Note: Descriptions are shown in the official language in which they were submitted.
This invention relates -to sulphur cenlents and concretes produced
-there:Erom.
Sulphur c~m~lts have a lony history of use in specializecl aE)pli-
ca-tions. T.hus, Canadian Pa-tent No. 71,686 issued -to George McKay provided
a sulphur-contail~g cc ~ osition useful for sealing purposes a-t a join-t, for
roofing purposes, for the forming of ornamental figures, and for the coating
of the exposed surfaces of iron or steel steps, the com~osition including
sulphur, brick-dust, tin, lead, bi.smuth, plaster of paris and korax.
~ lo~ver, attempts to make durable, high strength concre-te-like
materials fro sulphur cements have encountered cost, durability, or other
difficulties that precluded cc~nnercialization. Propo&als have been made to
increase the strength oE suLphur as a bonding agent by the adcli.tion of coal,
sand or pumice thereto. ~oreover pecuk~r cllarac-teris-tics were proposed to
be impart~d by the addltion there-to of bi-tumens, me-talllc sulphides, and
fibrous matel-ials. ~Iso United States Patent No. 3,459,717 patented ~ugust
5, 1969 b~ J.s~ Signouret, provided a sulphur-based plastic com~osition of
.improved firep.roofing characteristics by the incorpora-tion, into the molten
suLphur, of a dies-ter of dithiophosphoric acid and an ethylellic hydrocc~rbon.
C~ )n~ z~l tl cr~
~ major problem in the-c6nnQr~i~l~ti~n oE s~phur ce~ents has been the pro-
gressive em~ittlement and subsequent cr~nbling, ul~l~r thermal stress, of
~e s~phur cement. The cause of this en~rittlement is believed to be the
progressive crystallization of the initially amo.rphous suLphur. Partial
inhibi-ti.on of -the crystallization has been achieved through various organic
and inorgr~lic additives.
Thiokol products ~Trade Mark of Thiokol Chemical Corporation for
oleiin polysulphides) have been used to stabilize the amorphous form of sul-
phur in sulphur cements. mus, Canadian Patent No. 356,181 issued February
25, 1936 to W.W. Duecker, purports to provide a solution to the problem hy
dissolving, in the sulphur, certain olefin pc>lysulphides or polymerization
~;~, "~, - 1 - ~
products thereof. These cements, h~wever, were not practical on a large
scale due to their high cost and disagreeable odor. Dicyclopentadie~e has
good stabili~ation properties and more favourable economics, but in~arts a
nauseating odor to ~e sulphur cen~lt and has other shortcomings, e.g.,
its vapour, even at low concentrations, is highly toxic [see, for exa~ple,
Kinkead et al, "The M2mm~1ian Toxicity of Dicyclopentadiene", Tbxicology
and Applied Pharmacology, 20 552-561 (1971)]. ~loreover, dicyclopentadiene
requires refluxing with molten sulphur to;avoid excessive loss of material
in vapour ~orm.
An object of one aspect of this inveJntion is to provide a sulphur
ce~nt composition which does not suffer the disadvantages of the con~osi-
tions of the prior art.
An object of another aspect of this invention is to provide a more
durable suiphur cement.
An object of yet another aspect of this invention is to provide
a sulphur cement which can be made ~1ith off-~ade sulphur.
An object of still another aspect of this invention is to provide
a sulphur cement which i.s resistant to the cor~osive influence of salts,
most acids and solvents.
An object o a further aspect of this invention is to provide a
sulphur cem~t which provides good the~mal insulation ~d which develops
high strength without hours o cooling.
An object of yet a urther aspect of this invention is to provide
sulphur concretes made with the sulphur cements, which are self-exting~is,~-
ing.
By one broad aspect of this invention, a sulphur cement pre-mix
composition is provided consisting essentially of (a) sulphur; (b) a
.~
bonding agcnt which is adapted to stabilize thc sulphur ccment against pro-
gressivc cmbrittlcment and mcchanical failure undcr thcrmaI or physical
stress, the bonding agent comprising a viscosity incrcasing, surface actlve,
finely divided, particulate solid inorganic agent, thc inorganic agent being
of a size passing through a screen having a sieve opening of 0.005-0.147 mm,
and being selected from the group consisting of tly ash, dolomite, pulverized
limestone and a mixture of pyrites and pyrrhotites, wherein for each 100
parts by weight of sulphur, there are 10 to 150 parts by weight of the agent,
and an additive to provide fire resistance.
By another aspect, the present invention provides a sulphur cemcnt
composition consisting essentially of: (a) sulphur which has bcen melted,
and which con~:ains dispersed the melt (b) a bonding agent which is adapted
to stabilizc thc sulphur cernent against progressive cmbrittlcmcnt and mech-
anical failure under thermal or physical stress, the bonding agent comprising
a viscosity increasing, surface active, finely divided, particulate solid
inorganic agent, the inorganic agent being of a size passing through a screen
having a sieve opening of 0.005-0.147 mm, and being selccted from the group
consisting of fIy ash, dolomite, pulverized limcstonc and a mixture of pyrites
ard pyrrhotites, wherein for each 100 parts by weight of sulphur, therc are
10 to 150 parts by weight of the agent; (c) and an additivc to provide firc
resistance.
8y a variant of these two aspects oE this invention, at least 10%
by weight of~the particuLate solid inorganic material is unfragmented fly
ash, substantially all in the range of 0.005-0.147 mm; and the premix com-
position is convertible into shaped hard products of high compressive strength.
By another variant thereof, the particulate inorganic agent is of
a size passing through a screen having a sieve opening of 0.047 mm.
By yet another variant thereof, the particulate inorganic agent
consists entirely of fly ash.
By still another variant thereoE, the additive to provide fire
resistance comprises 1,5,9-cyclododecatriene.
By a still further variant thereof, the additive to provide fire
resistance comprises the reaction product of diphenoxyphosphinic acid with
sulphur and with ~-methyl styrene.
By another aspect of this invention, a sulphur concrete is pro-
vided comprising:(A) a sulphur cement pre-mix composition consisting essen-
tially of (a) sulphur and (b) a bonding agent which is adapted to stabilize
the sulphur cement against progressive embrittlement and mechanical failure
under thermal or physical stress, the bonding agent comprising a viscosity
increasing, surface active, finely divided, particulate solid inorganic a
agent, the inorganic agcnt being of a size passing through a screen having
a sieve opcning of 0.005-0.147 mm, and being selected from the group con-
sisting of fly ash, dolomite, pulverized limestone and a mixture of pyrites
and pyrrhotites, wherein for each 100 parts by weight of suLphur, there are
10 to 150 parts by weight of the agent and (c) an additive co provide fire
resistance; and (B) natural or manufact-lred aggregates.
By another aspect of this invention, a sulpl--lr concrete is provided
comprising:(A) a sulphur cement composition consistil-g essentially of (a)
sulphur which has been melted and which concains dispers~c~ in the melt, (b) a
bonding agent which is adapted to stabilize the sulphur cement against pro-
gressive embrittlement and mechanical failure under thermal or physical
stress, the bonding agent comprising a viscosity increasing, surface active,
finely divided, particulate solid inorganic agent, said inorganic agent being
of a size passing through a screen having a sieve opening of 0.005-0.147 mm,
and being selected from the group consisting of fly ash, dolomite, pulverized
limestone and a mixture of pyrites and pyrrhoCites, wherein for each 100
parts by weight of sulphur, there are 10 to 150 parts by weight of the agent, and
(c) an additive to provide fire resistance; and (B) natural or manufactured
aggregates.
_ 4 -
By still another aspect of this invention, a sulphur concrete
product is provided, composed of (B) natural or manufactured aggregates
distributed in (A) a solid matrix composecl of a sulphur composition consis-
ting essentially of (a) sulphur (b) 20% to 80% by weight, based on the total
composition weight, of a bonding agent which is adaptecl to stabilize the
sulphur cement against progressive embrittlement and mechanical failure under
thermal or physical stress, the bonding agent comprising a viscosity in-
creasing9 surface active, finely divided, particulate solid inorganic agent,
the inorganic agent being of a size passing through a screen having a sieve
opening of 0.005-0.147 mm, and being selected from the group consisting of
fly ash, dolomite, pulverized limestone and a mixture of pyrites and pyrr-
hotites, wherein for each 100 parts by weight of sulphur, there are 10 to 150
parts by weight of the agent, and (c) an additive to provide fire resistance.
By a variant thereof, the ratio of aggregate (B) to sulphur cement
(~) is 80-36:20-6~.
By another variant thereof, the additive to provide fire resistance,
is e.g~ 1,5,9-cyclododecatrene or the reaction product of diphenoxyphosphinic
acid with sulphur and with ~ -methyl styrene.
By a further variant thereof, the particulate, inorganic agel-t is
of a size passing through a screen having a sieve opening of 0.074 mm.
By still another variant thereof, the particulate, inorganic agent
consists entirely of fly ash of a size passing through a screen having a
sieve opening of 0.147 mm.
By yet another variant thereof, the least 10% by weight of the
particulate solid inorganic material is unfragmented fly ash substantially
all in the range of 0.005-0.147 mm; and wherein the concrete is convertible
into shaped hard products of high compressive strength.
- - 4a -
The present invention in one of its aspects provides a sulphur
cement which can be used for the manufacturc of a sulphur concrete having
numerous applications in the construction ~ield. It is substantially free
from the disadvantages of the proclucts describcd previously and has positive
advantages, as will be described hereinafter.
The sulphur cement according to one aspect of this invention as
described above employs, as the stabilizer, the particularly recited viscosity
increasing, surface active; finely divided particulate inorganic stabilizer.
~! - 4b -
The chcmical stabilizer used in sulphur ccment compositions dcs-
cribed herein is any of the olefinic hydrocarbon polymers dcriv~cl from pct-
roleum having a non-volatile c(ntcnt greater than 50% by weight and a minlmum
Wijs iodine number of 100 cg/g capable of reacting with sulphur to form a
sulphur-containing polymer. Typically, the chemical stabilizer is used in
amounts up to 100% by weight of the total sulphur, and more especially in the
proportion of 1 - 5~/u of the total sulphur by weight. The amount of such
chemical stabilizer required depends upon the end use of the cement and the
properties desired.
The chemical stabilizer can be incorporated into the final cement
mix by several reaction routes within the ambit of this invention. Prefer-
ably, the chemical is prereacted at approximately 140C. for 30 minutes with
a smallcr proportion of sulphur than is required in the final mix. The
resulting concentrate can then be either stored for future use or dissolved
in the residual sulphur (liquefied) required for the final mix at the mixing
temperature.
While any chemical stabilizer having the above properties may be
used, typical such chemical stabilizers are those kno~n by the following
Trade Marks: RP220, a product of Exxon Chemical Co.; RP020, a product of
Exxon Chemical Co.; CTL~, a product of En~ay Chcmical Co.; and Escopol, a
product of Esso Chemical AB (Sweden); all identifying a heat reactive ole-
finic liquid hydrocarbon obtained by partial polymerization of olefins.
In order to provide a sulphur-containing cement of aspects of this
invention having a worlcable consistency, it is necessary to add a finely
divided, viscosity increasing material, for example, fly ash, gypsum, dolo-
mite, pulverized limestone, a mixture of pyrites and pyrrhotites, or rock
dust of a size up to minus 100 mesh, but preferably of a size of minus 200
mesh. Fly ash from the burning of hydrocarbon fossil fuels and generally
in the form of tiny hollow spheres called cenospheres and consisting of
major amounts of silicon oxide and aluminum
- 5 -
oxide, with smaller quantît:~es of ferric oxide, calcium oxide, magnesiumoxide, sodlum oxide, potassium oxide and carbon, ls partlcularly effec-
tl~e ln this regard due to its small particle slze, shape and s~rface
texture. It has been found to impart an extra measure of durability to
the final cement, independent o~ its source? and serves the dual func-
tion of viscosity increaser and sulphur cement stabilizer. Depending
upon the degree of fineness of the fly ash and the consistency desired,
an amount up to one and one-half ti~es the total weight o~ the sulphur
may be beneficially added.
A notable feature of the sulphur cement o~ aspects of this
invention is that such sulphur cement does not require high purity sul-
phur and can be made with off-grade sulphur contain:Lng hydrocarbon
:impurities, blow dirt, and other ~'contaminants". The presence of
hydrogen sulphide (H2S) in the sulphur has been determined to be detri-
mental, but the simple process of remelting the sulphur usually reduces
the concentration of this contaminant to harmless levels.
The resultîng cement of an aspect of this invention is substan-
tially resistant to the corrosive in1uences of salts, most acids, and
solvents. Hot oxidizing acids at high concentrations and strong concen-
trated bases do attack the cement, however. The cement is essentiallyimpervious to moisture penetration. It provldes good thermal insulation,
is used hot with no water, and develops high strength within hours of
cooling. Thus, sulphur concrete pouring can take place in winter without
the usual freezing problems of conventional portland cement concretes,
which require the presence of water for setting.
A wide range of aggregates can be used with the sulphùr cement
of one aspect of this invent;on as described above, to make strong,
durable concretes of another aspect of this invention. Among the conven-
tional aggregates useful herein for preparing the concrete of another
aspect of this invention are sand, crushed cinders, brick dust, foundry
sand, crushed quartzite gravel, crushed limestone, siliceous tailing sand,
expanded shale, e~panded cla~, crushed barite, crushed brickj crushed
3~
portlancl cement concrete, and eru~hed grani-te. Preferably, the aggreyate
par-ticles are of anguLar shape and of rough .s~lrface -texture as can be ob,
talned by erushing. With a suffieiently fluid nLLX, or through use oE héated
molds, -the rrold surfaees are reprocluced preeisely. Where sulphur is readily
availahle, the cement and the concrete of aspeets of -tl~s inven-tion can ke
produeed at compe-titive cos-ts. The e~npatibility of the sulphur eement with
aggregates of wide ranging densities permits the design of concretes having
very wide ranges of densities ranging, for example, as low as 10 lbs. p~r
cubic foot, to ranges between 100 Lbs. per eubic foot and 230 lbs. per eubie
foot, or even as high as 530 lhs. per eubie foot. The suLphur eoncrete of
an aspect of this invention ean be re.inforeed in eonventional fashion by
the use of steel, a.sbestos or glass fibre, or other reinforcing.materials.
lhe sulphur concre-tes of aspects of this invention t~nd to be self-
extinguishin~ with ash )ntents approaehing two~thirds the ~eight of s-LLphur
and ean be made fire resistan-t, and/or to inhibit the formation of S02 when
heated, by the addition of suitable additives, e.g., 1,5,9-eyelododeeatriene
or the reaetion produet of dipheno~yphosphir~ie aeid with s~Lphur and v~~me-
~hyl styrene
The suLphwr eoneretes of anot-~her as~et o -this invellti~l derived
Erom the sulphur eements of a first a~speet of this .inven~ion are not refrac-
tory n~teri.als arlcl w:ill softerlc~r~:l melt if }~lted above :L~0C., altho~l~h the
rate of melting is slow due to the low -thermal eon~uetivity i~ar-ted to the
eonerete by the suLphur.
I'he prine.iples developed for the grading of aggregates used .in eon-
ventional eoneretes are essentially unehanged for sulp.hur eoneretes of
aspeets of this invention except for the much greater -tolerance of fines and
silt of the sulph~r concretes. 80% of the ultirnate concre-te stren~th is de-
veloped in one day; virt~ally 100% of ~he uLti~.ate strength is realized after
four days.
3Q T~ese sL~Lphur eoncretes may be used as a construction rnaterial
,;~
7 -
for a wide variety of precast and poured-in-place applications such as,
for example~ sidewalks, steps, parking curbs, highway medlan barriers,
sewer pipe, septic tanks, pilings, eootings, fotmdations, pavements,
industrial tanks, ponds, swimming pools,etc. The hot sulphur concrete
mix may also be pumped and sprayed for waterproof and erosion proof
coatings on earth-fill di~es, highway and railway embankments and as
linings for irrigation canals, farm ponds~ etc.
The examples given below are intended only to illustrate aspects
of the present invention.
Samples 1 - 7. Prereaction of the Hydrocarbon Stabilizers
The hydrocarbon stabilizer (at 25C.) was added to molten
sulphur (at 140C.) with vigorous stirring. Ileat was applied only to
maintain a reaction temperature of 1~0 to 150C. ~t this temperature
reaction titnes were in the order of 15 to 40 minutes. The progess of
the reaction could be monitored by the degree of homogeneity of the mix,
by careful observation of the temperature of the reaction mixture, or
by observation of the increasîng viscosity of the mixture. At sulphur-
stabili~er ratios of less than 4:1 by w~ight, control o the addition
rate was required to prevent ~he exothermici~y of the reactions raising
temperatures abo-ve 155C., at which point hydrogen sulphide (~12S) was
evolved with consequent oaming and degradation of the product~
When reactions were conducted under the above-prescr-Lbed con-
ditions, the product was a sulphur-containing polymer which, on cooling,
possessed glass-like properties which were retained indefinitely.
The properties of the olefinic hydrocarbon poiymers used for
illustrative purposes herein are given in Table 1. Reaction conditions
for the preparation of seven sulphur-containing polymers are contained
in Table 2.
'Table 1
'RP220 RP020 CTLA Escopol
Flash Point (COC) minlmum 150 138 150 125
Gravity (API) maximum 4 4.0 9.6 3
Iodine Number (lOOcg/g) minimum 200 160 255 135
Non-volatile Matter (~ by weight) 80 70 83 75
(3 hrs. @ 105C) minimum
Density (15.6C.) gm/cc 1~05 1.04 1.00 1.03
Viscosity (cst/100C) maximum 25 26 23 25*
*cst/sooc .
Ta~le 2
Reaction Conditions for the
Rreparation of Sulphur-con_a'ining'Polymers
Stabilizer ~ Reaction Reaction Product
Sample (STB? STB _ S Temp.(C)' Tlmé tMin~ Colour
1 CTLA 12.5 37.5 140 30 dark brown
2 CTLA 8.3 41.7 140 40 dark brown
3 Escopol10.0 40.0 150 15 light brown
4 Escopol14.5 35.5 140 20 light brown
RP220 8.3 41.7 150 15 dark brown
6 RP22012.5 37.5 140 20 dark brown
7 RP02012.5 37.5 140 15 dark brown
~ l to ~ ~ Sulphur Ce~ents and Concretes Derived I~erefrom
-
A first series of sulphur cements, Examples 1 through 9, were
prepared by addition of: the required sulphur (less than contained in
the prereacted material), the prereacted material, and lastly, fly ash
to achieve the desired consistency of the sulphur cement. Then the
aggregate was added to provide the sulphur concrete.
The components were mixed at 130C. in a heated ll3 cubic foot
concrete mixer for 15 minutes before pouring into molds. Compaction was
obtained through vibration or tapping of the molds. For simplicity of
representation, all the examples are chosen using RP220 as the hydrocar-
bon stabilizer.
Examples_ 0 to l3
A second series oE sulphur cements and sulphur co~cretes was
prepared in a manner analogous to that of Examples 1 to 9 with vhe
exception that raw stabilLzer ~i.e. not prereacted with sulphur) was
added directly ~o the mix at ~he previous point of prereacted material
addition. In order to allow complete reaction, the mixing time was
increased to 20 minutes.
Examples 14 to 22
A third series of sulphur cements and sulphur concretes were
prepared in a manner analogous to that of Examples 1 to 9 but ~ th the
omission of the hydrocarbon stabilizer. Sulphur concretes prepared
according to these mix designs would be limited to reasonably isothermal
applications, such as underground or underwater structures subjected to
very mild thermal cycling.
The results are summarized and tabulated below in Table 3.
-- 10 -`
r~ 3
Su~lur Concretes - Com~o.sltioll and l~ tie~
Chemical
Stabi- Compres-
Exam- Ag~re-- lizer 1)ensity sive*
ple gate_ Sulptlur Fly Ash ~'220 ( ~ c) Strength
1 Crushed quart~ite 71.720.4 7 4 0.502.38 7,160
~ravel
2 Cruslled limestone 73.5 26 - 0.502.41 5~290
3 Siliceous tailings 63.534.8 - 1.72.21 5,290
sand
4 Expanded shale 38.637.6 23.2 0.591.73 4,610
Expanded clay 38.4 32.029.2 0.38 1.778,350
6 Crushed barite 78.715.0 5.9 0.38~.18 7,520
7 Crushed brick 54.5 27.317.5 0.68 2.l78,530
8 Crushed ~ortland 64.124.1 11.2 0.602.23 5,690
cement co~cre-te
9 Crushed granite 65.920.0 12.6 0.502.39 7,760
Crushed quart~ite 64.419.6 15.5 0.492.38 8,710
gravel
11 Siliceous tailings 60.930.8 7.5 0.772.23 6,530
sand
12 Expanded shale 50.026.6 22.7 0.661.70 4~740
13 Crushed barite 79.113.2 7.4 0.333.28 7,650
20 14 Crushed qu.lrt~lte 65.6L8.8 15.6 -- 2.40 9,270
~ravel
Crushed limestolle 60.821.8 17.4 - 2.32 7,730
16 Cruslled ~ranltc 66.221.2 12.6 - 2.37 8,250
17 Crushed barite 79.612.8 7.6 _ 3.25 7,570
18 Siliceous tailings 61.234.8 4.0 - 2.20 6,420
sand
19 Ex~anded shale 35.835.8 28.4 - 1.68 4,860
Expanded clay 41.0 34.025.0 - 1.799,320
21 Crushed brick 55.0 27.417.6 - 2.1810,130
22 Crushed portland 64.823.0 12.2 - 2.24 7,840
c~r?~t concrete
* Mean of three (3) tests.
