Note: Descriptions are shown in the official language in which they were submitted.
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Thls inventlon ~elates to addit~ves ~or ent~ain~ng air in
hydraulic cementitious compositions and for maintaining such compositions
homogeneous when llght weight materials are used as aggregates.
United States Patent No. 3,819,391 of Sefton describes a
~ree flowing flake~like solid that ~s formed oP 12.5 to 37.5 percent by
weight of a bituminous material and by difference 87.5 to 62.5 percent
of a sur~ace actlve agent by dispersing the sur~ace actl~e agent and
bituminous materials in water and drying the dispersion to produce the
solid flakes.
When between 0.1 and 2.0 percent by weight based upon the
weight of the weight of the cement is added to a cementitious mixture
containlng expanded polystyrene particles as an aggregate, the binder
phase of the mixture becomes capable of entraining air to the extent of
~rom 13.5 to ~0 percent by volume and o~ malntaining the slurry in a homo-
geneous conditlon even though the particles of expanded polystyrene may
have a bulk density of one pound or less per cubic ~oot and normally have
a great tendency to agglomerate and rise to the surface of the mixture.
The invention is an improvement over the compositions
descsibed in the Sefton patent. The compositions of this invention are
simpler to compound and impart other advantages to the cementitious slurry
in addition to those described in the Sefton patent.
It has now been found that a water-soluble, substantially
homogeneous, powdery addltive can be prepared by a simple mechanical
blending of ingredients, and the blend will not only have the properties
of air entrainment and homogeneity maintenance of the composition described
in the Sefton patent but also has the additional advantages of (1) inhlbit-
ing the normal tendency of a cement slurry to "flash set", (2) providing
a better ~'wet edge", and (3) also improving the surface flnish of the
resulting concrete product.
The compositions of this inventlon are constltuted o~ the
surface active agents and bituminous materials described in the Sefton
patent and of additional materials cornprised of polyethylene oxide resins,
lignosulfonates, and diatomaceous earth.
The invention thus provides a water soluble, substantially
homogenPous powder like solid composition for use as an additive for
concrete composition.s containing expanded particles of polystyrene for
maintaining the aqueous slurry of concrete in a homogeneous condition
until it can cure to a solid, for entraining air in the binder phase,
for inhibiting flash setting, for maintaining for a period of time a wet
edge and for improving the surface finish; the composition comprising a
blend of major and minor components; the major component consisting
essentially of a mixture of ionic and non-ionic surface active agents and
diatomaceous earth, and the minor component consisting essentially of
liquid thermoplastic bituminous resin, poly (ethylene oxide) resin, and
lignosulfonate salt.
Preferably 40-60% by weight of the composition is the sur-
factants and bituminous materials and by difference 60-40~ the additional
materials.
In accordance with this invention there is charged to a
blender the surface active agents and the polyethylene oxide. The
blender, which may be a conventional ribbon blender, is operated until
the ingredients are well mixed and blended.
A wide variety of surface-active agents, anionic, cationic and
nonionic surface-active agents, are useful in the practice of the
invention. Particularly useful additives can be classified according to
their chemical structure as follows:
1. Anionic agents which include alkyl aryl sulfonates, such
as alkyl naphthalene sulfonates, commercially available under the
trademarks ALKANOL B, NEKAL BX-7~; sodium salts of formaldehyde condensed
naphthalene sulfonic acids commercially available under the trademarks
DARVAN NO. 1, DARVAN NO. 2 and TAMOL SN; alkyl sulfonates such as sodium
.~ lauryl sulfonate, commercially available under the trademark DUPANOL WA;
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sodium salts of polymeric carboxylic acids commerclall~ available under
the tradename of TAMOL 731.
2. Cationic agents which include quaternary ammonium ~alts
such as lauryl pyridinium chloride, and trimethyl octadecyl ammonium
bromide and secondary amines such as N~ methylheptylj ethanol amine
and N,N~-bis(l-methylheptyl) ethylene diamine.
3. Nonionic agents which include products of methylene sxide
condensed with fatty acids, alcohols, or phenols 6uch as alkylated aryl
polyester alcohols commercially avallable under various trademarks TRITON
X-120. Partieularly good nonionic agents, which preferably are uced in
mixtures are TWEEN 65 (trademark), which i5 a polyoxyethylene sorbitan
tri stearate, and SPAN 60 (trademark) which is a sorbi~an mono-stearate.
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It h~s been ~ounfl advantageous to use a mixtu~e of varlous
surfactants in the practlce of thls inven~ion. A preferred mixture is
comprlsed of about (a~ twelve parts by weight of the sodium salts of
formaldehyde condensed naphthalene sulPonic aclds (sold under the trade-
mark TAMOL SN), (b) two parts by welght of -the sodium salts Oe pol~meric
carboxylic acids (sold under the trademark TAMOL 731 SD, a spray dried
product), and (c) one part by weight of an alkyl phenoxypoly (ethyleneoxy)
ethanol which is the reaction product of an alkyl phenol with ethylene
oxide having the general structure R ~ ( 2 2 )n 2CH2H (sold under
the trademark IGEPAL DM). Both of the Pirst two surface active agents
are anionic and the third surface active agent is nonionic.
Also classed as nonlonic in nature are the poly (ethylene
oxide) resins used in this in~ention.
Polyethylene ox~de resins are homopolymers having the common
structure HO-CH2CH2-(0-cH2cH2)n-OH The degree of polymerization, n,
varies from about 2,000 to 100,000 with corresponding molecular weight
ranging from 100,000 to 5,000,000. It is preferred for this invention to
use a resin ha~ing a molecular weight of about 400,000. Such resins are
soluble in water and have been used as a pumping aid for concrete. These
resins possess extraordinary thickening power. Because the resins are
viscoelastic, they have the ability to absorb mechanical energy from
turbulent eddies and to release such stored energy slowly or in a delayed
action sequence. This efect, referred to as drag reduction, has the net
result of improving the transportation or movement of liquid through
conduits.
The duration of the mlxing is not particularly critical.
One skilled in the art can readily determine when this mixture has become
uniform.
After the foregoing mixing has become uniform, there i8
added the bituminous material. The bituminous materlal usable in accor-
dance with this in~ention may be any of the low viscoslty, low softening
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polnt materials selected ~rom asphalt, coal ta~, or de~lvatives there~rom.
The bituminous material must be a li~uid at roo~ temperature. Therefore,
the less viscous asphalts are con~emplated ln the practlce o~ thls
invention. Asphalts ha~ing a Saybolt Viscosity of 10 to ~,000 S~S at 50C.
are contemplated by this invention. Alternately, sol~ent cut asphalts may
be used, which solvent cut asphalts are ~ormed by dlluting ~cutting back)
a solid or semisolid asphaltic material with a petroleum distillate
fraction. The tars are brown to black ~iscous liquids produced from the
destructive distillation of such organic materials such as coal, petroleum
and wood. Particularly suitable are tars derived ~rom the destructive
distillation o~ coal. The tars must also be a llquid at room temperature.
The viscosity of the tars should be within the range of 10 to 4,000 SFS at
50C. The higher viscosity tars can be cutback with solvent to achieve
the desired ~iscosity. Besides the tars, distillates of the tars may be
used. Tar distillates such as creosote oil which distills at about 200
to 400C. and contain substantial amounts of naphthalene, anthracene and
phenanthrene are also suitable in the practice of the invention. Suitable
bituminous materials are dark thermoplastlc resins of polymeric poly-
nuclear hydrocarbons made by cracking petroleum under controlled conditions
to yield unsaturated aromatlcs and then polymerizing these aromatics to a
product having a low melting point. A substantially non-reactive, thermo-
plastic hydrocarbon type resin derived through the polymerization of
materials of a hydrocarbon nature and sold under the trademark NEBON~ is
particularly usable in the practice of the invention. The mixing at this
stage is continued until the color of the mixture shows that a good blend
has been achieved.
At this stage the salt of lignosulfonate is added. Ligno-
sulfonates prepared by the sulfonation o~ llgnln materlals, such as calcium
lignosulEonate, are co~msrclally available under the trademark ~ARASPE~S~ C,
and sodium lignosulfonates commercially a~ailable under the trademark
POL~FON ~. Especially reco~mended is the llgnosul~onate sold under the
trademark MARACON T.
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Finally the Diatomaceous earth is added. The blending is
continued until, as can be read~ly obse~ed, the ingredients are well
blended. The result is a powdery, water-soluble solid, light ~rown in
color.
In hot weather and in hot and dry climates, the portion of
the cement slurry that is in immediate contact with the hot forms tends
to cure or set much more rapidly than the other portlons of the slurry,
a phenomenon known in the art as "1ash set". This leads to problems
such as a failure due to this part that has flash set to be brittle and
not well joined to the other part o~ the cement structure. The additive
o~ this invention inhibits thls "flash settlng" without changing the over-
all setting time of the concrete composition.
~nother phenomenon which tends to occur, especially in hot
dry weather, is that subsequently poured sections do not bond well to
become a monolithic structure, even though only a short time period may
have elapsed between the pouring of the two sections. The ability to
retaln the property of one section joining with a subsequently poured
section of the concrete is known as having a "wet edge". The additive
of this invention enables the concrete composltion with which it is used
to have viable, for a longer period of time, the wet edge.
When expanded polystyrene is to be the aggregate, the
powdered additive can be added to expanded polystyrene particles at any
time after the particles have been preexpanded. The particles then are
ready to be used as the aggregate for a light weight cementitious compo-
sition. The admixture of the aggregate, i.e., the expanded polystyrene
particles and the additive may be done under carefully controlled factory
conditions. Then the aggregate need only to be added to the cement and
water in the field uslng conventional technlque~.
In the preferred use of the ad~ltlve composltlon of thls
invention, 1.5 to 3.5 but preferably about 2.5 pounds of the compo~ltion
described above ls admixed with about 9 cubic feet of expanded polystyrene
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partlcles, which pa~ticles h~e been expanded so that the ~inal density
thereof is ~ro~ about 1 to 10 pounds per cu~c ~oot ~ pre~erably in the
range of 1 to 3 pounds per cubic foot. Structurally, the particles have
discrete closed cells which make ~hem sub~tantially water impermeable and
thus obviating an increase ln the water requirements of the wet cement
mix. Such expandable polystyrene beads are com~ercially available ~rom
several nanufacturers. The expandable polystyrene particles have incor-
po~ated therein from 3 to 15 percent by weight of a volatile hydrocarbon
blowing agent, such as pentane or petroleum ether, which is readily
volatilized at elevated ternperatures. Heating these particles in an un-
confined state expandæ the polystyrene beads from 10 to 60 tlmes their
original size. Conventionally, the heat may be provided by hot air, steam,
hot water, infrared radiatlon, and the like.
Without ~urther elaboratlon, it is believed that one skilled
in the art can, by following the preceding descriptlon, utilize the ~resent
inVention. Accordingly, the following specific embodiment is to be con-
sidered as merely illustrative and not li1nitive of the dlsclosure.
The production o~ the additive is readily carried out by
charging, where parts are parts by weight unless otherwlse speci~ied, to
a conventional ribbon type blender 35 parts o~ the sodium salts of formal-
dehyde condensed naphthalene sulfonic aclds (Tamol SN), 6 part6 of the
sodium salts o~ polymeric carboxylic acids (TAMOL 731 spray dried to a
powder), 3 parts of a~k~ phenoxypoly (oxyethylene) ethanols (IGEPAL DM~
and 3 parts o~ poly (ethylene oxide) resin (POL~OX WSR~ 3000). The mixlng
is continued until the ingredients appear to be well blended.
Then 7 parts of the bitu~inous material (~EBO~Y L-55, a
liquid) is added and the mixing is continued until charge appears to be
of an even colo~, thereby ~howing that the lngredlents have been well
blended.
Thereafter 15 parts o~ the alkall salts of llgno~ulfonate
is added (MARACO~ T) and the m~xing continued until the appearance shows
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the product to be well blended.
~ t this tlme, 31 parts o~ diatomaceous earth ~CELITE) is
added and again the blending continued untll the blend appears to be
uniform.
In the production o~ the light weight concrete, 18 cubic
feet of expanded polystyrene partlcles (normally two bags containing 9
cubic feet each of expanded polystyrene) as the aggregate, S pounds of
the powder additive oP this invention, 564 pounds of Portland cement
(normally six conventional bags, each weighing 94 pounds) and 30 to 36
gallons of water are mixed in a conventional horizontal blender. The
result is a slurry that will produce 24 to 25 cubic feet of a concrete
structure having a final density of about 30 pounds per cubic foot and
containing about 50 percent entrained air in the binder phase.
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