CA1221389A - Manufacturing method of portland cement - Google Patents
Manufacturing method of portland cementInfo
- Publication number
- CA1221389A CA1221389A CA000425509A CA425509A CA1221389A CA 1221389 A CA1221389 A CA 1221389A CA 000425509 A CA000425509 A CA 000425509A CA 425509 A CA425509 A CA 425509A CA 1221389 A CA1221389 A CA 1221389A
- Authority
- CA
- Canada
- Prior art keywords
- asphalt
- portland cement
- cement
- port land
- carbon black
- 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.)
- Expired
Links
Classifications
-
- 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
- C04B28/04—Portland cements
-
- 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
- C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B14/02—Granular materials, e.g. microballoons
- C04B14/022—Carbon
-
- 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
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/10—Coating or impregnating
- C04B20/12—Multiple coating or impregnating
-
- 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
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/06—Inhibiting the setting, e.g. mortars of the deferred action type containing water in breakable containers ; Inhibiting the action of active ingredients
- C04B40/0633—Chemical separation of ingredients, e.g. slowly soluble activator
Abstract
A B S T R A C T
An improved Portland cement composition and process for producing same comprising dry powder of Portland cement and very fine particles of carbon black, wherein the dry powder of Portland cement is coated with an asphalt film prior to the addition of the carbon black.
An improved Portland cement composition and process for producing same comprising dry powder of Portland cement and very fine particles of carbon black, wherein the dry powder of Portland cement is coated with an asphalt film prior to the addition of the carbon black.
Description
3~3~
MANUFACTURING MUTED OF PORT LAND CEMENT
FIELD OF THE INV~TIO~
The present invention relates to an improved Port land cement composition and a method for preparing same.
BACKGROUND OF THE INVENTION
Improvements in waterproofing, compressive strength, durability, duration of packing during storage and other properties of Port land cement have been disclosed in US. Pat. Nos. 1,134,573; 1,772,999; 913,794; 1,076,028; and 1,305,645.
US. Pat. No. 1,134,573 relates -to a method and means of producing an admixture by adding lime or bentoni-te to asphaltum oil or asphalt and mixing i-t with ordinary cement, water and aggregates to produce concrete or mortar.
However, with the resulting concrete or mortar, there may be partial leakage and -the compressive strength, workability and duration of storage may not be preserved because the hydrophobic admixture has to be mixed with the unimproved traditional cement.
ITS Pat. No. 1,772,999 relates to a process of producing an admixture by mixing diatomaceous earth or benton3t~s with mineral oil or animal oil, and coating Port land cement therewith. Further, this reference relates to a method for -the production of an emulsion by rrlixing calcium chloride aqueous solution, which is used as a setting accelerator for concrete, with asphalt-dissolved crude oil mixed with bentonite or Fuller's earth. However, -the quality of the resulting composition is not uniform Jo i I;.' 1 - ~2;~3i!~319 because the admixture is made of natural oil and mineral r,la-terial which are impure and weak in hardness as to decrease -the strength and workability -thereof. In addition, there may be more creeks in the concrete with an increase in -the heat of hydration. Moreover, the reinforcing bars in -the concrete can become corroded by the corrosive property of the calcium chloride.
US. Pat. No. 913,794 relates -to a method for producing a waterproof cement by coating the emanate particles with a mixture obtained by admixing lime with an oleaginous substance without healing. However, -the workability and waterproofing strength in the resulting enroot may be decreased because no pore filler is used for the cement other than wax and an oleaginous substance with lime.
US. Pat. No. 1,076,028 relates to a method for coating emanate particles by passing the dry cement powder -through a spray zone of a molten state of fatty acid soap or wax. However, the strength, waterproofing and workability of the resulting concrete is decreased because -the cement is etude while it is forced -through the spray zone.
US. Pat. No. 1,305,645 relates to a method for mixing emanate with pitch powder pulverized below 100 mesh.
However, there is a decrease in workability, strength and waterproofing in the resulting concrete because pitch has to be admixed with -the cement during enrooting.
The disadvantages of using ordinary Port land cement in producing concrete or mortar are discussed below.
In the conventional mixing of concrete or mortar with ordinary Port land cement, there must be a surplus of
MANUFACTURING MUTED OF PORT LAND CEMENT
FIELD OF THE INV~TIO~
The present invention relates to an improved Port land cement composition and a method for preparing same.
BACKGROUND OF THE INVENTION
Improvements in waterproofing, compressive strength, durability, duration of packing during storage and other properties of Port land cement have been disclosed in US. Pat. Nos. 1,134,573; 1,772,999; 913,794; 1,076,028; and 1,305,645.
US. Pat. No. 1,134,573 relates -to a method and means of producing an admixture by adding lime or bentoni-te to asphaltum oil or asphalt and mixing i-t with ordinary cement, water and aggregates to produce concrete or mortar.
However, with the resulting concrete or mortar, there may be partial leakage and -the compressive strength, workability and duration of storage may not be preserved because the hydrophobic admixture has to be mixed with the unimproved traditional cement.
ITS Pat. No. 1,772,999 relates to a process of producing an admixture by mixing diatomaceous earth or benton3t~s with mineral oil or animal oil, and coating Port land cement therewith. Further, this reference relates to a method for -the production of an emulsion by rrlixing calcium chloride aqueous solution, which is used as a setting accelerator for concrete, with asphalt-dissolved crude oil mixed with bentonite or Fuller's earth. However, -the quality of the resulting composition is not uniform Jo i I;.' 1 - ~2;~3i!~319 because the admixture is made of natural oil and mineral r,la-terial which are impure and weak in hardness as to decrease -the strength and workability -thereof. In addition, there may be more creeks in the concrete with an increase in -the heat of hydration. Moreover, the reinforcing bars in -the concrete can become corroded by the corrosive property of the calcium chloride.
US. Pat. No. 913,794 relates -to a method for producing a waterproof cement by coating the emanate particles with a mixture obtained by admixing lime with an oleaginous substance without healing. However, -the workability and waterproofing strength in the resulting enroot may be decreased because no pore filler is used for the cement other than wax and an oleaginous substance with lime.
US. Pat. No. 1,076,028 relates to a method for coating emanate particles by passing the dry cement powder -through a spray zone of a molten state of fatty acid soap or wax. However, the strength, waterproofing and workability of the resulting concrete is decreased because -the cement is etude while it is forced -through the spray zone.
US. Pat. No. 1,305,645 relates to a method for mixing emanate with pitch powder pulverized below 100 mesh.
However, there is a decrease in workability, strength and waterproofing in the resulting concrete because pitch has to be admixed with -the cement during enrooting.
The disadvantages of using ordinary Port land cement in producing concrete or mortar are discussed below.
In the conventional mixing of concrete or mortar with ordinary Port land cement, there must be a surplus of
- 2 -~Z~3~
water, compared with -the necessary amount o-f water used for hydration of cement, in order to enhance workability.
Further, since air entraining necessarily occurs in concrete mixing, the surplus of water combined with the air entraining produces a lot of pore during hydration and setting. When the pores are interconnected, undesired leakage can occur.
In addition, the concrete or mortar formed with ordinary Port land cement has the problem of cracking due to the shrinkage and expansion caused by the heat of hydration and variations of the surrounding -temperatures during and after hardening. These creeks are undesirable because -they result in leakage.
Moreover, the conventional reinforced concrete using ordinary Port land cement has a drawback in -that it creates a water pool beneath the aggregates or the horizontal reinforcing bars due to bleeding. This produces more pores and cracking under the heat of hydration.
Also, in -the mixing of concrete or mortar with I ordinary Port land cement, i-t is very difficult to keep a low water-eontent ratio, due to poor workability, unless air entraining admixtures are used.
Further, the concrete produced using ordinary Port land cement does not have satisfactory compressive strength after long periods of -time.
In addition, ordinary Port land cement is highly water absorbent. This causes storage problems and results in hardening.
Moreover, additional waterproofing processes are required for concrete strutters made with ordinary Port land
water, compared with -the necessary amount o-f water used for hydration of cement, in order to enhance workability.
Further, since air entraining necessarily occurs in concrete mixing, the surplus of water combined with the air entraining produces a lot of pore during hydration and setting. When the pores are interconnected, undesired leakage can occur.
In addition, the concrete or mortar formed with ordinary Port land cement has the problem of cracking due to the shrinkage and expansion caused by the heat of hydration and variations of the surrounding -temperatures during and after hardening. These creeks are undesirable because -they result in leakage.
Moreover, the conventional reinforced concrete using ordinary Port land cement has a drawback in -that it creates a water pool beneath the aggregates or the horizontal reinforcing bars due to bleeding. This produces more pores and cracking under the heat of hydration.
Also, in -the mixing of concrete or mortar with I ordinary Port land cement, i-t is very difficult to keep a low water-eontent ratio, due to poor workability, unless air entraining admixtures are used.
Further, the concrete produced using ordinary Port land cement does not have satisfactory compressive strength after long periods of -time.
In addition, ordinary Port land cement is highly water absorbent. This causes storage problems and results in hardening.
Moreover, additional waterproofing processes are required for concrete strutters made with ordinary Port land
3 -.3~1 cement. No-t only is this very costly but also such processes cannot be used in a pressured area.
The durability of a reinforced concrete structure is closely related to the neutralization of the concrete material and corrosion of -the reinforcing bars. After setting, if the alkalinity of the concrete is lost by -the action of surface air or water, which contains carbon dioxide and sulfur dioxide, the concrete is neutralized.
This causes corrosion of the reinforcing bars and destruction of the concrete.
SUMMARY OF THE INVENTION
In accordance with a firs-t aspect of -the present invention, there is provided an improved Port land cement composition comprising a dry cement powder, the particles of which are coated with a film of asphalt, and particles of carbon black.
The present invention provides in a second aspect a method of preparing an improved Port land cement comprising the steps of adding molten or powdered asphalt to dry Port land cement powder, heating and agitating the mixture ox asphalt and cement powder at a temperature in the range of 100C to 150C (preferably 100 C to 120C), cooling the mixture, admixing the resulting asphalt filmed Port land cement particles with carbon black and agitating until a substantially homogeneous mixture is produced.
~2~3~3~
Preferably, -the proportion of -the constituents is such as to yield a product which contains 0.2% to 1% by weigh-t of straight asphalt and 0.2% to 1.5% by weight of carbon black.
BRIEF DESCRIPTION OF THE FIGURES
FIG. lo is a photograph taken under a metallurgical microscope of concrete containing ordinary Port land cement.
FIG. lb is a photograph taken under a metallurgical microscope of concrete containing Port land cement of the present invention.
FIG. 2 represents a porosity de-termination of enroot containing ordinary Port land cement (I) and concrete containing Port land cement of the present invention (II).
FIG. pa represents an electrophotomicrograph of concrete containing ordinary Port land cement.
FIG. 3b represents an electrophotomicrograph of concrete containing Port land cement of the present invention.
DETAIL DESCRIPTION OF THE INVENTION
The firs-t step of the manufacturing process of the present invention is to form thin films of hydrophobic asphalt around the surface of particles of ordinary Port land cement dry powder. Optionally, gypsum may have been admixed with the Port land emanate dry powder if desired.
~.~Z9;~ ~1L3~
Next, very fine particles of carbon black 9 having a diameter less than 70 millimicrons are added to asphalt-filmed cement powder particles and blended in-to a homogeneous mixture.
The improved Port land cement of the present invention can be used just like ordinary Port land cement in producing concrete or mortar. Further, the improved Port land cement of the present invention provides excellent waterproofing in 28 days without utilizing conventional waterproofing methods.
The asphalt employed in the present invention is hydrophobic and plastic under heat. Further, the asphalt gains good fluidity above the softening point, but loses fluidity and is -transformed into an elastic solid state below the softening point. The heat plasticity of the asphalt is primarily used -to form -the asphalt film around the particles of cement powder.
The asphalt is heated in-to a molten state and i-t is added -to the cement dry powder in an amount of 0.1-2% by the weigh-t of the cement. After blending the asphalt with -the cement, the heat is maintained between 100 C. -to 150 C.
with agitation. In -this manner, the liquefied asphalt forms a very thin film around the particles of -the cement dry powder.
The asphalt -to be used in -the present invention should have a softening point between ~0 -to 90 C. and can be either straight asphalt or blown asphalt.
Carbon black having a diameter preferably less -than 60 millimicrons is added to -the filmed particles and agitated to form a homogeneous mixture.
The concrete or mortar formed with cement of the present invention is -tight enough -to be waterproof under high water pressure even a-t 15 kg/cm2 after curing.
With concrete containing cement of the present invention some of the pores that occur during hydration are filled by the very thin asphalt film and the very fine carbon black.
As shown in FIGS. lo and lb, the leakage through the pore network is prevented due to -the hydrophobic asphalt and carbon black. That is, FIG. lo represents a photograph of concrete made with orindary Port land cement and FIG. lb represents a photograph of concrete made with the Port land cement of the present invention.
The above described porosity effect is further demonstrated in FIG. 2. That is, FIG. 2 demonstrates that -the porosity is larger in concrete containing ordinary Port land cement, whereas it is much smaller in -the concrete containing Port land cement of the present invention in terms of both the number and the diameter of developed pores.
pence, concrete or mortar containing -the cement of -the present invention has excellent waterproofing proper-ties, even under water pressure as high as 15 kg/cm2.
In concrete or mortar containing Port land cement of -the present invention, -the asphalt prevents water leakage -through -the pores. When the temperature of -the concrete rises due to the heat of hydration or changes in the surrounding temperature, the asphalt absorbs the heat and it softens. When the temperature falls, the asphalt resumes its solid state.
Another role of the asphalt in the present invention is to resist cracking. The asphalt film interrupts the movement of water through -the pores in -the 3~3~
concrete. This results in much less cracking and thus, enhances the waterproofing property thereof.
FIGS. pa and 3b illustrate electron micro graphs of hardened concrete containing ordinary Port land cement (pa) and Port land cement of the present invention (3b). These figures show that the cement of -the present invention provides excellent results in preventing cracks from interconnecting. This is because concrete containing Port land cement of the present invention has fewer and shorter cracks than concrete containing ordinary Port land cement.
As stated above, the Port land cement of the present invention contains carbon black having a diameter preferably less than 60 millimicrons and is very light in weight. The specific gravity of the cement and carbon black is about 3.2 and 1.8, respectively. The carbon black acts as a dispersing agent in addition to acting as a pigment. These properties bring about an improved workability of the resulting cement. Accordingly, in the construction field, the concrete formed using cement of the present invention enhances working conditions and the stability of the waterproofing strutter.
Numerous specimens of concrete have been prepared at various water cement ratios ranging from 60 to 45% by weight with the various slumps ranging from 18 to 8 centimeters No leakage was found in these specimens. Some of the specimens were molded into three 24 hour stages and cured for 28 days at room temperature. The -test results indicated that no leakage occurred under a continuing pressure of 15 kg/cm over the course of one week.
g _ I L3~9 .
Hence, the Port land cement of the present invention improves workability and water tightness of -the concrete as a result of -the characteristics of the micro asphalt coating and carbon black. Further, the Port land cement of the present invention acts to more firmly join together the part of the stage placement which is inserted into -the entire concrete.
Although the compressive strength of the 28 day aged concrete containing Port land cement of -the present invention is slightly weaker, i.e., 4-6% weaker, than that containing ordinary Port land cement, concrete containing Port land cement of -the present invention is on average about 15% stronger after 40 days -than that containing ordinary Port land cement. This is due to the phenomenon that even -though the asphalt in the cement retards setting by absorbing the heat of hydration in the early stages, the carbon black improves water tightness over the course of -time.
Concrete containing -the Port land cement of the present invention no-t only exhibits water tightness, but also exhibits an anti-corrosion effect on the reinforcing bars because -the hydrophobic asphalt film and chemically s-table carbon black improve the water -tightness and protect the concrete from corrosion. Once the asphalt in the concrete is softened by the heat of hydration and then returns to a solid state it provides very close adherence around the reinforcing bars. This also protects the reinforcing bars from corrosion.
Several tests have been conducted which show -that the concrete containing the Port land cement of the present invention produces an average of about a 30% increase in -the adhesive strength of the reinforcing bars compared with ordinary Port land cement. Thus, -the Port land cement of -the present invention gives rise to a more durable rein-forced concrete structure.
Since the concrete containing -the Port land cement of the present invention consists of particles covered with a hydrophobic asphalt film, -the concrete can be stored for longer periods of time without solidification.
In addition, since with concrete containing the Port land cement of -the present invention no leakage occurs at the high pressure of 15 kg/cm2, there is no need for additional waterproofing.
The Port land cement of the present invention can be used from both an economical and technical standpoint in a variety of construction works including subways, tunnels, dams, and substructures of buildings.
The present invention is illustrated by the -Following examples. The examples are in no way in-tended to limit the scope of the present invention.
The asphalt used in -the examples below had a sweetening point of 40 - 90 C. The carbon black used in -the examples below had a diameter of less than 60 millimicrons.
A Port land cement comprising 99.6% by weight dry powder of ordinary Port land cement clinker, 0.2% asphalt by weight and 0.2% by weight carbon black.
A Port land cement comprising 97.5% by weigh-t dry . ' - 11 -38~
powder of ordinary Port land cement clinker, 1% by weigh-t asphalt and 1.5% by weight carbon black.
A Port land cement comprising 99% by weigh-t dry powder of ordinary Port land cement clinker, 0.5% by weight asphalt and 0.5% by weigh-t carbon black.
A Port land cement comprising 97.3% by weigh-t dry powder of ordinary Port land cement clinker, 2% by weight gypsum, 0.2% by weight asphalt and 0.5% by weight carbon black.
EXAMPLE S
A Port land cement comprising 92.5% by weight dry powder of ordinary Port land cement clinker, 5% by weigh-t gypsum, 1% by weigh-t asphalt and 1.5% by weigh-t carbon black.
A Port land cement comprising 95.8% by weigh-t dry powder of ordinary Port land cement clinker, 3% by weigh-t gypsum, 0.5% by weight asphalt and 0.7% by weigh-t carbon black.
A Port land cement comprising 99.8% by weight dry powder owe ordinary Port land cement clinker and 0.2% by weight carbon black.
A Port land cement comprising 98% by weight dry powder of ordinary Port land cement clinker and 2% by weigh-t carbon black.
A Port land cement comprising 99% by weigh-t dry powder of ordinary Port land cement clinker and 1% by weight carbon black.
A Port land cement comprising 97.8% by weight dry powder of ordinary Port land cement clinker, 2% by weight gypsum, 0.2% by weight carbon black.
A Port land cement comprising 93% by weight dry powder of ordinary Port land cement clinker, 5% by weight gypsum and 2% by weight carbon black.
A Port land cement comprising 96.4% by weight dry powder of ordinary Port land cement clinker, 3% by weigh-t gypsum and 0.6% by weight carbon black.
Examples 1-3 were prepared in the following manner:
A dry powder of Port land cement clinker was obtained by pulverization of Port land cement clinker.
Thereafter, molten or powdered asphalt was added to the dry powder and the resulting mixture was heated and agitated in a settle with heating and agitation devices at 100-150 C.
(straight asphalt 100-120 C., or blown asphalt 130-150 C.) and a pressure of 1 elm, for 2 hours. The resulting mixture was cooled to room temperature -to obtain the asphalt filmed Port land cement particles. Then, carbon black was added -to the asphalt filmed Port land cement powder and agitated until homogeneously mixed therewith.
Examples 4-6 were prepared according to Examples 1-3 except that gypsum was admixed with -the dry powder of ~22~
Port land cement clinker prior -to the addition of -the asphalt (and the temperature appropriately selected below the dehydration level of gypsum).
Comparative Examples 1-3 were preparing in the following manner:
A dry powder of ordinary Port land cement clinker was obtained by pulverization. Thereafter, carbon black was admixed with the cement dry powder at room -temperature until a homogeneous mixture was produced.
Comparative Examples 4-6 were prepared in the same manner as Comparative Examples 1-3 except that gypsum was also admixed with the cement dry powder and carbon black.
Concrete containing the cements of Examples 1-6 and Comparative Examples 1-6 were measured for compressive strength, water permeability at 15 kg/cm2 and adhesive strength of the reinforced bars by conventional method. The results are shown in Table A, below.
\ Item Compressive Strength Water Perle- Adhesive \ _ ability (aged Strength to \ 28 days a-t reinforcing Cement \ (aged 28 days) (aged 40 days) 15Kg/Cm bar Ordinary Portlcmd Lowe 100% 100% 100%
cement _ _ _ _ _ improved Port land cement according 94-98% 100-125% 0% 110-150%
invention While the present invention has been described in detail and with reference -to specific embodiments -thereof, it would be apparent to one skilled in the art that various - I
I
changes and modifications can be made therein without departing from the spirit and slope -thereof.
The durability of a reinforced concrete structure is closely related to the neutralization of the concrete material and corrosion of -the reinforcing bars. After setting, if the alkalinity of the concrete is lost by -the action of surface air or water, which contains carbon dioxide and sulfur dioxide, the concrete is neutralized.
This causes corrosion of the reinforcing bars and destruction of the concrete.
SUMMARY OF THE INVENTION
In accordance with a firs-t aspect of -the present invention, there is provided an improved Port land cement composition comprising a dry cement powder, the particles of which are coated with a film of asphalt, and particles of carbon black.
The present invention provides in a second aspect a method of preparing an improved Port land cement comprising the steps of adding molten or powdered asphalt to dry Port land cement powder, heating and agitating the mixture ox asphalt and cement powder at a temperature in the range of 100C to 150C (preferably 100 C to 120C), cooling the mixture, admixing the resulting asphalt filmed Port land cement particles with carbon black and agitating until a substantially homogeneous mixture is produced.
~2~3~3~
Preferably, -the proportion of -the constituents is such as to yield a product which contains 0.2% to 1% by weigh-t of straight asphalt and 0.2% to 1.5% by weight of carbon black.
BRIEF DESCRIPTION OF THE FIGURES
FIG. lo is a photograph taken under a metallurgical microscope of concrete containing ordinary Port land cement.
FIG. lb is a photograph taken under a metallurgical microscope of concrete containing Port land cement of the present invention.
FIG. 2 represents a porosity de-termination of enroot containing ordinary Port land cement (I) and concrete containing Port land cement of the present invention (II).
FIG. pa represents an electrophotomicrograph of concrete containing ordinary Port land cement.
FIG. 3b represents an electrophotomicrograph of concrete containing Port land cement of the present invention.
DETAIL DESCRIPTION OF THE INVENTION
The firs-t step of the manufacturing process of the present invention is to form thin films of hydrophobic asphalt around the surface of particles of ordinary Port land cement dry powder. Optionally, gypsum may have been admixed with the Port land emanate dry powder if desired.
~.~Z9;~ ~1L3~
Next, very fine particles of carbon black 9 having a diameter less than 70 millimicrons are added to asphalt-filmed cement powder particles and blended in-to a homogeneous mixture.
The improved Port land cement of the present invention can be used just like ordinary Port land cement in producing concrete or mortar. Further, the improved Port land cement of the present invention provides excellent waterproofing in 28 days without utilizing conventional waterproofing methods.
The asphalt employed in the present invention is hydrophobic and plastic under heat. Further, the asphalt gains good fluidity above the softening point, but loses fluidity and is -transformed into an elastic solid state below the softening point. The heat plasticity of the asphalt is primarily used -to form -the asphalt film around the particles of cement powder.
The asphalt is heated in-to a molten state and i-t is added -to the cement dry powder in an amount of 0.1-2% by the weigh-t of the cement. After blending the asphalt with -the cement, the heat is maintained between 100 C. -to 150 C.
with agitation. In -this manner, the liquefied asphalt forms a very thin film around the particles of -the cement dry powder.
The asphalt -to be used in -the present invention should have a softening point between ~0 -to 90 C. and can be either straight asphalt or blown asphalt.
Carbon black having a diameter preferably less -than 60 millimicrons is added to -the filmed particles and agitated to form a homogeneous mixture.
The concrete or mortar formed with cement of the present invention is -tight enough -to be waterproof under high water pressure even a-t 15 kg/cm2 after curing.
With concrete containing cement of the present invention some of the pores that occur during hydration are filled by the very thin asphalt film and the very fine carbon black.
As shown in FIGS. lo and lb, the leakage through the pore network is prevented due to -the hydrophobic asphalt and carbon black. That is, FIG. lo represents a photograph of concrete made with orindary Port land cement and FIG. lb represents a photograph of concrete made with the Port land cement of the present invention.
The above described porosity effect is further demonstrated in FIG. 2. That is, FIG. 2 demonstrates that -the porosity is larger in concrete containing ordinary Port land cement, whereas it is much smaller in -the concrete containing Port land cement of the present invention in terms of both the number and the diameter of developed pores.
pence, concrete or mortar containing -the cement of -the present invention has excellent waterproofing proper-ties, even under water pressure as high as 15 kg/cm2.
In concrete or mortar containing Port land cement of -the present invention, -the asphalt prevents water leakage -through -the pores. When the temperature of -the concrete rises due to the heat of hydration or changes in the surrounding temperature, the asphalt absorbs the heat and it softens. When the temperature falls, the asphalt resumes its solid state.
Another role of the asphalt in the present invention is to resist cracking. The asphalt film interrupts the movement of water through -the pores in -the 3~3~
concrete. This results in much less cracking and thus, enhances the waterproofing property thereof.
FIGS. pa and 3b illustrate electron micro graphs of hardened concrete containing ordinary Port land cement (pa) and Port land cement of the present invention (3b). These figures show that the cement of -the present invention provides excellent results in preventing cracks from interconnecting. This is because concrete containing Port land cement of the present invention has fewer and shorter cracks than concrete containing ordinary Port land cement.
As stated above, the Port land cement of the present invention contains carbon black having a diameter preferably less than 60 millimicrons and is very light in weight. The specific gravity of the cement and carbon black is about 3.2 and 1.8, respectively. The carbon black acts as a dispersing agent in addition to acting as a pigment. These properties bring about an improved workability of the resulting cement. Accordingly, in the construction field, the concrete formed using cement of the present invention enhances working conditions and the stability of the waterproofing strutter.
Numerous specimens of concrete have been prepared at various water cement ratios ranging from 60 to 45% by weight with the various slumps ranging from 18 to 8 centimeters No leakage was found in these specimens. Some of the specimens were molded into three 24 hour stages and cured for 28 days at room temperature. The -test results indicated that no leakage occurred under a continuing pressure of 15 kg/cm over the course of one week.
g _ I L3~9 .
Hence, the Port land cement of the present invention improves workability and water tightness of -the concrete as a result of -the characteristics of the micro asphalt coating and carbon black. Further, the Port land cement of the present invention acts to more firmly join together the part of the stage placement which is inserted into -the entire concrete.
Although the compressive strength of the 28 day aged concrete containing Port land cement of -the present invention is slightly weaker, i.e., 4-6% weaker, than that containing ordinary Port land cement, concrete containing Port land cement of -the present invention is on average about 15% stronger after 40 days -than that containing ordinary Port land cement. This is due to the phenomenon that even -though the asphalt in the cement retards setting by absorbing the heat of hydration in the early stages, the carbon black improves water tightness over the course of -time.
Concrete containing -the Port land cement of the present invention no-t only exhibits water tightness, but also exhibits an anti-corrosion effect on the reinforcing bars because -the hydrophobic asphalt film and chemically s-table carbon black improve the water -tightness and protect the concrete from corrosion. Once the asphalt in the concrete is softened by the heat of hydration and then returns to a solid state it provides very close adherence around the reinforcing bars. This also protects the reinforcing bars from corrosion.
Several tests have been conducted which show -that the concrete containing the Port land cement of the present invention produces an average of about a 30% increase in -the adhesive strength of the reinforcing bars compared with ordinary Port land cement. Thus, -the Port land cement of -the present invention gives rise to a more durable rein-forced concrete structure.
Since the concrete containing -the Port land cement of the present invention consists of particles covered with a hydrophobic asphalt film, -the concrete can be stored for longer periods of time without solidification.
In addition, since with concrete containing the Port land cement of -the present invention no leakage occurs at the high pressure of 15 kg/cm2, there is no need for additional waterproofing.
The Port land cement of the present invention can be used from both an economical and technical standpoint in a variety of construction works including subways, tunnels, dams, and substructures of buildings.
The present invention is illustrated by the -Following examples. The examples are in no way in-tended to limit the scope of the present invention.
The asphalt used in -the examples below had a sweetening point of 40 - 90 C. The carbon black used in -the examples below had a diameter of less than 60 millimicrons.
A Port land cement comprising 99.6% by weight dry powder of ordinary Port land cement clinker, 0.2% asphalt by weight and 0.2% by weight carbon black.
A Port land cement comprising 97.5% by weigh-t dry . ' - 11 -38~
powder of ordinary Port land cement clinker, 1% by weigh-t asphalt and 1.5% by weight carbon black.
A Port land cement comprising 99% by weigh-t dry powder of ordinary Port land cement clinker, 0.5% by weight asphalt and 0.5% by weigh-t carbon black.
A Port land cement comprising 97.3% by weigh-t dry powder of ordinary Port land cement clinker, 2% by weight gypsum, 0.2% by weight asphalt and 0.5% by weight carbon black.
EXAMPLE S
A Port land cement comprising 92.5% by weight dry powder of ordinary Port land cement clinker, 5% by weigh-t gypsum, 1% by weigh-t asphalt and 1.5% by weigh-t carbon black.
A Port land cement comprising 95.8% by weigh-t dry powder of ordinary Port land cement clinker, 3% by weigh-t gypsum, 0.5% by weight asphalt and 0.7% by weigh-t carbon black.
A Port land cement comprising 99.8% by weight dry powder owe ordinary Port land cement clinker and 0.2% by weight carbon black.
A Port land cement comprising 98% by weight dry powder of ordinary Port land cement clinker and 2% by weigh-t carbon black.
A Port land cement comprising 99% by weigh-t dry powder of ordinary Port land cement clinker and 1% by weight carbon black.
A Port land cement comprising 97.8% by weight dry powder of ordinary Port land cement clinker, 2% by weight gypsum, 0.2% by weight carbon black.
A Port land cement comprising 93% by weight dry powder of ordinary Port land cement clinker, 5% by weight gypsum and 2% by weight carbon black.
A Port land cement comprising 96.4% by weight dry powder of ordinary Port land cement clinker, 3% by weigh-t gypsum and 0.6% by weight carbon black.
Examples 1-3 were prepared in the following manner:
A dry powder of Port land cement clinker was obtained by pulverization of Port land cement clinker.
Thereafter, molten or powdered asphalt was added to the dry powder and the resulting mixture was heated and agitated in a settle with heating and agitation devices at 100-150 C.
(straight asphalt 100-120 C., or blown asphalt 130-150 C.) and a pressure of 1 elm, for 2 hours. The resulting mixture was cooled to room temperature -to obtain the asphalt filmed Port land cement particles. Then, carbon black was added -to the asphalt filmed Port land cement powder and agitated until homogeneously mixed therewith.
Examples 4-6 were prepared according to Examples 1-3 except that gypsum was admixed with -the dry powder of ~22~
Port land cement clinker prior -to the addition of -the asphalt (and the temperature appropriately selected below the dehydration level of gypsum).
Comparative Examples 1-3 were preparing in the following manner:
A dry powder of ordinary Port land cement clinker was obtained by pulverization. Thereafter, carbon black was admixed with the cement dry powder at room -temperature until a homogeneous mixture was produced.
Comparative Examples 4-6 were prepared in the same manner as Comparative Examples 1-3 except that gypsum was also admixed with the cement dry powder and carbon black.
Concrete containing the cements of Examples 1-6 and Comparative Examples 1-6 were measured for compressive strength, water permeability at 15 kg/cm2 and adhesive strength of the reinforced bars by conventional method. The results are shown in Table A, below.
\ Item Compressive Strength Water Perle- Adhesive \ _ ability (aged Strength to \ 28 days a-t reinforcing Cement \ (aged 28 days) (aged 40 days) 15Kg/Cm bar Ordinary Portlcmd Lowe 100% 100% 100%
cement _ _ _ _ _ improved Port land cement according 94-98% 100-125% 0% 110-150%
invention While the present invention has been described in detail and with reference -to specific embodiments -thereof, it would be apparent to one skilled in the art that various - I
I
changes and modifications can be made therein without departing from the spirit and slope -thereof.
Claims (11)
1. A Portland cement composition comprising (a) dry powder of Portland cement, whose surface is coated with an asphalt film; and, (b) particles of carbon black.
2. A Portland cement composition as in claim 1, wherein said asphalt film comprises a film of straight asphalt or blown asphalt.
3. A Portland cement composition as in claim 2 wherein said asphalt has a softening point between 40°C-90°C.
4. A Portland cement composition as in claim 3 wherein said asphalt is present in an amount of 0.2% to 1.0% by weight.
5. A Portland cement composition as in claim 1 wherein said carbon black has a particle diameter of 60 millimicrons or less.
6. A Portland cement composition as in claim 5 wherein said carbon black is present in an amount of 0.2% to 1.5% by weight.
7. A Portland cement composition as in claim 1, wherein gypsum is present in said Portland cement in an amount of 2% to 5% by weight.
8. A method of preparing a Portland cement composition comprising the steps of:
(a) adding molten or powdered asphalt to a dry powder of Portland cement;
(b) heating and agitating the mixture of step (a) at 100 to 150°C;
- Page 1 of Claims -(c) cooling the product of step (b) to room temperature;
(d) admixing the resulting asphalt filmed Portland cement particles of step (c) with carbon black and agitating until a substantially homogeneous mixture is produced.
(a) adding molten or powdered asphalt to a dry powder of Portland cement;
(b) heating and agitating the mixture of step (a) at 100 to 150°C;
- Page 1 of Claims -(c) cooling the product of step (b) to room temperature;
(d) admixing the resulting asphalt filmed Portland cement particles of step (c) with carbon black and agitating until a substantially homogeneous mixture is produced.
9. A method for producing a Portland cement composition as in claim 8 wherein said asphalt is straight asphalt and heating and agitating in step (b) is conducted at 100°C to 120°C.
10. A method of producing a Portland cement composition as in claim 8 wherein said asphalt is blown asphalt and said heating and agitating in step (b) is conducted at 130°C to 150°C.
11. A method for producing a Portland cement composition as in claim 8 wherein gypsum is present in the dry powder of Portland cement of step (a) prior to the addition of said asphalt.
- Page 2 of Claims -
- Page 2 of Claims -
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000425509A CA1221389A (en) | 1983-04-08 | 1983-04-08 | Manufacturing method of portland cement |
| AU13296/83A AU560840B2 (en) | 1983-04-08 | 1983-04-11 | Improved portland cement with carbon black |
| GB08316034A GB2141421B (en) | 1983-04-08 | 1983-06-13 | Portland cement and method of manufacture thereof |
| IN1141/CAL/83A IN167369B (en) | 1983-04-08 | 1983-09-19 |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000425509A CA1221389A (en) | 1983-04-08 | 1983-04-08 | Manufacturing method of portland cement |
| AU13296/83A AU560840B2 (en) | 1983-04-08 | 1983-04-11 | Improved portland cement with carbon black |
| GB08316034A GB2141421B (en) | 1983-04-08 | 1983-06-13 | Portland cement and method of manufacture thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1221389A true CA1221389A (en) | 1987-05-05 |
Family
ID=36778163
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000425509A Expired CA1221389A (en) | 1983-04-08 | 1983-04-08 | Manufacturing method of portland cement |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU560840B2 (en) |
| CA (1) | CA1221389A (en) |
| GB (1) | GB2141421B (en) |
| IN (1) | IN167369B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5236500A (en) * | 1990-09-07 | 1993-08-17 | Schneider John F | Homogeneous composition of cementitious and tar components and process for forming shaped articles therefrom |
| AU762548B2 (en) * | 1998-09-03 | 2003-06-26 | Guy Shaun Bright | A cementitious composition for inhibiting the formation of efflorescence |
| WO2000014027A1 (en) * | 1998-09-03 | 2000-03-16 | Richard John Bright | A cementitious composition for inhibiting the formation of efflorescence |
| CN107226655B (en) * | 2017-06-20 | 2019-09-03 | 上海微晶防水材料有限公司 | Water-proofing anticracking crystallite and villa basement leakage method for repairing and mending |
| CN113563025B (en) * | 2021-08-06 | 2022-12-27 | 宁夏嘉惠道路资源再生利用有限公司 | Grouting material for grouting type composite asphalt pavement |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB244603A (en) * | 1925-01-22 | 1925-12-24 | Otto Simon | Improvements in the process of making cement and mortar |
| GB404787A (en) * | 1931-11-05 | 1934-01-25 | Straba Strassenbaubedarfs Ag | Method of producing hydraulic building materials |
| GB505357A (en) * | 1937-10-05 | 1939-05-05 | Binney & Smith Co | Improvements in and relating to the production of cement and the like |
| GB520149A (en) * | 1938-10-12 | 1940-04-16 | Cabot Godfrey L Inc | Improvements in or relating to the manufacture of cement |
| DE1918904A1 (en) * | 1968-04-16 | 1969-11-06 | Shell Int Research | Concrete-based waterproof building material and process for its manufacture |
-
1983
- 1983-04-08 CA CA000425509A patent/CA1221389A/en not_active Expired
- 1983-04-11 AU AU13296/83A patent/AU560840B2/en not_active Ceased
- 1983-06-13 GB GB08316034A patent/GB2141421B/en not_active Expired
- 1983-09-19 IN IN1141/CAL/83A patent/IN167369B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| GB8316034D0 (en) | 1983-07-20 |
| GB2141421B (en) | 1986-08-28 |
| AU560840B2 (en) | 1987-04-16 |
| IN167369B (en) | 1990-10-13 |
| GB2141421A (en) | 1984-12-19 |
| AU1329683A (en) | 1984-10-18 |
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