USRE31682E - Process for manufacturing concrete of high corrosion resistance - Google Patents
Process for manufacturing concrete of high corrosion resistance Download PDFInfo
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- USRE31682E USRE31682E US06/431,097 US43109782A USRE31682E US RE31682 E USRE31682 E US RE31682E US 43109782 A US43109782 A US 43109782A US RE31682 E USRE31682 E US RE31682E
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- cement
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- silica
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Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B7/00—Hydraulic cements
- C04B7/02—Portland cement
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00034—Physico-chemical characteristics of the mixtures
- C04B2111/00215—Mortar or concrete mixtures defined by their oxide composition
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Definitions
- the present invention relates to the manufacture of corrosion resistant concrete compositions having especially high resistance against attack from concentrated salt solutions such as nitrates, chlorides and sulfates.
- pozzolana additives are known to improve the corrosion resistance to some degree.
- Pozzolana consists of finely divided, pulverized, silica-containing fillers which, apart from filling the pores of the concrete, to some degree also acts as a binding agent for the lime component, Ca(OH) 2 . The latter is formed during the hardening of the concrete whereby less soluble and more resistant compounds are formed.
- Commonly used pozzolanas are made from fly ash which contains varying amounts of carbon (1-20%). The presence of carbon, however, is rather unfavourable since it causes more shrinking of the concrete.
- natural pozzolanas like diatomite, etc. are also used. Most of the natural pozzolanas, in addition to amorphous silica also contain large amounts of iron oxides and alumina. Some compounds, being inactive in the natural state, can be activated by calcination. Addition of pozzolana is known to improve the concrete's ability to resist attacks from sea water and other aqueous liquids. It has also been suggested that the addition of pozzolana might prevent reaction between the alkaline components of the cement and the alkali sensitive skeleton, the latter being responsible of the binding capacity of the concrete. However, particularly with respect to the resistance to corrosion in salt-containing and other strongly corrosive environments, no concrete composition is known which possesses a sufficiently effective protection against corrosion.
- reactive silica is silica fines recovered during the purification of flue gases from melting furnaces in the manufacture of ferrosilicon.
- U.S. Pat. No. 2,410,954 discloses a hydraulic cement modified by incorporating 3-5 weight percent of highly reactive silica of the above mentioned type. According to the patent, this addition makes the cement particularly suited for making mortar, stuccature, etc.
- reactive silica as a filler in cement in amounts of up to 10 weight percent, based on the weight of the cement.
- the main object of the present invention is to provide a new and improved method of manufacturing concrete of such a high corrosion resistance that it will be resistant also in the most corrosive environments such as, e.g., concentrated nitrate salt solutions.
- the improved method of manufacturing concrete according to the present invention comprising that a concrete mixture is made using a low aluminate cement, preferably comprising less than 5 weight percent of aluminate (C 3 A), and that at least 10 weight percent of finely divided, reactive silica is added, blended and uniformly distributed in the concrete mixture in order to react completely with calcium hydroxide formed in connection with the hydration of the calcium silicates contained in the cement, whereupon the concrete is cast and subjected to aftertreatment in the usual known manner.
- a concrete mixture is made using a low aluminate cement, preferably comprising less than 5 weight percent of aluminate (C 3 A), and that at least 10 weight percent of finely divided, reactive silica is added, blended and uniformly distributed in the concrete mixture in order to react completely with calcium hydroxide formed in connection with the hydration of the calcium silicates contained in the cement, whereupon the concrete is cast and subjected to aftertreatment in the usual known manner.
- a further object of the present invention is to provide a cement composition
- a cement composition comprising 70 to 90 parts by weight of low aluminate cement, 10 to 30 parts by weight of reactive silica as well as minor amounts of commonly used cement additives, such as, e.g., dispersing agents.
- low aluminate cement a cement which has low aluminate (C 3 A) content, preferably less than 5 weight percent.
- compositions were prepared according to the invention using different amounts of the reactive silica, in Series I using 0% and 10% silica, and in Series II using 0, 5, 10, 15, 20, 25 and 40% silica, by weight calculated on the cement.
- Type 1 SR-cement (sulfate resistant cement): 55% 3 CaO.SiO 2 (C 3 S), 20% 2 CaO.SiO 2 (C 2 S) 1.6% 3 CaO.Al 2 O 3 (C 3 A) and 15.2% 4 CaO.Al 2 O 3 .Fe 2 O 3 (C 4 AF) (Common abbreviations used below are given in brackets).
- Type 2 Ordinary Portland cement PC 300: 60% C 3 S, 14% C 2 S, 8.5% C 3 A, and 9% C 4 AF
- the sand composition used had the following specifications:
- the blending operation was performed with two constant water/cement (w/c) ratios, viz., 0.45 and 0.75.
- the blending of the cement and sand was performed such that the consistency was 10 cm slump.
- the concrete compositions in the test series represent the mortar part of the concrete in a common quality range.
- the prisms were stored vertically in saturated salt solutions, the liquid level of which reached half way up on the prisms, without being in contact with the undissolved salt crystals at the bottom of the container. For control tests another set of prisms were completely submerged.
- the test pieces were cured in water at 20° C. for 28 ⁇ 4 days before being exposed to a saturated calcium nitrate solution at about 20° C. This solution was selected because it was found to give extreme corrosion.
- the calcium nitrate used contains in solid form 85% NH 4 NO 3 .5 Ca(NO 3 ) 2 .10 H 2 O and 15% Ca(NO 3 ) 2 . On the average, 10 weight percent of silica was added, based on the amount of cement used.
- This series comprised about 800 specimens in the form of mortar prisms having the dimensions 4 cm ⁇ 4 cm ⁇ 16 cm which were cured for 28 ⁇ 3 days in water at 20° C. and then dried for 50 ⁇ 3 days at 20° C. and 50% R.H. before being exposed to salt solutions which, in addition to nitrate salt solutions also comprised sulphate and chloride salt solutions.
- Corrosion attacks can be attributed to a combination of two mechanisms:
- the calcium nitrate formed reacts gradually with hydrated calcium aluminate, for instance in the following way:
- This reaction product corresponds to an increase in volume, which will break down the concrete and cause cracks in the structure.
- Equation 2 the reaction product according to Equation 2 is tobermorite which is the most important binding agent of concrete.
- the increase in the strength of the concrete confirms that the latter reaction (Equation 2) occurs.
- SiO 2 10-25 weight percent of SiO 2 (based on the weight of cement) should be added to the commercial-cement qualities tested.
- positive effects are obtained also by using smaller amounts.
- silica amounts 5 10, 15, 20, 25 and 40 percent in our experiments (cf. the above), and obtained satisfactory results in the most aggressive and corrosive environments. In practice, an upper limit of 30% SiO 2 will be used.
- the active components may be added individually from separate supplies.
- the said objects are attained and, at the same time, the handling and dosing of the silica fines is improved by means of a specific additive composition particularly suited for use in the preparation of the concrete.
- This composition is prepared separately and is packed in suitable bags and the like. During the preparation of the concrete, further cement low in aluminate is added until optimum weight ratios have been obtained.
- the said additive composition has the following formulation:
- a preferred floor concreting composition has the following formulation:
- composition is packed and used as an additive in a SR-cement (having C 3 A ⁇ 5%) in an amount of 20% calculated on the cement weight.
Abstract
Concrete having high resistance to corrosion is prepared by using low aluminate (C3 A) cement, preferably having less than 5 weight percent of aluminate, and, in addition to conventional concrete constituents, at least 10 weight percent of finely divided, reactive silica based on the cement weight.
A highly corrosion resistant cement composition comprises, in addition to conventional cement constituents, 70-90 parts by weight of low aluminate cement and 10-30 parts by weight of reactive silica.
An additive useful for making concrete highly corrosion resistant comprises 80-90 weight percent of reactive silica, 0-10 weight percent of low aluminate cement, 3-8 weight percent of formaldehyde condensed sodium sulfonate, 3-8 weight percent of lignosulfonate.
Description
This is a reissue application of U.S. 4,118,242 which matured from Ser. No. 815,418, filed July 13, 1977. .Iaddend.
The present invention relates to the manufacture of corrosion resistant concrete compositions having especially high resistance against attack from concentrated salt solutions such as nitrates, chlorides and sulfates.
Concrete made from the most common types of hydraulic cement, such as Portland cement, are known to be relatively resistant to corrosion in air and water and under conditions where iron and steel structures are less resistant. In more aggressive environments, e.g. by concentrated salt attacks from nitrate, sulfate and chloride solutions, the concrete surface and structures are also exposed to strong corrosion. One example exists in connection with the extensive spreading of salt on roads and other areas carrying traffic. Under Norwegian winter conditions extreme damage has been caused to the concrete in bridges, roads, etc.
Chemical process industry and the production of chemicals in bulk represent other fields where corrosion damage to concrete causes serious problems.
Today some of the most acute corrosion problems seem to be encountered in connection with concrete exposed to nitrate solutions. The concrete floors of bulk stores for nitrogenous fertilizer products, such as NPK, ammonium nitrate, calcium nitrate etc., are severely damaged within a short period. So far, little has been done in explaining the mechanism of this corrosion. Instead one has tried to protect the most exposed surfaces by special coatings, such as asphalt, synthetic resins etc. However, this has not been very successful, since the coatings have either been too expensive or have been lacking in the required resistance.
A great number of different additives and compositions are known from the prior art which are expected to improve the mechanical and chemical properties of cement and concrete. Thus, the so-called pozzolana additives are known to improve the corrosion resistance to some degree. Pozzolana consists of finely divided, pulverized, silica-containing fillers which, apart from filling the pores of the concrete, to some degree also acts as a binding agent for the lime component, Ca(OH)2. The latter is formed during the hardening of the concrete whereby less soluble and more resistant compounds are formed. Commonly used pozzolanas are made from fly ash which contains varying amounts of carbon (1-20%). The presence of carbon, however, is rather unfavourable since it causes more shrinking of the concrete. In addition to fly ash, natural pozzolanas like diatomite, etc. are also used. Most of the natural pozzolanas, in addition to amorphous silica also contain large amounts of iron oxides and alumina. Some compounds, being inactive in the natural state, can be activated by calcination. Addition of pozzolana is known to improve the concrete's ability to resist attacks from sea water and other aqueous liquids. It has also been suggested that the addition of pozzolana might prevent reaction between the alkaline components of the cement and the alkali sensitive skeleton, the latter being responsible of the binding capacity of the concrete. However, particularly with respect to the resistance to corrosion in salt-containing and other strongly corrosive environments, no concrete composition is known which possesses a sufficiently effective protection against corrosion.
From the patent literature it is known per se to use finely divided, amorphous SiO2 of the reactive type formed by sublimation and quenching of silica-containing raw-material, as additives to cement compositions. One example of this type of reactive silica, in the following termed "reactive silica," is silica fines recovered during the purification of flue gases from melting furnaces in the manufacture of ferrosilicon.
U.S. Pat. No. 2,410,954 (Sharp) discloses a hydraulic cement modified by incorporating 3-5 weight percent of highly reactive silica of the above mentioned type. According to the patent, this addition makes the cement particularly suited for making mortar, stuccature, etc.
Finally, it is also known in the art to use reactive silica as a filler in cement in amounts of up to 10 weight percent, based on the weight of the cement.
The main object of the present invention is to provide a new and improved method of manufacturing concrete of such a high corrosion resistance that it will be resistant also in the most corrosive environments such as, e.g., concentrated nitrate salt solutions.
Said object is attained by the improved method of manufacturing concrete according to the present invention: the improvement comprising that a concrete mixture is made using a low aluminate cement, preferably comprising less than 5 weight percent of aluminate (C3 A), and that at least 10 weight percent of finely divided, reactive silica is added, blended and uniformly distributed in the concrete mixture in order to react completely with calcium hydroxide formed in connection with the hydration of the calcium silicates contained in the cement, whereupon the concrete is cast and subjected to aftertreatment in the usual known manner.
Further specific features of the present method will appear from the following disclosure.
A further object of the present invention is to provide a cement composition comprising 70 to 90 parts by weight of low aluminate cement, 10 to 30 parts by weight of reactive silica as well as minor amounts of commonly used cement additives, such as, e.g., dispersing agents.
By the term "low aluminate cement" a cement is meant which has low aluminate (C3 A) content, preferably less than 5 weight percent.
Concrete compositions were prepared according to the invention using different amounts of the reactive silica, in Series I using 0% and 10% silica, and in Series II using 0, 5, 10, 15, 20, 25 and 40% silica, by weight calculated on the cement.
There were used two types of cement, one low in aluminate, i.e., about 1.6%, and the other with an aluminate content of 8.5%. The chemical compositions of these cements are specified as follows:
Type 1: SR-cement (sulfate resistant cement): 55% 3 CaO.SiO2 (C3 S), 20% 2 CaO.SiO2 (C2 S) 1.6% 3 CaO.Al2 O3 (C3 A) and 15.2% 4 CaO.Al2 O3.Fe2 O3 (C4 AF) (Common abbreviations used below are given in brackets).
Type 2: Ordinary Portland cement PC 300: 60% C3 S, 14% C2 S, 8.5% C3 A, and 9% C4 AF
The sand composition used had the following specifications:
______________________________________
Sand 0-4 mm
Retained on 4 mm sieve:
3-5%
2 mm sieve: 23-28%
1 mm sieve: 60-76%
0.5 mm sieve: 90-93%
0.25 mm sieve: 96-98%
0.125 mm sieve: 97-99%
______________________________________
The blending operation was performed with two constant water/cement (w/c) ratios, viz., 0.45 and 0.75.
The blending of the cement and sand was performed such that the consistency was 10 cm slump. Thus, the concrete compositions in the test series represent the mortar part of the concrete in a common quality range.
Corrosion tests were carried out on 544 standard mortar prisms having the dimensions 4 cm×4 cm×16 cm.
The prisms were stored vertically in saturated salt solutions, the liquid level of which reached half way up on the prisms, without being in contact with the undissolved salt crystals at the bottom of the container. For control tests another set of prisms were completely submerged. The test pieces were cured in water at 20° C. for 28±4 days before being exposed to a saturated calcium nitrate solution at about 20° C. This solution was selected because it was found to give extreme corrosion. The calcium nitrate used contains in solid form 85% NH4 NO3.5 Ca(NO3)2.10 H2 O and 15% Ca(NO3)2. On the average, 10 weight percent of silica was added, based on the amount of cement used.
Bearing in mind that lower w/c ratios provide a better resistance, the results of the tests of this series are summarized in the following Table I.
TABLE I
______________________________________
Time of
exposure
PC 300 SR-cement
months 0% SiO.sub.2
10% SiO.sub.2
0% SiO.sub.2
SiO.sub.2
______________________________________
1 Fissures Not Fissures Not
attacked attacked
2 Corrosion Not Corrosion
Not
and fissures
attacked and fissures
attacked
3 Strongly Not Strongly Not
attacked attacked attacked attacked
4 Some remain-
Not Some remain-
Not
ing compress-
attacked ing compress-
attacked
ion strength ion strength
5 Completely Fissures Completely
Not
destroyed destroyed
attacked
6 Completely Fissures Completely
Not
destroyed destroyed
attacked
10 Completely Cracks Completely
Not
destroyed destroyed
attacked
14 Completely 70% of the
Completely
15% of the
destroyed test pieces
destroyed
test pieces
strongly attacked
attacked
______________________________________
Apart from ocular tests and inspection of photographs, compression strength values were also measured in connection with these tests. These measurements verify the data stated in Table I.
On the basis of the ocular tests were have reached the conclusion that SR-cement+10% SiO2 provides a durability 10 times that of normal concrete.
However, we found for PC 300 as well as for SR-cement a slightly decreasing compression strength (after 6 months and, in particular, after 10 months).
This indicates that adding 10% SiO2 is not sufficient and that the optimum amount must be somewhat higher. Said estimate is also supported by our theoretical calculations based on the chemical reaction equations and the experiments of Series II given below.
This series comprised about 800 specimens in the form of mortar prisms having the dimensions 4 cm×4 cm×16 cm which were cured for 28±3 days in water at 20° C. and then dried for 50±3 days at 20° C. and 50% R.H. before being exposed to salt solutions which, in addition to nitrate salt solutions also comprised sulphate and chloride salt solutions.
In contrast to Series I, two thirds of the prisms were now stored vertically, the saturated salt solution reaching half way up on said prisms, but the lower 2 cm thereof were actually immersed in the salt sludge.
The remaining one third of the specimens were completely immersed in the salt sludge. The same materials as in Series I were utilized and the consistency was 5-6 cm slump.
Due to the amount of SiO2 fines addition being systematically varied, viz., 0-5-10-15-20-25-40% SiO2, calculated on the total amount of cement, it was not possible to maintain a constant w/c factor. Two constant mixing ratios of cement:sand=1:2 and 1:3.3 were selected, which, at the selected consistency, provided the following w/c ratios:
______________________________________
Mixing ratio
SiO.sub.2 addition in %
Cement sand
0 5 10 15 20 25 40
______________________________________
1:2 0.39 0.41 0.44 0.53 0.61 0.72 1.15
1:3.3 0.52 0.56 0.61 0.70 0.79 0.91 1.44
______________________________________
9 months have passed since the specimens of Series II were exposed to aggressive materials. In chloride and sulfate solutions attacks have been recorded for 0 and 5% SiO2 additions under storage in sulfate and calcium chloride solutions, whereas, obviously, more time is needed for the higher additions.
For the above indicated storage conditions in calcium nitrate solution the results can be summarized as indicated in the following Table II:
TABLE II
______________________________________
Mixing
ratio
SiO.sub.2 cement: Exposure time in months
fines Cement sand 1 3 6 9 12 15
______________________________________
0% PC300 1:2 R S/T 0
1:3.3 VA 0
SR 1:2 R S/T 0
1:3.3 S/T 0
5% PC300 1:2 O VA VA 0
1:3.3 R VA 0
SR 1:2 O R VA 0
1:3.3 O S/T 0
10% PC300 1:2 O R VA 0
1:3.3 O S/T VA 0
SR 1:2 O O S/T VA
1:3.3 O R VA 0
15% PC300 1:2 O O O R
1:3.3 O O O S/T
SR 1:2 O O O O
1:3.3 O O O O
20% PC300/SR 1:2/1:3.3
O O O O
25% " " O O O O
40% " " O O O O
______________________________________
O = NOT ATTACKED
R = FISSURES
S/T = CRACKS/CORROSION
VA = SUBSTANTIALLY ATTACKED
0 = DETERIORATED
By studying photographs of these specimens it is found, what is previously known, that a better mixing ratio (a lower w/c factor) is advantageous and that SiO2 additives should be above 10%. At SiO2 =0 no difference between both of the indicated cement qualities is observed.
At 5% SiO2 there are indications in favour of SR-cement, and at 10% SiO2 there are significant differences.
The experiments confirm the following hypothesis behind our present work in this field:
Corrosion attacks can be attributed to a combination of two mechanisms:
1. Mere acid attacks caused by the reaction of Ca(OH)2 formed in the concrete during the hydration process--with NH4 -containing salts and thereby driving off NH3 according to the following equation:
NH.sub.4 NO.sub.3 +Ca(OH).sub.2 →Ca(NO.sub.3).sub.2 +NH.sub.3.
2. The calcium nitrate formed reacts gradually with hydrated calcium aluminate, for instance in the following way:
3 CaO.Al.sub.2 O.sub.3 +Ca(NO.sub.3).sub.2.4 H.sub.2 O→
3 CaO.Al.sub.2 O.sub.3.Ca(NO.sub.3).sub.2.10 H.sub.2 O.
This reaction product corresponds to an increase in volume, which will break down the concrete and cause cracks in the structure.
By selecting a cement low in aluminate one can secure the presence of only small amounts of aluminates, which might react with salt molecules that penetrate into the concrete. Further, the addition of silica will secure that Ca(OH)2 which always is formed as a reaction product during the hydration of calcium silicates while the concrete is curing, will not be available in connection with a starting acid attack. The silica will in fact react with Ca(OH)2 during the course of its formation. The reactions are believed to be the following:
Ca(OH).sub.2 +SiO.sub.2 →CaO.SiO.sub.2 +H.sub.2 O
3 Ca(OH).sub.2 +SiO.sub.2 →3 CaO.2 SiO.sub.2 +3 H.sub.2 O
According to these reactions further calcium silicate hydrates are formed. Thus, the reaction product according to Equation 2 is tobermorite which is the most important binding agent of concrete. The increase in the strength of the concrete confirms that the latter reaction (Equation 2) occurs. We assume that maximum corrosion resistance will be achieved when all the calcium hydroxide formed has reacted with silica and thereby has been converted to silicate. Theoretically, this means that, for optimum effect, 10-25 weight percent of SiO2 (based on the weight of cement) should be added to the commercial-cement qualities tested. However, positive effects are obtained also by using smaller amounts. We have used silica amounts of 5, 10, 15, 20, 25 and 40 percent in our experiments (cf. the above), and obtained satisfactory results in the most aggressive and corrosive environments. In practice, an upper limit of 30% SiO2 will be used.
In the manufacture of the concrete according to the invention the active components may be added individually from separate supplies.
Adding SiO2 fines alone, however, provides a significant increase in the water demand and water/cement ratio, as well as a certain increased shrinkage. The said drawbacks can be overcome and the concrete quality improved by adding dispersing agents and other commercially available concrete additives to the SiO2 fines.
According to the invention the said objects are attained and, at the same time, the handling and dosing of the silica fines is improved by means of a specific additive composition particularly suited for use in the preparation of the concrete. This composition is prepared separately and is packed in suitable bags and the like. During the preparation of the concrete, further cement low in aluminate is added until optimum weight ratios have been obtained.
The said additive composition has the following formulation:
80-90 weight percent of reactive silica
0-10 weight percent of low aluminate cement
3-8 weight percent of Lomar D®(formaldehyde condensed sodium sulfonate)
3-8 weight percent of lignosulfonate
A preferred floor concreting composition has the following formulation:
80 weight percent of SiO2 fines
10 weight percent of SR-cement containing 1.6% C3 A
5 weight percent of Lomar D
5 weight percent of lignosulfonate.
The composition is packed and used as an additive in a SR-cement (having C3 A<5%) in an amount of 20% calculated on the cement weight.
With 300 kg cement per m3 concrete+60 kg additive as stated above, the water/cement ratio was reduced from 0.64 to 0.45 and the compression strength after 28 days increased from 330 kg/cm2 to 850 kg/cm2.
Per se, it is possible to avoid completely the content of cement low in aluminate in the above mentioned additive composition and instead optimize the composition by varying the amounts of the other stabilising additives.
Claims (13)
1. In a method of manufacturing concrete having resistance to corrosion, which comprises mixing cement, sand.[.,.]. .Iadd.and .Iaddend.water, .[.reactive silica and, optionally, conventional concrete additives,.]. the improvement wherein the cement has a low aluminate content, and at least 10 weight percent of finely divided, .[.nonpozzolanic,.]. reactive silica .Iadd.formed by sublimation and quenching of a silica-containing raw material.Iaddend., based on the weight of the cement, .Iadd.and an effective amount of an additive to reduce the increase in water demand caused .Iaddend.by said silica, .[.is.]. .Iadd.are .Iaddend.incorporated in and distributed uniformly throughout the concrete.
2. .[.A.]. .Iadd.The .Iaddend.method according to claim 1, wherein the cement has an aluminate content of less than 5 weight percent based on the weight of the cement.
3. .[.A.]. .Iadd.The .Iaddend.method according to claim 2, wherein the reactive silica is added to the concrete in an amount of 10-30 weight percent based on the weight of the cement.
4. .[.A.]. .Iadd.The .Iaddend.method according to claim 2, wherein the reactive silica is added to the concrete in an amount of 10-25 weight percent based on the weight of the cement.
5. .[.A.]. .Iadd.The .Iaddend.method according to claim 2, wherein the reactive silica is added to the concrete in an amount of 15-25 weight percent based on the weight of the cement.
6. .[.A.]. .Iadd.The .Iaddend.method according to claim 2, wherein the cement is sulfate resistant cement having an aluminate content of 1.6 weight percent and further containing 55 weight percent of 3CaO.SiO2, 20 weight percent of 2CaO.SiO2 and 15 weight percent of 4CaO.Al2 O3.Fe2 O3.
7. .[.A.]. .Iadd.The .Iaddend.method according to claim 2, wherein the reactive silica is silica fines recovered during purification of flue gases from a melting furnace used in manufacturing ferrosilicon.
8. A cement composition having corrosion resistance, comprising 70-90 parts by weight of cement having a low aluminate content, 10-30 parts by weight of .[.nonpozzolanic,.]. reactive silica .Iadd.formed by sublimation and quenching of a silica-containing raw material .Iaddend.and, .Iadd.an effective amount of an additive to reduce the water demand of the cement composition caused by said silica when employed .Iaddend.to produce concrete .[.optionally, minor amounts of conventional cement additives.]..
9. .[.A.]. .Iadd.The .Iaddend.composition according to claim 8, wherein the cement has an aluminate content of less than 5 weight percent based on the weight of the cement.
10. .[.A.]. .Iadd.The .Iaddend.composition according to claim 9, wherein the reactive silica is silica fines recovered during purification of flue gases from a melting furnace used in manufacturing ferrosilicon.
11. An additive for imparting corrosion resistance to concrete, comprising:
80-90 weight percent of .[.nonpozzolanic,.]. reactive silica .Iadd.formed by sublimation and quenching of a silica-containing raw material.Iaddend.,
0-10 weight percent of cement having a low aluminate content,
3-8 weight percent of formaldehyde condensed sodium sulfonate, and.Iadd./or .Iaddend.
3-8 weight percent of lignosulfonate.
12. .[.An.]. .Iadd.The .Iaddend.additive according to claim 11, wherein the cement has an aluminate content of less than 5 weight percent based on the weight of the cement.
13. .[.An.]. .Iadd.The .Iaddend.additive according to claim 12, comprising:
80 weight percent of .[.nonpozzolanic,.]. reactive SiO2 fines .Iadd.formed by sublimation and quenching of a silica-containing raw material, .Iaddend.
10 weight percent of sulfate resistant cement containing 1.6 weight percent of aluminate,
5 weight percent of condensed naphthalene sulfonates, and
5 weight percent of lignosulfonate.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO762401 | 1976-07-09 | ||
| NO762401A NO138112C (en) | 1976-07-09 | 1976-07-09 | PROCEDURE FOR MANUFACTURE OF CONCRETE WITH HOEY CORROSION RESISTANCE |
| KR7701593A KR820000152B1 (en) | 1976-07-09 | 1977-07-09 | Process for manufacturing concrete of nigh corrosion resistance |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US05/815,418 Reissue US4118242A (en) | 1976-07-09 | 1977-07-13 | Process for manufacturing concrete of high corrosion resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| USRE31682E true USRE31682E (en) | 1984-09-25 |
Family
ID=26626014
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US05/815,418 Ceased US4118242A (en) | 1976-07-09 | 1977-07-13 | Process for manufacturing concrete of high corrosion resistance |
| US06/431,097 Expired - Lifetime USRE31682E (en) | 1976-07-09 | 1982-09-30 | Process for manufacturing concrete of high corrosion resistance |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US05/815,418 Ceased US4118242A (en) | 1976-07-09 | 1977-07-13 | Process for manufacturing concrete of high corrosion resistance |
Country Status (24)
| Country | Link |
|---|---|
| US (2) | US4118242A (en) |
| JP (1) | JPS538617A (en) |
| KR (1) | KR820000152B1 (en) |
| AR (1) | AR216767A1 (en) |
| AT (1) | AT370063B (en) |
| AU (1) | AU507096B2 (en) |
| BE (1) | BE856653A (en) |
| BR (1) | BR7704493A (en) |
| CA (1) | CA1088110A (en) |
| CH (1) | CH633500A5 (en) |
| DE (1) | DE2730943B2 (en) |
| DK (1) | DK155727B (en) |
| ES (1) | ES460536A1 (en) |
| FI (1) | FI77013C (en) |
| FR (1) | FR2357500A1 (en) |
| GB (1) | GB1532178A (en) |
| IN (1) | IN149470B (en) |
| IT (1) | IT1081532B (en) |
| NL (1) | NL7707505A (en) |
| PH (1) | PH11956A (en) |
| PT (1) | PT66762B (en) |
| RO (1) | RO72773B (en) |
| SE (1) | SE426479B (en) |
| ZA (1) | ZA774105B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0384898A1 (en) * | 1989-02-24 | 1990-08-29 | Sandoz Ag | Cementitious material for masonry constructions |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DK151378C (en) * | 1978-11-03 | 1988-05-16 | Aalborg Portland Cement | SHAPED ARTICLES AND COMPOSITION MATERIALS AND PROCEDURES FOR PRODUCING SAME |
| US5234754A (en) * | 1978-11-03 | 1993-08-10 | Bache Hans H | Shaped article and composite material and method for producing same |
| ES8102999A1 (en) * | 1978-11-03 | 1981-02-16 | Aalborg Portland Cement | Shaped article and composite material and method for producing same. |
| NO148995C (en) * | 1979-08-16 | 1986-06-12 | Elkem As | PROCEDURE FOR MANUFACTURING CEMENTS LURRY WITH LOW WEIGHT FOR USE BY CEMENTATION OF OIL AND GAS BURNS. |
| LU82089A1 (en) * | 1980-01-16 | 1981-09-10 | Sipac | PROCESS FOR THE PREPARATION OF A CATION EXCHANGER AND METHOD FOR THE USE OF THIS EXCHANGER FOR THE EXTRACTION OF METALS FROM LIQUIDS |
| DE3165630D1 (en) * | 1980-04-11 | 1984-09-27 | Ici Plc | Cementitious composition and cement product produced therefrom |
| JPH0448743B2 (en) * | 1980-05-01 | 1992-08-07 | Denshito As | |
| US4390372A (en) * | 1980-09-23 | 1983-06-28 | Hardin George E | Dry pre-mixed mortar |
| US4465519A (en) * | 1980-09-23 | 1984-08-14 | Hardin George E | Dry mortar mix with adhesive |
| US4472201A (en) * | 1981-08-15 | 1984-09-18 | Kurosaki Refractories Co., Ltd. | Hydraulic heat-resisting material and premold product made of such hydraulic heat-resisting material |
| FR2520348A1 (en) * | 1982-01-22 | 1983-07-29 | Plat Daniel | Mortar concrete or grouting mixt. - contg. finely powdered sodium aluminosilicate or hydrated silica providing resistance to corrosion and increasing strength |
| DE3215777C2 (en) * | 1982-04-28 | 1985-11-28 | Alex Dr. 6000 Frankfurt Gregor | Dry mix for a cement flow mortar |
| NO153566B (en) * | 1982-12-07 | 1986-01-06 | Elkem As | ADDITIONAL MIXTURE FOR CONCRETE AND MORTAL, PROCEDURE FOR PREPARING THE MIXTURE, AND USE THEREOF. |
| US5275652A (en) * | 1982-12-07 | 1994-01-04 | Elkem Materials Inc. | Concrete additive comprising a multicomponent admixture containing silica fume, its method of manufacture and concrete produced therewith |
| US5472501A (en) * | 1982-12-08 | 1995-12-05 | Elkem Materials Inc. | Concrete additive comprising a multicomponent admixture containing silica fume, its method of manufacture and concrete produced therewith |
| AT384206B (en) * | 1982-12-07 | 1987-10-12 | Elkem As | Additive for cement or mortar |
| US4466834A (en) * | 1983-01-03 | 1984-08-21 | W. R. Grace & Co. | Corrosion inhibiting additive for cement compositions |
| US4505753A (en) * | 1983-06-30 | 1985-03-19 | Research One Limited Partnership | Cementitious composite material |
| US4482385A (en) * | 1983-06-30 | 1984-11-13 | Research One Limited Partnership | Cementitious composite material with stainless steel particulate filler |
| GB2148871B (en) * | 1983-10-31 | 1987-01-07 | Pilkington Brothers Plc | Sheet material of fibre-reinforced cement |
| JPH0712966B2 (en) * | 1984-07-16 | 1995-02-15 | 花王株式会社 | Manufacturing method of concrete |
| JPS6265962A (en) * | 1985-09-17 | 1987-03-25 | 電気化学工業株式会社 | High strength cement composition |
| DK337186D0 (en) * | 1986-07-15 | 1986-07-15 | Densit As | PROCEDURE AND MATERIALS FOR THE MANUFACTURE OF A FORMATED ITEM |
| NO165021B (en) * | 1987-11-09 | 1990-09-03 | Norsk Hydro As | HYDRAULIC HEAVY WEIGHT CEMENT SUSPENSION SPECIFICALLY USED FOR CEMENTING OF OIL / GAS BURNER AND PROCEDURE FOR THE PREPARATION OF THE SUSPENSION. |
| DE3932908C2 (en) * | 1989-09-30 | 1998-09-10 | Mci Sa | Glass fiber reinforced cement or concrete |
| US5250113A (en) * | 1991-07-31 | 1993-10-05 | W. R. Grace & Co.-Conn. | Dry castable concrete compositions and methods of preparing and dry casting the same |
| SE501511C2 (en) † | 1993-04-30 | 1995-03-06 | Vladimir P Ronin | Process for making cement |
| US5916361A (en) * | 1993-10-12 | 1999-06-29 | Henry J. Molly & Associates, Inc. | Glass fiber reinforced cement composites |
| RU2160723C2 (en) * | 1998-11-25 | 2000-12-20 | ООО "Предприятие Мастер Бетон" | Method of preparation of concrete complex modified and concrete complex modifier(versions) |
| RU2152914C1 (en) * | 1999-02-09 | 2000-07-20 | Сытник Александр Александрович | Concrete composition |
| FR2967999A1 (en) * | 2010-11-25 | 2012-06-01 | Vicat | NEW CEMENT RESISTANT TO INTERNAL SULFATIC REACTIONS AND EXTERNAL SULFUR ATTACKS |
| RU2495067C1 (en) * | 2012-07-03 | 2013-10-10 | Юлия Алексеевна Щепочкина | Putty |
| CN105271852A (en) * | 2015-10-09 | 2016-01-27 | 中国建筑材料科学研究总院 | Seawater erosion resistant sulphoaluminate cement |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2410954A (en) * | 1944-10-12 | 1946-11-12 | Permanente Cement Company | Silica modified cement |
| US3135617A (en) * | 1959-10-06 | 1964-06-02 | W J Newell | Cement plaster |
| US3880664A (en) * | 1971-08-05 | 1975-04-29 | Herbert C Schulze | Method for extrusion |
| US3969567A (en) * | 1973-03-13 | 1976-07-13 | Tac Construction Materials Ltd. | Improvements in and relating to board products |
| US3995086A (en) * | 1975-06-27 | 1976-11-30 | Mark Plunguian | Shaped articles of hydraulic cement compositions and method of making same |
| US4036839A (en) * | 1975-06-27 | 1977-07-19 | Mark Plunguian | Shaped articles of hydraulic cement compositions having a reflective surface |
| US4088808A (en) * | 1976-01-16 | 1978-05-09 | Cornwell Charles E | Shaped articles of hydraulic cement compositions with a glossy reflective surface and reinforced with fiber glass |
| US4310486A (en) * | 1976-01-16 | 1982-01-12 | Cornwell Charles E | Compositions of cementitious mortar, grout and concrete |
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|---|---|---|---|---|
| GB314749A (en) * | 1928-11-21 | 1929-07-04 | Robert Henry Davis | Improvements in breathing apparatus |
| DE1054366B (en) * | 1957-10-25 | 1959-04-02 | Dyckerhoff Zementwerke Ag | Sulphate-resistant Portland cement |
| US3650786A (en) * | 1969-06-18 | 1972-03-21 | United States Steel Corp | Oil well cement and method of making the same |
| GB1359516A (en) * | 1970-08-06 | 1974-07-10 | Italiana Azioni Produzio | Cement products |
| AT312490B (en) * | 1971-01-05 | 1974-01-10 | Sika Ag | High strength cement mix |
-
1976
- 1976-07-09 RO RO90985A patent/RO72773B/en unknown
-
1977
- 1977-07-04 CA CA281,939A patent/CA1088110A/en not_active Expired
- 1977-07-05 PT PT6676277A patent/PT66762B/en unknown
- 1977-07-05 GB GB2812977A patent/GB1532178A/en not_active Expired
- 1977-07-05 AU AU26769/77A patent/AU507096B2/en not_active Expired
- 1977-07-06 AR AR26833877A patent/AR216767A1/en active
- 1977-07-06 NL NL7707505A patent/NL7707505A/en active Search and Examination
- 1977-07-06 SE SE7707894A patent/SE426479B/en unknown
- 1977-07-07 ZA ZA00774105A patent/ZA774105B/en unknown
- 1977-07-08 IT IT2553677A patent/IT1081532B/en active
- 1977-07-08 PH PH19974A patent/PH11956A/en unknown
- 1977-07-08 DK DK311077AA patent/DK155727B/en not_active Application Discontinuation
- 1977-07-08 ES ES460536A patent/ES460536A1/en not_active Expired
- 1977-07-08 JP JP8110177A patent/JPS538617A/en active Granted
- 1977-07-08 BE BE179219A patent/BE856653A/en not_active IP Right Cessation
- 1977-07-08 BR BR7704493A patent/BR7704493A/en unknown
- 1977-07-08 CH CH850477A patent/CH633500A5/en not_active IP Right Cessation
- 1977-07-08 DE DE2730943A patent/DE2730943B2/en not_active Ceased
- 1977-07-08 FR FR7721130A patent/FR2357500A1/en active Granted
- 1977-07-08 FI FI772140A patent/FI77013C/en not_active IP Right Cessation
- 1977-07-09 KR KR7701593A patent/KR820000152B1/en active
- 1977-07-11 AT AT497877A patent/AT370063B/en not_active IP Right Cessation
- 1977-07-13 US US05/815,418 patent/US4118242A/en not_active Ceased
-
1978
- 1978-06-30 IN IN491/DEL/78A patent/IN149470B/en unknown
-
1982
- 1982-09-30 US US06/431,097 patent/USRE31682E/en not_active Expired - Lifetime
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2410954A (en) * | 1944-10-12 | 1946-11-12 | Permanente Cement Company | Silica modified cement |
| US3135617A (en) * | 1959-10-06 | 1964-06-02 | W J Newell | Cement plaster |
| US3880664A (en) * | 1971-08-05 | 1975-04-29 | Herbert C Schulze | Method for extrusion |
| US3969567A (en) * | 1973-03-13 | 1976-07-13 | Tac Construction Materials Ltd. | Improvements in and relating to board products |
| US3995086A (en) * | 1975-06-27 | 1976-11-30 | Mark Plunguian | Shaped articles of hydraulic cement compositions and method of making same |
| US4036839A (en) * | 1975-06-27 | 1977-07-19 | Mark Plunguian | Shaped articles of hydraulic cement compositions having a reflective surface |
| US4088808A (en) * | 1976-01-16 | 1978-05-09 | Cornwell Charles E | Shaped articles of hydraulic cement compositions with a glossy reflective surface and reinforced with fiber glass |
| US4310486A (en) * | 1976-01-16 | 1982-01-12 | Cornwell Charles E | Compositions of cementitious mortar, grout and concrete |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0384898A1 (en) * | 1989-02-24 | 1990-08-29 | Sandoz Ag | Cementitious material for masonry constructions |
Also Published As
| Publication number | Publication date |
|---|---|
| AU507096B2 (en) | 1980-01-31 |
| PT66762A (en) | 1977-08-01 |
| CA1088110A (en) | 1980-10-21 |
| KR820000152B1 (en) | 1982-02-23 |
| FR2357500B1 (en) | 1984-05-25 |
| JPS538617A (en) | 1978-01-26 |
| DE2730943A1 (en) | 1978-01-12 |
| PT66762B (en) | 1978-12-14 |
| AT370063B (en) | 1983-02-25 |
| FR2357500A1 (en) | 1978-02-03 |
| AR216767A1 (en) | 1980-01-31 |
| FI77013B (en) | 1988-09-30 |
| IN149470B (en) | 1981-12-19 |
| RO72773A (en) | 1984-03-15 |
| GB1532178A (en) | 1978-11-15 |
| FI77013C (en) | 1989-01-10 |
| RO72773B (en) | 1984-03-31 |
| SE426479B (en) | 1983-01-24 |
| IT1081532B (en) | 1985-05-21 |
| BR7704493A (en) | 1978-04-18 |
| BE856653A (en) | 1978-01-09 |
| SE7707894L (en) | 1978-01-10 |
| JPS6128618B2 (en) | 1986-07-01 |
| DE2730943B2 (en) | 1979-05-10 |
| ZA774105B (en) | 1978-04-26 |
| ES460536A1 (en) | 1978-05-16 |
| ATA497877A (en) | 1982-07-15 |
| DK311077A (en) | 1978-01-10 |
| US4118242A (en) | 1978-10-03 |
| PH11956A (en) | 1978-09-20 |
| CH633500A5 (en) | 1982-12-15 |
| FI772140A (en) | 1978-01-10 |
| AU2676977A (en) | 1979-01-11 |
| DK155727B (en) | 1989-05-08 |
| NL7707505A (en) | 1978-01-11 |
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