Sept., 1913
T H E JOL7R.Y=1L OF I S D C S T R I r 3 L A S D EA\*GI."\'EERI.YG C H E J I I S T R Y
It eliminates also a n y possibility of heating due t o an irregular flow of oil. I n t h e wide and sudden variations of highway automobile traffic t h e bearings are often subjected t o greater strain t h a n a n oil film can stand, b u t not a graphitized surface when once well formed. Such protection from undue wear and sudden strains t h a t cannot be avoided in highway locomotion add greatly t o t h e safety and length of service of the finely adjusted mechanism. Assuming properly selected materials in construction, no doubt t h e most uncertain element in t h e proper operation and in t h e economic durability of a n automobile is t h e friction of its moving parts. I t s sure control protects t h e mechanism of t h e moving parts and materially reduces the expense of operation.
THE ACTION O F VARIOUS SUBSTANCES ON CONCRETE1 By RICHARD K. MEADE
The following experiments on the action of various substances on concrete were begun some five or six years ago! about the time t h a t the agitation over t h e destruction of concrete b y t h e alkaline waters of the West was first started and was undertaken not only t o see i f such acTion was really likely t o take place b u t also to determine which of t h e salts ordinarily found in ground waters m-ere the cause of such destruction. m
TESTSOF
THE
All briquettes were made from a mixture of one part cement and three parts standard Ottawa sand. They were allowed t o harden 2 8 days in air and then immersed in a solution of t h e salt. The briquettes were piled in such manner t h a t t h e solution had access t o almost their entire surface. The solutions in all cases except t h a t of the calcium sulfate, which was a saturated solution, were made up of one part of t h e salt t o I O O parts of water, t o form practically a one per cent solution. At first t h e solutions were changed every few days, b u t after t h e first month t h e solutions were changed weekly and after t h e first year less often. The results obtained are given in the table below: ACTION OF VARIOUS SALTS ON CEMENT MORTARS Age in a i r . , , , . , . , , . 28 days Age in the solution.. 0 days 7 days 28 days 3 mas. 6 mos. 1 yr. 2 yr TENSILE STRENGTH I n MgSO4 . . . . . . . . . . . 219 268 272 28; 196 Disinte... grated Disinte. . . . . . . . . 219 245 300 315 202 115 grated
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CASE SCHOOL OF APPLxEn SCIEKCE CLEVELAND, OHIO
ANALYSISA
723
CEMENTEMPLOYED
Silica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
............ .........................
Lime . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ Magnesia.. . . . . ............ Sulfur dioxide. Loss on ignition.. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20.20 2.50 6.96 62.40 3.01 1.60 2.38
PHYSICAL TESTS
Steam O.K. Cold water O.K. Boiling O.K. Air O.K. Fineness-Passing No. 100.. ................. 94.3% Passing No. 200.. . . . . . . . . . . . . . . . . . 97 .8% Setling Time-Initial set-2 hrs. and 15 min. Final set-6 hrs. and 30 min. Tensile Sfrengfh- 1 day neat. ............. 315 lbs. 7 days n e a t . . . . . . . . . . . . . 765 7 days s a n d . . . . . . . . . . . . . 245 '' 28 d a y s n e a t . . . . . . . . . . . . . 876 " 28 days sand.. . . . . . . . . . . . 340 I ' 3 mos. neat.. . . . . . . . . . . . 885 " 3 mas. s a n d . . . . . . . . . . . . . 415 '+ 6 days neat . . . . . . . . . . . . . 855 6 days sand.. . . . . . . . . . . . 435 '' 1 yr. neat ............... 890 '' 1 yr. s a n d . . 510 "
In In In In
Cas04 . . . . . . . . . . . . Na2SO4 . . . . . . . . . . . NaCl . . . . . . . . . . . . . NazCOa . . . . . . . . . . .
219 219 219 219
227 257 236 225
300 334 268 277
334 354 299 324
314 378 287 320
..
............
The salts usually found in the so-called "alkali waters" of t h e West are also those which occur in sea water and are those present in largest amounts in many spring and river waters. They are sodium chloride, magnesium sulfate, calcium sulfate, sodium sulfate and sodium carbonate. I n order t o test t h e effect of solutions of these substances on cement mortars, a sample of normal Lehigh Valley cement was selected and from it a large number of sand briquettes were made. Read a t the Sixteenth Annual Meeting of the American Society for Testing Materials, Atlantic City, June 26, 1913.
"
141 325 360
First, it should be remembered t h a t the 28-day strength of briquettes kept in air is much less t h a n t h a t of those kept in water. X s will be seen from the results given in t h e table, the sulfates have a marked action on concrete which seems t o be most apparent in t h e case of the magnesium salt. The action of magnesium sulfate on cement mortars has been discussed quite voluminously of late, and. I will not go into i t t o any length in this paper beyond t h e fact t h a t we carefully analyzed the affected portion and the unaffected portion of a sand briquette which has been stored in a solution of magnesium sulfate. These analyses follow:
Soundness-
..
209 271 310 337
After immersion 7 -
Percentages
Alumina.
Before immersion . . . . . . . . . . . . . . 75.12 . . . . . . . . . . . . . . 0.52
.........
.................. . ............
Magnesia.. Sulfur trioxide., Loss on ignition..
0.70 0.33 7.02
Unaffected portion 73.96 0.60 1.30 14.50 1.66 0.83 7.14
1
Affected portion 60.40 0.30 0.64 14.21 3.64 5.78 14.97
T h e large increase in t h e magnesia and sulfur trioxide and t h e decrease on the oxides of iron and alumina indicate t h e elements which react with each other. The loss in silica may be due t o chemical action also, b u t as the surface of t h e briquettes was very much attacked and t h e sand grains could be scraped away with t h e finger, I a m inclined t o think t h a t t h e lower silica in t h e disintegrated portion is probably due t o mechanical causes rather t h a n chemical action. It will be noted t h a t in almost all cases t h e first effect of t h e solution was t o increase t h e strength of t h e briquettes and t h a t signs of disintegration in no cases became evident until after a period of three months in t h e solution. Some of t h e briquettes were even boiled in a 5 per cent solution of magnesium sulfate for several days and in all cases t h e briquettes were much stronger
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
7 24
after boiling than they were before and fully as strong as briquettes boiled in pure water, showing how slow t h e action of the sulfates is. T h e briquettes which failed were much swollen and presented much t h e appearance of a baked potato which had burst its jacket. Various authorities have proposed a t different times the use of divers ingredients in concrete exposed t o sea water with a view t o reacting with t h e salts of t h e latter t o form insoluble compounds which would protect t h e concrete. Most persistently suggested of these are the salts of barium which form with sulfates insoluble barium sulfate. I tried both barium chloride and barium carbonate. These were ground very finely and mixed with t h e cement. I employed z per cent of barium chloride with t h e cement and also 2 per cent and 5 per cent of barium carbonate, respectively. Sand briquettes were made from these mixtures and t h e test pieces stored in a magnesium sulf a t e solution containing I O grams of t h e salt t o t h e liter. M y results follow and, as will be seen, none of these compounds arrest in any way t h e destruction: ACTION OF MAGNESIUMSULFATE ON CEMENT MORTARSCONTAINING BARIUMCOMPOUNDS 14 days Age in a i r . . . . . . . . . . . . . . Age in 1 per cent MgSO4 0 days 7 days 28 days 3 mos. 6 mos. solution.. 1 yr. TENSILE STRENGTH OF BRIQUETTESCONTAINING
............
...... ........ 5 per cent BaCO8........
2 per cent BaClr.. 2 per cent BaCOa
...
181 115
221
213 246
306 311
265 204
166
257
346
346
274
146 Disintegrated
Some years ago a n English chemist suggested t h e use of finely ground burnt red brick as an admixture for concrete which was t o be used in sea water. After reading this paper i t occurred t o me t h a t the resistance t o sea water claimed for high iron cements might be due t o t h e presence of oxide of iron in the cement. I, therefore, had sand briquettes made up containing oxide of iron i n various forms and conditions, v i z . , red or ferric oxide, magnetic oxide of iron, venetian red (an impure oxide of iron made from low-grade iron ores, so-called “paint ores” of the Lehigh District) and finely ground red brick, using 5 per cent of t h e weight of t h e cement of these in each case and placing t h e briquettes in a I per cent solution of magnesium sulfate. The results follow: ACTIONOF MAGNESIUM SULFATE ON CEMENT MORTARSCONTAINING I R O N OXIDES, ETC. I Age in air.. 14 days Age in solution.. 0 days 7 days 28 days 3 mos. 6 mos. 1 year TENSILE STRENGTHOF BRIQUETTES CONTAINING 5 p e r c e n t ferric oxide 218 275 310 355 310 125 Spercentmagneticoxide. 225 280 340 340 280 105 5 per cent venetian r e d . . 165 225 300 345 215 Disintegrated 5 per cent brickdust 970 220 275 310 205 ‘‘
............
........
....
.....
As will be seen, the additions of iron compounds are in no way beneficial t o cements t o be employed in sea water. I next tried waterproofing the mortar on the theory t h a t if t h e circulation of water through t h e pores of the mortar could be stopped no chemical action could take place. I employed for this purpose both a high
VoI. 5, No. 9
calcium and a magnesium hydrated lime, road oil as recommended by Page, a mixture of solution of silicate of soda and fish oil (a well-known waterproof compound) and lime soap (the basis of many waterproofing compounds). I also tried dipping the briquettes first in a hot solution of soap and then in one of alum (Sylvester’s Process). The result of sand briquettes made from these mixtures and stored in magnesium sulfate solution ( I O grams t o t h e liter) will be found below: ACTIONOF MAGNESIUM SULFATESOLUTION O N WATERPROOFED(?) MORTARS
Age in air.. . . . . . . . . . . . . . . 14 days Age in 1 per cent magnesium sulfate solution.. , , , , . 0 days 7 days 28 days 3 mos. 6 mos. 1 year TENSILE STRENGTH OF BRIQUETTESCONTAINING 15 per cent hydrated lime 215 315 245 200 120 (Ca) ................... 215 I5 per cent hydrated lime 260 245 105 215 225 320 (Mg).. . . . . . . . . . . . . . . . . 260 210 140 10 p e r c e n t r o a d oil 165 200 210 275 230 180 2 per cent lime soap 185 210 250 260 225 165 200 2 per cent oil-silicate of soda 160 245 265 Treatedwith alum andsoap. 220 235 275 215 185
.. .
........ .......
It will be noted t h a t while t h e disintegration is evidently taking place in these test-pieces, all of these compounds seem t o arrest it t o some extent a t a n y rate and in the case of t h e lime soap this is quite marked. I also investigated the action of magnesium sulfate solution on cements high in silica. For this purpose a sample of commercial cement high in silica and low in alumina and one low in silica and high in alumina were selected and sand briquettes were made of this and immersed in a solution of magnesium sulfate containing 2 0 grams t o t h e liter, or practically a 2 per cent solution. The cements selected had t h e following analyses: Percentages Silica.. Iron oxide.. Alumina Lime Magnesia.. Sulfur trioxide..
............................. ......................... ............................ ............................... ..........................
.....................
Low-alumina High-alumina cement cement 19.86 23.24 2.56 2.25 7.60 5.03 63.12 63.55 3.10 3.05 I .66 1.51
As will be seen b y t h e following results, t h e lowalumina cement resists t h e action of magnesium sulfate much better t h a n t h e high-alumina one: ACTIONOF MAGNESIUM SULFATESOLUTION ON HIGH-A N D LOW-ALUMINA CEMENTS Age in air 2 yrs. 0 days 7 days 28 days 3 mos. 6 mos. 1 yr. Age in solution..
....
High-alumina cement. 242 Low-alumina cement.. 225
318 307
404 430
402 476
230 472
Disintegrated 500 425
I n t h e above experiments both cements were commercial cements, b u t t h e high-alumina cement when received was not quite so finely ground as t h e other one, so i t was ground t o practically the same degree of fineness in a small jaw mill (or t o 8 6 . 2 per cent passing the No. zoo sieve) so t h a t the fineness of the two samples might, in no way, influence the results. Both these cements were made from cement rock and limestone. I n connection with t h e u’se of concrete for mine props, where i t is often exposed t o t h e action of dilute solutions of sulfuric acid, the following experiment was tried: Sand briquettes were allowed t o harden 2 8
Sept., 1913
T H E J O U R N A L OF I N D U S T R I A L
days and then were placed in a solution containing 2 5 0 grams of sulfuric acid (HPSOI)t o t h e gallon. The solution was changed frequently and the briquettes broken a t regular intervals. The disintegration of concrete by such acid water is shown b y t h e following: Age in the solution.. 0 days 7 days 28 days 3 mos. 6 mos. Tensile strength.. . . . . 226 299 300 280 176
1 year Disintegrated
Several years ago the question of the action of oil on concrete was brought up a t one of t h e meetings of this society in connection with a paper by Prof. Carpenter. I n his experiments oil was mixed in with t h e concrete. I n t h e discussion which followed the reading of the paper, a number of gentlemen suggested t h a t what was needed most was information relative t o t h e action of oil on concrete which had already hardened, in view of the employment of concrete for machinery foundations, engine room and factory floors, etc., where i t is subjected t o t h e oil which leaks from t h e bearings of the machinery. I went home from this meeting and had a lot of sand briquettes made and allowed them t o harden 2 weeks in air. These were stored in air, in engine oil, in cylinder oil, and in black oil. They were then broken a t stated periods with t h e following results: ACTIONOF OIL O S CONCRETE Age in air.. . . . . . . . . . . . . . . . . 14 days Age in o i l . . . . . . . . . . . . . . . . . . 7 days 28 days 3 mos. 6 mos.
TENSILE STRENGTHO F BRIQUETTES KEPT Engineoil . . . . . . . . . . . . . . . . . . 253 Cylinder oil . . . . . . . . . . . . . . . . . 235 . . . . . . . . . . 234
240 273 222
251 221 181
232 209 131
Air ........................
233
287
303
248
1. year
IN
23 1 203 Brokein clips 293
It will be noted t h a t t h e engine oil and the cylinder oil have practically no effect upon concrete. One would think t h a t as the latter has a considerable proportion of animal oil in its composition i t would be a p t t o effect appreciably concrete exposed t o it. On t h e other hand, t h e action of t h e black oil seems strange in view of the fact t h a t i t is a straight mineral product, All of these briquettes had absorbed considerable oil, t h e actual gain in weight of each set a t the end of t h e year being as follows: Per cent Set in engine oil . . . . . . . . . . . 10.6 Set in cylinder oil. .................... 10.0 12.0 Set in black o i l . . ......................
The briquettes in t h e black oil had not swollen perceptibly and seemed merely t o be weak. The experiments given above were all made upon very small test-pieces and hence t h e action of t h e solutions upon them were much more rapid t h a n they would be upon a large mass of concrete, and while in most of t h e above cases a year was sufficient t o completely disintegrate t h e test-pieces, in a large body of concrete, such as a pier or wall, many years a t least would be required t o bring about this result. The experiments merely serve t o show t h a t even very dilute solutions of the salts of magnesium and the sulfates in general do have a destructive action on concrete and t h a t the generally proposed remedies do not appreciably retard this. They indicate t h e desirability of
A N D E-YGIiX'E E R I N G CHE&fI S T R Y
72.5
employing low-alumina cements for sea-water construction. The experiments with the oils show t h a t no destructive action is likely t o take place where cement is used for floors in machine shops and engine rooms. 202 NORTHCALVERT S T . BALTIMORE
THE DECOMPOSITION OF FELDSPAR AND ITS USE IN THE FIXATION OF ATMOSPHERIC NITROGEN By WILLIAMH.Ross' Received July 21. 1913 INTRODUCTION
The extensive search for sources of potash salts which has been undertaken in this country during t h e past two years has naturally led t o renewed efforts in devising methods for its extraction from feldspar and other silicate rocks. The investigations in t h e use of feldspar as a source of potash have, however, not been confined t o the past few years, b u t date back t o the time when t h e part played by potash as a fertilizer in t h e production of crops was first recognized. Even as early as 1847 a British Patent, No. 11,555, was issued t o Richard Albert Tilghman for a process of obtaining potassium sulfate from feldspar b y heating t o bright redness for 8 hours, z parts of feldspar with I part each of limestone and gypsum. Within a few years a number of other patents appeared in England and other countries outlining methods for obtaining potash not only from feldspar, but also from leucite and other eruptive minerals. The discovery of the importance of potash salts in agriculture took place also simultaneously with the discovery in 18j1 of the great salt beds a t Stassfurt, Germany, and in 1861 the first factory for refining crude potash minerals was established. The discovery a t this time of such an enormous source of soluble potash salts naturally detracted from t h e interest which was being taken in t h e extraction of potash from t h e refractory silicates, and as a result no investigations for obtaining potash from these minerals were patented for 2 9 years. The increasing demand in this. country for potash fertilizers has again turned attention t o t h e silicate rocks as a possible source. Owing t o t h e commercial application of any successful method which might be devised, most of the investigations have been carried on in secret, and before t h e publication of any results, patents have been applied for in almost every case covering processes which have been proposed for t h e extraction of potash from this source. The number of patents of this kind which have been issued during t h e past few years is surprisingly large. N o less t h a n seven have been issued during 1 9 1 2 alone, and i t is known t h a t a number of other patents have been applied for, b u t have not yet been issued, so t h a t t h e processes t o which they relate are still kept secret. PROCESSES F O R THE DECOMPOSITIOK O F SILICATE ROCKS
The total number of patents which are concerned with t h e extraction of potash from silicate rocks numScientist in Soil Laboratory Investigations, Bureau of Soils, U. S. Dept. Aar.
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