage: (wreaks—n mafia/mt; 203le outfit-matting, 't’acg’/eral¢?l?+ta_- @ . G? (a? (c)Disadvantage: Mid 051 ’ l9 5 t e, :a‘ f‘ ‘ 5w tears l’megs, 4) <5? (d) Disadvantage: MW 13. The strength and stiffness of a composite erial can be obtained by a simple superposition oftheir individual properties (True org (13 )_E__ firmware, is“ fairer Hie/nTeIiO'" AM +u be, +akm Tn’ra account" 14. When short fibers are used, the main failure mode is probably a be I" A failure. 15. — 16. For a composite material with the following properties determine its strength: Fibers: Tensile strength (om) = 3000 MPa Diameter (d): 0.1 mm Length (1) : 50 mm Bond strength (1m) = 3 MPa Volume fraction (Vf) = 0.3 Orientation efficiency (n9) = 1.0 (all fibers aligned with load) Matrix: Tensile strength (on) = 150 MPa Brittle material, with ultimate strain lower than that of the fibers. l Igor 0' d For! >1ch 771:1-2—c; Useful formulas: Bond: 16, = 1“ Efficiency (111): 6” firm"? a? flu mm Z-Tfi. For! <16” m =Tfu L firm/Mot jive/5 PM $071151 . of“ d Mgm. Composite strength: 0m = O'mu-(l—Vf)+(7]1-?]3 «71% -Vf) aw: g 5': MPa fiWW = 150-(/..03) +0519 / K amxw) woon: : 9’55 W?“ I. 17. For engineering purposes, wood is usually taken as an: a. isotropic material orthotropic material c. anisotropic material (1. none of the above ( l 7) b Name 18. The typical bending strength of a select dense structural wood when tested paralle with its grain is probably: (a) less than 100 psi (b) between 100 and 1000 psi (c) between 1000 and 5000 psi greater than 5000 psi (18) g! 19. The typical wood will begin to gain strength when the water begins to be removed from the cell wall ru or False) 0 (19).]; 20. The typical equilibrium moisture content for wood is: a. 0% t0 5% b. 5% to 10% <9 10% to 20% d. 20% to 35% e. none of the above (20) C 21. -22 The typical design strengths given for wood are the bending, compression parallel and perpendicular to the grain, and shear strength. Please list them in order of descending strength (strongest to weakest) for a typical wood. i. he/VICX t mg: (strongest) ii. g-Eipreseim .2 afl'o’tl/e{ n rass‘tm aficular‘ iii. iv. 5 he“ 1" ' (weakest) __....—w—__ 23. Which of the layers shown in the si picture provides the largest g1 ‘ contribution to the strength of wood? Inner layer (53} Middle layer (52) Secondary ’ . ' -——0uterla er(Sl) (23) fi/lnfi , (52) in“ ‘-. ‘1,“ y Q. Middle lamella l I Name 24. What are two important properties of wood that impact its structural behavior but no that of metal structures? (6 J orth on p WWW-Pkg Tcwblax % [of)g.~.¢5ac,‘F—e; Jan/Hg. ~10 twat/m - r d b ' . ” ‘ (a) circa? an ( ) g PM [2mg 4‘ m1: attack 25. Shrinkage of wood is least along which direction? a i4 I‘m afian r offal} tow 7.2m 7”an . 26. What are the ranges in resistance factors (somewhat akin to the reciprocal of a factor of safety) for wood? a. 0.9 to 1.0 b. 0.8 to 0.9 c. 0.6 to 0.8 (g? 0.2 to 0.6 e. None of the above come/L 27. What are three advantages of glulam? _________ ecT_€__¢inLaUa&fé_-mm___ 0 ear__12L?l°€-_rm_/}Lm_nib_wfi____ ' _M_Qfl&[email protected]&%mm¢_ad_fimflfif contra/E). Imam/Wank dhmbflit Imiroved {ma resistance, Aggregate: 28. A single aggregate rock can be composed of several different minerals. @or False) (28)_ T F 29. Fine aggregate passes the #200 sieve and is retained on the #4 sieve. (True 01$ (29)_ «Flora/x, 30. State yam/properties of an aggregate which strongly influence the properties of hardened Portland cement concrete: Property}: S?F‘gfll'eifl9 guflgagg: jag—114%, (Jewrng Property 2 : 4c“. .91 a Property3: mgx‘!m.5w_\ aqqggfi-E/ gg‘gfi/ 31. If an aggregate sample’s absorption capacity is 0.5% and its oven dry mass is 250g, how much water is required to bring this sample from oven dry to SSD? (3 1)_ A z 53* Eye x, 9‘g% "H..— Name 32. Determine the specific gravity of a 50/50 blend of lightweight coarse aggregate (SG=0.9) and recycled concrete aggregate (SG=2.2). (avg (of?) '7” (0.§)K ( 2‘2)=/t§f (32) A55- 33.-35 Given below are the results for a sieve analysis for a fine aggregate: (a) What is the fineness modulus? PM = 335 (b) Is this a usable aggregate? Why? EM §___J_’i__ __LZ_W_L0:L-%fl(i£\gg_JEMEC__W______________W_______ % 5' m— _ sumo M50 mac nose no.8 no.4 Fineness modulus = a g; g g g g E E K) 8 8 3 2 :3. g "' If! ‘9 N Standard size: of seizure [Eff/Jka Dug {1 cm lac, Bonus Questions (2 points each = 6 points): 651' at; 4-; Who is the Secretary of the Treasury? I‘m _ 67 t” W 7—01 5 km 15 fl 3 +6\ nah Name the capital of one of the former Soviet republics in Central Asia: 5:: km IEFfiVa/VL) "7"}; la: ,‘ Who is the speaker of the House of Representatives (USA): it "garngéz & es “I ...
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This note was uploaded on 06/04/2009 for the course CEE 3020 taught by Professor Moser during the Spring '09 term at Georgia Tech.

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CEE 3020 Exam 2_S09 - Name Mm CE 3020 Construction...

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