of los angeles
US RE16732 E
Description (OCR text may contain errors)
Reissued Sept. 6, 1927.
UNITED STATES PATENT o Frc-E.
RUDOLPH J. WIG, OF1LOS ANGELES, CALIFORNIA, ASSIGNOR TO THE CELITE COM PANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF DELAWARE.
MATERIAL I'OR USE IN CEMENT COMPOSITIONS.
1T0 Drawing. Original No. 1,584,579, dated May 11, 1926, Serial No. 96,304, filed March 20, 1926.
,Application for reissue filed July 5,- 1927. Serial No. 203,668.-
, My invention relates to a: definite product for use in cement compositions or as an admixture to cement to develop certain desirable physical characteristics. Such product,
5 the methods of using such product, andthe results obtained thereby are described in the following specification.
This application is a continuation in part of my application filed May 26, 1925, Serial No. 33,043. v a
The object of this invention is to provide a finely divided material obtained from'diatomaceous earth, suchmaterial being added in, small quantities to cement or cement compositions to give greater workability and strength, and more homogeneous structure, than such cement might otherwise develop.
It is intended thatthe term cement as used herein be taken to mean and include any cement, such as Portland cement, ferrogeneous cement, or' any hydraulic cement used in combination with or without other materials in the making of concrete, plaster, stucco, etc. Furthermore, it is intended that the term plastic materials as used herein be construed throughout the specification to mean and include allsuch plastic materials as are made by the combination of any hydraulic cement,\with sand, gravel, rock, or
other similar aggregate to produce concrete, plaster, stucco, etc. The particular examples cited in this specificationwill refer to the use of my'product with Portland cement, sand, and rock, although my invention is not limited to such use.
The use of diatomaceous earth (otherwise known as kieselguhr, tripoli, molar, fossil, flour, infusorial earth, etc.) in cement or cement compositions. has been known in a gen- 40 eral way for some time, but such use has or successfully apnever been commercially plied; practically all of the known data reers to experimental results. This condition is pr.imar1ly due to the variable results obtained, and the lackof actual knowledge as to the properties of diatomaceous earth used in such experimental work.
I have found that the successful use=of diatomaceous earth in cement compositions depends upon the fineness or particle size of the diatomaceous earth, and on the quantities of this material which are used. I find that diatomaceous earth must be finely ground or disintegrated, and furthermore that'such disintegration must fall within fairly well defined limits. My invention discloses .and states the particular limits for the fineness to which thediatomaceous earth must be disintegrated.
N 0 one, to my knowledge, has shown what grade or fineness of diatomaceous earth is best adapted to the purposes of my invention and the fact that the fineness of the diatomaceous earth varies the results obtained by its use in cement has not been disclosed in the prior art. For example, my
work has shown thateoarsely ground diatomaceous earth (a material containing particles the size of a pea, for example) produces a weak cement orcOncrete, while a diatomaceous earth reduced to a state of ultimate division of the particles (for example, composed entirely of particles less than 0.001 mm. in size) does not give results which I I deem favorable. A diatomaceous earth product made. in accordance with: my invention-should contain not more than 25% (by weight of the total amount) of particles having a' greater average size than 0.02
mm. These limits may be varied to a cer-,
tain extent depending upon the methods used in determining the size of the particles, but at no time should more than approximately 3% be left on a- 30 mesh screen nor is it desirable to have more than of the material finer than:0.001. mm. in size. 'Sedimentation methods may be used to determine the particle size, but microscopic methods may also be used. When sedimentation methods of determining particle size are used, I distinguish 0.02 mm. particles as those acting under Stokes law as spherical particles of approximately 0.02 mm. in diameter.
Because of stream-line and surface effects, long needle-like particles and flat plate-like particles do not settle at a rate equivalent to the rate exhibited by a. spherical particle of the same mass as of said angular particles. For example, in a diatomaceous earth of 2.1 specific gravity, spherical particles of about 0,02 mm. in diameter will settle at a rate of about 1.44 cm. per minute at 20 0., in distilled Water although in fact particles of such diatomaceous earth settling at such rate may be, and very oftenare, anisotropic articles 0.025 or 0.040 mm. long, depen ing upon their cross section and mass. These particles, however, both isotropic and anisotropic, are identified by me as 0.02 mm. particles. The sedimentation'methods described by The Svedberg in his American Chemical Society monograph on Colloid chemistry have been used successfully and may be used for this determination.
The following particle size analyses represent fairly well the grades of'diatomaceous earth which'I have developed and found most efi'ective for use in cement compositions Size of particles. No. 1 No. 2. No. a.
Ber Per Per cent. rem. cent Greater than 20 microns. 23 17 10 to 20 microns 1o 7 7 to 10 microns 13 15 8 1 to 5 microns 34 21 15 Less than 1 micron v 70 The exceedingly fine particle size of the materials tabulated above may be appreciated by considering that 1. micron is equiva lent to 0.001 millimeter. In other words, a particle of 20 microns in diameter is only 7 0.00078 inches in diameter, or a particle which would be approximately 650 mesh. It
is to be remembered that diatomaceous earth is composed of microscopically. small siliceous particles and may be disintegrated to exceeding fineness, while sand, quartz, or'
other forms of silica cannot be readily reduced to such fine state of division because of their structural strength and'crystalline formation. My invention therefore consists in the production of a finely disintegrated diatomaceous earth product of certain definite particle size, such material giving results, in cement compositions, hitherto unattained.
The above specifications for disintegrated diatomaceous carth for use in cement "compositions were .developedafter numerous ex periments and practical applications, and although the theory underlying-the particular effectiveness of the product is not entirely clear, it may be similar to that which under lies the classification of aggregates for concrete. I do not wish to limit myself to any theory, but rely primarily on the facts disclosed during my investigation. For example, if appreciably more than 25% of the disintegrated diatomaceous earth is larger than 0.02 mm. in size, the product is not quite as effective as a material falling within the above described limits. The reason for the above action may lie in the fact that diatomaceous earth alone has relatively no.
strength and the coarse particles do not act as a structural material, for example, sand; that 1s, they do not impart strength to the v is most readily accomplished in air Similarly, a material cement compositions.
containing more than approximately of 0.001 mm. and smaller particles does not produce 'the workability in cement compositions which characteristic of the compositions made with diatomaceous earth disintegrated to the extent specified by me.
A diatomaceous product in accordance with the above specifications may be easily manufactured-by disintegrating raw or natural diatomaceous earth by means of suitable apparatus and then classifying the disintegrated material to get a product of the This classification separating apparatus, or conical chambers, through which the disintegrated material is carried by means of a vehicle such as air .or gas. The heavier and consequently larger partic'les are left in such chambers, while the finer particles are carried on'until finally they are removed in other suitable-chambers. My invention pertains to the product made and not to the method of manufacture, howrequired particle size.
ever, and is not to be limited to the method or apparatus used in such manufacture.
I have found that a very effective product may also beobtained by calcining or heating the diatoma'ceous earth either before or afterv disintegration, the latter process, that is, calcination after disintegration, or partial disintegration, being preferable. This calcination removes a certain'amount of organic matter which may or may ot be present (dependingupon the purity of the diatomaceous earth 1n its natural state), and I otherwise changes the physical characteristics of the material, but should not be car ried to such extent as to affect the serviceability of such'calcined diatomaceous earth for use in cement compositions.
In using my specially prepared and classified diatomaceous earth productin cement compositions, I prefer to add to such composition from approximately. to about 10% of my product by weight of the cement with which it is to'be used. For example, ina 1:2 :5 concrete I have found it desirable to use from approximately 2% to 6% of my disintegrated diatomaceous earth by weight 0 the Portland cement used to such concrete mixture.
The effect of using such diatomaceous earth product in cement compositions, for example, Portland hicle (water) which carries the aggregate and sand, thus tending to maintain the ho- 'mogeneity, plasticity and consequently" the better working quality of the concrete as a whole. When used in quantities not exceeding about 10%, the strength of the cement mixture is generally increased and the work-- cement, seems to be the thickening of the ve- 1120 1.- 5: 6' Concrete.
Crushing strength Percentage of diatomaceous earth.
. (28 days).
0 per cent Q.
1.7 per cent", 1,155 162 3.3 per cent", 1, 129 144 51) per cent 1,002 84 10.0 per mm 936 53 15.0 percent--.
It will be seen that in the above tests the of 10.6% in strength. The workability givenunder the third column shows an arbi- I concrete may be worked being shownlby a reduction of the workability figure. though the above results indicate that 1.7%
of my product develops greatest stren 'th in the 1 3: 6 concrete, citedas an exampl e,.the efi'ectinay be varied by the grade of Port-- land cement used amount of water, "size and fineness modulus of the aggregate, etc., so
that I. do not wish to 'be limited to any definite amount of my productin such concrete or in other concrete mixtures other than that such addition does not exceed about 10% on weight of the cement used. The
addition of my classified diatomaceous earth may be made either to the cement at its place of manufacture, or to the cement immediately. before or during itsmixt-urc with water, sand, rock, and any or all other ingredients, preparatory to the use of such cement or cement composition on a job.
It is commonly accepted that an increase in the amount'of water used in'mixing a cement composition, say 1 z2r4'concrete, re duces the strength of the concrete. This, I have found, is not altogether truelwhen a diatomaceous product such as I have described, is used. Forexample, a 1:224 concrete without my product was mixed'using 9.68% water on'weight of aggregate and cement, and showed a workability of 386, and a flow (as determined in accordance with A. S. T. M. methods) of 90. The crushing strength in 28 days was 1885 lbs.
per sdiiare inch. When to another bfich of the same concrete I'added 2% by weight of cement of my diatomaccous product, and
used 10.01% water on weight of cement and .aggre ate, theflow was only 80, but the worka ility was increased to- 231 -and the crushingstrength to 2088 lbs. per square inch. vIn general, therefore, it may .be dc sirable to add to cement compositions containing my product only enough water to give a smaller flow than .that of plain cement compositions.
\Vhen slump is used as a criterion of consistency of concrete it 1 may be said thatgenerally no additional water should be added .to concrete mixtures containing my: product, in excess of that required to, give the same slump as that of plain concrete.
The relative ineffectiveness of using a disintegrated diatom'aceous. earth! containing more than ap roximately 70% by weight of 0.001 mm. an smaller particles may be seen from the followilig resultsby a 1:224 con.-'
crete using 2% of the diatomaceous earth- I maximum strength was devolped with 1;7% i welght 9 Portland ement:
of my'product and it represented an increase In addition to the increased workability which results from the useof my disintegrated diatomaceous earth in cement compositions, and which materially reduces the labor cost of placing, such compositions, I .find that my product produces an increased yield-of such cement compositiom'such'increase in yield generally exceeding what would be expected by mere addition of-an inert material. For example, duplicate columns of. 1 2 13 concrete were poured, v3 disintegrated diatomaceous earth of the preferred particle size on weight of Portlandcement being usedin one and no dia-- tomaceous earth in the other. columns were thoroughly set, they were carefully measured and it was found that the column in which'my product was used had a volume of 5.3% greater than the plain cement. k
' These results have been checked on many structural operations -with practically the same results, and show the benefitderived by the use of my material, such benefit being negligible when thediatomaceous earth f x contains more'than approximately 70% of particles smaller than 0.001 mm. and greatly reduced when the diatomaceous earth con tains more than approximately 25% of particles greater than 0.02 mm.
Actual structural concrete work has After the a tions, a finely disintegrated diatomaceous shown that the folloyving percentages of my by Weight of cethan approximately 25% by Weight of par-- ticles larger than 0.02 mm. and no more than approximately by weight of particles smaller than 0.001 mm. in size.
2. A finely divided ,diatomaceous earth product for use in cement compositions containing not less than approximately by Weight of particles smaller than 0.02 mm.
3. As an admixture to cement composieartli product comprising not more than approximately 3% by Weight of particles left on a 30 mesh screen, and no more than approximately 7 0% by weight of particles smaller than 0.001 mm. in size.
4. A plastic composition comprising hydraulic cement, sand, an aggregate, and finely divided diatomaceous earth containing not less than approximately 75% by weight of particles smaller than 0.02 mm. in size;
the amount of the diatomaceous earth used being approximately from 1% to 10%- by weight of the cement used.
5. A plastic composition for the purpose specified comprising cement, sand, an aggregate, and a finely divided diatomaceous earth containing not more than approximately 25% by weight of particles about 0.02 mm.
or, larger in size, and approximately 75% of particles smaller than 0.02 mm. in size.
6. A plastic composition comprising cement, sand, an aggregate, and a finely divided diatomaceous earth containing not more than approximately 25% of particles about 0.02 mm. or larger in size, and not more than approximately 70% of particles smaller than 0.001 mm. in size; the amount of the diatomaceous earth used being froapproximately 1% to 10% by Weight of me cement used.
7. A plastic composition for the purpose specified comprising cement. a suitable aggregate, and a finely divided diatomaceous earth containing approximately 75% of particles smaller than 0.02 mm. in size.
8. A plastic composition comprising hydraulic cement; sand an aggregate; a finely divided diatomaceous product containing not more than approximately 25% of particles about 0.02 mm. or larger in size, and not more than approximately 75% by weight of particles 0.02 mm. or smaller in size; the amount of the diatomaceous product being approximately 1% to 10% by weight of the cement used; and Water in such amount as togive the plastic composition a slump no greater than that of a plastic composition not containing the diatomaceous product.
9. A diatomaceous earth product for use in plastic compositions containing not more than approximately 25% by weight of particles having sedimentation characteristics equivalent to particles of 0.02 mm. or larger diameter of specific gravity equal to that of the diatomaceous earth and no more than approximately 70% by weight of particles having sedimentation characteristics equivalent to particles of 0.001 mm. and smaller in diameter.
RUDOLPH J. WIG.