Dry mixes and granular wet cement compositions containing cellulose ethers as lubricating additives for roller compacted concrete applications and methods of using the same

Abstract

The present invention provides a dry mix composition consisting of a low viscosity cellulose ether (50 to 750 mPa-s at 1 wt% solids, 20°C and 514 s-1 shear rate using a strain controlled rotational rheometer (e.g., ARES-G2 TM , TA Instruments)), a graded aggregate, and a hydraulic cement, or a granular wet cement composition consisting of the cement, a graded aggregate, and an admixture including the cellulose ether. The wet granular hydraulic cement composition behaves like an asphalt composition and has a zero or near zero slump, high lubricity, and water from 5 wt% to less than 13 wt%, or preferably greater than 5 wt% to 10.5 wt% based on the total weight of the granular wet cement composition. The low viscosity cellulose ether enables lubricity without compromising compaction and without causing air entrainment.

Description

[0001] This invention relates to a dry-mix composition for roller-compacted concrete (RCC) and a low-slump or zero-slump wet cement composition made therefrom, as well as a method of spreading the wet cement composition. More specifically, the invention relates to a dry-mix composition comprising hydraulic cement, aggregates (such as sand), finely granular materials (such as limestone), and one or more cellulose ethers based on 0.05% to 1.3% by weight, or preferably 0.08% to 1.1% by weight, of the total weight of the dry-mix composition, and wherein the wet cement composition made from the dry-mix composition and water based on a total weight of up to 13% by weight or up to 10.5% by weight of the granular wet cement composition exhibits a slump of less than 6 mm, or preferably less than 4.5 mm, as determined according to ASTM C143 (2010) using a stainless steel cone with a height of 80 mm, a top diameter of 40 mm, a bottom diameter of 90 mm, and a steel rod mixer with a diameter of 9.5 mm and a length of 266.7 mm.

[0002] Roller-compacted concrete (RCC) is a durable, low-cost paving technology that has been used for secondary roads. Unlike conventional concrete pavements, RCC can be paved using asphalt pavers without the use of formwork, molds, or reinforcing steel. RCC roads can be restored to use as quickly as one day after paving, while conventional concrete pavements require weeks of curing before traffic can resume. The easier paving method and rapid restoration make RCC an ideal choice, provided it can maintain a smooth appearance and the high durability characteristic of concrete pavements. However, RCC has a higher volumetric aggregate compared to conventional concrete; and the exposed surface of RCC pavements is known to have a high exposed aggregate area fraction and can be rough, and is subject to rapid degradation due to insufficient compaction and post-paving strength loss, thus limiting the use of RCC for parking lots, industrial roads, base courses, and shoulders.

[0003] In known versions of RCC, compaction and workability issues have been managed through the addition of chemical admixtures and formulation optimization. The term "compaction" is defined as the act or result of densifying material by removing air voids while maintaining moisture content. However, an alternative path of "consolidation" may emerge when compacting pavement under pressure during paving, where material densification is achieved by removing both air voids and water. Water removal has adverse effects on paved materials and can ultimately lead to failure and strength loss. Creating a water composition gradient can also be detrimental when compaction is performed only from the top surface, as a lower top water level adversely affects cement curing, while excess water at the bottom can lead to a layer curing in a swollen state. However, admixtures are designed to be present in the fluid or paste phase of the cement, with the cement itself being limited in the RCC composition. Extremely high levels of admixtures are required to observe their effects on desired compaction and workability, making them prohibitively expensive and / or adversely affecting strength or workability. It is desirable to produce a dry mix that forms RCC, which can achieve good compaction without a high proportion of admixture components.

[0004] US Patent 8,377,196 B2, granted to Bury et al., discloses a dry-cast cementitious composition comprising a rheology modifier containing at least one shear-thinning additive A (such as cellulose ethers, including salts of hydroxyalkyl cellulose, carboxyl cellulose, carboxylhydroxyalkyl cellulose, hydroxyalkylhydroxyalkyl cellulose, and mixtures thereof) and a non-shear-thinning additive B. This composition may be able to improve cycle time, workability, compressive strength, and compression ratio. However, Bury et al.'s composition requires molds and does not produce sufficient viscosity to provide a composition exhibiting little or no slump when mixed, which precludes its use in any compacted concrete paving solution.

[0005] According to the present invention, the inventors have solved the problem of providing a dry mix that provides a wet cement composition exhibiting good compaction and little or no slump, and that the wet cement composition is suitable for, for example, rolling or paving methods. Summary of the Invention

[0006] According to the present invention, the dry-mix composition comprises:

[0007] Hydraulic cement, such as ordinary Portland cement, aluminate cement, fly ash, pozzolanic ash, and mixtures thereof, is present in an amount of 10% to 23% by weight, or preferably 12% to 20% by weight, based on the total weight of the dry-mix composition; graded aggregate is present in an amount of 70% to 89.95% by weight, or preferably 75% to 89.65% by weight, based on the total weight of the dry-mix composition, the graded aggregate comprising...

[0008] i) one or more coarse aggregates having a screened particle size of 500 micrometers to 20 mm or preferably 1 mm to 18 mm, such as sand, limestone, gravel, granite or clay, or preferably sand or gravel, or preferably a combination of a first coarse aggregate and a second coarse aggregate, wherein the screened particle size of the first coarse aggregate is 200 micrometers to 3000 micrometers and the screened particle size of the second coarse aggregate is 2000 micrometers to 20 mm, wherein the ratio of the screened particle size of the second coarse aggregate to the screened particle size of the first coarse aggregate is in the range of 15:1 to 1.5:1 or preferably 10:1 to 2:1, and

[0009] ii) one or more fine aggregates, preferably limestone or sand, having a screened particle size of 40 micrometers to less than 3000 micrometers or preferably 70 micrometers to 3000 micrometers, and

[0010] A cellulose ether composition comprising one or a mixture of two or more cellulose ethers, wherein the amount based on the total weight of the dry-mixed composition is from 0.05% to 1.3% by weight, or preferably from 0.08% to 1.1% by weight, or more preferably from 0.08% to 0.35% by weight, wherein the cellulose ether or the mixture of two or more cellulose ethers is present at 1% cellulose ether solids, 20°C, and 514s. -1 The aqueous solution viscosity range at the shear rate is 50 mPa•s to 750 mPa•s, or preferably 80 mPa•s to 500 mPa•s, as determined by using a strain-controlled rotational rheometer (preferably an ARES-G2 from TA Instruments, Newburgh, Delaware). ™ It is equipped with a Peltier temperature controller and TRIOS ™ Data acquisition software (TA Instruments) and a DIN (German for Deutsches Institut für Normung eV, meaning German Institute for Standardization) sample holder including concentric cylinders were used. Strain rates ranging from 0.03 / s to 300 / s were scanned at ten points per group, and the average of two tests for each cellulose ether composition was reported. The aqueous solution was prepared by drying the cellulose ether powder overnight in a vacuum oven at 70°C, dispersing it in hot water at 70°C to dissolve it, cooling it to room temperature by stirring, and then refrigerating it overnight at 4°C.

[0011] The weight ratio of total coarse aggregate to total fine aggregate in this graded aggregate ranges from 4:1 to 0.9:1, or preferably from 3:1 to 1:1; and

[0012] Furthermore, all weight percent sums up to 100%. The dry-mix composition according to the invention may also contain one or more superplasticizers selected from superplasticizers containing polycarboxylate ethers, naphthalene sulfonates, lignin sulfonates, or mixtures thereof, preferably superplasticizers containing polycarboxylate ethers.

[0013] In the dry-mix composition according to the invention, the hydraulic cement may be selected from ordinary silicate cement, aluminate cement, pozzolanic cement or mixtures thereof, or preferably selected from ordinary silicate cement, aluminate cement or mixtures thereof.

[0014] Preferably, in the graded aggregate of the dry-mixed composition according to the invention, the ratio of the total coarse aggregate to the fine aggregate is in the range of 10:1 to 2:1 or preferably 8:1 to 2:1.

[0015] More preferably, the dry-mixed composition according to the invention comprises a mixture of a first coarse aggregate (such as sand or gravel) with a sieve particle size of 300 micrometers to 2000 micrometers and a second coarse aggregate (such as gravel or stone) with a sieve particle size of 2000 micrometers to 18 mm as coarse aggregate in the graded aggregate, wherein the ratio of the sieve particle size of the second coarse aggregate to the sieve particle size of the first coarse aggregate is in the range of 15:1 to 1.5:1 or preferably 10:1 to 2:1.

[0016] In the dry-mixed composition according to the invention, the side chain of at least one of the one or more cellulose ethers is selected from hydroxyethyl, hydroxypropyl, methyl, and combinations thereof, or preferably hydroxyethyl and methyl. More particularly, at least one of the one or more cellulose ethers is a hydroxyethyl methyl cellulose ether with a hydroxyethyl content (MS) ranging from 0 to 0.4 and a methoxy content (DS) ranging from 1.2 to 1.8, or a hydroxyethyl cellulose with a hydroxyethyl content (MS) ranging from 1.4 to 2.4 or preferably 1.8 to 2.2.

[0017] In the dry-mixed composition according to the invention, a superplasticizer (when present) may be used in the following amounts: 0.1% to 0.5% by weight of polycarboxylate ether, 0.2% to 5.0% by weight or 0.3% to 1.0% by weight of a material containing naphthalene sulfonate or lignin sulfonate, preferably 0.1% to 0.5% by weight of polycarboxylate ether.

[0018] Preferably, based on the total weight of the dry blend composition, the dry blend composition according to the invention comprises a total of less than 2% by weight of cellulose ether plus a superplasticizer.

[0019] When mixed with a single component of water in an amount of 5.0% to 13.0% by weight, or preferably greater than 5.0% to 10.5% by weight, based on the total weight of the resulting composition, the dry-mix composition according to the invention provides a granular wet cement composition according to a second aspect of the invention, wherein the slump of the composition is less than 6 mm, or preferably less than 4.5 mm, as per ASTM standards. C143 (2010) is defined by the following method: mixing the dry mixture in a plastic bag; adding the powder to the indicated amount of water in a Hobart mixing bowl; mixing twice at speed 1 for 15 seconds each time, stopping and scraping the sides of the bowl after each mixing; maturing the mixture for 10 minutes; and pouring the mixture in three equal layers into a stainless steel cone (80 mm high, 40 mm top diameter, and 90 mm bottom diameter), which has been moistened with water by a sponge and placed on a non-absorbent surface; filling each layer and mixing in a circular motion with a stainless steel rod (preferably 266.7 mm long and 9.5 mm in diameter); positioning the rod parallel to the sides of the cone and working in a vertical position to finish at the center; finishing the surface of the wet cement composition flush with the top of the cone; pulling the cone up and away from the wet cement composition; and recording the slump over 30 seconds by measuring the total height of the cone and reporting the difference between the measured height and 80 mm.

[0020] The dry blend composition according to the invention may comprise a single component of a two-component composition, wherein the first component comprises the dry blend composition and the second component comprises water, wherein the first or second component comprises one or more cellulose ethers, and, if used, any one or more superplasticizers.

[0021] According to a second aspect of the invention, the granular wet cement composition derived from the dry-mixed composition and water comprises:

[0022] Hydraulic cement, such as pozzolanic cement, ordinary Portland cement, aluminate cement, fly ash, and mixtures thereof, in an amount of 10% to 23% by weight, or preferably 12% to 20% by weight, based on the total weight of the dry-mixed composition.

[0023] The graded aggregate, based on the total weight of the dry-mixed composition, comprises 70% to 89.95% by weight, or preferably 75% to 89.65% by weight, of the graded aggregate.

[0024] i) one or more coarse aggregates having a screened particle size of 200 micrometers to 20 mm, such as sand, limestone, gravel, granite, or clay, or preferably sand, or more preferably a combination of a first coarse aggregate and a second coarse aggregate, wherein the screened particle size of the first coarse aggregate is 200 micrometers to 3000 micrometers and the screened particle size of the second coarse aggregate is 2000 micrometers to 20 mm, wherein the ratio of the screened particle size of the second coarse aggregate to the screened particle size of the first coarse aggregate is in the range of 15:1 to 1.5:1 or preferably 10:1 to 2:1, and

[0025] ii) One or more fine aggregates, preferably limestone, having a screened particle size of 40 micrometers to 3000 micrometers or preferably 70 micrometers to 3000 micrometers.

[0026] The cellulose ether or a mixture of two or more cellulose ethers, in an amount of 0.05% to 1.3% by weight, or preferably 0.08% to 1.1% by weight, or more preferably 0.08% to 0.35% by weight, wherein the cellulose ether or the mixture of two or more cellulose ethers is in a state of 1% cellulose ether solids, at 20°C and 514s. -1 The viscosity of the aqueous solution at the shear rate ranges from 50 mPa•s to 650 mPa•s, or preferably from 80 mPa•s to 500 mPa•s, as determined by using a strain-controlled rotational rheometer (preferably an ARES-G2 from TA Instruments, Newburgh, Delaware). ™ It is equipped with a Peltier temperature controller and TRIOS ™ Data acquisition software (TA Instruments) and a DIN (German for Deutsches Institut für Normung eV) sample holder including concentric cylinders were used to scan at strain rates from 0.03 / s to 300 / s in groups of ten points, expressed as the average of two tests for each cellulose ether. The aqueous solution was prepared by drying the cellulose ether powder overnight in a vacuum oven at 70°C, dispersing it in hot water at 70°C and dissolving it, while simultaneously cooling it to room temperature by stirring and refrigerating it overnight at 4°C; and water, in an amount of 5.0% to 13.0% by weight, or preferably greater than 5.0% to 10.5% by weight, based on the total weight of the granular wet cement composition.

[0027] The water saturation level of the wet cement composition is less than 58%, or preferably 56.5% or less, and this water saturation level is defined by the percentage of voids filled with wet cement or cement mixed with water, as expressed by the following equation:

[0028] Water saturation = (V w +V c ) / V V,

[0029] Where V w V is the volume of water in the wet cement composition. c It is the volume V of the cement. c =m c / ρ c , where m c It is the mass of cement in the wet cement composition and ρ c It is the material density of cement, and V V It is the total void volume in the total mixture, which is determined by measuring the particle density ρ of each material except cement and water. i Measure the total mass m of each material except cement and water. i The total volume V of all materials except cement and water is measured by thoroughly mixing them and pouring them all into a container, and the void volume V is calculated. v = V – Σ(m i / ρ i ),

[0030] Furthermore, the weight ratio of total coarse aggregate to total fine aggregate in this graded aggregate ranges from 4:1 to 0.9:1 or preferably from 3:1 to 1:1; and

[0031] Furthermore, the total weight percentage of all components in the dry-mixed composition is 100%.

[0032] According to the granular wet cement composition of the present invention, the ratio of the total coarse aggregate screening size to the fine aggregate screening size can be in the range of 20:1 to 1.5:1 or preferably 10:1 to 2:1.

[0033] More preferably, the granular wet cement composition according to the second aspect of the invention comprises a mixture of a first coarse aggregate (such as sand or gravel) with a sieve size of 300 micrometers to 3000 micrometers and a second coarse aggregate (such as gravel or stone) with a sieve size of 2000 micrometers to 18 mm as coarse aggregate in the graded aggregate, wherein the ratio of the sieve size of the second coarse aggregate to the sieve size of the first coarse aggregate is in the range of 15:1 to 1.5:1 or preferably 10:1 to 2:1.

[0034] According to a second aspect of the invention, the granular wet cement composition may comprise a mixture of two-component compositions, wherein the first component comprises a dry-mix composition and the second component comprises water, wherein the first or second component comprises one or more cellulose ethers in the amount stated for the dry-mix composition, and, if used, any one or more superplasticizers in the amount stated for the dry-mix composition.

[0035] The granular wet cement composition according to the second aspect of the invention may further contain one or more superplasticizers selected from superplasticizers containing polycarboxylic acid ethers, naphthalene sulfonates, lignin sulfonates, or mixtures thereof.

[0036] In the granular wet cement composition according to the second aspect of the invention, the superplasticizer may be used in the following amounts: 0.1% to 0.5% by weight of polycarboxylate ether, 0.2% to 5.0% by weight or 0.3% to 1.0% by weight of a material containing naphthalene sulfonate or lignin sulfonate, preferably 0.1% to 0.5% by weight of polycarboxylate ether, all amounts being based on the total weight of the dry-mixed composition.

[0037] The granular wet cement composition according to a second aspect of the invention further comprises one or more superplasticizers as part of a first component of the dry-mix composition, the superplasticizers being selected from polycarboxylate ethers, naphthalene sulfonates, lignin sulfonates, or mixtures thereof.

[0038] The granular wet cement composition according to the second aspect of the invention may further comprise one or more superplasticizers as part of a dry-mix composition mixed with water, the superplasticizers being selected from superplasticizers containing polycarboxylic acid ethers, naphthalene sulfonates, lignin sulfonates, or mixtures thereof.

[0039] Preferably, the slump of the granular wet cement composition according to the second aspect of the invention is 6 mm or less, or preferably 4.5 mm or less, as per ASTM standards. C143 (2010) uses a stainless steel cone with a height of 80 mm, a top diameter of 40 mm, and a bottom diameter of 90 mm, and a steel rod mixer with a preferred diameter of 9.5 mm and a length of 266.7 mm, determined by the following method: mixing the dry mixture in a plastic bag; adding the powder to the indicated amount of water in a Hobart mixing bowl; mixing twice at speed 1 for 15 seconds each time, stopping and scraping the sides of the bowl after each mixing; maturing the mixture for 10 minutes, and pouring the mixture in three equal layers into the stainless steel cone, which has been moistened with water by a sponge and placed on a non-absorbent surface; filling each layer and mixing with the stainless steel rod in a circular motion; positioning the rod parallel to the side of the cone and working in a vertical position to finish at the center; finishing with the surface of the wet cement composition flush with the top of the cone; pulling the cone up and away from the wet cement composition; and recording the slump over 30 seconds by measuring the total height of the cone and reporting the difference between the measured height and 80 mm.

[0040] More preferably, the lubricity of the wet cement composition according to the second aspect of the invention is 22° to 36.8° or less, or preferably 26° to 36°, or 36.0° or less, which is determined as the angle of inclination of the yield curve of the normal stress at which the composition yields in a shear test relative to the normal stress (on the abscissa), wherein the normal stress varies between 25% and 80% of the normal stress before shearing, according to ASTM D6773–16 (2016), preferably using an automated shear tester (Dietmar Schulze, Warfenbitter, Delaware) controlled by software RSTCONTROL 95 for MS Windows, with 50,000 Pa as the normal stress before shearing, and then reducing the normal stress and measuring at point intervals of 5 points / 10 points in the normal stress range of 12,500 Pa to at least 40,000 Pa, as a percentage of the normal stress before shearing.

[0041] In a third aspect of the invention, a method for manufacturing and using a granular wet cement composition according to a second aspect of the invention comprises forming the granular wet cement composition by: mixing water, hydraulic cement, and graded aggregate to form a wet cement composition; adding a cellulose ether composition as dry powder and any superplasticizer thereto and mixing in a pump or pug mill mixer to form the granular wet cement composition; applying the granular wet cement composition to a substrate without molds or templates; and then paving or compacting the wet cement composition to form concrete or a cement layer, such as a road or pavement. A steam roller without steam or conventional asphalt paving equipment can be used, preferably paving or compaction without the addition of heat.

[0042] In the method of a third aspect of the invention, the granular wet cement composition comprises water and a dry-mixed composition consisting of:

[0043] Hydraulic cement, such as pozzolanic cement, ordinary Portland cement, aluminate cement, fly ash, and mixtures thereof, in an amount of 10% to 23% by weight, or preferably 12% to 20% by weight, based on the total weight of the dry-mixed composition.

[0044] The graded aggregate, based on the total weight of the dry-mixed composition, comprises 70% to 89.95% by weight, or preferably 75% to 89.65% by weight, of the graded aggregate.

[0045] i) one or more coarse aggregates having a screened particle size of 200 micrometers to 20 mm, such as sand, limestone, gravel, granite, or clay, or preferably sand, or more preferably a combination of a first coarse aggregate and a second coarse aggregate, wherein the screened particle size of the first coarse aggregate is 200 micrometers to 3000 micrometers and the screened particle size of the second coarse aggregate is 2000 micrometers to 20 mm, wherein the ratio of the screened particle size of the second coarse aggregate to the screened particle size of the first coarse aggregate is in the range of 15:1 to 1.5:1 or preferably 10:1 to 2:1, and

[0046] ii) One or more fine aggregates, preferably limestone, having a screened particle size of 40 micrometers to less than 3000 micrometers or preferably 70 micrometers to 3000 micrometers.

[0047] The amount of cellulose ether or a mixture of two or more cellulose ethers, based on the total weight of the dry-mixed composition, is from 0.05% to 1.3% by weight, or preferably from 0.08% to 1.1% by weight, or more preferably from 0.08% to 0.35% by weight, wherein the cellulose ether or the mixture of two or more cellulose ethers is present at 1% cellulose ether solids, 20°C, and 514s. -1 The aqueous solution viscosity range at shear rates is 50 mPa•s to 650 mPa•s, or preferably 80 mPa•s to 500 mPa•s, as determined by using a strain-controlled rotational rheometer (ARES-G2, TA Instruments, Newburgh, Delaware). ™ It is equipped with a Peltier temperature controller and TRIOS ™ Data acquisition software (TA Instruments) and a DIN sample holder including concentric cylinders were used to scan at strain rates from 0.03 / s to 300 / s in groups of ten, expressed as the average of two tests for each cellulose ether. The aqueous solution was prepared by: drying the cellulose ether powder overnight in a vacuum oven at 70°C; dispersing the powder in hot water at 70°C to dissolve the particles with stirring; and simultaneously cooling the slurry to room temperature and refrigerating it overnight (4°C) to form the aqueous solution; and

[0048] Water is present in an amount of 5.0% to 13% by weight or preferably greater than 5% to 10.5% by weight, based on the total weight of the granular wet cement composition.

[0049] Furthermore, the water saturation level of the wet cement composition is less than 58%, which is defined by the percentage of voids filled by the wet cement (i.e., cement plus water), as expressed by the following equation:

[0050] Water saturation = (V w +V c ) / V V ,

[0051] Where V w V is the volume of water in the wet cement composition. c It is the volume V of the cement. c =mc / ρc, where mc is the mass of cement in the wet cement composition and ρc is the material density of cement, and V V It is the total void volume in the total mixture, which is determined by measuring the particle density ρ of each material except cement and water. i Measure the total mass m of each material except cement and water. i The total volume V of all materials except cement and water is measured by thoroughly mixing them and pouring them all into a container, and the void volume V is calculated. v = V – Σ(m i / ρ i );

[0052] Furthermore, the weight ratio of total coarse aggregate to total fine aggregate in this graded aggregate ranges from 4:1 to 0.9:1 or preferably from 3:1 to 1:1; and

[0053] Furthermore, wherein all weight percent of the dry-mixed composition adds up to 100%. Preferably, according to the method of applying a wet cement composition according to a third aspect of the invention, the composition comprises a mixture of a lower sieve size material with a sieve size of 200 micrometers to 3000 micrometers and a higher sieve size aggregate (such as sand or gravel) with a sieve size of 500 micrometers to 20 mm or preferably 1.5 mm to 18 mm as coarse aggregate in the graded aggregate.

[0054] The ratio of the total coarse aggregate to the fine aggregate in the wet cement composition can be in the range of 20:1 to 1.5:1 or preferably 10:1 to 2:1.

[0055] A method for applying a wet cement composition according to a third aspect of the invention, wherein the wet cement composition comprises a mixture of two-component compositions, wherein the first component comprises a dry-mix composition having or not having one or more cellulose ethers, and, if used, any one or more superplasticizers, and the second component comprises water, wherein the first component or the second component comprises the same amount of one or more cellulose ethers as described for the dry-mix composition, and, if used, any one or more superplasticizers as described for the dry-mix composition. A method for applying a wet cement composition according to a third aspect of the invention, wherein the wet cement composition further comprises one or more superplasticizers as part of the first component dry-mix composition mixed with water as the second component, or as a separate second component in water as a solution or dispersion of the first component dry-mix composition, wherein these superplasticizers are selected from polycarboxylate ethers, naphthalene sulfonates, lignin sulfonates, or mixtures thereof.

[0056] In the method of applying a wet cement composition according to a third aspect of the invention, wherein a superplasticizer is used in the wet cement composition in the following amounts: 0.1% to 0.5% by weight of polycarboxylate ether, 0.2% to 5.0% by weight or 0.3% to 1.0% by weight of a material containing naphthalene sulfonate or lignin sulfonate, or preferably 0.1% to 0.5% by weight of polycarboxylate ether, all amounts being based on the total weight of the dry-mixed composition.

[0057] Preferably, in the method of applying a wet cement composition according to the third aspect of the invention, the slump of the wet cement composition is less than 6 mm or preferably less than 4.5 mm, as per ASTM standards. C143 (2010) uses a stainless steel cone with a height of 80 mm, a top diameter of 40 mm, and a bottom diameter of 90 mm, and a steel rod mixer with a preferred diameter of 9.5 mm and a length of 266.7 mm, determined by the following method: mixing the dry mixture in a plastic bag; adding the powder to the indicated amount of water in a Hobart mixing bowl; mixing twice at speed 1 for 15 seconds each time, stopping and scraping the sides of the bowl after each mixing; maturing the mixture for 10 minutes, and pouring the mixture in three equal layers into the stainless steel cone, which has been moistened with water by a sponge and placed on a non-absorbent surface; filling each layer and mixing with the stainless steel rod in a circular motion; positioning the rod parallel to the side of the cone and working in a vertical position to finish at the center; finishing with the surface of the wet cement composition flush with the top of the cone; pulling the cone up and away from the wet cement composition; and recording the slump over 30 seconds by measuring the total height of the cone and reporting the difference between the measured height and 80 mm.

[0058] More preferably, in the method of applying a wet cement composition according to the third aspect of the invention, the wet cement composition has a lubricity of 22° to 36.8° or less, or preferably 26° to 36°, or 36.0° or less, which is determined as the angle of inclination of a yield curve plotted relative to the normal stress (on the abscissa) at the level of normal stress at which the composition yields in a shear test, wherein the normal stress varies between 25% and 80% of the normal stress before shearing, according to ASTM D6773–16 (2016), preferably using the standard test method for bulk solids using a Schultz annular shear tester, using an automated shear tester controlled by RSTCONTROL 95 software for MS Windows (Dietmar, Warfenbitter, Delaware). Schulze (the company) used 50,000 Pa as the pre-shear normal stress, and then reduced the normal stress and measured at point intervals of 5 points / groups of 10 points in the normal stress range from 12,500 Pa to at least 40,000 Pa, representing the percentage of the pre-shear normal stress.

[0059] Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” include plural referents. Unless otherwise defined, the terms used herein have the same meaning as commonly understood by those skilled in the art.

[0060] Unless otherwise specified, any term containing parentheses may alternatively refer to the entire term as if it did not contain parentheses, as well as the same term contained within parentheses, and combinations of each alternative. Thus, the term "(meth)acrylate" in alternatives includes methacrylates, or acrylates, or mixtures thereof.

[0061] The endpoints of all ranges involving the same component or property include endpoints and can be combined independently. Thus, for example, the disclosed range of 1.5:1 to 4.5:1, or preferably 2:1 to 4:1, or more preferably 2.5:1 to 3.7:1 means any or all of the ranges of 1.5:1 to 4.5:1, or 1.5:1 to 2:1, or 1.5:1 to 2.5:1, or 1.5:1 to 3.7:1, or 1.5:1 to 4:1, or 2:1 to 4.5:1, or preferably 2:1 to 2.5:1, or preferably 2:1 to 3.7:1, or preferably 2:1 to 4:1, or more preferably 2.5:1 to 4:1, or more preferably 2.5:1 to 3.7:1.

[0062] Unless otherwise specified, the temperature and pressure conditions are room temperature (23°C) and standard pressure (101.3 kPa), also known as “ambient conditions”. Furthermore, unless otherwise specified, all conditions include a relative humidity of 50% (RH).

[0063] All ranges listed are inclusive and composable. For example, a disclosure of 0.25 wt% to 0.5 wt%, or preferably 0.35 wt% to 0.45 wt%, will include all of 0.25 wt% to 0.5 wt%, or preferably 0.35 wt% to 0.45 wt%, or 0.25 wt% to 0.35 wt%, or 0.25 wt% to 0.45 wt%, or 0.35 wt% to 0.5 wt%, or 0.45 wt% to 0.5 wt%.

[0064] As used herein, the term “acrylic or vinyl” refers to addition polymerizable monomers or α,β-olefinically unsaturated monomers, such as alkyl and hydroxyalkyl (meth)acrylates, vinyl ethers, olefinically unsaturated carboxylic acids, alkyl (meth)acrylamides, or monomers containing oxidized olefinic groups, such as methoxy polyethylene glycol (meth)acrylate (mPEG(M)A) or polyethylene glycol (meth)acrylate (PEG(M)A) and allyl polyethylene glycol (APEG).

[0065] As used herein, the term "aqueous" means that the continuous phase or medium is water and, based on the weight of the medium, constitutes 0 to 10% by weight of the water-miscible compound. Preferably, "aqueous" refers to water.

[0066] As used in this article, the term "ASTM" refers to the publications of ASTM International, West Conshohocken, PA.

[0067] As used herein, the term "hydraulic cement" includes substances that solidify and harden in the presence of water, such as Portland cement, silicate-based cement, aluminate-based cement or high-alumina cement, pozzolanic cement, and composite cement.

[0068] As used herein, the term "dry blend" or "dry powder" refers to a storage-stable powder containing cement, cellulose ether, any other polymer additives, and any fillers, as well as drying additives. Dry blends do not contain water; therefore, they are storage-stable.

[0069] As used herein, the term “DS” is the average number of alkyl-substituted OH- groups per dehydrated glucose unit in a cellulose ether, and the term “MS” is the average number of hydroxyalkyl-substituted OH- groups per dehydrated glucose unit, as determined by the Zeisel method. The term “Ziesel method” refers to the Zeisel cleavage procedure used to determine MS and DS; see G. Bartelmus and R. Ketterer, Fresenius Zeitschrift fuer Analytische Chemie, Vol. 286 (1977, Springer, Berlin, DE), pp. 161–190.

[0070] As used herein, the term "lubricity" refers to the slope of the yield curve, expressed as the angle of a linearized yield trajectory plot measured by a shear test using an automated shear tester (Dietmar Schulze, Warfenbitter, .D.) controlled by RSTCONTROL 95 software for MS Windows, with a given pre-shear stress of 50,000 Pa. Lubricity measures the ability of particles to move relative to each other under shear, and lower relative normal forces and a lower slope are better. In other words, a lower "internal friction" angle implies higher lubricity, because internal friction is the ratio of the maximum internal shear force resisting movement between material particles to the normal force (compaction) between particles, or the resistance to movement of particles relative to each other under compaction and shear.

[0071] As used in this article, the term "overnight" refers to a period of 10 to 14 hours.

[0072] As used herein, the term "paste" refers to a mixture of hydraulic cement and water; paste does not include aggregates.

[0073] As used herein, unless otherwise specified, the phrase “polymer” includes homopolymers and copolymers derived from two or more different monomers, as well as segmental and block copolymers.

[0074] As used herein, the term “screening size” of material refers to the particle size determined by continuously screening the material through a smaller mesh screen until at least 10% by weight of the material remains on a given screen, and recording the size of the screen that is one screen size larger than the first screen that retains at least 10% by weight of the material.

[0075] As used herein, the term “total coarse aggregate sieve size” for mixtures of coarse aggregates refers to the weighted average of the sieve sizes of all coarse aggregates in the mixture. For example, the sieve size of a 50:50 w / w mixture of 1 mm sieve size coarse aggregate and 10 mm sieve size coarse aggregate is (1 mm × 0.5) + (10 mm × 0.5) or 5.5 mm.

[0076] As used herein, the term “slump” refers to the lateral or downward flow of a static sample of a wet cement composition over a given time period, and it can be measured in several ways.

[0077] As used herein, the term “storage stable” means that, for a given powdered additive composition, the powder will not clump, and for a given aqueous composition, when allowed to stand on a shelf at room temperature and standard pressure, the liquid composition will not become cloudy, separate, or precipitate after 5 days or preferably 10 days.

[0078] As used herein, the phrases “total solids,” “solids,” or “as solids” refer to the total amount of any or all non-volatile components or materials present in a given composition, including synthetic polymers, monomers, natural polymers, acids, defoamers, hydraulic cement, fillers, inorganic materials, and other non-volatile materials and additives, such as initiators. Water, ammonia, and volatile solvents are not considered solids.

[0079] As used in this article, the term "water saturation" refers to the water saturation obtained from the equation water saturation = (V / V) w +V c ) / V V The given results, where V w V is the volume of water in the wet cement composition. c It is the volume V of the cement. c =mc / ρc, where mc is the mass of cement in the wet cement composition and ρc is the material density of cement, and V V It is the total void volume in the total mixture, which is determined by measuring the particle density ρ of each material except cement and water. i Measure the total mass m of each material except cement and water. i The total volume V of all materials except cement and water is measured by thoroughly mixing them and pouring them all into a container, and the void volume V is calculated. v = V – Σ(m i / ρ i The void volume is also called porosity or interparticle porosity ϵ= [V –Σ(m i / ρ i)] / V, and is the reciprocal of the “stacked fraction” given by 1- ϵ. As used herein, unless otherwise specified, the term “weight%” refers to the weight percentage based on the indicated denominator.

[0080] According to the present invention, the inventors have discovered a granular hydraulic cement composition that behaves similarly to an asphalt composition using a low-viscosity cellulose ether in a cement admixture. The granular wet cement compositions according to the invention have a slightly lower saturation in water and, because they do not accumulate or settle under their own weight, appear and behave like dirt. Similarly, wet cement compositions formed by mixing the dry-mix composition according to the invention with water and optionally an admixture containing a cellulose ether do not accumulate or settle under their own weight. The compositions of the present invention enable paving via “compaction” or volumetric compression to achieve maximum strength without loss of any wet cement material. The composition provides viscosity to slow consolidation, or to reduce the loss of water and cement by mass relative to compaction. Additionally, the composition enhances lubricity in the formulation, which facilitates aggregate particle movement required for compacted pavements, densification, and removal of air voids to achieve optimal strength. In particular, the inventors have discovered that in roller-compacted concrete (RCC), lower viscosity cellulose ethers or mixtures thereof (ranging from 50 mPa•s to 750 mPa•s, for 1 wt% cellulose ether solids, at 20°C and 514 s) are suitable for use. -1 At shear rate, ARES-G2 ™ A strain-controlled rotational rheometer (TA Instruments, Newburgh, Delaware), scanning at strain rates from 0.03 / s to 300 / s in groups of ten points, surprisingly improved compaction and thus concrete strength, particularly based on the weight of the granular wet cement composition to which water was added to produce RCC, having 10.5% by weight or less water. In the wet cement composition according to the invention, at 20°C and 514 s... -1 The measured viscosity of the interstitial aqueous phase achieves optimal strength and compaction. Furthermore, when the aqueous phase is within this low viscosity range, the useful amount of cellulose ether can be varied for easier formulation.

[0081] Because admixtures are added by volume, not by mass, in the field of RCC blends, formulation limits for excessive or insufficient admixture dosage are critical. RCC blends are overly sensitive to high-viscosity cellulose ether grades, where a one percent variation can reduce the strength of the RCC blend, making their use impractical in this field. We have found that lower viscosity grades of cellulose ethers enable the achievement of the desired formulation limits for producing reliably compactable or pavable RCC blends.

[0082] According to the invention, the improved lubricity achieved by the water-soluble cellulose ether of the invention is insensitive to aggregate particle size, sphericity, and roughness. This is surprising because RCC has a higher volume of aggregate and lower levels of cement and water compared to conventional concrete. While this formulation difference results in pavements with zero or near-zero slump, the high aggregate and low water content in the formulation also makes RCC very resistant to compaction, resulting in a rougher product relative to conventional concrete pavements. Currently known viscosity modifiers (VMAs, such as polyvinyl alcohol) developed for concrete and used in RCC do not reduce yield strength (the force required to cause yielding or compaction of the mixture) nor improve lubricity. Instead, using known commercially available VMAs to achieve optimal viscosity and avoid consolidation would require impractically high levels of VMA in the RCC wet cement composition.

[0083] Furthermore, by combining cellulose ethers with superplasticizers, the lubricity and strength of products obtained from roller-compacted cement compositions can be further improved. The addition of superplasticizers (including plasticizers containing polycarboxylate ethers, lignin sulfonates, and naphthalene sulfonates) can further improve the yield strength and viscosity of RCC concrete and the wet cement composition used to manufacture it. When combined with cellulose ethers, using too much superplasticizer may adversely affect the yield strength, while too little superplasticizer will not change the strength or lubricity of concrete made from a wet cement composition containing superplasticizers. Therefore, according to the present invention, based on the total weight of the wet cement composition, a combination of typically less than 1% by weight of superplasticizer with a total amount of 2.5% by weight or less, or preferably 2% by weight or less of cellulose ether, yields optimal results for RCC pavement compaction and strength.

[0084] According to the invention, the dry-mix composition and wet cement formulation include cellulose ethers, granular materials, hydraulic binders or cement, and optionally other chemical admixtures. The wet cement composition comprises a dry-mix composition mixed with water in an amount of 5.0% to 13.0% by weight, or preferably greater than 5.0% to 10.5% by weight, based on the total weight of the granular wet cement composition, and optionally supplemental cementitious material (SCM). As the particle size of the graded aggregate (and especially coarse aggregate) increases, the water requirement decreases. Therefore, for example, when the sieved particle size of the coarse aggregate is 5 mm or larger, or 6 mm or larger, a suitable water content range is 5% to 6.5% by weight based on the total weight of the granular wet cement composition.

[0085] One or more cellulose ethers according to the invention comprise low-viscosity cellulose ethers. The one or more cellulose ethers may constitute part of a dry blend composition, or they may constitute part of a solution or dispersion in water as a second component of a two-component composition, wherein the first component comprises a dry blend composition (excluding cellulose ethers). The side chain of at least one of the one or more cellulose ethers is selected from hydroxyethyl, hydroxypropyl, methyl, and combinations thereof, or preferably hydroxyethyl and methyl. Therefore, the most preferred low-viscosity cellulose ether comprises hydroxyethyl methylcellulose.

[0086] In the low molecular weight cellulose ethers of the present invention, alkyl substitution is described in cellulose ether chemistry by the term "DS". DS is the average number of substituted OH groups per dehydrated glucose unit. Methyl substitution may be reported, for example, as DS (methyl) or DS (M). Hydroxyalkyl substitution is described by the term "MS". MS is the average number of moles of etherifying agent bound in ether form per mole of dehydrated glucose unit. Etherification with the etherifying agent ethylene oxide is reported, for example, as MS (hydroxyethyl) or MS (HE). Etherification with the etherifying agent propylene oxide is correspondingly reported as MS (hydroxypropyl) or MS (HP). Side groups are determined using the Zeisel method (reference: G. Bartelmus and R. Ketterer, Fresenius). Zeitschrift fuer Analytische Chemie 286 (1977), 161-190.

[0087] According to the present invention, one or more types of cement refers to any hydraulic cement that sets and hardens in the presence of water. Suitable non-limiting examples of hydraulic cement include silicate cement, hydraulic quicklime, aluminate cement, such as calcium aluminate cement, calcium sulfoaluminate cement, and hemihydrated calcium sulfate cement; volcanic ash, which is a siliceous or aluminosilicate material containing quicklime, which is finely crushed in the presence of water, and reacts chemically with calcium hydroxide released through the hydration of silicate cement to form a material with cementitious properties, such as diatomaceous earth, flint, clay, shale, fly ash, silica fume, volcanic tuff, and pumice, for example, volcanic ash mixed with quicklime; refractory cement, such as ground granular blast furnace slag; magnesium oxide cement, such as magnesium phosphate cement, potassium magnesium phosphate cement, and mixtures thereof. As used commercially, silicate cement means a hydraulic cement produced by pulverizing and calcining together with a clinker composed of one or more forms of calcium sulfate in a mill feed. According to ASTM C150, silicate cement is classified into types I, II, III, IV, or V.

[0088] Granular materials include, but are not limited to, sand, limestone, gravel, granite, and clay, and are graded aggregates comprising at least one coarse aggregate and at least one fine aggregate. Mixing smaller fine aggregate particles with larger coarse aggregate particles, such as compositions having more than one particle size distribution, reduces void volume and thus reduces cement requirements, and allows for improved packing and therefore higher strength with less water added at a constant water-to-cement ratio. Suitable fine aggregates are materials with a sieve size of, for example, less than 3000 micrometers, such as limestone, finely crushed silica, talc, fillers, or pigments. Suitable coarse aggregates have a sieve size of 2000 micrometers or larger. Examples include silica, quartz, crushed round marble, glass beads, granite, coarse limestone, calcite, feldspar, alluvial sand, or any other durable aggregate, natural or artificial sand, and mixtures thereof.

[0089] Admixtures include, but are not limited to, plasticizers, superplasticizers, retarders, accelerators, defoamers, and viscosity modifiers. Admixtures contain additives. Furthermore, the compositions of the present invention may contain conventional additives in wet or dry form, such as cement curing accelerators and retarders, air-entraining agents or defoamers, shrinkage agents and wetting agents; surfactants, particularly nonionic surfactants; mineral oil dust suppressants; biocides; plasticizers; organosilanes; antifoaming agents, such as poly(dimethylpolysiloxane) (PDMS) and emulsified PDMS, silicone oils, and ethoxylated nonionic compounds; and coupling agents, such as epoxysilanes, vinylsilanes, and hydrophobic silanes. Example

[0090] The following examples illustrate the invention. Unless otherwise specified, all parts and percentages are by weight, all temperatures are in °C, and all preparation and testing procedures were performed at room temperature (23 °C) and pressure (1 atm). In the examples below and in Tables 1, 2, and 3, the following abbreviations are used: CE: cellulose ether; MPEG: methoxy poly(ethylene glycol); MAA: methacrylic acid; AA: acrylic acid; MMA: methyl methacrylate; PEO: poly(ethylene oxide).

[0091] The following materials were used in the following examples (all components were used as is):

[0092] Silica sand: sieved to a particle size of 300 microns (Fairmount Minerals 730, Fairmount Minerals LLC, Oklahoma City, Oklahoma).

[0093] Crushed limestone: CaCO3, sieved to a particle size of 44 microns (MICRO-WHITE). ™100, Nagase Specialty Materials NA LLC, Itasca, Illinois;

[0094] Artificial sand: 6mm sieve size;

[0095] Silicate cement: Type 1 silicate cement;

[0096] Water (deionized);

[0097] Cellulose ether 1: Hydroxyethyl methylcellulose (HEMC), WALOCEL ™ MW 15000 PFV cellulose ether, The Dow Chemical Co., Midland, Michigan (Dow), MS=0.17, DS=1.40);

[0098] Cellulose ether 2: HEMC (WALOCEL) ™ M-20678 cellulose ether, Dow, MS=0.32, DS=1.73).

[0099] Cellulose ether 3: Hydroxyethyl cellulose, CELLOSIZE ™ QP 15000H cellulose ether, Dow, MS=2.0, DS=0;

[0100] Cellulose ether 4: HEMC, WALOCEL ™ MT 30000 cellulose ether, Dow, MS=0.40, DS=1.85).

[0101] Cellulose ether 5: Hydroxypropyl methylcellulose, METHOCEL ™ 240S cellulose ether, DuPont, Wilmington, ., MS=0.15, DS=1.81;

[0102] Cellulose ether 6: HEMC, WALOCEL ™ MT 10000 cellulose ether, Dow, MS=0.40, DS=1.85;

[0103] Cellulose ether 7: HEMC WALOCEL ™ MKW 15000 cellulose ether, MS=0.22, DS=1.64;

[0104] Cellulose ether 8: HEMC WALOCEL ™ MKX 15000 cellulose ether, MS=0.258, DS=1.60;

[0105] Viscosity modifier A: Diutan Gum, a natural high molecular weight gum produced through aerobic fermentation; KELCOCRETE ™ DG-F adhesive, Cp Kelco, Atlanta, Georgia;

[0106] Viscosity modifier B: Vinyl alcohol / vinyl acetate copolymer V-MAR ™ Aqueous solution of F100 polymer, WR Grace GCP Applied Technologies, Chicago, Illinois (Grace).

[0107] Viscosity modifier C: A blend of sodium gluconate water-reducing agent and polyacrylate carboxylic acid ester viscosity modifier, V-MAR ™ VSC500, Grace

[0108] Superplasticizer 1: Polyaromatic (quinoline) sulfonate water-reducing agent VISCTROL ™ Euclid Chemicals, Inc. (Euclid), Easton, Pennsylvania.

[0109] Superplasticizer 2: Melflux ™ 2651 F polycarboxylate, BASF, Ludwig Port, Delaware.

[0110] Superplasticizer 3: Sodium lignosulfonate or calcium lignosulfonate water-reducing agent, Eucon LR, Euclid;

[0111] Superplasticizer 4: 200g 2000 MW MPEG (MPEG 2000)p and 44.2g esterification product of hydrated poly(acrylic acid) (AA / MPEG) composite polymer containing sodium hypophosphite, 50% by weight solids, pH=3 and viscosity of 500 mPa.s, as measured by Brookfield Viscometer using #2 shaft at 30 rpm and 25°C;

[0112] Superplasticizer 5: Sodium naphthalenesulfonate or calcium naphthalenesulfonate water-reducing agent (TAMOL) ™ SN, Dow.

[0113] PEO: CarboWax ™ Polyethylene glycol 400 (380 g / mol to 420 g / mol), Dow.

[0114] Table A: Viscosity of 1% (w / w) aqueous cellulose ether or viscosity modifier at 20°C

[0115]

[0116] * indicates a comparison example.

[0117] To measure the values ​​in Table A above Viscosity Before use, the cellulose ether powder was dried overnight in a vacuum oven at 70°C. Additionally, all viscosity modifiers were used as is in deionized water at a 1% wt% solids content. A 1% wt% solids cellulose ether solution for testing was prepared by dispersing the dried powder in hot water at 70°C, then dissolving it with stirring while cooling to room temperature and refrigerating overnight (4°C). A strain-controlled rotational rheometer (ARES-G2) was used. ™ (TA Instruments, Newburgh, Delaware) measures viscosity; this rheometer is equipped with a Peltier temperature controller and TRIOS... ™ Data acquisition software (TA Instruments) and a DIN sample holder consisting of concentric cylinders were used, except in the cases of viscosity modifiers B and C, where the DIN sample holder was replaced by a double-walled concentric cylinder sample holder. Two tests were performed on each sample, and the average of the two tests was reported.

[0118] The following preparation method is used in the following embodiments:

[0119] Preparation of dry mixture and wet cement All sand, limestone, cement, cellulose ether, and superplasticizer shown in Tables 1A, 1B, 1C, 1D, 1E, and 1F were dry-mixed in a plastic bag for two minutes and then added to water in a mixing bowl (Hobart N50 mixer, Hobart Corporation, Troy, Ohio). Each formulation was mixed at a low rotation speed (136 RPM) for 15 seconds while scraping the sides of the mixing bowl and returning it to the bottom. The formulations were then mixed again at the same rotation speed. In all tests, the wet cement compositions were tested within 10 minutes of preparation. All compositions totaled 800 g of powder solids, of which 800 g represented 100% of the total dry powder fraction. Water by weight % is based on the total weight of the formulation (granular wet cement), which includes both powder solids and water.

[0120] Table 1A: Comparative formulations without cellulose ethers and superplasticizers 1

[0121]

[0122] Table 1B: Formulations of cellulose ethers with 54% water saturation 2

[0123]

[0124] Table 1C: Comparative formulations with cellulose ether and 56% water saturation 3

[0125]

[0126] Table 1D: Formulations with 0.1% to 0.25% cellulose ether and 56% water saturation 4

[0127]

[0128] Table 1E: Comparative formulation 5 with 0.15% cellulose ether and 56% water saturation

[0129]

[0130] Table 1F 1 6. Formulations containing superplasticizers and cellulose ethers or viscosity modifiers

[0131]

[0132] 1 In Table 1F, the compositions of the present invention contain cellulose ethers, while the comparative examples do not contain cellulose ethers.

[0133] Table 1G: Formulations containing 0.15% cellulose ether on the solid component of the formulation 7

[0134]

[0135] Table 1H: Formulations containing superplasticizer and 0.15% cellulose ether on the solid component of the formulation.

[0136]

[0137] Test methods The following test methods are used in the following embodiments:

[0138] water saturation Water saturation is defined as the percentage of voids filled by cement paste. Cement paste includes the volume fractions of cement and water, but excludes graded aggregates. Water saturation is given by the following equation.

[0139] Water saturation = (V w +V c ) / V V ,

[0140] Where V w V is the volume of water in the wet cement composition. c It is the volume V of the cement. c =m c / ρ c , where m c It is the mass of cement in the wet cement composition and ρ c It is the material density of cement, and V V It is achieved by measuring the particle density ρ of each material except cement and water. i The total void volume in the determined total mixture. The mass m of each material other than cement and water is measured. i The density ρ of each material, excluding cement and water, is determined by measuring its volume in a graduated container. i The volume V of water is measured by pouring it into a graduated container. w Record the mass m of the water. WSimilarly, to measure the density and mass of cement, ρ i and m i Therefore, the "void volume" V is calculated. v = V – Σ(m i / ρ i The void volume is also called porosity or interparticle porosity ϵ = [V – Σ(m i / ρ i )] / V, and is the reciprocal of the "packed fraction" given by 1- ϵ. To measure water saturation Measure the volume V of the water shown. w Volume V of dry cement c And the mass and density of the cement. Record the cement volume as V. c =m c / ρ c , where m c It is the mass of cement in the sample and ρ c This refers to the material density of cement. Water saturation = In order to measure Water saturation in wet cement composition A dry mixture of sand and aggregate, excluding cement and water, is prepared, and the dry volume V of a given mixture is measured by pouring each mixture into a graduated container. A wet cement composition is then formed as shown, and the void volume is determined.

[0141] Ring shear test Shear tests were performed according to ASTM D6773–16 (Standard Test Method for Bulk Solids Using a Schulz Ring Shear Tester, 2016). Parameters were measured using an automated ring shear tester (Dietmar Schulze, Warfenbitter, .D., controlled by RSTCONTROL 95 software for MS Windows) with a given pre-shear stress of 50,000 Pa. After 10 minutes of curing, the wet cement composition samples shown were loaded into the ring test unit. The weight of each sample was recorded. The test unit was then placed in the ring shear tester and the ring shear test program was started. Three parameters were measured to quantify the properties of the wet cement composition: unconstrained yield strength, cohesion, and internal friction angle. Unconstrained yielding Strength or yield strength The strength of bulk solids in an unconstrained state (unconstrained sidewalls) at compacted or consolidated levels was quantified and determined as the stress level (normal) that causes the wet cement composition in an unconstrained (unsupported) state to yield in response to shear. The slope of the yield curve determined by shear testing was used to determine... Internal friction angle (lubricity) Internal friction is the ability of particles in a composition to move relative to each other under shear. Internal friction is equal to the resistance to the movement of particles relative to each other under compaction and shear, and is the ratio of the maximum internal shear force resisting particle movement to the normal force between the particles. lubricity The slope of the yield curve, determined by a ring shear tester, is used to plot the relationship between the maximum internal shear as particles resist movement and the normal stress of the composition when exposed to normal compressive stress. Lower internal friction indicates higher lubricity. Cohesion Determine the strength of the wet cement composition when no external force is applied, and quantify the attraction between particles.

[0142] Extrusion of wet cement composition A strain-controlled capillary rheometer was used to characterize extrusion performance under final use conditions. The rheometer consisted of a vertically mounted test frame (INSTRON Model 5985, Instron, Norwood, Massachusetts) equipped with BLUEHILL3 data acquisition software (INSTRON); a 250-kN pressure sensor mounted below the crosshead; a U-shaped pin (rated 100kN) connecting the pressure sensor to a cylindrical metal piston (44.45 mm diameter); a fixed cylindrical metal cylinder (200 mm length, 44.45 mm diameter) anchored to the lower test frame stage, designed to guide the downward movement of the piston (44.45 mm diameter); and a tapered transition from the cylinder to the lower attached metal capillary (12.7 mm diameter, 50.8 mm length). The apparatus was placed in a constant temperature / humidity chamber (23°C (73°F), 50% humidity). 300 grams of the freshly prepared wet cement composition shown was manually filled into a metal cylindrical cylinder, and the composition was pushed downwards from the cylinder into a capillary via a piston, eventually exiting the capillary as a paste extrusion. A slow piston speed (20 mm / min) was applied until a force F of 0.2 kN was reached, and then the speed was increased to 500 mm / min for the remaining extrusion. The force F, measured as a function of the piston displacement D, was measured by a force sensor. The piston displacement sometimes stopped before the maximum displacement (160 mm), at which point the force sensor was close to its upper force limit (90 kN). Steady-state flow was identified when the extrusion force F measured by the pressure sensor became insensitive to the piston displacement D. The average force at a displacement of 100 mm (F at D = 100 mm) was recorded as the steady-state force F. SS Extrusion at 500 mm / min is completed within 9 to 20 seconds. Extrusion stress or σ Record the force F divided by the capillary cross-sectional area A, and calculate as follows: σ (MPa) = (F[N] / {π• (D 模头 [m] / 2) 2}) • (10 -6MPa / Pa), where D 模头[m] = 0.50 inches / 39.3700787 inches / M = 0.0127 M. The extrusion shear strain rate at the capillary wall is dγ / dt (dγ / dt) = 32Q / [π•(D 模头 ) 3 = 514 / s based on paste volumetric flow rate Q (Q = v 活塞 • π• (D 模头 [m] / 2) 2 ), capillary diameter D 模头 [m] and piston speed (v) 活塞 ). (The capillary wall at...) Shear viscosity ƞ (Pa•s) is defined as extrusion stress. σ The extrusion shear strain rate at the capillary wall dg / dt (514s) -1 The ratio of ).

[0143] Rheology of wet cement compositions The stress-controlled rotational rheometer (AR-G2, TA Instruments, Newburgh, Delaware) equipped with a Peltier temperature controller was used at 20.0°C, and the RHEOLOGY ADVANTAGE was employed. ™ Rheological data were measured using data acquisition software (TA Instruments, v5.5.24). The material was sheared by rotating a four-bladed stainless steel rotor within a stainless steel cup with an inner radius of 15.00 mm. The outer radius of the blades was 14.00 mm. The cup was filled to an immersion height of 42.00 mm. The sample volume was approximately 28.72 mL. The expression used to convert the transducer data into rheological data was associated with a DIN concentric cylinder fixture; therefore, the rheological data were labeled as apparent rheology. The wet cement composition was studied immediately after preparation in a Hobart mixer. First, the recovery of the composition from the stream in the Hobart mixer was monitored for 15 minutes using time-resolved small-amplitude oscillating shear flow (angular oscillation frequency of 1 rad / s, stress amplitude in a linear viscoelastic mechanism). The recovered unconstrained paste was determined using stress amplitude scanning (1 Pa to 5000 Pa, 25 points / group of ten). Yield stress (σ) Y ) The yield stress was determined as the stress amplitude associated with the inflection point of the dependence of the complex shear modulus |G*| on the stress amplitude σ0. The inflection point was quantitatively determined by nonlinear fitting of the data on the semi-logarithmic axis using a sigmoid function. Three replicate studies were conducted using equal aliquots of fresh wet cement composition, and the results were averaged.

[0144] slump of wet cement compositionThe slump was determined as follows: the dry ingredients were mixed in a plastic bag; the powder was added to the indicated amount of water in a Hobart mixing bowl; the mixture was mixed twice at speed 1 for 15 seconds each time, stopping after each mix and scraping the sides of the bowl; the mixture was allowed to mature for 10 minutes, and then poured into three equal layers into a stainless steel cone (80 mm high, 40 mm top diameter, and 90 mm bottom diameter), which had been moistened with water via a spray bottle and placed on a non-absorbent surface; each layer was filled and mixed in a circular motion with a steel rod; the rod was positioned parallel to the sides of the cone and worked in a vertical position to finish at the center; the surface of the wet cement composition was flush with the top of the cone; the cone was pulled up and removed from the wet cement composition; and the slump was recorded by measuring the total height of the cone and reporting the difference between the measured height and the initial 80 mm height.

[0145] Table 2: Cellulose ether ring shear test of wet cement composition at 54% water saturation

[0146]

[0147]

[0148] * indicates a comparative example; 1. A stress-controlled rotational rheometer (AR-G2, TA Instruments) was used at 20.0°C.

[0149] As shown in Table 2 above, only Examples 1-2 to 1-15 of the Invention exhibit an acceptable yield strength of 45 kPa or higher at an acceptable low lubrication angle of less than 37 degrees. Therefore, the compositions of the present invention are easy to compact without consolidation and provide sufficient yield strength to resist shape change without compressive force.

[0150] Table 3: Extrusion and rheological test data at 56% water saturation

[0151]

[0152]

[0153] * indicates a comparison example.

[0154] As shown in Table 3 above, the wet cement compositions of the present invention in Examples 2-2, 2-3, 2-4 and 2-5, which have low viscosity cellulose ethers, were compacted without consolidation and compacted to a point where the force no longer shifted.

[0155] Table 4: Extrusion and oscillatory rheological tests with various superplasticizers at 56% water saturation.

[0156]

[0157] * indicates a comparison example.

[0158] As shown in Table 4 above, all wet cement compositions 3-1 to 3-7 of the present invention give acceptable lubrication angles and yield strengths, except for Examples 3-4, which have 56% water saturation, a large amount of water, and are difficult to compact.

[0159] Table 5: Slump of the wet cement mixtures shown

[0160]

[0161] * indicates a comparison example.

[0162] As shown in Table 5 above, the slump, which is directly related to the yield stress of the mixture, is a sensitive function of water saturation. At 54% water saturation, all examples 5-4, 5-5, and 5-6 exhibit yield stresses above the self-consolidation critical limit. At 56% water saturation, despite the low viscosity of cellulose ether 1, the compositions of the present invention in Example 5-2 achieve limited or controlled slump compared to the composition without cellulose ether in Comparative Example 5-1. Meanwhile, the superplasticizer increases the slump within reasonable limits.

Claims

1. A granular wet cement composition derived from a dry-mix composition and water, said granular wet cement composition comprising: Hydraulic cement, based on the total weight of the dry-mix composition, is present in an amount of 10% to 23% by weight. The graded aggregate, based on the total weight of the dry-mixed composition, comprises 70% to 89.95% by weight, wherein the graded aggregate includes i) one or more coarse aggregates with a sieve size of 200 micrometers to 20 mm, and ii) one or more fine aggregates with a sieve size of 70 micrometers to less than 3000 micrometers, wherein the weight ratio of i) total coarse aggregate to ii) total fine aggregate in the graded aggregate ranges from 4:1 to 0.9:

1. The amount of cellulose ether or a mixture of two or more cellulose ethers, based on the total weight of the dry mixture, is from 0.05% to 1.3% by weight, wherein the cellulose ether or the mixture of two or more cellulose ethers is in a state of 1% cellulose ether solids, at 20°C and 514s. -1 The viscosity of the aqueous solution at shear rates ranged from 50 mPa•s to 750 mPa•s, determined by scanning at strain rates from 0.03 / s to 300 / s using a strain-controlled rotational rheometer at ten points per group, expressed as the average of two tests for each cellulose ether. The aqueous solution was prepared by drying the cellulose ether powder overnight in a vacuum oven at 70°C, dispersing the powder in hot water at 70°C, dissolving it with stirring, cooling it to room temperature, and then refrigerating it overnight at 4°C to form the aqueous solution. Water, based on the total weight of the granular wet cement composition, is present in an amount of 5.0% to 13% by weight. The water saturation level of the granular wet cement composition is less than 58%, and the water saturation level is defined by the percentage of voids filled with wet cement, i.e., cement plus water, which is expressed by the following equation: Water saturation = (V w +V c ) / V V , Where V w V is the volume of water in the granular wet cement composition. c It is the volume V of the cement. c =mc / ρc, where mc is the mass of cement in the granular wet cement composition and ρc is the material density of the cement, and V V It is the total void volume in the total mixture, which is determined by measuring the particle density ρ of each material except cement and water. i Measure the total mass m of each material except cement and water. i The total volume V of all materials except cement and water is measured by pouring them into a container and mixing them thoroughly, and then the total void volume V is calculated. v = V – Σ (m i / ρ i ); The slump of the granular wet cement composition is 6 mm or less, which is determined according to ASTM C143-2010 using a stainless steel cone with a height of 80 mm, a top diameter of 40 mm, a bottom diameter of 90 mm, and a steel rod with a diameter of 9.5 mm and a length of 266.7 mm by mixing the dry mix in a plastic bag; adding the powder to the indicated amount of water in a Hobart mixing bowl; Mix twice at speed 1 for 15 seconds each time, stopping and scraping the sides of the bowl after each mix; let the mixture mature for 10 minutes, and then pour the mixture into the stainless steel cone in three equal layers, which has been moistened with water by a sponge and placed on a non-absorbent surface; fill each layer and mix in a circular motion with the steel rod stirrer; position the steel rod stirrer parallel to the side of the cone and work in a vertical position to finish in the center; The surface of the granular wet cement composition is made flush with the top of the cone; the cone is pulled up and removed from the granular wet cement composition; and the slump is recorded over 30 seconds by measuring the total height of the cone and reporting the difference between the measured height and 80 mm. as well as Wherein, the total weight percentage of all components in the dry mixture is 100%.

2. The granular wet cement composition according to claim 1, wherein the granular wet cement composition comprises water, and the amount of water is greater than 5.0% by weight to 10.5% by weight based on the total weight of the granular wet cement composition.

3. The granular wet cement composition according to claim 1, wherein the cellulose ether or a mixture of two or more cellulose ethers is at 1% by weight cellulose ether solids, 20°C and 514s. -1 The viscosity of the aqueous solution at the shear rate ranged from 80 mPa•s to 500 mPa•s, and was determined using a strain-controlled rotational rheometer equipped with a Peltier temperature controller and a TA Instruments TRIOS instrument. ™ Data acquisition software and a DIN sample holder including concentric cylinders were used to scan at strain rates from 0.03 / s to 300 / s in groups of ten points, expressed as the average of two tests for each cellulose ether. The aqueous solution was prepared by drying the cellulose ether powder overnight in a vacuum oven at 70°C, dispersing it in hot water at 70°C, dissolving it with stirring, cooling it to room temperature, and refrigerating it overnight at 4°C to form the aqueous solution.

4. The granular wet cement composition according to claim 1, wherein the coarse aggregate in the graded aggregate comprises a mixture of a first coarse aggregate with a screen size of 300 micrometers to 2000 micrometers and a second coarse aggregate with a screen size of 2000 micrometers to 18 mm, and wherein the ratio of the screen size of the second coarse aggregate to the screen size of the first coarse aggregate is in the range of 15:1 to 1.5:

1.

5. The granular wet cement composition according to claim 1, wherein the granular wet cement composition further comprises one or more superplasticizers selected from polycarboxylate ethers, naphthalene sulfonates, lignin sulfonates, or mixtures thereof.

6. The granular wet cement composition according to claim 1, wherein the slump is 4.5 mm or less, as determined according to ASTM C143-2010 using a stainless steel cone with a height of 80 mm, a top diameter of 40 mm, a bottom diameter of 90 mm, and a steel rod mixer with a diameter of 9.5 mm and a length of 266.7 mm.

7. The granular wet cement composition of claim 1, wherein the lubricity is 22° to 36.8° or less, said lubricity being determined as the angle of inclination of a yield curve plotted relative to the normal stress at which the granular wet cement composition yields in a shear test, at a normal stress level at which the granular wet cement composition yields, wherein said normal stress varies between 25% and 80% of the pre-shear normal stress, using 50,000 Pa as said pre-shear normal stress according to ASTM D6773–16-2016, and then reducing the normal stress and measuring at point intervals of 5 points / groups of 10 points in the normal stress range of 12,500 Pa to at least 40,000 Pa, representing the percentage of pre-shear normal stress.

8. The granular wet cement composition according to claim 7, wherein the lubricity is 22° to 36.0°.

9. The granular wet cement composition according to claim 1, wherein the side chain of at least one of the cellulose ethers or a mixture of cellulose ethers is selected from hydroxyethyl, hydroxypropyl, methyl, and combinations thereof.

10. The granular wet cement composition according to claim 9, wherein at least one of the cellulose ethers or mixtures of cellulose ethers is a hydroxyethyl methyl cellulose ether with a hydroxyethyl content MS ranging from 0 to 0.4 and a methoxy content DS ranging from 1.2 to 1.8, or a hydroxyethyl cellulose with a hydroxyethyl content MS ranging from 1.4 to 2.

4.

11. A method, the method comprising: The granular wet cement composition according to claim 1 is formed by mixing water, hydraulic cement, and graded aggregate to form the wet cement composition. The cellulose ether composition and any superplasticizer are added as dry powder and mixed in a pump or mortar mixer. The granular wet cement composition is applied to the substrate without molds or templates, and then... Spread or compact the granular wet cement composition to form concrete or a cement layer.

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