Ma eee tn SSN lag Pn nae W. M, BUELL a cen t . W, LARSO TRHESIg ( OO. a ne 77 15 | 210 t- A Comparative Analysis of Five Michigan Cements. A Theeis Submitted to The Faculty of Michigan Agrioultural College “wes * By ‘} Lc ot " _* \ Y “i SOND E. W. Lareon, W. M. Buell — - "a Candidates for the Degree of Bachelor of Science. June 1916. TH ESsIS COL o ww INTRODUCTION. ‘The object of this Thesis is to determine the rel- ative adaptability of five Michigan brands of Portland cement, for engineering construction; all being subjected to the Same chemical and physical tests, under the same conditions, eas far as possible. The commercial names of the cements are Aetna, Burt, Michigan, Newaygo, and Peninsular. These are of particular interest to us, due to the fact that they are being used at the present time in the construction of several buildings on the M. A. C. Campus. Samples of the cements were obtained from regular trade depots in Lansing, Michigan, and the utmost care was exercised in selecting representative samples of good fresh cement in each oase. The tests were made in accordance with the Standazd Bpecifications and Uniform Methods of Testing and Analysis for Portland cement, which have been adopted by the committees on Standard Specifications for cement of the Amerioan Society for Testing Materiales. The routine of tests were as follows: I Specific Bravity (a) Le Chatelier's Specific Gravity Apparatus. II Fineness (a) Standard Sievee III Tensil Strength (a) Neat Cement 1- Rheile Testing Machine 102440 IV. vi. VII. Constency of Volume (a) Pate in air (bo) " ©" water (o) ™ ©" gteam bath. Normal Consistency (a) Vicat Needle Apparatus (bo) Pat test. Time of setting (a) Initial (o>) Final. Chemical Analysis (a) Insoluble Residue (bo) Chemical Constituents (c) Loss on Ignition. Specific Gravity Test. The determination of the Specific Gravity was made with a standard LeChatelier apparatus, which is simply a flask with a graduated neck on it. The method of procedure in seach case was as follows: The flask was filled with Benzine up to the lower mark on the neok of the flask and 64 grammes of dry cement was added slowly through a funnel. After the cement was in- troduced the level of the liquid rose to some division on the graduated neck. This reading, plus 20 cu. cm. is the volume displaced by the 64 gms. of cement and the Bpecific Gravity equals weight of cement in gms. divided by displaced volume in cu. om. The results obtained were as follows: Specimen Specific Gravity Aetna- 5.23 Burt 3.23 Michigan 3.15 Newaygo 3-18 Peninsular 32 30 The Specific Gravity should not fall below 3.10. In all cases it was above this value. Fineness. The fineness wes determined by placing fifty grammes of dried cement on a 100 sieve, which has a No. 3200 Sieve underneath, to these are attached a pan and oover and then moved backward and forward about 200 times per minute, at the same time striking the side gently with the palm of the hand. The operation is continued until very little cement passes through the screens. The residue on each of the soreens is then weighed. It shall leave by weight a residue of not more than 8% on the #100 sieve, and not more than 35% on the #300 sieve. The average results obtained were as follows: Cement Residue on Residue on Amount Passing #100 sieve #800 sieve #200 sieve Aetna 3% 19.1% 77.9 % Peninsular 8% 25% 67% Mi chigan B. 2% 34.8% 73% Burt 5.6% 33.6% 70.8% Newaygo 7.9% 23.08% 70.08% From thie data we find that the Aetna is the finest and Peninsular the coarsest cement. -4- Normal Consistenoy. The normal consistency was made by means of the Vicat Apparatus. Five hundred gms. of the cement was made into a paste by kneading with the hands. It was made into a ball and placed into the larger end of a rubber ring. The cement was then placed in the Vicat Apparatus, and the needle placed at the top of the ring, and then released and allowed to settle into the cement. - Trial pastes were made with varying percentages of water, until a paste was obtained that allowed the needle to sink only 10 om. in 30 seo. The percentages of water used for the different cements were as follows: Specimen Water used Aetna 33% Burt | 31% Michigan 33% Newaygo 20% Peninsular 19% ~5- Constancy of Volume. The tests for Constancy of Volume comprises "normal tests," which are made in air and water, and "accelerated tests" which are made in stean. Pate about 3 in. in dia. and 3 in. thick at center and tapering to a thin. edge were made, and placed on clean glass plates, and stored under moigt cloths for 24 hrs. After this 34 hres. several pats were placed in water and observed at intervals of five days each for 25 days, and all of the pats seem to lose a small amount of their hardness but not enough to cause them to distort or disinte- grate. Several other pats were placed in the air (which was asnear 70 Fahr. as possible) and examined at intervals of five days each for 25 days. All pats became very hard and firm, and the Peninsular and Michigan had the tendency of cracking in places. A number of pats were placed in an atmosphere of steam about 1 in. above boiling water for a period of 5 hre. and maintained at atmospheric pressure. All specimens seemed to have a scaley aprearance, but none were oracked to a very great extent. The most significant thing found was that the Michigan and Peninsular seemed to show a tendency of orack- ing, disintegrating and expanding when left exposed to the atmosphere for a period of 38 days, which in our estimation, tends to render them unsound. The most important quality of a cement is ite soundness, for no matter how high a degree of tensil strength, a cement may develop at comparatively short period, if it fails to resist the disintegrating influenoes of the atmos- phere or water in which it is placed, it is useless as a material of construction.. This fault is usually due to an improper propor- tioning of the raw materiale, allowing an excess of lime over What will combine with the silica and alumina of the cement mixture, or improper burding, failing to raise the temperature to a point where, all of the lime may combine with the silica and alumina, thus leaving some in an uncombined state; or from insufficient grimding of the raw materials making it impossible for all of the lime to come in contact and unite with the silica and alumina. This free or loosely coh bined lime on coming in contact with the moisture of -the atmosphere is alacked and expands, causing the cement to crack and fall to pieces. Tensil Strength. The tensil strength of cement was determined by making briquettes of neat mortar of normal consistency. The material was weighed, placed on a non-absorbant surface and thoroughly mixed with water by meading with the hands. The mortar was then placed in the molds with the hands, pressed in firmly with the fingers and smoothed off with a trowel without ramming. During the first 24 hours after molding a moist cloth was kept over the briquettes, later they were stored in a water tank. The specimens were tested at 7,14 and 28 days ona Rheile Briquette Testing Machine. Specimen 7 days 14 days 28 days Aetna 775 760 680 660 670 720 600 760 710 685 680 730 Average 680 710 710 Miohigan 490 620 780 600 620 620 670 550 690 620 700 620 Average 576 632 677 Specimen 7 days 14 days 28 days Peninsular 760 680 670 820 620 670 750 660 550 670 770 700 Average 740 682 622 Newaygo 600 750 820 730 720 790 760 680 795 550 680 830 Average 660 707 806 Burt 730 675 660 680 785 740 500 675 800 720 700 770 Average +657 708 742 These results show that the Newaygo cement has the greatest teneil strength at 28 days and the Michigan cement the lowest tensil strength. | The minimum requirements for tensil strength for briquettes ane square inoh in oross section shall be 500¢ for 7 days and 600# for 328 days, and the cement shall show no retrogression in strength within the periods specified. All of the cements are within the mimimum require- ments except the Peninsular, whose strength decreases after the deven day test. Time of Setting. The time of settng was determined with a Vicat Apparatus in the following manner: A paste of normal consistency was molded in a hard rubber ring, and placed under the needle of the Viocat Appar&tus. The needle which is 1 mm. in dia. is carefully drought in contact with the pastey and then released quickly. The cement is considered to have acquired its ini- tial set, when the needle ceases to pass a point 5 mm. above the glass plate; and final set, when the needle does not sink visibly into the paste. } Specimen Initial Set Final Set Aetna S$ hre. OO min 5 hrs. 40 min Newaygo a8 © 40 * 5 ®*§ 30 " Burt 3 *" 10 °° 5 "= 30 *N Peninsular an 20 =" 6 * 20 +" Michigan a " 565 * 5 "= 50 * These results show that the Peninsular is the slowest setting cement, and the Newaygo the fastest setting cement. The minimum requirements for time of setting is that it shall not develop initial set in less than thirty minutes, and must develop hard set in not less than one hour, nor more than ten hours. -10- Chemical Analysis. Silica (Si. 0, ) One-half gram of cement was placed in a ocaserole moistened with enough water to prevent lumping, and 5 to 10 o.c. Of strong HCL added, and digested with aid of gentle heat and agitation until solution was complete. The solution was then evaporated to dryness onthe sand bath. The residue is then treated to 5 to 10 c.c. HCL which is then diluted to half strength. The dish was then covered and digestion allowed to go on for 10 minutes on the bath, after which the solution was filtered and the separated Silica washed thoroughly with water. The filtrate was again evaporated to dryness, the residue without further heating taken up with acid and water, and the small amount of silica it contains separated into another filter paper. The papers containing the residue were transferred wet to a weighed platinum orucible, dried, ignited, first over a Bunsen burner until the carbon of the filter paper was completely consumed, and finally over the blast for 15 minutes, and checked by further blasting or to constant weight. The following results were obtained: Speoimen Percent of Silica Peninsular 24-30% Aetna 23.42% Newaygo 33.00% Miohigan 33.61% Burt 33.03% The Silica combined with lime to form calcium silica te ~l)-— furnishes the aotive factor in the cement's hardsning. From the results obtained it oan be seen that the Michigan has the greater amount of silica and the Aetna the least. -13- Alumina and Iron (Al, 0, and F, 0, ) The filtrate about 350 o.o. from the sedond evapor- ation for 8i 0 was made alkaline with NH O48 after adding HCL to insure 10 to 15 6.6. strong acid, and then boiled to expel excess of NH The precipitate iron and aluminum hydrates, after settling, are washed once by decantation, and slightly on the filter.: Setting aside the filtrate, the precipitate is dissolved in hot dilute HCL, the solution passing into the veaker in which the precipitation was made. The aluminum and iron are then reprecipitated by NH O48 boiled, and the second precipitate collected and washed on the same filter paper used in the first instance. The filter paper, with the precipitate, is then placed in a weighed platinum crucible, the paper burned off and the precipitate ignited and blasted for 5 minutes, and weighed as Al QO Fe, O Specimen | Peroent Al, O,+ Fe, 0, Burt 8.00% Miohigan 10.00% Newaygo 9.00% Aetna 7.00% Peninsular 9.04% These results show that the Michigan hasthe highest percent and Aetna cement the lowest peroent of alumina and iron. The alumina tends to quicken the setting and dscrease the ultimate tensil strength. The ferrio oxides exerts very little influence upmm the »hysical properties of the material. The dark gray oolor an | Ron of cement is due to the presence of iron compounds. Lime (Ca 0 ) To the combined filtrate of the Al, 0, and Fe, 0, precipitate a few drops NH O8 was added and the solution brought to boiling. To the bbiling solution 30 co of a Saturated solution of ammonium exalate was added, and the boiling continued until the precipitated Ca C, 0, assumed @ well-defined granular form. It was then allowed to stand until the precipitate settled, and then filtered and w:shed. The precipitate and filter are placed wet in a platinum orvw cible, and the paper burned off over a Bunsen burned. It was then ignited, redissolved in HCL and the solution made up to 100 6.0 with water. Ammonia was added in slight excess, and the liquid boiled. The lime was then represipi- tated by ammonium oxalate, allowed to stand until settled, filtered and washed. The precipitate with filter paper was itnited and blasted in a covered crubible to constant weight. The followins results were obtained: Speoimen Ca O Aetna 60.00% Michigan 60.49% Peninsular 61.40% Newaygo 61.33% Burt 63.13% -14~ Magnesia (Meg 0) The combined filtrates from the calcium preoipi- tates were acidified with HCL and conoentrated on the steam bath to about 150 oc, 10 co o of saturated solution of Na (N H,) HPO, was added, and the solution boiled for several minutes. It was then removed from the flame and cooded in ioe water. After cooling, NH OH is added drop by drop with oonstant stirring until the orystalline ammonium magnesium ortho-phosphate began to form, the stirring being continued for several minutes. It was then set aside for several hours in a cool atmosphere and then filtered. The precipitate is redissolved in hot dilute HCL the solution made up to 100 c.c. l co of saturated solution Nea (N H,) HP 0, added, add ammonia drop by drop, with constant stirra&ng until the precipitate is again formed as described and the ammonia ia slight excess. It was then allowed to stand for about two hours when it ws filtered on a paper, ignited, cooled and weighed. The following results were obtained: Specimen Me. O Aetna 3.34 % Michigan 8.83 % Burt 2.81 % Peninsular 2.00 &% Newaygo 3.57 % The maximum amount of Magnesia allowable is 4%. All of the cements contained less than this amount. aw ) R_ Sulphuris Acid ( 8 0, ) One gram of the cement was dissolved in 15 cc of HCL, filtered and the residue wasted thoroughly. This solution wes made up to 350 o oc in a beaker and boiled. To the boiling solution 10 oo of saturated solution of Ba Cl, was added slowly drop by drop from a pipette and the boiling continued until the precipitate was well formed. It was then set aside over night, or for a few hours, filtered, ignited, and weighed as Ba S 0, . The following pescentages of 8 0, were obtained: Spe oimen Peroent of S 0, Aetna 1.65 Michigan 1.63 Newaygo 1.68 Burt 1.68 Peninsular 1.75 Aocording to these results the Peninaular has highest percentage of S 0, (1.75) and Michigan lowest of (1.63) The maximum allowed by specification is 1.75 and all fall at or below this amount. -16- Ignition Test. Half a gram of cement was weighed out ina platinum cruoible, placed in a hole in an asbestos board Bo that about 3/5 of the orucible projects below, and blasted for 15 minutes. The loss by weight, which is checked by a@ second blasting of 5 minutes, is the loss on ignition. In all cases the loss vas less than .5 of 1%. -17- Chemical Analysis Aetna Michigan Newaygo Burt Peninsular Sikica 22243 23-61 383.00 383.03 24.20 Alumina & iron 7.00 10.00 9.02 8.00 9.04 Magnesia 3-a% Be 3.57 2.81 3.00 Sulphur Trioxide . 1.65 1.63 1.68 1.68 1.75 Lime 60.00 60.44 61.23 63.138 61.40 99.17 99.50 98.50 98.64 98.39 Amount unaczounted for- .83 e 50 l. 50 1.36 1.61 ~ 18—= Conclusion. In summing up the rdsults of our analysis of the various cements, we find that several of the samples are nearly on @ par. In the Specific Gravity tests, our results ranged from 3.13 to 3.30 and all being over the required amount of 3.10, we considered that none had been adulterated. The resulta of our fineness tests showed the follow- ing in order of fineness, Aetna, Michigan, Burt, Newaygo and Peninsular. The fineness of the material is a measure of its cementing value, and a fine cement acoordingly will be much stronger when mixed in a mortar, or it oan be mixed with a larger portion of sand than a coarse one, and yet attain the Bame strength. A test for fineness is nearly always included in oement specifications, as the indications from a fair degree of fineness coupled with proper tensile strength, neat, are that the cement will give good resulta ,when mixed with sand. The tensile strength test gave best results for the Newaygo, with the Burt, Aetna, Michigan and Peninsular next in order. In reality, the neat break is not of so much value as we are apt to suppose, and taken by itself it is a little oriterion of the qualtty of cement, Unsound cement often gives notoriously high results and the addition of plaster or gypsum will also tnorease the neat strength. in both these instances there is apt to be on long time breake a falling off 19 of strength, permanent in the former case, and usually only temporary in the latter case. The Peninsular cement gave very high results for the 7-day test, but showed a marked decrease in the 14 and 28 day tests. According to the Standard Specifications no cement shall show retrogression in strength within periods specified. In the time of setting tests the results for the initial set variéd.fron 3 hours to 3 hours, 55 minutes, and the final set from 5 hrs. 30 minutes to 6 hrs. and 20 minutes. Accosding to the Standard Spoifications it shall not develop initial set in less than thirty minutes and must develop hard set in not less than one hour, nor more than ten hours, The rapidity with which a cement sets furnishes us with no ifdiocation of its strength. The test is usually made to determine the fitness of a material for a given piece of work. The slow-setting cements can be mixed in larger quanti- ties than quick-setting, and do not have to be handled so quickly. The Aetna cement ranks first in fineness, third in tensile,strength, and second in length of time of setting. It has a low percent of silica and lime whioh tends to decrease the strength. The pegsoent of Magnesia is quite large which decreased the strength. The Burt cement ranks third in fineness, second in tensid strength and first in length of time of setting. It has a largest percent of lime and silica which are the —30- two main strength producing constituents of cement. It has a very low percent of Magnesium which is a defeotive agent in producing cracking and disintregation. The Michigan cement ranks seoond in fineness, fourth in strength and third in length of time of setting. It has a very 8mall peroent of lime and sblica and. an extra large amount of iron andalumina in it. It also bends to be unsound judging from the conatanoy of Volume Test. The Newaygo cement ranks first in tensil strength fourth in fineness, fourth in length of setting. It has a large peroent of lime and silioa and also a large percent of magnesium the latter being a very harmful constituent. The Peninsular cement ranke last in tensil strength l23st in fineness, and last in leggth of time of setting. It contains a large peroentage of alumina and iron.and supphur. It also showed a retrogresaion in tensil atrength after seven days, and gave very poor results in soundness test. Taking into consideration the above results, we believe that the Burt Cement is the best for building oonstruction, because it contains more of the good qualities mentioned at the beginning of this artiole, although the Aetna and Newaygo also have many pood points in their favor. and could be used with very good results. , — ry Toc ee i eee MICHIGAN STATE UNIVERSITY LIBRARIES Li iii i