Question

Design the concrete mix according to the following conditions: Design Environment Pavement slab, Bozeman, Montana (cold climate) Required design strength = 3000 psi Slab thickness = 12 in. Statistical data indicate a standard deviation of compressive strength of 250 psi is expected (more than 30 samples). Only air entrainer is allowed. Available Materials Air entrainer: Manufacture specification is 0.15 fl oz/1% air/100 lb cement. Coarse aggregate: 2 in. nominal maximum size, crushed stone Bulk oven-dry specific gravity = 2.573, absorption = 2.8% Oven-dry rodded density = 120 pcf Moisture content = 1% Fine aggregate: Natural sand Bulk oven-dry specific gravity = 2.540, absorption = 3.4% Moisture content = 4.5% Fineness modulus = 2.68

Answer 1

Answer :

given data ;

required design strength = 3000 psi

slab thickness = 12 inches

air entrained : specification 0.15 fl oz/1% air / 100 lb cement

coarse aggregate :

bulk oven dry specific gravity =2.573

absorption = 2.8%

oven dry density = 120 psf

moisture content = 1%

fine aggregate - Natural sand :

bulk oven dry specific gravity  = 2.540

absorption = 3.4%

moisture content = 4,.5%

fineness modulus = 2.68

assume slump of the concrete = linch approximate) water content = 240 (forsen's enlained Concrete etc ratro 0:59 Cain entrained concrete) Ctoom table 6-34ca)) We = 0.5 (Hecom table 6.3.4(b) CE i consider w 0.5 240 * = 05 a uso eblog table 6:3-6 bolume of coarse aggregate cduy 700dia) por 2.68 0.75² ft² oro coarse aggregate & 0.752 x 27 ft dry unit weight at coarse aggregate = 0+5)* 27x120 - 2436.4 & 1b

How Determination of Wight 0fene aggregale thom table 6.3-4.1 Quilmed weight of fresh concrete + 3950 lb net water miung 2240 coment = 480 dry ccolse aggregate = 2436.48 total = 3456.48 lb weight of fine aggregate & 8950 -- 3156-48 + 793-52 lb fine aggregate weight = 793 * 110367 = 822 66 se aggregate wulgho - 2436 x 101 = 2460 lb water contributed by CA 1-0.1 = 0.9% water concubeeted by FA - 3-67 -0.2 -3-44 y. adjusted water content = 2460 Koo9 240 - (0o 82283.47 100 240 - 50-66 = 189. 3416

batch culeught estimated :- water content - 1891 Cement - 480 lb Pine aggregate - 82216 coarse aggregate - 24600 Mix design C:FA:CA 480! 822 2460 1: 107125: 5125 189 hatto = = 0.39 T: Wle ratio = 0.89 1