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strength a n d t i m e of setting, t h e same cement when used with a so-called “dirty” sand, was greatly ret a r d e d in time of setting or did n o t harden a t all. It is of interest t o know what foreign constituents in t h e s a n d , other t h a n inorganic matter, might be responsible for t h e failure of t h e cement t o set. Experiments were accordingly undertaken with organic compounds typical of such classes a s might be expected t o be present in t h e soil or s a n d deposits. Schreiner a n d Reed’ s t a t e t h a t t h e subsoil contains on t h e average 0.83 per cent organic matter, a s found in thousands of samples from all parts of t h e United States. Prominent among these organic compounds are t h e carbohydrates, proteids a n d lecithins, which exist in t h e living cells of plants. During decomposition of t h e l a t t e r , primary a n d secondary decomposition products may result. EXPERIMENTAL
Vol. 6, N o .
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accept Richardson’s theory t h a t t h e initial set of cement is due t o t h e decomposition of t h e calcium aluminates with t h e accompanying crystallization of calcium hydroxide, then a n y substance, which can effect t h e removal of t h e calcium ion b y forming a n insoluble precipitate, will be able t o hasten t h e initial set of t h e mortar. The five substances which react t h u s are t a n n i n , straw infusion, oxalic acid, quinoline a n d soap-all greatly accelerated t h e initial set a n d all formed precipitates with cement a n d calcium chloride. These substances also exerted t h e greatest retarding influence in t h e final set. If t h e latter be represented as due t o a secondary reaction between t h e aluminates a n d calcium hydroxide t o form a basic aluminate, as held b y Le Chatelier, a n y substance causing t h e removal of calcium hydroxide will retard t h e reaction. TABLE11-CHEMICAL REACTIOXS OF ORGANIC REAGENTS WITH CEMENT REAGENTS Methyl alcohol Oxalic acid
A N D CALCIUMCHLORIDE CEMENT CALCIUM CHLORIDE Yellow precipitate No action Heat liberated Precipitate Precipitate No action No action No action White precipitate when boiled Gray precipitate Yellow precipitate Gray precipitate Gray precipitate Precipitate Precipitate Flocculent precipitate No action No action Brown precipitate No action No action N o action No action Light precipitate No action Precipitate Precipitate
Samples of cement were prepared from t h e clinker from t w o plants (the Olympic brand is made by t h e Cane sugar wet mix a n d t h e Superior b y t h e dry mix process). Citric acid infusion T h e medium-sized clinker was screened out for use, Straw Tannic acid soap crushed a n d ground in a pebble mill until 99.8 per cent Liquid Glycocoll extract passed t h e Ioo-mesh sieve a n d 80.0 per cent t h e 2 0 0 - Soil Isoborneol mesh sieve. Four different samples were prepared, Cumarine Asparagine namely, each b r a n d straight a n d each brand ground Quinoline with 2 1 / 2 per cent of gypsum. All samples were used COXCLUSIONS within t w o weeks after grinding a n d all were kept in I-The retarding effect on t h e setting of cement air-tight Mason fruit jars. I n order t o carry on t h e experiment a t as nearly can not be attributed t o a n y class of compounds. 11-Certain organic substances form insoluble comconstant temperature a s possible, t h e work was done pounds with t h e calcium of cement a n d these retard in a concrete basement which contained t h e moist closet, water a n d other materials. Standard methods2 t h e final set. 111-In some cases insoluble compounds were formed of testing were followed. ’Instead of following t h e usual plan of mixing different cements t o t h e same .with components other t h a n t h e calcium of t h e cement consistency, here t h e q u a n t i t y of water necessary for a n d these also exerted a retarding influence b u t t o a less extent. normal consistency was used throughout: IV-There is no evidence of catalysis a n d t h e action T h e percentage of water required for A was 26; takes place principally by disturbing t h e equilibrium. B, 2 5 ; C , 2 6 ; D, 23. LABORATORY O F INDUSTRIAL CHEMISTRY T h e accompanying diagrams show t h e results of UNIVERSITY OF WASHINGTON tests made with various percentages of organic comSEATTLE pounds, t h e time of setting being shown in hours. I n addition t o these substances, admixtures of one-half THE USE OF FINE EARTH IN MORTARS per cent of t h e compounds enumerated in Table I By H. I(. BENSONAND J. S. HERRICK were studied. Received July 7 , 1914 TABLEI-RETARDATION OP SETTINGCEMENT A-Olympic B-Olympic
straight plus gypsum A
C-Superior D-Superior B
straight plus gypsum C
D
C_____h_r--
....... ..
Asparagine Cumarine...... Glycocoll ......... Isoborneol ........ Quinoline . . . . . . . .,
Initial Final Initial Final 0.00 20.00 2.00 24.00 0.01 32.00 6.30 22.00 0 . 0 1 21.00 3 . 0 0 31.00 0.00 21.00 5.00 16.00 0 . 0 0 13.30 4.30 14.00
Initial Final 24.00 29.00 23.30 32.00 17.00 36.00 10.00 23.00 11.30 26.00
Initial Final 10.00 24.00 8 . 3 0 21.00 14.00 31.00 7 . 0 0 17.00 6 . 0 0 14.00
DISCUSSIOS
T h e addition of t h e various substances in some cases was accompanied by apparent chemical action such as heat liberation, color change a n d formation of precipitate. T h e nature of these reactions is indicated in Table 11. T o ascertain t h e component of t h e cement with which such reaction takes place, comparison is made with a calcium salt in solution. If we 1 2
BuZl. 47, Bureau of Soils, U. S. Dept. of Agriculture. Circ. 33, U. S. Bureau of Standards.
I n t h e construction of concrete foundations for paving country roads, sand a n d gravel are often transported considerable distances. It is evident t h a t much advantage can be derived b y using t h e soil itself if it can be shown t h a t sufficient strength can be developed in mixtures of soil and a suitable binder. A number of experiments were accordingly undertaken a n d t h e results, although partial a n d incomplete, are herewith presented. T h e soil of t h e campus of t h e University of Washington is described; as t h e Everett gravelly sandy loam, is formed f r o m a deep glacial till, a n d is representative of a large proportion of t h e Puget Sound Basin. From a cut twelve feet in depth, samples of soil were t a k e n a t different levels. Sample N o . I was a fine sand, 1 “Reconnaissance Soil Survey of Eastern Part of Puget Sound Basin.” Bureau of Soils, U. S. Department of ilgriculture.
T H E J O C R N A L O F I N D C S T R I A L A N D ENGIATEERING C H E M I S T R Y
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containing considerable clay, taken at the bottom of the cut. Sample No. 2 , from the middle of t h e next stratum, about 4 feet above the bottom of t h e cut, was very hard and compact in the bank and contained numerous pebbles. Sample No. 3, from t h e next stratum above, about 6 feet from t h e bottom of the cut, was stained yellow a n d was sandy in texture. Sample No. 4, I O feet from the bottom of t h e cut, was a yellow loam containing considerable fine material a n d humus and resembled a typical garden soil in texture and appearance. Sample No. 5, t h e subsoil, was apparently a decomposed glacial till, having t h e same color and characteristics as No. 2 b u t not being hard or difficult t o loosen. Sample No. 6 was taken from t h e surface, formerly a garden, and contained considerable humus. ,411 t h e samples were air-dried, a n d passed through a ten-mesh sieve, t h e residue, comprising 30 t o 40 per cent, being discarded. The analyses of the fine earths thus obtained, together with t h a t of Sample 7 , a n ordinary mortar sand, are given in Table I. TABLEI-SIEVE ANALYSISOF FINE EARTHS Percentages passing mesh indicated Sample No. 1 ........ 2........ 3 ........ 4........ 5 6
........ ........
200 77.2 17.0 6.4 10.7 17.2 14.6 0.5
100 98.0 29.7 14.3 18.7 32.5 26.8 5.0
50 99.0 64.4 57.5 52.8 68.7 64.5 71.9
40 All 74.3 69.1 65.0 79.5 76.7 90.0
-
30
20
10
85:O 82.7 79.8 87.8 85.5 97.5
90:s 92.2 91.7 93.1 93.1 All
95:6 All All All All
........ .. For t h e preparation of t h e mortar from the fine earth and t h e cementing agent, t h e general procedure was t o mix thoroughly, add 1 2 per cent water, silo in a moist closet for 24 hours, mold into bricks, I in. X 4 in. X 4 in., a n d press into shape under a hydraulic pressure of 2 0 0 0 pounds per square inch. These bricks, after air-drying for 2 4 hours, were then placed in a n autoclave and subjected t o the action of live steam under 8 0 pounds pressure for 8 to 16 hours. The bricks were then broken in an Olsen machine, each brick being laid on t h e flat surface. Tables I1 and I11 give t h e results obtained by the use of various mixes of fine earth and cementing agent. 7
TABLE 11-FINE EARTH MIXTURES WITH LIMEA X D WITH PORTLAND CEMENT Percentage r
Fine Sample No. earth 1 . . . . . . . . . . . . 90 80
2....
..
..
80 3. 4 . . .. . . 5 . . .. . . 6 ..
7............
Lime 10 20
..
80 70 85
..
Crushing strength Lbs. per sq. in. 5497 6200
20
3460
10 20 30 10 20 20 30
3290 2740 2650 2540 2440 3680 3820 2980
20 30 15
2520 3410 6200
10
............
-
..
Percentage Crushing strength Fine Portland Lbs.,per earth cement sq. in. 10 20 30 10 20 30
..
... ...
..
80 90
20 10 20
6250 1500 5850
10 20 30 10 20 30
1940 2920 6070 4700 4800 9750
..
80 90
80 70 90
..
..
..
.. 80 .. .. 70 I n using Portland cement, siloing of t h e mixes was of course impracticable, b u t t h e other steps were followed as above outlined. Since i t has been shown by Acheson and others t h a t soluble organic matter increases t h e colloidal content of clay, i t was believed t h a t soils of loamy character might be advantageously
..
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treated with straw infusion made by boiling oats straw with water and decanting the clear liquid. A quantity of t h e infusion necessary t o produce t h e maximum plasticity was then incorporated with t h e lime and fine earth mixtures a n d t h e resulting bricks tested. The earths of sandy texture either disintegrated in the autoclave or gave low strength tests while t h e loamy earths gave a crushing strength of above 3000 lbs. in mixtures containing less t h a n I O per cent lime. Similar results were obtained with a 2 per cent solution of tannic acid. T o confirm t h e results given in Table 11, new mixtures were made up with varying quantities of lime, t h e results of which are given in Table 111.
’
TABLE111-LIME-FINE EARTH MIXTURES Percentage I Crushing strength Lbs. per sq. in. Lime Sample No. Fine earth * 5550 10 3 . . . . . . . . . . . . . . . 90 15 4630 4 . . . . . . . . . . . . . . . . 85 3300 2.5 97.5 5820 7.5 6200 5 . . . . . . . . . . . . . . . . 92.5 95 5.0
CONCLUSIONS
As the result of this work, i t is shown t h a t under t h e influence of heat and pressure, various fine earth plastics may be hardened t o an extent approaching t h a t of concrete. The presence of soluble organic matter does not prevent t h e hardening of loamy mixtures of fine earth a n d lime. Furthermore, as small quantities of lime as z1/2 per cent develop considerable strength in t h e hardened brick. LABORATORY OF IIQUSTRIAL CHEMISTRY OF WASHINGTON UNIVERSITY SEATTLE
WATER PURIFICATION BY OZONE-WITH THE ANN ARBOR PLANT
t
REPORT OF
B y R. Ti. FRYER Received June 13, 1914
The problem of obtaining a safe water supply is one of t h e greatest questions of the day for many cities. The difficulty of obtaining a pure water in sufficiently large quantities has proved too great for most cities of any considerable size, and compelled them t o use a less desirable supply a n d , t o purify t h e same. A method of purification t h a t has met with some success in several European cities is t h a t of ozonization. Some cities t h a t have all, or part of their water supply purified in this way, are Paris, Lille and Nice in France, Ginnekin in Holland, a n d St. Petersburg in Russia. I n this country there are only a few of these plants, none of them of any great size, and none of them attracting any particular notice as examples of cheap efficient water purification. I n the summer of 1912a large force of men were a t work just above t h e intake of the Ann Arbor Water Co. plant, building a d a m for t h e Eastern Michigan Edison Co. The situation was very similar t o t h a t a t Ithaca, New York, a t the time of t h e epidemic of typhoid fever in 1903; with this disastrous experience in mind, these two companies united to avoid, if possible, a n epidemic in Ann Arbor. The major p a r t of the work was done during this
