'F‘y. C o I I! v .I . . 4 J 5.. ID .I c . o I V“. Ur T. . 0mm. s .. WW5 Be U D {fl TS-D 0.1 3“.“an elm LURE me; ATAY 3 . TX e0 MMQN-I IE A t . - . .RTm rw . Emu. cm . HCU .sD Ewm w . h INACMm T R . o.0¢'\\III! \(‘I I, . \ . . o ... I ., I (‘0 .. 71.}, .‘3 ’lII .I u . . I I II . , I. _I. ._ ...I ..... I I .2. LI .. .I. . . u.\ I. .. ,. .I I .I I, .. I . . . I .sII ‘.IIII» ,. I . ”.I. . . _ .. . _ . I ,_ .. . .. . . . . I .II.I-III.IIII; II .. .. I _ . .. . I.. . .. .. .... , 1) .. . .. . I ..v . . I . a... . .I . . .I.. . .a.’ ‘1...)- ...' . 0'4?! [7.50.1 " . . . . . . . I I. . . CHI .. ..I . ..I. . . . ...p . Iv... . .. . II . vII. . . . . . . .. . 11"»{5'13-“II .. I .1 . . I ,. . . .p .. .. . . IIQI .I. .. .u I, .... . ,. . .1. .n I. 3. I I.. . . . . .10.... IIJJ .. I'.UI.'I.- ..25ad .2. .mu m :w .4 .. _.I n». .,4IxhrI . . n .. .. .4......n.h\.r - I ,I.:v Irwuw.;- y . ,. . . r.. . . .. . I . I . .I. .. .. I. ., I. I . I I . . a J In.\"IJNN.I..J‘A£ . I . .. ... . I . I . . I . . .. . I....I.I. I . I; a.. . . . .A .. . . I I . .. . .I. . , . . I I u . .I.. . II .I .I II , . . I. . _. . ¢\ '3. lo .‘II‘IIIIIOIIWI II I . . a! I‘.LII' "‘l‘. . I ., , . I I. ...l.u. . .J . I $1.00!.IOI.I\, IAw'OI . .I.. .I. . . . ...I|It.¢ 1"..‘I’K3O‘VIIH. an. t . _ I I I. . . . . . . I ‘41. III ' 5 -II .I «I w. . I... . II... 41‘!!! .¥.r.sr. .1 .I .. . . .. I . I . . . v 1.; o ...\u.! (I! I . . . 1.. . I II 2‘ . . (r... . . . . .. . , . . , I. I. . . . . 3:11. i I I.) \ . .JLI .rI‘I.n.\ 3.1....” «.7! I , . \ . . I I. fill III I ‘u’.. . I .I . .. .L.4IA £43?! I. ,. I., .~ I .q ’0.‘ OI !. I . I .. .. ..I .I. I . . . .. . .. .. I.,. . .. . ..III . x . .. .I...!..-...II.I........MI.. 4.- . o... I I, . . . .. . . . ...I..o.it...9.!.1_6>..).!. . ,. I.) v. I I d‘ttl 1&5! . I. I . . . ,. I. .I . I . . . Q . .. .I . . I . I. O '53.... .10.. I. '3 .|!.- .I. . I.1. |\ol. .fi! r. .I. .II“.\\' ’i.-tCUJQ {IIII 0 I). IJ’IK-lu. a . .\ o I\ ‘JO.3HI !l_.~.ll!‘n I '1‘! 3 .r n.J.v... a? '5».- 3 .- ‘ .51. - I ,- ‘ .. ‘ ‘ ‘1' . -‘- < ‘. h “ I_ ‘ . _ ' t, . I . ‘l v- I I. ' L i w ' I‘ .r . . l firgfi‘? (2") 1' l .“ . I ‘. ' '-.‘ - ‘ o ‘9‘} #xxfivf‘fi :4whi‘uxf" ‘7. .I.; : . _5La’ . . .V . ‘ ‘pi’ $23.2". ‘r:j; . I ' .'.“ 73'“ m 4’ ' I “9‘31.” _. . Jill-.303 ‘-‘: . I. ,II ,, - - . ' u' I'3."'-I'-"". $1.."h‘u‘fi'fi.’ , I... -' I . e ...’«(.(‘a'.-'«'* ‘ .0. I" ,.L’.\IJf:’:a;"\‘I\IK‘ ‘ ‘ (' l H. _ g. . x - V I ;.Y ' - -.‘:\‘i‘2, 'f‘g‘r‘v _'l_“ \ ' ' " LI ‘m’r‘fl 9 . - ' ' " '0 l ‘ '4 I o 1 o .I.” ‘ \V (QIV‘ AI? ' \~ .,J' Q X .I'.’ 'kh“ ‘2‘,”«9' ' ~‘ II.‘ 4- - . .. _ . , ' f z’ff‘hv‘ "*gfiil..‘33¥3 .5? I - ‘, ’ " ’1 ' If. ‘ fie» 11v - _ . ’ I ~ . _» u - . ,1" q, ‘f "I‘: Hi I'd '._ )- ,._‘u.-IV_5-“ 1 . 2.5 ~ff“?"‘- . 3 ‘. o b a“ I I :\.-"" 1 ' ' in“ . .53}, ‘3'}? '.\ . 45“..- “. It. .__ -3.‘3"‘4.".'.“( 3?;3' . ‘ .. If " 571‘ "— 5.;1 2:. .- -.~ ‘0‘} 'I \‘ ' -- ‘J-"f; 5,173 ! I‘ ' i .\ , ‘ A II _. ":4- ~ .3 AP :.:~,..- A, o I... ' D 4'. _ 3 v1'. . . . I 3’ ',_ L. A’ I . I Ov' f‘ ‘P‘ In 1-: y, I <4 -.‘ *7 ."I‘ -‘ ‘f . ‘ ‘hn . ,5: - t-‘g - e - g. ' <- ‘R: "o M: .- ‘1 h‘. "M s I .u' '.'|J ." V.“ 'l.’ w‘d.‘ 3 I lr~.)§o 2‘. ‘1 . is"— ' o -"-r ¢'&yu" . , v .1! .~, ° W, 7:3 .‘V . . : "$;~:(\".."\.;‘i§f ' .\ ' 1 _ :.-‘ ra\~".'.\'\-‘I "3 , , _ , ‘ . . . ‘ . '..\I-’ u WW“. ,. ., - , I. . . -I .w ”an; ' ' I. , . ' I .. ‘l I.‘ I“ - I - ~ , t.."-\ " . . '2 *I - -_ .. «.r I... ,. .. ' t.”'.\ 1" . . 1‘3.‘,I'_,- '-'.,' ,< N . I I - “4-.h. . . . 'r . *- - 3" I ' ' ‘ An Experimental Study of Concrete Mixtures With Heepect to Quality, Density, and Yield A Thesis Submitted to The Faculty of MICHIGAN STATE COLLEGE of AGRICULTURE AND APPLIED SCIENCE by D. W. Stonecliffe Candidate for the Degree of Bachelor of Science June, 1936 .v le‘g‘\ ACKNOWLEDGEMENT The writer wishes to eXpress his appreciation to PROF. L. J. ROTHGERY whose thoughtful assistance and helpful guidance made this thesis possible. tttltttiitt-) wemeetset tittttt tittt tot Q 1, 03:31 T" INTRODUCTION The subject of the design of concrete mixtures is one that has been experimented with for many years, and need- less to say, much has been published on this important tOpic. The outstanding contribution of the mass of published data is unquestionably that of Duff Abrams. His principle or law of the importance of the ratio of water to cement has formed the basis of practically all methods of mix design. Elm suite of all the available data on the subject of mixes, a great many in the industry are still using arbi- trary volume proportions such as 1—2—4 etc., with no thought given to the possibilities of economy and quality by using the water-cement ratio principle and so adjusting the characteristics of the aggregate to insure quality and get the most concrete for a given quantity of cement.] While this thesis admittedly will do more to deve10p' the technique, judgement and experience of the writer on the subject of good concrete mixtures than it will to con- tribute something original to the concrete industry, at the same time this seems an excellent Opportunity to show by experiment some definite relationships. The object of this thesis then is to demonstrate the relation between grading and size of aggregates, the rela- tive amounts of fine and coarse aggregates, the total quan— tity of water-cement parts and the quality, density and yield of concrete, all mixes using a constant water-cement ratio and constant slump. Concrete exposed to the weather must be water-tight. That means it must contain a minimum of air spaces or pores which allow the entrance of water. These pore Spaces are due primarily to two causes, - first, harshness or in— sufficient mortar to fill the voids in the coarse aggregate or if enough cement was used the mix may be described as undersanded; and second, too great a water content. Less than three gallons of water per sack of cement are neces- sary to thoroughly hydrate the cement; beyond this point, the water merely acts as a lubricant for the batch. Too much water will prove a detriment, because after the cement has been hydrated and the batch lubricated, the excess water will dry out leaving pores in the concrete. This tends toward a porous mix. All these conditions must be 'guarded against in designing mixes for economical, good qual- ity, dense concrete. As a basis for yield in this study, it was thought best to obtain data for unit-weight curves for each of six different combinations of sand and ooarse aggregate. Fine sand, coarse sand, coarse aggregate less than one inch, coarse aggregate greater than one inch, and a combined coarse aggregate were to be the aggregates used in making these curves. The high points on these curves would then represent those mixes which had the greatest unit—weight of aggregate -- the first step in getting a dense mix. [in order that as many variables as possible could be eliminated in these mixes, a constant water-cement ratio t’u‘l " and slump would be used. The constant water-cement ratio should also produce a constant strength, thereby eliminat- ing another variable. The values then remaining to be computed and observed would be weight or density and yield. PROCEDURE It was first necessary to obtain material to work with. There was enough fine sand in the bins of the con- crete laboratory to take care of all the needs; also there was some mixed coarse aggregate, which had to be screened through a one inch screen to separate all the material greater than one inch from that less than one inch. As there was no coarse sand to work with, and seemingly not enough coarse aggregate, a trip was made out to the Boichot Sand & Gravel Company on Highway U. S. 27, north of Lansing. Here, there was a good grade of coarse sand, and a coarse aggregate that had a lot of material greater than one inch present. One cubic yard of each aggregate was ordered and delivered within a few days. As soon as all the material was delivered, the coarse sand was immediately put in large drying pans, placed over a slow-burning flame, and dryed out until the surface mois- ture had disappeared.‘ It was advantageous to stOp drying at this point, so that none of the inner moisture of the sand particles would be drawn out. If this inner moisture had been drawn out, extra water above the water-cement ratio point would necessarily have been added to be reab- sorbed into the particles. The same drying process was repeated with the fine sand, and the two sands put in separate barrels until ready for use. When the cubic yard of newly acquired coarse aggregate was screened, it was found that much more fine material was present than had been expected, and it looked as if there might be a shortage of material greater than one inch. Such did not prove to be the case, however. As the coarse aggregate had been washed previous to delivery, it was not necessary to rewash it, so the two screened aggregates were put in individual bins and left to dry from room temperature. After all the aggregate, both sand and coarse, had dried out sufficiently, a 1000 gram representative sample of each was picked out, and a sieve analysis of each was run. The Tyler Standard Screen System of square openings was used. Numbers M, 8, 1H, 28, 48, and 100 were used for the sands, while the 1%", fi", and 3/8, and number H were used for the coarse aggregate. The weights retained on each screen were ‘ recorded, and percentages were computed with the possibility in view of finding a relationship between these values and yield or density. All that remained to be done then before beginning the unit weight charts, was the determination of the dry, rodded, unit weight of each aggregate. This was found by taking a representative sample of each aggregate, filling a half cubic foot measure one quarter full, rodding 25 times, filling the measure one half full, rodding another 25 times, filling three-quarters full, rodding another 25 times, then filling the measure level full, rodding a last 25 times, leveling off, and finally weighing on a Howe Seales which weighed to the closest one-half pound. Multiplying the net weight of the aggregate by two resulted in the unit weight required per cubic foot. Two methods were used to get data for the unit weight charts. The first was unsuccessful, the later worked out very well. The first method was as follows: One cubic foot of coarse aggregate was weighed out and placed on a canvas blanket. 10% of a cubic foot of sand by weight, was added to the coarse aggregate. The mixture was rolled on the canvas to insure good mixing, then the one-half cubic foot measure was filled, being rodded as described above. The measure was weighed, and the unit weight of the 10% sand mixture determined, by doubling this net weight. 10% more sand was added to the cubic foot of coarse aggregate making a total of 20% sand present in the mixture. The unit weight of this was found and the process repeated until 50% of a cubic foot of sand was present to one cubic foot of coarse aggregate. The process was then reversed and one cubic foot of sand was mixed with 10% by weight of coarse aggregate; the aggregate was mixed well and the unit weight found as be- fore. 10% more of coarse aggregate was added, and so on until 50% of coarse aggregate was mixed with the cubic foot of sand. ,The curve was supposed to check out at the 50% point, but obviously, as was later realized, one cubic foot of coarse aggregate plus one half cubic foot of sand will not have the same unit weight as one cubic foot of sand plus one half cubic foot of coarse aggregate; consequently, the curve did not check out. This rebuttal forced the adoption of a different method. It was plain to see that in order to get a smooth curve; as 10% of sand was added to the cubic foot of coarse aggregate, 10% of coarse aggregate would have to be removed, leaving 90% of coarse aggregate in the mixture. In this manner, a whole cubic foot by weight of sand and coarse ag- gregate was present in each mixture, because as 10% of sand was added, another 10% of coarse aggregate would be taken away. Finally, the next to the last point on the curve was the unit weight of a mixture of 90%lsand and 10% coarse aggregate. In order to have better control over the unit- weight of each mixture, a special cubic-foot measuring box was built. The box was constructed of white pine in the Building and Grounds WoodshOp. The inside dimensions of the base were 9.3 inches on a side, the height of the box being 20 inches, thereby making 1 inch of height equal 5% of a cubic foot. Every inch of height was marked around the L Cubic-Foot Measuring Box inside of the box, then as a mix of a certain percentage of sand and another percentage of coarse aggregate was placed in the box, it could be noted just what percentage of a cubic foot the given mixture occupied. The weight of the given percentage being known, the unit weight of the mix- ture was then accurately computed. The above procedure was followed out with six different combinations of sand and coarse aggregate: 1. Fine sand and 51"-) C.A. 2. Fine sand and l"+) C.A. 3' €3,258Zazfinzninfiflifedcfi" 5: Coarse sand and (1"+; CIA: . Coarse sand and Combined C.A. The data was recorded in each case and suitable curves were drawn up to show the variation in unit weights. At this point it might be well to mention that for each curve, the percentage of voids in the coarse aggregate was computed; this value being plotted as a vertical line along the horizontal scale of each curve as a sand percentage. The theory was that back of that void percentage line, the sand content would not be great enough and the mix would be harsh. Such was proven to be the case. UNIT WEIGHTS OF MATERIALS Fine Sand ................ .106.5 1 Coarse Sand ............... 112.5 83;? .1 Coarse Aggregate....107.5 Coarse Aggregate....103.0 Combined Coarse Aggregate.lll.5 .3. per Cu. Ft. I! H i! I. 'I I! I. I II I! Percent Voids in Coarse Aggre ate in Mixtures Voids = 1 - Absolute Vol. Combined C. A. and Coarse Sand - % Voids Combined 0. (1M) 0. A. (it) c. A. (1%) c. A. (1'+) C. A. A. and Fine Sand - % Voids and Coarse Sand - % Voids and Fine Sand — % Voids and Fine Sand - % Voids and Coarse Sand - % Voids l - 111. a .33 2. x .5 a 1 - 111.5 a .33 2.55x52.5 = - 10 . a .35 2. x 2.5 a - 10 . s .35 2. x 2.5 = - 102 = .38 2. 5x 2.5 = - 10 = .38 2. x .5 11'3) COARSE AGGREGATE AND FINE SAND A t S d gartionsof__ ngght 0 Weight of re a e an .Ft. am— am le S m 1e r Mix % Weight % Weight' 1e Occupies p c:.th.pe l 100 107.50 00 00.00 1.00 107.50 107.5 2 90 96.75 10 10.75 .92 107.50 117.0 a 80 86.00 20 21.25 .87 107.25 122.0 70 73.25 0 2.00 .82 107.25 126.2 5 60 6 .50 O 2.50 .8 107.00 127.5 6 28 3.75 50 53.25 .85 107.00 126.0 7 3.00 60 6 .00 .87 107.00 123.0 8 30 32.25 70 7M.50 .89 106.75 11 .0 9 20 21.50 80 85.25 .93 106.75 11 .9 10 10 10.75 90 95.75 .95 106.50 112.0 11 00 0.00 100 106.50 1.00 106.50 106.5 (1'-) COARSE AGGREGATE AND COARSE SAND Portionsof ngght of Weight of A re te Sand _Cu.Ft. am- ample Sample per Mix % {Egght % Weight ple Occupies Cu. Ft. 1 100 107.50 00 00.00 1.00 107.50 107.5 2 90 96.75 10 11.25 .95 108.00 113.8 2 $8 $68? 28 a??? '33 {83°88 hit 5 60 63:50 go 5:00 263 109250 12u25 6 28 3.75 50 56.25 .88 110.00 123.0 7 3.00 60 67.50 .89 110.50 12 .1 8 30 32.25 70 78.75 .91 111.00 122.0 9 20 21.50 80 90.00 .93 111.50 120.0 10 10 10.75 90 101.25 .97 112.00 115.5 11 00 00.00 100 112.50 1.00 112.50 112.5 i . ghmfl V WMKRNV \o. m Avx§\o\\ \VNNK \o A.“ . A Aw . A a? tweak _ . . 7 KW NQMr...\MW\.h a“: aw. "w 4/ rpm .3/ A. 57% finxx t. r u\. A . EN b L 1‘ {f w h/ L J < . . _ c . o 910# V: 9 v e‘ b-0 0 hi I n y o e 6 . d . VI c-0l o 0.1; . A OJ. . C.‘ e .9 1‘ .19 ..1 A . 0‘ > P‘ H. 0'00 3 Y O c o A .r n e '.6 0 fl.- . . . . Tr . a. - A? ‘n‘ . a 4 a ‘w . . . ,. nuhb bkmlxcrw \Q UEYQL \0 30m \o . Q3103“ Nut pk.» -- Amps) A. _ o\. . as a. a. w. A an . . . . . . . . K... AV . 0] N 00“ u o A . . . . . . Z . . . . . . . /. -1 . . . . - A A . . A A v p A o . . A . o . A . T)..- . . A A . 11. n . I] Ll A v u A A o p . / . x A I . o . A I. O T O . 0. . e I . . A . o 0). . . . 0 A A A . A o . .0 e A c - -6 o Q‘A or . o.IA1- O . 0 A . e . . . . e c o o A -Av .- . . to a . t o A 0' o.» e ‘ A e .04 n . A A f A a 9 o o u . 77 A A ‘A o . A e u. A o 0 A A 0 .IA A o . A . . . . . f. . , t. . . . . . . l v . o . o I. k. . A A O . . C . A e o A A o A ..| o. .|. A .I. . . A . A o . o A A . O n o 0 e u 9 . 09 e e e o 9 .Hi ‘ e I s I C I a e . C 0 ‘ O s o O . . . . . A A . A . A . . . . . A . . . . . . A o . r v c . i o a o e c - IA ~ . ‘ O v . . . O A 9 e c . . L > IN 9 h o I. o o . . . A v . . A . A . I. A . v o . n . . . . . . w . A . o a A 0 'It . v A . O O c O 9'. v‘ . o o 4 u 6 . ' \II o A . ‘0 A v u 0 Q A A h OIIOI . p . or y I. e ‘ o A.Io I. .‘ 4 b . i' 0 . . I A a A . A. A A . o o A . . . . . I .6. :0! 0| 0 to o . A o I. & YI v- t - O V v o e - . 1 n v A or in 1 0| 1 v . A A . .0 o a CI IOII 1“ 9|.l . . - . . A .I. 11“. . . . A . e - A e . A . A A ll: 1:1 o ‘1. A A . A A » e a II OI A but IA | . IA A . . . a A o A b It 6 o o . . o o n .l 1 ‘v A Oil I t I e n It o o O o 9 l . c. O A 'l A 0|. it a u A o l . b 0 A I]. . A A . A . . A . A . A A t or . A ‘ A l O n . n A O O . O a . . . . A . AI . o A A . . . O 11':)_COARSE AGGREGATE AND FINE SAND A S d gortfian of ngght of"1 Weight of re ate an u. .Sam- ample Sa 1e er Mix % We§g5t "Naight ple Occupies CquFt.p l 100 103.00 00 0.00 1.00 103.00 103.0 2 90 92.75 10 10.75 .91 103.50 113.7 a 80 82.50 20 21.25 .87 10 .75 119.3 70 72.00 38 2.00 .8h 10 .00 123.8 g 60 61.75 2.50 .83 10h.25 125.7 23 1.50 50 53.25 .83 10h.75 126.0 7 1.25 6C 6 .00 .86 105.25 122.5 8 30 31.00 70 7h.50 .87 105.50 121.2 9 20 20.50 80 85.25 .91 105.75 116.0 10 10 10.25 90 95.75 .95 106.00 109.5 11 00 0.00 100 106.50 1.00 106.50 106.5 113+) COARSE AGGREGATE AND COARSE SAND d Portionsof figight of Weight of A e te San Cu.Ft. am- ample Sample per Mix % We§ght eight 1e Occupies Cu. Ft. 1 100 103.00 00 00.00 1.00 10 .00 10 .0 2 90 92.75 10 11.25 .91 10 .00 11 .3 a 80 82.50 20 22.50 .87 105.00 120.9 70 72.00 0 3.75 .83 105.75 127.5 5 60 61.75 0 5.00 .83 106.75 128.5 6 38 1.50 50 56.25 .85 107.50 126.5 7 1.25 60 67.50 .87 108.75 12 .0 8 30 31.00 70 78.75 .88 109.75 12 .5 9 20 20.50 80 90.00 .91 110.50 121.5 10 10 10.25 90 101.25 .97 111.50 115.0 11 00 00.00 100 112.50 1.00 112.50 112.5 WQVQWW: Kc. N buck... a HQUVL 4‘ “ L. RAE .. . a Q N a . 11$. wash O ‘ O b I A A A A I c I .Q As . . . Ab. AK. . a. 5 A ow 0 e a o A A -.A A A A o u A O A A A Q A e 9. e . I . v A A A o o . o. . . . o A- A A . A A A A . a . . o O A A A A u A o . A . . A A A A o o o A A A . A A o A o o A A A A v .I. A o I I. . A A o A V . . v A v . . AA lotA A A A I- . A. A . o . A . . b A IA A A A .IA IAIIO. All‘ -‘ AID A. A c o 1 o A a .-o . e A r A 40 o A 9 F A 0'. n ‘0 A -e.‘ 6...‘ v A A- A b v A n . l, . c . o A A.A - A A e o o 0 e o ’IAAIO A . 0119‘ .I. 010'- -4. AAA. o A 0.. e o A O O a V o c A A A A e . o- . vov .lal.'A ..o a 0.11.-. .Al‘AlOALIA .A o . . o A A A o o . A . v A e .A Q o A a e I. A A o 0. A Alclollvl. .0..A v . A's . A A A e A A o . .o ¢ 5 IQVO I 0.0 OIAT I. A .A o Icl.‘ .AAAO. A IAI A 0 . . e . A A A - . A o 'L . . A o A o A .9 . . c 9 AO‘TIOIOA A w. . A c . o . . . - A A u A elvl. A . .0 .I. 9.. 3'0..-‘ 0 . 0 .d I .IOI 0.. . . A o a A-.- . A .iv .-o -A .I. o o VI. .l. \A A A _A. . . A o A A A . A . . A o .u. e I— v o o A a A . O o . cl. .0 A O. A A I A A» O A A w u A D } . 4 A. o .o. .u . . - . o o A e 0 AI. o A . .1 A . o A o .4. v o .A e A 6 V A o I .L 0 cl 3". AAI 1.6 .611.-. o i A O O . O A . A |. 9. A-.- o 019. . v o A A e r A b A ‘ ol 1' 'eIA .ic e a o A . . n» . 9.... . A o. A f o o o A . I. 1 1' A... 0.. v c . A A . A . a o A A A V A . 1 .A -o ’A .‘c o A A A A . A I. . IVOIA - .A . A A I . 9 o . .0 .6 O . A v o a v0 .0 6 Oil. 0|. -. A A Olb.‘ O .A v A A A .A a . o o A- 0 A u A A A v o 9 v.0 t AI 5 A .. A . o > . A n . O A a A A a 1...‘ o 0 ¢ 0 d . .. . . A . . .-A A . . . AAA . re . A. n.-‘. 00v 9 A I . o 5.. v.-1 o o a A 0". AI. e o v o . e d l A u o.‘ .I.: -I . - o Al . n 6.c . v A c All 0. A . .AAAio A . A . A A . . o o y .9. o A A A A .5... o . 40 O . . o a V. A T .— .o A .. .I‘ A .-. A - . A-A - 1Alv . T. .- :41? . .I. A - -A .000 a. 4.4 A. «.8. 14!.1. Ac . s o A . . A :0 o O A l5. ‘ .Y. {it IA. 1.! . A A 0.0 A v 9|. L0 O. o .01, '.h,9-6 .' T- i A . . A o A A u r. .. h.|o .O'oAAIIOAIOA .l'TAIQ‘oid..¢ fiIA'4 will AAA .4 . . A v v .I. o A .? wLuA o. '1'- A , +-ITALI «.0.-- a- 1A-; I. I . I. 1 A - A Aw . o. . A-" A A- . A- . o . A. II 011.! _ An . n . o fd'et .1 0" A- v A 4 o v. . ..* o -1..! 9-...-- .AA - h‘ c AIAA A p o 0 I A p e 9 Olloll A .0 0 0.. o A .A... A l 0|. . .-A A c . . A .l A .9 lolA 9‘. o o o A A A A A A c t A A . 0 c'. '4. 0 0 Al 4 I. A A v 0 I I A a O I O . b l . . . . - . . . (‘1 A A o A A A AI- .. A.‘ I e A e 1 o a e A o e . O o A o A A . A .0 A A A A 35\ . . . . . . ‘1“ ‘ COMBINED COARSE AGGREGATE AND FINE SAND .- L . A S d Portionsof Weight of' eight of re te an Gu.Ft. am— Sample Sam 1e er Mix 1 Weight We g_t_p1e Occupies _ Cu.th.p 1 100 111.50 00 00.00 1.00 111.50 111.5 2 90 100.25 10 10.75 .93 111.00 119.5 a 80 89.25 20 21.25.87 110.25 126.8 70 78.00 0 2.00 110.00 129.: 5 67. 00 0 2.50 :§ 109.50 132.6 6 E0 2. .75 50 53.25 109.00 130.0 7 0 .50 60 6 .00 108.50 126.2 8 33.50 70 7h.50 .88 108.00 122.8 9 20 22.25 80 85.25 .91 107. 50 118.0 10 10 11.25 90 95.75 .95 107. 00 112.5 11 00 00.00 100 106.50 1.00 106. 50 106.5 COMBINED COARSE AGGREGATE AND COARSE SAND Portion of Weight of Weight of A re ate Sand Cu.Ft. Sam- Sample Sample per gix We ght Weight ple Occgpiee Cu. Ft. 1 100 111.50 00 00.00 1.00 111.50 111.5 2 90 100.25 10 11.25 .95 111.50 117.5 a 80 89.25 20 22. 50 .90 111.75 12M.0 70 78. 00 38 3. 75 .88 111.75 127.0 5 60 67.00 5. 00 .87 112.00 128.8 6 2g 2. .75 50 56.25 .87 112.00 128.8 7 .50 6O 67. 50 .88 112.00 127.3 8 30 33.50 70 78. 75 .91 112.25 123.5 9 20 22. 25 80 90. 00 .95 112.25 118.0 10 10 11. 25 90 101.25 .98 112.50 115.0 11 00 00. 00 100 112.50 1.00 112.50 112.5 1 ___J I . Q 0 ¢ t c n v t o . n s I t | Q 7 S g . c o 1 v u Q l’; ‘ q. 1 c I. ~ 9 t O A u . . O o h D ‘ \ . A o a m . a o u o b 4 _ o 1 I O o ' I _ a I o o I . I o 7, 1 0 t ‘ Q 0 I . I I . a I I: I . I I ill] I V . I I o I I ’5 I . I . . - I . . . - fa . . - I I o I I I (J0 g . I I I 4 - I . . . - . . . I/ . . I . . HI. I. 4 I I a t I 9 I o I I V I I I d . I III p I A I I I I o A v 4 I I 0|. / . 7 I I I I b, . r I . oo 9, I y o I I 6 I o _ o I — ' O O . u . o a It I o I < I O ‘ I I o o . . f o u . u . I ., I. . . I v c I‘ . O O A . . o o O . n a I I . . . I I 9 o I II I Q n I o . II I o I. I o o . I I. I u v . . I II I . I I . o I I I I . I . I . I . o t A I . 9 4 I o o o I . . IO . o I . I o .6 o 9 u . o a A o I II I t s . I I. O r o I 0 I d. I. O v'c I . o . I o o . I I . A A O o I o o # ~ ‘00 I II. IoI. . .I. I . y o b o A . I l O O Q a . b O I n . a $0.. I o . o . — a o I . I o O o a Q o ‘ I o o c I I I V . . I I O I o . I 0 . . o r o I a o o # II I 6I6 o .I I . II I . l¢ . Aw I I o I II a o 7 I I DIN . . '6‘ u I . o I. t I. I OIAY A I .II .I. I I I . 0 a . I . L b I. o I. . QII‘ A V n I O v I t u I . . I . . I ¢ 0 0.119 I ~ 0 O . o i I.I 0 + II It .I u A o I I g C O 0 I a I 0 0?.» I o I I OI -‘l‘ I. Q. I o I O o ‘ o c . a o I I I. u .I. I If . 6 I O III I .I I o . . 0 Q I . .. o I v I I . .0 lo .IIIIYI‘IIOI .ITII I O I A I O I O o o .I o v . Q o I I I b I , ‘JY‘II‘ II. I... ,9 YII. I‘. o .0 I v Q I ' . _ . . I IO.I I‘Io I . o c .IIIIIIol-IL .IIIoIoIfllu o o .I. I o I. . . . 3. O I II V I III. III I. I I .‘ v VIFIQIVI III I I . 0 -01 I I. IV / I II. I I 1 I I I c v. I; II... IIIL Ill'lg III. .I IIBI I III/ I. o . I I n 6 I u 0 I06 .00 -4 Q ‘It IQIv I. II. I n O I 0 I. .r . o o o . I o o o I I I I II . fl o I. I . o v I I I o . ¥ . ‘ ‘n. ‘ I. 1 O . ) I I I K I I I I I Iv I . I . \ I 500 A ~-\\A\\J ~1x«.fi~. \ . L L0 c ;.B k 2x . :1? 4.) I . n o o o . t ‘ o 0 n . c n . . . . u o v o - . u y o - o n . . a n O . Q I n - . n . Q o n . / . -nv . . c ¢ . . V . a o . . i . . o o o o o . . . . . . _ v r I a . a b 0 Ab . V v . v o o . . . . u b A g . . r: .’ r > L-l . J 4 1 . . o . . - . . . o . o v . a I. 6' 1‘. . . u 9 v V 0 ol 0 V . < . . . . . o- n 0 o v . . . o - V o 4 4 o O : o . o ‘ . 9 o l . ‘ O ‘ . O . l O O t .:./. o v ‘I9 . u . o . ‘ o 0 Au- 0 o .‘ . YIJI,O.I|¢ v .'A v ‘ . Y A o o o! ~ . . - "oL . ¢ . v . . .I..,o c .c. . . ov.lo. 00-. vioq>lo . r o $-O o o '0; n I. ..9 0| 90‘1 o . . . o . o . . . u‘ t v -I. v V ¢ '4'.-. O T 90 . . ,v . .I. o O “ OUT: 0 V69|o.*.o j . o . o O . Oi 9 o . V: o It . .I.?! - ox .. . . 9 . a 9 o . 5 o . o‘o v.1‘lv 4. .9 . . u v .I. I’ .Ilo o v A o o 4 +:' o 9 o v . . . O h‘uh.W. p O A o - 9 . . o o . 010‘ . 4 O < . ; on o o . o C . o a g I O . . . . . . . o 019'. 9 a . . a o .10: 0‘. . c. o . o . o .0 o n I L. . \b } r F > Ly, 41 . A. 1 4 1 n 4 1 4 4 o . 9 ¢. . . .1 ‘5 . f l +‘ . . . 5 .1 o u . 0 V y 1 o; v . . . v _ I9 0 . . o . . o 9.. o . ‘ . ‘ . o c . 7| . v 0.. u o o . . .4 t ‘ v'. A 0.. o I ~ 0 A v 0 . v . 9 V I ‘ . I o .Vlo 0 Q. h . y. .I. . o. . 0 V o . v ; T¢.. . . . . o . . o f ... . .,.l. f . . . . o . .-. . . . o . .o . .,- . . . . o o . o u o o s . y lo ?‘|6 . . . a . . . 0 0¢ 0 o a . . ' § ~ . o . . o b n ¢ . c . . Jr. 0 .0 11v. . . c 9 . -0 v o... ‘ .L A . o . . ‘ H 9.9I . V - o . . 19 y . a . T . v ~ .u. . A .. . I . Q ‘ . o v o a..- . . ‘ .0 0 v . . O o A a. v .0 . o _ . o . v t . O . «. . . o . . o . c o o.» L r I} . t . o o . . . 3 o . . . . . n a . - ‘ O . . o . . _ o .u. . v _ o . . . . c o . . . . I . ‘ t o n v o p - . 0 o |.Io v o . u, A A 9 . C -t n I o . OI. . v . o . v r . . n V o . . O 9 o ., . n . . O O u . o n n o . . v . 0., . . o o -a 0 ¢ . r c . . . . . . a . n . . . . D . ‘ n . . AV 0 c I . o . . . ‘ . o . . . . v . . . . ' . . . u v f . o I! . . ‘Itv — . o . . I v . . . V o v u o o u . I o . c . . r. v . . . . V . . ‘ n . ' O I o . 1 o . 9 fix--. _ u o o . . . Y . o . v I y p O a .I . I. I V h 7 Q T 7' . u . . v . I . 0 v , . . O . . o . o . ~ . .5 a .u . o v o . c c . a ll - l u . _ . v. u . o t v a o . o o . u o I n o o u . v 0 I n 0 9 4 o C Q o o . . . V . ‘o o . . u . v o . . . .I. u .' ll 0 o . ~ '0 . ' u . . o I o v . c a ‘ A O . V 0 .9 O 6:: v.. . v ‘ v . . . v o . . _ . O . 4 {v . ¢ VII. a '.T0 . . . o . O » u . . . o p o . ‘ c . v A . .o o . r . 4 ly. .I.:.r v . . . . nu . ‘9 . . . . . . O v v . . t v o a o . . . ‘ . V G v ' . a o . . . _ . . . . . . . fl . . u . . . . . . . c . . . . . c . . t . . n ' ‘ow. . . . o . v - >1 . 4 u‘. . . . . . . ~ . . . . . v . , . n n n u . . c . . . . . . . . o . . D In order to judge all the mixes on the same basis, a constant water-cement ratio of .80 was used in each case. This water-cement ratio is equivalent to the use of six gallons of water per bag of cement and according to the curve ' in "Concrete Practice” by H001 and Pulver, this ' ratio should have given concrete capable of withstanding 3000 pounds per square inch in each case. One half cubic foot of aggregate was estimated to be sufficient to fill two test cylinders 6" x 12' likewise l/lO bag or 9.5 lbs. of cement was thought to be sufficient. The computed weight of water to be used, relative to the 9.5 lbs. of cement, was 5 lbs. plus 0.5 lb. for absorption making a total of 15 lbs. of mortar for each batch. The mixing trough was first dampened to do away with any surface absorption, then the carefully weighed out por- tions of sand and coarse aggregate were thoroughly mixed together in the trough. The mortar was mixed separately in a pail; first 9.5 lbs. of cement were weighed out, then 5.5 lbs. of water were added and the mortar thoroughly mixed. The mortar was added to the aggregate until the well-mixed concrete gave a slump of four inches. After observing the quality of each mix as to harshness, oversandedness, etc., the concrete was placed in cylinders and allowed to set for twenty-four hours. After the desired slump of four inches had been reached, the remaining mortar was weighed to deter- mine what portion had been used in the mix. Then the weights of all materials being known, the weight of the batch per sack of cement was computed, and the yield per sack of cement was computed by the absolute volume method: Absolute V01ume = gait Wt. x v01ume Specific gravity x unit wt. of water The following mixes were made in the above manner: Cylinder Mi; ‘Quality 1-2 0% Coarse Sand & 70% Combined C.A. Harsh Mix 3-.. Ba - .. 60% ~ .. .. a... massaged 5'6 50% ' " 50% u " ' n ' gvegsanded 7-8 45% ' " 55% ' ” " Best Mix 9—10 33% Fine Sand & 70% I I I Harsh Mix 11-12 % I I" 60% I I I Slightly Harsh 13-1“ 50% I " 38% " ' ' Good Mix 15-16 60% I I % I I I Oversanded 17-18 30% Coarse Sand & 70% (1‘9 ' ' Very Harsh—unworkable 19-20 0% ' ' 60% ” " ' Still Harsh 21-22 50% I I 50% I I I Better but still Harsh 23-2“ 60% ” " h0% " " " Best of group but not good 25-26 30% Fine Sand & 0% “ “ ' Very Harsh 27-28 0% I I 0% I I I Still Harsh 29-30 50% " " 50% " ' ' Good Mix 31-32 60% " " “0% ' ' ' Oversanded 33-3h 38% ' " 70% (l”+) ' ' Harsh—bad mix 35-36 % ” " 60% ” " " Harsh 37_g§ 50% I I 50% I I I Good Mix 9- 30% Coarse Sand & 70% I I I Harsh l—h2 50% ” " 50% “' ' ' Good Mix After the cylinders had set for 2“ hours, they were strip- ped, numbered, and placed in the moist closet for the remainder of the seven day curing period. At the end of seven days, the cylinders were weighed to check density, then broken in the large hydraulic testing machine. The total net load which the.cylinder stood divided by 9‘1} gave the seven day strength in pounds per square inch. The twenty-eight day strength was computed from the formula of H001 and Pulver: 323.. S7!- 30 E7— Photographs were taken of the broken cylinders to show the placement of aggregate and mortar in the various mixes. spam ANALYSES Fine Sand - Unit Weight = 106.5# Weight of sample = 1000 grams wt. Retained on No. u - 2.0 u u' I g _ 15.3 n w n 1n _ 51.3 ' " " 28 - 115.6 I I I us - h22.h " " " 100 - 333.h " " " Pan - 60.0 Coarse Sand - Unit Weight = 112.5# Weight of sample : 1000 grams wt Retained on No. 4 - u u I 8 "' 8807 I I. n In ‘5 21106 n n n 28 _ 2h}.5 u u w kg _ 313.7 " ' " 100 - 119.5 N a I Pan _ 13.9 33:33:91 10.1 grams 3* bigwa OWNnJPKfiPJ O C ox» mm HIJl c>$n=omuue 7% 8.87 21.10 2h.15 31.17 11.95 1.39 SIEVE ANALYSES (1“-) Coarse Aggregate - Unit Weight = 107.5# Weight of sample = 1000 grams ‘ Wt. Retained on 1 1/2" - . . I I 3/un - 2ho.h 2n.uo " " 3/3” - 529.2 52-9 " " No. h - 203.9 20.39 N ” Pan - 26.5 2.65 (1"4) Coarse Aggregate - Unit Weight = 103.0# Height of sample = 3000 grams , wt. Retained on 1 1/2” - 955 grams 31.3 n n 3/uu _ 2O 5 n 68.2 I I 3/SI - 00 00.0 I I No. I 00 00.0 WEIGHTS PER SAMPLE Sand 0. A. ’Cement 01 water Weight of Batch 16.75 39.00 7.75 u.5 68.00 316.75 39.00 7.75 1.3 68.00 22.50 33.50 5.85 3. 65.25 22.50 33.50 5.85 3.1 65.25 28.25 28.00 6.15 3.6 66.00 28.25 28.00 6.15 3.6 66.00 25.25 30.50 6 95 .05 66.75 25.25 30.50 6 95 n.05 66.75 16.00 39.00 u.u3 2.57 62.00 16.00 39.00 u.u3 2.57 62.00 21.25 33.50 7.n5 u.3 66.50 21.25 33.50 7.u5 I.3 66.50 26.25 28.00 11.72 6.78 72.75 26.25 28.00 11.72 6.78 72.75 32.00 22.25 12.3u 7.16 73.75 32.00 22.25 12.31 7.16 73.75 17.00 37.75 7.6 u.n 66.75 17.00 37.75 7.6 u.u 66.75 22.50 32.25 8.2u n.76 67.75 22.50 32.25 . 8.2h n.76 67.75 28.25 27.00 9.65 5.6 70.50 28.25 27.00 9.65 5.6 70.50 33.75 21.50 11.25 6.5 73.00 33.75 21.50 11.25 6.5 73.00 16.00 37.75 7.76 1.19 66.00 16.00 37.75 7.76 n.19 66.00 21.25 32.25 9.65 5.6 68.75 21.25 32.25 9.65 5.6 68.75 26 75 26.75 12 20 7.05 72.75 26 75 26.75 12 20 7.05 72.75 32 00 21.50 12 5 7.25 73.25 32 00 21.50 12 5 7.25 73.25 (Cont'd) (Cont'd) WEIGHTS PER SAMPLE FyTinder Z Sand Sand 0. A. Cement later Weight 0? Batch 3 30 16.00 36.00 7.3 n.20 63.50 3 0 16.00 36.00 7.3 n.20 63.50 35 0 21.25 31.00 10. 5 6.05 68.75 36 no 21.25 31.00 10.u5 6.05 68.75 37 50 26.75 25.75 10.6 6.15 69.25 38 50 26.75 25.75 10.6 6.15 69.25 33 30 26.75 36.00 7.75 h.5 75.00 38 26.75 36.00 7.75 h.5 75.00 I1 28.25 25.75 8.25 n.75 67.00 I2 - 50 28.25 25.75 8.25 n.75 67.00 WEIGHTS PER SACK OF CEMENT Cylinder Z §an§Sand C. A. “Cement Water W 1 30 19n.5 n53.o 95.0 52.3 79n.8 2 38 195.5 “33.0 95.0 52.3 79n.8 3 365.0 5 .0 95.0 55.2 1059.2 no 65.0 nn.0 95.0 55.2 1059.2 5 50 36.0 32.0 95.0 55.6 1018.6 6 0 n 6.0 n32.0 95.0 55.6 1018.6 7 5 3 5.0 n16.0 95.0 55.n 911,u 8 n5 3n5.0 n16.0 95.0 55.n 911.n 9 30 3n2.5 835.0 95.0 55.0 1327-5 10 38 3n2.5 835.0 95.0 52.0 1327.5 11 271.0 n27.0 95.0 5 .8 8n7.8 12 no 271.0 n27.0 95.0 5n.8 8n7.8 1 50 212.5 226.5 95.0 5n.9 588.9 1 50 212.5 226.5 95.0 5n.9 588.9 15 60 2n6.0 171.0 95.0 55.0 567.0 16 60 2n6.0 171 0 95.0 55.0 567.0 17 30 212.0 n72.0 95.0 55.0 83n.0 18 33 212.0 n72.o 95.0 52.0 83n.0 19 259.0 372.0 95.0 5 .9 780.9 20 no 259.0 372.0 95.0 5n.9 780.9 21 50 278.0 268.0 95.0 55.1 696.1 22 50 278.0 268.0 95.0 52.1 696.1 2 60 28n.0 181.5 95.0 5 .8 615.3 2 60 28n.0 181.5 95.0 5n.8 615.3 25 30 196.0 n62.0 95.0 55.0 808.0 26 38 196.0 n62.0 95.0 55.0 808.0 27 209.0 317.0 95.0 55.1 676.1 28 no 209.0 317.0 95.0 55:11 676.1 29 50 205.0 205.0 95.0 55.0 560.0 30 50 205.0 205.0 95.0 55.0 560.0 31 60 2n3.0 163.5 95.0 55.0 556.5 32 60 2n3.0 163.5 95.0 55.0 556.5 (Cont'd) ____'§.-__ n68. n68. 282. 282. 230. 230. 000000 ement \0 U1 0 \D\O\O\O\O \J'IU'IUIEflUl O O O O O ater 5n.6 54.6 55.0 55.0 55.0 55.0 M1 0 Mi . 296. 296. 0000 OOOO \O\O\O\O UTU'IUlU'I mmmm 42mm 0 O O O stH H YIELD PER SACK OF CEMENT T Sand 0. . Cylin- Unit Vol. Abs. Unit Vol. Abs. der Wt. Vol. Wt. Vol. Cement Water Yield 1 112.5 1.73 1.18 111.5 n.06 2.7n .n9 .8n .2 2 112.5 1.7 1.18 111.5 n.06 2.7n .n9 .8n 2.2? a 112.5 3.2 2.20 111.5 n.88 3.29 .n9 .89 6.87 112.5 3.2n 2.20 111.5 n.88 3.29 .n9 .89 6.87 5 112.5 3.87 2.63 111.5 3.88 2.62 .n9 .89 6.63 6 112.5 3.87 2.63 111.5 3.88 2.62 .n9 .89 6.63 7 112.5 3.07 2.09 111.5 3.73 2.52 .n9 .89 5.99 8 112.5 3.07 2.09 111.5 3.73 2.52 .n9 .89 5.99 9 106.5 3.22 2.07 111.5 7.50 5.06 .n9 .88 8.50 10 106.5 3.22 2.07 111.5 7.50 5.06 .n9 .88 8.50 11 106.5 2.5n 1.6n 111.5 3.83 2.58 .n9 .88 5.59 12 106.5 2.5n 1.6n 111.5 3.83 2.58 .n9 .88 3.59 1 106.5 2.00 1.29 111.5 2.03 1.37 .n9 .88 .03 1 106.5 2.00 1.29 111.5 2.0 1.37 .n9 .88 n.03 15 106.5 2.31 1.n9 111.5 1.5 1.0n .n9 .88 3.90 16 106.5 2.31 1.n9 111.5 1.5n 1.0n .n9 .88 3.90 17 112.5 1.89 1.29 107.5 n.n0 2.86 .n9 .88 5.52 18 112.5 1.89 1.29 107.5 n.n0 2.86 .n9 .88 5.52 19 112.5 2.30 1.57 107.5 3.n6 2.25 .n9 .88 5.19 20 112.5 2. 0 1.57 107.5 3.n6 2.25 .n9 .88 2.19 21 112.5 2. 7 1.68 107.5 2.50 1.63 .n9 .88 .68 22 112.5 2.n7 1.68 107.5 2.50 1.63, .n9 .88 n.68 2 112.5 2.52 1.72 107.5 1.69 1.10 .n9 .88 n.19 2 112.5 2.52 1.72 107.5 1.69 1.10 .n9 .88 n.19 25 106.5 1.76 1.13 107.5 n.30 2.80 .n9 .88 5.30 26 106.5 1.76 1.13 107.5 n.30 2.80 .n9 .88 5.30 27 106.5 1.96 1.26 107.5 2.95 1.92 .n9 .88 .55 28 106.5 1.96 1.26 107.5 2.95 1.92 .n9 .88 n.55 29 106.5 1.92 1.2n 107.5 1.91 1.2n .n9 .88 3.85 30 106.5 1.92 1.2n 107.5 1.91 1.2n .n9 .88 3.85 31 106.5 2.28 1.n7 107.5 1.52 .99 .n9 .88 3.83 32 106.5 2.28 1.n7 107.5 1.52 .99 .n9 .88 3.83 (Cont'd) (Cont'd) ggsLn PER SACK 0w CEMENT —__—“—‘ Sand C. A Cylin- Unit V01. Abs. Shit V01. Abs. der Wt. Vol. Wt. Vol. Cement Water 3 106.5 1.95 1.26 103.0 n.55 2.83 .n9 .88 3 106.5 1.95 1.26 103.0 n.5 2.83 .n9 .88 35 106.5 1.81 1.17 103.0 2.7 1.71 .n9 .88 36 106.5 1.81 1.17 103.0 2.7n 1.71 .n9 .88 37 106.5 2.2n 1.nn 103.0 2.23 1.39 .n9 .88 38 106.5 2.2n 1.nn 103.0 2.23 1.39 .n9 .88 9 112.5 2.91 1.98 103 0 n.28 2.67 .n9 .88 0 112.5 2.91 1.98 103 0 n.28 2.67 .n9 .88 n1 112.5 2.89 1.97 103 0 2.88 1.79 .n9 .88 n2 112.5 2.89 1.97 103 0 2.88 1.79 .n9 .88 STRENGTH Cylinder Weight Constant Load Met Load S7i/sq.in.‘§28#/sq.in. 1000# 1000# 1 29.50 27 9o 3 1875 1 n 2 29.36 30 72 22 1n90 36K8 a 29.29 30 78 n8 1700 2938 29.19 30 82 52 18n0 3130 5 28.76 30 63 33 1170 2196 6 28.82 30 53 23 81n 1672 7 28.93 30 65 35 1238. 229% 8 29.02 30 63 33 1168. 219n 9 29.02 27 6 36 1275. 23n6 10 29.60 27 5 27 956. 1985. 11 28.60 27 72.5 n5.5 1610. 2813. 12 28.92 27 75. n8. 1 00. 29 8. 1 28.13 27 67. n0. 1 15. 25 3. 1 28.00 27 75. n8 1700. 2938. 1 27.35 27 87.5 60.5 21n0. 3529. 1 27.30 27 87.5 60.5 21n0. 3529. 17 29.n5 27 88 61. 2160. 35 5. 18 29.93 n1 106. 65 2300. 7 19 29.23 n1 12n. 83 29n0. 569 20 29.56 27 82.5 55.5 1965. 3297 21 28.83 n1 11n.0 73.0 2580. ion 22 28.66 n1 118.0 77. 2720. n28n 2 28.15 n1 92.5 51.5 1825. 3109 2 28.10 n1 102.5 61.5 2175. 3576 25 29.n3 n1 99 58 2050 n12 26 29.3 n1 113 72 2550 065 27 29.1 n1 113 72 2550 n06 28 28.9n n1 111 70 2n80 99 29 28.09 n1 116 75 2650 195 30 28.19 n1 10 68 2n00 3870 31 27.80 n1 9 53 1875 317h 32 27.5n n1 99 58 2050 3n12 (Cont'd) (Cont 'd) STRENGTH mincfer Weight onstant Tic—ad NetToad S-fiqudn. Sggill/SqJn. 1000i 1000# 3 29.22 n1 9 56 1980 3215 3 29.3 n1 6; 23 81n 1669 35 29.2 n1 10n 63 2230 36n6 36 29.02 n1 99 58 2050 3n09 37 28.93 n1 97 56 1980 3215 38 28.58 n1 100 59 2090 3n58 9 29.n2 2 n9 n7 1665 2889 30 30.09 2 n n7 1665 2889 n1 28.83 2 6 62 2195 3599 n2 29.38 2 6n 62 2195 3599 PHOTOGRAPHS SHOWING PLACEMENT OF AGGREGATE AND MORTAR 1. Fine Sand & Combined C.A. 2. Coarse Sand & Combined C.A. .rine Sand & (1I—) C.A. r. L5 5. Fine Sand & 6. Coarse Sand & (1"+ CONCLUSIONS 1. Sieve Analyses The three groups which produced the most yield all contained coarse sand which had the most material re- tained on No. n8 screen, then on No. 28, and then on No. 14. The fine sand also had most of its material retained on the No. n8 screen, but then the tendency was toward the finer No. 100 screen. This shows that the coarser sand particles tend to make a denser mix of better yield. 2. ,Grading of Aggregate The mix that produced the greatest yield with a correSponding superior weight was the mix of coarse sand and combined coarse aggregate showing that not alone can coarse aggregate greater than one inch produce good yield, and not alone can coarse aggregate less than one inch pro- duce good vield. It takes a uniform grading of the two from less than one inch to the largest practical coarse aggregate to give best results. 3. Quality In every case a batch made up with a percentage of sand lying below or back of the vertical percentage void line was found to be harsh showing that the voids in the coarse aggregate were not being filled with mortar. On the average, those mixes containing an equal percentage of sand and coarse aggregate were of the best quality, while beyond a zone between the 50% sand and 60% sand, the mixes tended to be oversanded. n. Density and Yield With one exception, all the groups showed a ten- dency for weight per sack of cement and yield per sack of cement to decrease as the percentage of sand increased. This shows conclusively that oversanding is uneconomical as it decreases both density and yield. 5. Strength Although the strengths were to have been constant with a given water-cement ratio, there was still quite a variation. As a rule, the good quality mixes, in which the percentages of sand and coarse aggregate were about the same, gave the highest strength. A trend towards either harshness or oversanding would tend to weaken the concrete. In general a mix using a coarse aggregate uniformly graded to the largest maximum size practical under job condi- tions and a coarse sand containing only enough fines for good finishing should produce a concrete having greatest den- sity and Yield per sack of cement. Harsh mixes will give greater yield although the density tends to be less, and mixes of even proportions -- 50% of each -~ give better quality and higher strength. In mixes using coarse aggre- gate uniformly graded above one inch, it is probable that the ideal mix will lie between the no% and 50% sand content. Regardless of the grading of coarse aggregate, the ideal mix will contain 5% to 10% more fine material than the per- centage of voids in the compacted coarse aggregate. ......u u...“ .... ...2 a.» fine... 51%.)... A. . ft {Pant-Joni i...|o 13!... ‘i1.\ 1‘ +7 '...¢~F h. ,. .... ... .1.. ...... w. .. ..O ...”... .1 . .‘h P. finkuiflwvgngt . . «5:5 (I. 5 k .1 i. __,.. I. 0 Ir I :l- ’3- ' v K I: ? ,‘u v', I... . 2. .65" . I It .1 , it 9. A" . I'll III | Ill! |||I| ||