CA2354825A1 - Composition of materials for production of acid resistant cement and concrete and methods thereof - Google Patents
Composition of materials for production of acid resistant cement and concrete and methods thereof Download PDFInfo
- Publication number
- CA2354825A1 CA2354825A1 CA 2354825 CA2354825A CA2354825A1 CA 2354825 A1 CA2354825 A1 CA 2354825A1 CA 2354825 CA2354825 CA 2354825 CA 2354825 A CA2354825 A CA 2354825A CA 2354825 A1 CA2354825 A1 CA 2354825A1
- Authority
- CA
- Canada
- Prior art keywords
- lime
- ground
- composition
- silicate
- cement
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
A cement composition for use in acidic environment containing liquid alkali silicate, vitreous silicate setting agent, lime containing material and inert filler and building materials made therefrom as well as the method of making such building materials. The liquid alkali silicate may include sodium silicate or potassium silicate. The vitreous silicate setting agent may include soda-lime glass powder or coal fly ash. The lime containing material refers to the materials containing more than 20% lime and may include quicklime, hydrated lime, Portland cement, blast furnace slag or steel slag.
The inert fillers include ground quartz, ground ceramic, and/or clay.
The inert fillers include ground quartz, ground ceramic, and/or clay.
Description
COMPOSITION OF MATERIALS FOR PRODUCTION OF ACID
RESISTANT CEMENT AND CONCRETE AND METHODS THEREOF
FIELD OF THE INVENTION
This invention relates in general to compositions and a method of use of such compositions to produce cement pastes; mortars and concrete, which are resistant to corrosion in an acidic environment.
BACKGROUND OF THE INVENTION
The acid corrosion of hardened cement and concrete materials has drawn more and more attention recently due to the corrosion of concrete sewer pipes and concrete structures at municipal wastewater treatment plants, chemical plants, coke ovens and steel plants. Further the impact of animal feed and manure are of concern regarding the acid corrosion resistance of concrete.
Conventional Portland cement concrete corrodes relatively quickly in an acidic environment. Some limited research results have indicated that the use of supplementary cementing materials such as silica fume, fly ash and ground blast furnace slag can improve the resistance to acid attack of concrete. pH adjustment and corrosion resistant linings are often used for concrete sewer pipes and concrete structures at municipal wastewater treatment plants at a substantial additional cost.
A recent study conducted by Shi and Stegemann entitled "Acid Corrosion Resistance of Different Cementing Materials" and published in Cement and Concrete Research, Vol. 30, No. 5, (2000) indicates that the corrosion of conventional cementing materials in acid solutions depends on the nature of the hydration products rather than the porosity of the hardened cementing materials. Up to now, the widely held belief has been that a high alkalinity of cement improves a cement's acid corrosion resistance and improves the acid neutralization capacity of the material. For example, the USEPA Toxicity Characteristic Leaching Procedure [Federal Register, 1986] examines the solubility of metals upon addition of a limited amount of acid and is usually used to evaluate the resistance of cement-solidified wastes in an acidic environment. In fact, passivation by deposition of reaction products plays an important role in corrosion resistance and prevents the matrix from further corrosion. Some cementing materials may have low acid neutralization capacity, but high acid corrosion resistance due to the passivation effect.
Acid resistant cement and concrete are well-known in the art. Early acid resistant cements mainly consisted of liquid sodium silicate, sodium hexafluorosilicate as a setting agent for liquid alkali silicate and ground quartz or silica flour as a filler.
In the past, sodium hexafluorosilicate was a readily available by-product from production of phosphate fertilizers. Now, however, it is difficult to economically obtain this material due to changes in the production of phosphate fertilizers. Other disadvantages with presently known acid resistant cements are that they exhibit low strength if cured at temperatures over 35°C, the cement needs to be cured in a dry environment instead of moist environment, and the hardened cement does not show good resistance to water or dilute acids unless an acid treatment is carried out before being exposed to those environments.
' -3-U.S. Patent No. 4,138,261 to Adrian et al.
discloses the use of condensed aluminum phosphates as hardeners for liquid alkali silicates. U.S. Patent No.
4,482,380 to Schlegel discloses aluminum iron phosphates as hardeners for liquid sodium or potassium silicate.
The hardeners have an atomic Al/Fe ratio of 0.052 to 95 and an atomic P/(A1+Fe) ratio of 0.9 to 3, and the cement is waterproof 16 days after it is manufactured.
This patent does not discuss the acid resistance of the cement. In fact, both condensed aluminum phosphates and aluminum iron phosphates are very expensive. U.S.
Patent No. 4,221,597 to Mallow discloses the use of a spray dried hydrated sodium silicate powder instead of liquid sodium silicate for the manufacture of acid resistant cement. However, it does not overcome any disadvantages as mentioned above.
U.S. Patent No. 5,989,330 to Semler et al.
discloses an acid resistant cement composition composed of a colloidal silica sol and an acid resistant particulate aggregate without any setting agent. This cement has to be pre-cured and is mainly suitable for use as a mortar in acidic autoclave environments.
U.S. Patent No. 5,352,288 to Mallow discloses an acid resistant cement comprised of, by weight, 1 to 1.5 parts of calcium oxide material containing at least about 60~ CaO, 10 to 15 parts of pozzolanic materials containing at least 30~ amorphous silica and 0.025 to 0.075 parts of alkaline metal catalyst. However, after an immersion of the invented material in a 0.70 pH
sulfuric acid for two weeks, a white softened skin about 1/32" depth forms on the surface of the tested samples.
Setting agents, which are cheap, environmental friendly, and technically sound are available. Such setting agents include powdered recycled glasses or coal fly ash. Many cities in North American cannot find applications for recycled mixed glasses, which are mainly soda-lime silicate glasses, and must landfill all or part of them. Coal fly ash is also widely available at very low cost. Notwithstanding this, the prior art does not disclose or even hint at the use of sodium-lime silicate glasses as setting agents for liquid sodium silicate. Furthermore, the prior art does not mention improvements in moisture and high temperature curing of acid resistant cement.
SUMMARY AND OBJECT OF THE INVENTION
In view of the foregoing limitations and shortcomings of conventional concretes, there exists a need to develop alternative acid resistant concretes which use inexpensive and environmentally friendly raw materials and can be cured at elevated temperatures.
More particularly, it is a purpose of this invention to provide a method of manufacturing a cement capable of resistance to water, dilute acid solutions and strong acid solutions without any prior treatment.
A further objective of this invention is the ability to cure cement pastes, mortars and concretes in a moist saturated environment.
A further objective of this invention is the ability to cure cement pastes, mortars and concretes in moist conditions and at elevated temperatures to acquire high early strength.
Yet another objective of this invention is to provide an alternative which can use inexpensive recycled materials.
The aforementioned objectives are achieved by an acid resistant cement in accordance with the present invention.
Briefly, therefore, the invention is directed to a type of cement which can be cured in steam at room and elevated temperatures, is characterized by excellent mechanical properties and is resistant to acid attack corrosion. The cements according to the present invention are composed of about 50 to about 100 parts of liquid alkali silicate with a Si02 to Na20 or K20 ratio ranging from 1.6 to 3.0, up to about 350 parts of vitreous silicate as a hardener, together with up to about 50 parts of lime containing material. Preferably, up to 200 parts of inert filler, including ground silica or ground ceramics are added to the formulation. Water may be required to produce workable mixtures. The amount of water utilized for a particular composition and manufacturing procedure is readily determined by routine experimentation. The hardened cement, mortar or concrete can be cured in either dry or moist environment at room or elevated temperatures, and can be contacted by water or dilute acid without any pretreatment.
One of the important constituents of the cement of the present invention, and which further distinguishes it from prior art cements, is the use of lime containing material serving as a property modifier. This constituent may include hydrated lime, quick lime, ground granulated blast furnace slag, ground steel slag, or Portland cement. On one hand, these modifier materials accelerate the condensation of liquid silicates and act as a hardener for liquid water glass.
On the other hand, they improve the moisture and high temperature curing properties of the cement, and enable the concrete to withstand direct contact with water and dilute acid without any pretreatment.
With the forgoing and other objects, features and advantages of the invention that will become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the following detailed description of presently preferred mechanical embodiments of the invention and the appended claims given for the purpose of disclosure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The essential materials in the present invention are the liquid alkali silicate, setting agent and lime containing material. An additional component such as inert filler can be utilized.
The formulation of the present cement composition includes liquid sodium or potassium silicate with a Si02 to Na20 or K20 ratio ranging from 1.6 to 3Ø A ratio between 2.0 to 2.8 is preferred in this invention as being a more practical commercial product and providing adequate workability for the mixture. If the ratio is too low, it may result in higher strengths, but the hardened cement pastes, mortars or concretes have poor resistance to acid attack. If the ratio is too high, the viscosity of the liquid silicate and the formulated mixtures increases, which affects the workability of cement paste, mortar or concrete mixtures.
As used herein, the setting agent is vitreous silicates, which include recycled glasses or coal fly ash. Preferably, a waste material such as recycled glasses is used. Preferred recycled glass are container glasses and plate glasses, which have at least 90~ of their particles passing 100 Mesh.
Based on ASTM C618, coal fly ash is classified into Class C and Class F categories. Fly ash belongs to Class F if it contains greater than 70~ of the sum of Si02+A1203+Fe203, and to Class C if it contains between 50% and 70°a of the sum of Si02+A1203+Fe203. Usually, Class F fly ashes have a lower content of Ca0 and exhibit pozzolanic properties, but Class C fly ashes contain a high content of Ca0 and exhibit cementitious properties. Since Class C fly ash has cementitious properties, it can be used as a binder directly. Class F fly ash is a pozzolanic material and possesses little or no cementitious value but will, in the presence of moisture, chemically react with calcium hydroxides at ordinary temperatures to form compounds possessing cementitious properties. In this invention, it is preferred that a Class F fly ash with a carbon content of less than 6~ be used.
The lime containing material should contain more than 20~ CaO. It can be any one or a combination of the materials such as blast furnace slag, steel slag, Portland cement, cement kiln dust, quicklime or hydrated lime. The use of these materials has also been found to be important to the steam curing properties, and resistance to water and dilute acid solution of the product concrete.
Additional water may be required to produce workable mixtures. The amount of water utilized for a particular composition and manufacturing procedure is readily determined by routine experimentation.
_8-Further illustrations of the characteristics and practical advantages of the compositions described in this invention are provided in the following examples:
EXAMPLE I
A batch of samples was made with 100 parts of liquid sodium silicate (with a ratio of Si02 to Na20 of 2.58), 120 parts of ground recycled plate glass and 270 parts of fine quartz sand. In another batch, 50 parts of ground blast furnace slag was added in addition to those materials described above. The dry materials were first blended uniformly, and liquid sodium silicate was then mixed with the dry blended material. No additional water was added. The mixtures were cast into 2"x2"x2" cubes.
After 4 hours of still time in a sample preparation room, the cubes with molds were placed into a heated dry chamber for 15 hours of curing at 85°C.
At the end of the curing period, the cubes were cooled to room temperature and demolded. Three cubes from each curing chamber were tested for compressive strength. Another six samples were immersed in water.
The results in Table 1 indicated that the addition of ground blast furnace slag increased the strength of the cement mortars significantly. After 28 days of immersion in water, the strength of the first batch of the mortars decreased to approximately 30% of the strength before water immersion. However, the strength of the batch with ground blast furnace slag did not show a significant change in strength. This indicates that the addition of ground blast furnace slag improves the water resistance of the hardened cement mortars.
Table 1 Effect of the Addition of Blast Furnace Slag on the Strength of the Cement before and after Water Immersion Batch Batch Composition (Parts by weight) Liquid sodium silicate (ratio of 2.58) 100 100 Ground recycled glass 120 120 Ground granulated blast furnace slag 0 50 Fine quartz sand 270 270 Compressive Strength (MPa) After 15 hours of dry curing at 85C 36.0 54.4 Immersion in water 28 days after the dry X15 curing 13.1 52.1 EXAMPLE II
A batch with 65 parts of liquid sodium silicate (with a ratio of Si02 to Na20 of 2.58), 80 parts of ground recycled plate glass, 40 parts of ground quartz, 10 parts of ground granulated blast furnace slag and 270 parts of fine quartz sand was prepared. The dry materials were first blended uniformly. Water was added into the liquid sodium silicate and mixed uniformly:
Then, the diluted sodium silicate was mixed into the dry blended material. The constituents of this batch are set forth in Table 2.
The mixture was cast into 2"x2"x2" cubes. After 4 hours of still time in a sample preparation room, the cubes with molds were placed into heated chambers for curing. Some cubes were cured in a moisture chamber at 85°C, while others were cured in a dry chamber at 85°C.
A batch of conventional Portland cement mortars was also prepared and cured in the moisture chamber as a reference.
After 15 hours of elevated temperature curing, the test cubes were cooled to room temperature and demolded.
Three cubes from each curing chamber were tested for compressive strength. The results in Table 3 indicate that there is no significant difference in strength for the cubes cured in dry or moisture conditions. Six steam cured cubes were immersed in water, 10% H2S04 and 40%
H2S04 solutions. The change in mass of these cubes was then monitored. After 28 days of immersion, the cubes cured in water and 10% H2S04 solution showed a strength decrease of 10% and 20%, respectively, while cubes in 40%
H2S04 solution did not exhibit any strength change.
Visual examination did not identify any deterioration on the surface of any of these test cubes.
The weight of the test cubes immersed in water and acid was monitored during the immersion test. It was found that the weight of these acid resistance cement mortar cubes changed less than 2% during the test in both 10% and 40% H2S04. However, conventional Portland cement mortars dissolved completely after 2 weeks of immersion in a 10% H2S04 solution. This means that the cement of the present invention is resistance to acid attack.
Table 2 Composition (Parts by weight) Ziquid sodium silicate (ratio of 2.58) 65 Ground recycled glass g0 3 0 Ground granulated blast furnace slag 10 Silica flour 40 Fine quartz sand 270 Water 15 Table 3 Strength of Acid Resistant Cement Mortar Before and After Acid Immersion Compressive Strength (MPa) After l5 hours of dry curing at 85°C 33.9 After 15 hours of steam curing at 85°C 31.1 Immersion in water 28 days after steam curing 28.8 Immersion in 10~ HZSO4 Solution for 28 days after 1 0 steam curing 24.0 Immersion in 40~ HZSO4 solution for 28 days after steam curing 31.6 EXAMPLE III
r1 5 The objective of this example was to show the acid corrosion resistance of concrete according to the present invention. As set forth in Tables 4 and 5, test sample preparation and curing of the concrete cubes was similar 20 to that described in Example II, except that coarse quartz sand and quartz gravel was used instead of fine quartz sand. It can also see that steam or dry curing did not show a significant effect on the strength of the concrete. After 28 days of immersion in loo H2S04 25 solution, both batches of cubes showed a slight increase in strength. Visual observation did not identify any deterioration on the surface.
Table 4 Composition (Parts by weight) Liquid sodium silicate (ratio of 2.58) 65 Ground recycled glass g0 Ground granulated blast furnace slag 10 Silica flour 40 Coarse quartz sand 241 Quartz gravel 362 Water 15 Table 5 Strength of Acid Resistant Cement Concrete Before and After Acid Immersion Compressive Strength (MPa) After 15 hours of dry curing at 85°C 26.6' After 15 hours of steam curing at 85°C 24.4 Immersion in lOg HZSO4 Solution for 28 days after 29.7 2 0 dry curing Immersion in 10$ H2S09 solution for 28 days after 27.5 steam curing The foregoing has described the invention and certain embodiments thereof. It is to be understood that the invention is not necessarily limited to the precise embodiments described therein but variously practiced with the scope of the following claims.
RESISTANT CEMENT AND CONCRETE AND METHODS THEREOF
FIELD OF THE INVENTION
This invention relates in general to compositions and a method of use of such compositions to produce cement pastes; mortars and concrete, which are resistant to corrosion in an acidic environment.
BACKGROUND OF THE INVENTION
The acid corrosion of hardened cement and concrete materials has drawn more and more attention recently due to the corrosion of concrete sewer pipes and concrete structures at municipal wastewater treatment plants, chemical plants, coke ovens and steel plants. Further the impact of animal feed and manure are of concern regarding the acid corrosion resistance of concrete.
Conventional Portland cement concrete corrodes relatively quickly in an acidic environment. Some limited research results have indicated that the use of supplementary cementing materials such as silica fume, fly ash and ground blast furnace slag can improve the resistance to acid attack of concrete. pH adjustment and corrosion resistant linings are often used for concrete sewer pipes and concrete structures at municipal wastewater treatment plants at a substantial additional cost.
A recent study conducted by Shi and Stegemann entitled "Acid Corrosion Resistance of Different Cementing Materials" and published in Cement and Concrete Research, Vol. 30, No. 5, (2000) indicates that the corrosion of conventional cementing materials in acid solutions depends on the nature of the hydration products rather than the porosity of the hardened cementing materials. Up to now, the widely held belief has been that a high alkalinity of cement improves a cement's acid corrosion resistance and improves the acid neutralization capacity of the material. For example, the USEPA Toxicity Characteristic Leaching Procedure [Federal Register, 1986] examines the solubility of metals upon addition of a limited amount of acid and is usually used to evaluate the resistance of cement-solidified wastes in an acidic environment. In fact, passivation by deposition of reaction products plays an important role in corrosion resistance and prevents the matrix from further corrosion. Some cementing materials may have low acid neutralization capacity, but high acid corrosion resistance due to the passivation effect.
Acid resistant cement and concrete are well-known in the art. Early acid resistant cements mainly consisted of liquid sodium silicate, sodium hexafluorosilicate as a setting agent for liquid alkali silicate and ground quartz or silica flour as a filler.
In the past, sodium hexafluorosilicate was a readily available by-product from production of phosphate fertilizers. Now, however, it is difficult to economically obtain this material due to changes in the production of phosphate fertilizers. Other disadvantages with presently known acid resistant cements are that they exhibit low strength if cured at temperatures over 35°C, the cement needs to be cured in a dry environment instead of moist environment, and the hardened cement does not show good resistance to water or dilute acids unless an acid treatment is carried out before being exposed to those environments.
' -3-U.S. Patent No. 4,138,261 to Adrian et al.
discloses the use of condensed aluminum phosphates as hardeners for liquid alkali silicates. U.S. Patent No.
4,482,380 to Schlegel discloses aluminum iron phosphates as hardeners for liquid sodium or potassium silicate.
The hardeners have an atomic Al/Fe ratio of 0.052 to 95 and an atomic P/(A1+Fe) ratio of 0.9 to 3, and the cement is waterproof 16 days after it is manufactured.
This patent does not discuss the acid resistance of the cement. In fact, both condensed aluminum phosphates and aluminum iron phosphates are very expensive. U.S.
Patent No. 4,221,597 to Mallow discloses the use of a spray dried hydrated sodium silicate powder instead of liquid sodium silicate for the manufacture of acid resistant cement. However, it does not overcome any disadvantages as mentioned above.
U.S. Patent No. 5,989,330 to Semler et al.
discloses an acid resistant cement composition composed of a colloidal silica sol and an acid resistant particulate aggregate without any setting agent. This cement has to be pre-cured and is mainly suitable for use as a mortar in acidic autoclave environments.
U.S. Patent No. 5,352,288 to Mallow discloses an acid resistant cement comprised of, by weight, 1 to 1.5 parts of calcium oxide material containing at least about 60~ CaO, 10 to 15 parts of pozzolanic materials containing at least 30~ amorphous silica and 0.025 to 0.075 parts of alkaline metal catalyst. However, after an immersion of the invented material in a 0.70 pH
sulfuric acid for two weeks, a white softened skin about 1/32" depth forms on the surface of the tested samples.
Setting agents, which are cheap, environmental friendly, and technically sound are available. Such setting agents include powdered recycled glasses or coal fly ash. Many cities in North American cannot find applications for recycled mixed glasses, which are mainly soda-lime silicate glasses, and must landfill all or part of them. Coal fly ash is also widely available at very low cost. Notwithstanding this, the prior art does not disclose or even hint at the use of sodium-lime silicate glasses as setting agents for liquid sodium silicate. Furthermore, the prior art does not mention improvements in moisture and high temperature curing of acid resistant cement.
SUMMARY AND OBJECT OF THE INVENTION
In view of the foregoing limitations and shortcomings of conventional concretes, there exists a need to develop alternative acid resistant concretes which use inexpensive and environmentally friendly raw materials and can be cured at elevated temperatures.
More particularly, it is a purpose of this invention to provide a method of manufacturing a cement capable of resistance to water, dilute acid solutions and strong acid solutions without any prior treatment.
A further objective of this invention is the ability to cure cement pastes, mortars and concretes in a moist saturated environment.
A further objective of this invention is the ability to cure cement pastes, mortars and concretes in moist conditions and at elevated temperatures to acquire high early strength.
Yet another objective of this invention is to provide an alternative which can use inexpensive recycled materials.
The aforementioned objectives are achieved by an acid resistant cement in accordance with the present invention.
Briefly, therefore, the invention is directed to a type of cement which can be cured in steam at room and elevated temperatures, is characterized by excellent mechanical properties and is resistant to acid attack corrosion. The cements according to the present invention are composed of about 50 to about 100 parts of liquid alkali silicate with a Si02 to Na20 or K20 ratio ranging from 1.6 to 3.0, up to about 350 parts of vitreous silicate as a hardener, together with up to about 50 parts of lime containing material. Preferably, up to 200 parts of inert filler, including ground silica or ground ceramics are added to the formulation. Water may be required to produce workable mixtures. The amount of water utilized for a particular composition and manufacturing procedure is readily determined by routine experimentation. The hardened cement, mortar or concrete can be cured in either dry or moist environment at room or elevated temperatures, and can be contacted by water or dilute acid without any pretreatment.
One of the important constituents of the cement of the present invention, and which further distinguishes it from prior art cements, is the use of lime containing material serving as a property modifier. This constituent may include hydrated lime, quick lime, ground granulated blast furnace slag, ground steel slag, or Portland cement. On one hand, these modifier materials accelerate the condensation of liquid silicates and act as a hardener for liquid water glass.
On the other hand, they improve the moisture and high temperature curing properties of the cement, and enable the concrete to withstand direct contact with water and dilute acid without any pretreatment.
With the forgoing and other objects, features and advantages of the invention that will become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the following detailed description of presently preferred mechanical embodiments of the invention and the appended claims given for the purpose of disclosure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The essential materials in the present invention are the liquid alkali silicate, setting agent and lime containing material. An additional component such as inert filler can be utilized.
The formulation of the present cement composition includes liquid sodium or potassium silicate with a Si02 to Na20 or K20 ratio ranging from 1.6 to 3Ø A ratio between 2.0 to 2.8 is preferred in this invention as being a more practical commercial product and providing adequate workability for the mixture. If the ratio is too low, it may result in higher strengths, but the hardened cement pastes, mortars or concretes have poor resistance to acid attack. If the ratio is too high, the viscosity of the liquid silicate and the formulated mixtures increases, which affects the workability of cement paste, mortar or concrete mixtures.
As used herein, the setting agent is vitreous silicates, which include recycled glasses or coal fly ash. Preferably, a waste material such as recycled glasses is used. Preferred recycled glass are container glasses and plate glasses, which have at least 90~ of their particles passing 100 Mesh.
Based on ASTM C618, coal fly ash is classified into Class C and Class F categories. Fly ash belongs to Class F if it contains greater than 70~ of the sum of Si02+A1203+Fe203, and to Class C if it contains between 50% and 70°a of the sum of Si02+A1203+Fe203. Usually, Class F fly ashes have a lower content of Ca0 and exhibit pozzolanic properties, but Class C fly ashes contain a high content of Ca0 and exhibit cementitious properties. Since Class C fly ash has cementitious properties, it can be used as a binder directly. Class F fly ash is a pozzolanic material and possesses little or no cementitious value but will, in the presence of moisture, chemically react with calcium hydroxides at ordinary temperatures to form compounds possessing cementitious properties. In this invention, it is preferred that a Class F fly ash with a carbon content of less than 6~ be used.
The lime containing material should contain more than 20~ CaO. It can be any one or a combination of the materials such as blast furnace slag, steel slag, Portland cement, cement kiln dust, quicklime or hydrated lime. The use of these materials has also been found to be important to the steam curing properties, and resistance to water and dilute acid solution of the product concrete.
Additional water may be required to produce workable mixtures. The amount of water utilized for a particular composition and manufacturing procedure is readily determined by routine experimentation.
_8-Further illustrations of the characteristics and practical advantages of the compositions described in this invention are provided in the following examples:
EXAMPLE I
A batch of samples was made with 100 parts of liquid sodium silicate (with a ratio of Si02 to Na20 of 2.58), 120 parts of ground recycled plate glass and 270 parts of fine quartz sand. In another batch, 50 parts of ground blast furnace slag was added in addition to those materials described above. The dry materials were first blended uniformly, and liquid sodium silicate was then mixed with the dry blended material. No additional water was added. The mixtures were cast into 2"x2"x2" cubes.
After 4 hours of still time in a sample preparation room, the cubes with molds were placed into a heated dry chamber for 15 hours of curing at 85°C.
At the end of the curing period, the cubes were cooled to room temperature and demolded. Three cubes from each curing chamber were tested for compressive strength. Another six samples were immersed in water.
The results in Table 1 indicated that the addition of ground blast furnace slag increased the strength of the cement mortars significantly. After 28 days of immersion in water, the strength of the first batch of the mortars decreased to approximately 30% of the strength before water immersion. However, the strength of the batch with ground blast furnace slag did not show a significant change in strength. This indicates that the addition of ground blast furnace slag improves the water resistance of the hardened cement mortars.
Table 1 Effect of the Addition of Blast Furnace Slag on the Strength of the Cement before and after Water Immersion Batch Batch Composition (Parts by weight) Liquid sodium silicate (ratio of 2.58) 100 100 Ground recycled glass 120 120 Ground granulated blast furnace slag 0 50 Fine quartz sand 270 270 Compressive Strength (MPa) After 15 hours of dry curing at 85C 36.0 54.4 Immersion in water 28 days after the dry X15 curing 13.1 52.1 EXAMPLE II
A batch with 65 parts of liquid sodium silicate (with a ratio of Si02 to Na20 of 2.58), 80 parts of ground recycled plate glass, 40 parts of ground quartz, 10 parts of ground granulated blast furnace slag and 270 parts of fine quartz sand was prepared. The dry materials were first blended uniformly. Water was added into the liquid sodium silicate and mixed uniformly:
Then, the diluted sodium silicate was mixed into the dry blended material. The constituents of this batch are set forth in Table 2.
The mixture was cast into 2"x2"x2" cubes. After 4 hours of still time in a sample preparation room, the cubes with molds were placed into heated chambers for curing. Some cubes were cured in a moisture chamber at 85°C, while others were cured in a dry chamber at 85°C.
A batch of conventional Portland cement mortars was also prepared and cured in the moisture chamber as a reference.
After 15 hours of elevated temperature curing, the test cubes were cooled to room temperature and demolded.
Three cubes from each curing chamber were tested for compressive strength. The results in Table 3 indicate that there is no significant difference in strength for the cubes cured in dry or moisture conditions. Six steam cured cubes were immersed in water, 10% H2S04 and 40%
H2S04 solutions. The change in mass of these cubes was then monitored. After 28 days of immersion, the cubes cured in water and 10% H2S04 solution showed a strength decrease of 10% and 20%, respectively, while cubes in 40%
H2S04 solution did not exhibit any strength change.
Visual examination did not identify any deterioration on the surface of any of these test cubes.
The weight of the test cubes immersed in water and acid was monitored during the immersion test. It was found that the weight of these acid resistance cement mortar cubes changed less than 2% during the test in both 10% and 40% H2S04. However, conventional Portland cement mortars dissolved completely after 2 weeks of immersion in a 10% H2S04 solution. This means that the cement of the present invention is resistance to acid attack.
Table 2 Composition (Parts by weight) Ziquid sodium silicate (ratio of 2.58) 65 Ground recycled glass g0 3 0 Ground granulated blast furnace slag 10 Silica flour 40 Fine quartz sand 270 Water 15 Table 3 Strength of Acid Resistant Cement Mortar Before and After Acid Immersion Compressive Strength (MPa) After l5 hours of dry curing at 85°C 33.9 After 15 hours of steam curing at 85°C 31.1 Immersion in water 28 days after steam curing 28.8 Immersion in 10~ HZSO4 Solution for 28 days after 1 0 steam curing 24.0 Immersion in 40~ HZSO4 solution for 28 days after steam curing 31.6 EXAMPLE III
r1 5 The objective of this example was to show the acid corrosion resistance of concrete according to the present invention. As set forth in Tables 4 and 5, test sample preparation and curing of the concrete cubes was similar 20 to that described in Example II, except that coarse quartz sand and quartz gravel was used instead of fine quartz sand. It can also see that steam or dry curing did not show a significant effect on the strength of the concrete. After 28 days of immersion in loo H2S04 25 solution, both batches of cubes showed a slight increase in strength. Visual observation did not identify any deterioration on the surface.
Table 4 Composition (Parts by weight) Liquid sodium silicate (ratio of 2.58) 65 Ground recycled glass g0 Ground granulated blast furnace slag 10 Silica flour 40 Coarse quartz sand 241 Quartz gravel 362 Water 15 Table 5 Strength of Acid Resistant Cement Concrete Before and After Acid Immersion Compressive Strength (MPa) After 15 hours of dry curing at 85°C 26.6' After 15 hours of steam curing at 85°C 24.4 Immersion in lOg HZSO4 Solution for 28 days after 29.7 2 0 dry curing Immersion in 10$ H2S09 solution for 28 days after 27.5 steam curing The foregoing has described the invention and certain embodiments thereof. It is to be understood that the invention is not necessarily limited to the precise embodiments described therein but variously practiced with the scope of the following claims.
Claims (22)
1. An acid resistant cement, which comprises:
a) an alkali silicate with a SiO2 to Na2O or K2O
ratio ranging from about 1.6 to about 3.0;
b) a silicate glass powder as a hardener; and c) a lime containing material.
a) an alkali silicate with a SiO2 to Na2O or K2O
ratio ranging from about 1.6 to about 3.0;
b) a silicate glass powder as a hardener; and c) a lime containing material.
2. The composition of claim 1 wherein the alkali silicate is present at about 50 to about 100 parts.
3. The composition of claim 1 wherein the silicate glass powder is present at up to about 350 parts.
4. The composition of claim 1 wherein the lime containing material is present at up to about 50 parts.
5. The composition of claim 1 further containing up to about 200 parts of an inert filler.
6. The composition of claim 1 wherein the silicate glass powder is ground container or plate glass.
7. The composition of claim 1 wherein the silicate glass powder is coal fly ash.
8. The composition of claim 1 wherein the lime containing material contains more than 20% lime and is selected from the group consisting of ground granulated blast furnace slag, ground steel slag, Portland cement, cement kiln dust, lime, and mixtures thereof.
9. The composition of claim 1 wherein the filler is selected from the group consisting of silica flour, ground ceramics, clays, and mixture thereof.
10. The composition of claim 1 including fibrous materials selected from the group consisting of ceramic, graphite, steel and cellulose fibers.
11. A method of making acid resistant cement comprising the steps of: mixing an alkali silicate with a SiO2 to Na2O or K20 ratio ranging from 1.6 to 3.0 with a silicate glass powder as a hardener and a lime containing material.
12. The method of claim 11 wherein the silicate glass powder is ground container or plate glass.
13. The method of claim 11 wherein the silicate glass powder is coal fly ash.
14. The method of claim 11 wherein the lime containing material contains more than 20% lime and is selected from the group consisting of ground granulated blast furnace slag, ground steel slag, Portland cement, cement kiln dust, lime or mixture thereof.
15. The method of claim 11 wherein the filler is selected from the group consisting of silica flour, ground ceramics, clays and mixture thereof.
16. The method of claim 11 including a fibrous material selected from the group consisting of ceramic, graphite, steel and cellulose fibers.
17. An acid resistant construction material, which comprises:
a) an alkali silicate with a SiO2 to Na2O or K2O
ratio ranging from 1.6 to 3.0;
b) a silicate glass powder as a hardener; and c) a lime containing material.
a) an alkali silicate with a SiO2 to Na2O or K2O
ratio ranging from 1.6 to 3.0;
b) a silicate glass powder as a hardener; and c) a lime containing material.
18. The acid resistant construction material of claim 17 wherein said silicate glass powder is ground container or plate glass.
19. The acid resistant construction material of claim 17 wherein the silicate glass powder is coal fly ash.
20. The acid resistant construction material of claim 17 wherein the lime containing material refers to the material containing more than 20% lime and is selected from the group consisting of ground granulated blast furnace slag, ground steel slag, Portland cement, cement kiln dust, lime or mixture thereof.
21. The acid resistant construction material of claim 17 wherein the filler is selected from the group consisting of silica flour, ground ceramics, clays or mixture thereof.
22. The acid resistant construction material of claim 17 including a fibrous material selected from the group consisting of ceramic, graphite, steel and cellulose fibers.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US63422000A | 2000-08-09 | 2000-08-09 | |
| US09/634,220 | 2000-08-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2354825A1 true CA2354825A1 (en) | 2002-02-09 |
Family
ID=24542886
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2354825 Abandoned CA2354825A1 (en) | 2000-08-09 | 2001-08-08 | Composition of materials for production of acid resistant cement and concrete and methods thereof |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2354825A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115477524A (en) * | 2022-10-08 | 2022-12-16 | 蒋世祥 | Low-alkali cement concrete acid-resistant pile and preparation method thereof |
| CN115925349A (en) * | 2022-05-20 | 2023-04-07 | 邢台建德水泥有限公司 | Quick-setting environment-friendly high-strength cement and preparation method thereof |
-
2001
- 2001-08-08 CA CA 2354825 patent/CA2354825A1/en not_active Abandoned
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115925349A (en) * | 2022-05-20 | 2023-04-07 | 邢台建德水泥有限公司 | Quick-setting environment-friendly high-strength cement and preparation method thereof |
| CN115925349B (en) * | 2022-05-20 | 2023-12-15 | 邢台建德水泥有限公司 | Quick-setting environment-friendly high-strength cement and preparation method thereof |
| CN115477524A (en) * | 2022-10-08 | 2022-12-16 | 蒋世祥 | Low-alkali cement concrete acid-resistant pile and preparation method thereof |
| CN115477524B (en) * | 2022-10-08 | 2023-07-25 | 蒋世祥 | Low-alkali cement concrete acid-resistant pile and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6749679B2 (en) | Composition of materials for production of acid resistant cement and concrete and methods thereof | |
| Liu et al. | An overview on the reuse of waste glasses in alkali-activated materials | |
| EP0809613B1 (en) | Fly ash cementitious material | |
| JP3990452B2 (en) | Curable composition and cured product | |
| US8257486B2 (en) | Composition for building material and a process for the preparation thereof | |
| CN108793893A (en) | Heat resistance concrete and preparation method thereof | |
| WO2011135584A2 (en) | Geopolymer concrete | |
| JP3857372B2 (en) | Acid-resistant cement composition | |
| WO2021024192A1 (en) | Cement compositions based on amorphous bagasse ash | |
| Naghizadeh et al. | Pozzolanic materials and waste products for formulation of geopolymer cements in developing countries: a review | |
| Manjunath et al. | Alkali-activated concrete systems: A state of art | |
| CN114804736A (en) | Geopolymer prepared from fly ash and bottom ash generated by burning household garbage and preparation method thereof | |
| Kumar et al. | Experimental study on strength properties of metakaolin and GGBS based geopolymer concrete | |
| Kupaei et al. | A review on fly ash-based geopolymer concrete | |
| CN114149187B (en) | Preparation method of modified phosphogypsum-based reinforced and toughened cementing material | |
| Sitarz et al. | The immobilisation of heavy metals from sewage sludge ash in geopolymer mortars | |
| CA2354825A1 (en) | Composition of materials for production of acid resistant cement and concrete and methods thereof | |
| Gopalakrishnan et al. | Durability of alumina silicate concrete based on slag/fly-ash blends against acid and chloride environments | |
| JP4340671B2 (en) | Acid resistant concrete products | |
| Abd Elaty et al. | Improvement the setting time and strength gain of the fly ash-based geopolymer mortars by using mineral additives | |
| US20230192565A1 (en) | Activation system, including at least one alkaline metal salt and calcium and/or magnesium carbonate for activating ground granulated blast furnace slag and binder comprising the same for the preparation of mortar or concrete composition | |
| KR100560276B1 (en) | A Block Being Made from Used Lime for Building and Construction and its Method for Production | |
| Puertas et al. | Alkali-activated slag cements and concrete | |
| Gao et al. | Chemistry, design and application of hybrid alkali activated binders | |
| Alhassan | Alkali-Activated Geopolymer Mortar with Sewage Sludge Ash as Precursor and Effects of Quicklime Addition |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |