DRY MIXES AND CEMENTS CONTAINING CELLULOSE ETHERS AS LUBRICATIVE ADDITIVES FOR ROLLER COMPACTED CONCRETE APPLICATIONS AND METHODS OF USING THEM

Abstract

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

Claims

1. A granular wet cement composition from a dry mix composition and water comprising: hydraulic cement in the amount of from 10 to 23 wt. %, based on the total weight of the dry mix composition, graded aggregate in the amount of from 70 to 89.95 wt. %, based on the total weight of the dry mix composition, comprising i) one or more coarse aggregates having a sieve particle size of from 200 microns to 20 mm, and ii) one or more fine aggregates having a sieve particle size of from 70 microns to less than 3000 microns, wherein the weight ratio of the i) total coarse aggregates to the ii) total fine aggregates in the graded aggregate ranges from 4:1 to 0.9:1, a cellulose ether or a mix of two or more cellulose ethers in the amount of from 0.05 to 1.3 wt. %, based on the total weight of the dry mix composition, wherein the cellulose ether or mix of two or more cellulose ethers have an aqueous solution viscosity at 1 wt. % cellulose ether solids, at 20° C., and a 514 s.sup.−1 shear rate, as determined using a strain-controlled rotational rheometer, employing a strain rate sweep from 0.03 to 300/s at ten points/decade, and as expressed as the average of two trials for each cellulose ether, ranging from 50 to 750 mPa.Math.s, wherein the aqueous solution was made by drying the cellulose ether powder overnight in a 70° C. vacuum oven, dispersing the powder into hot water at 70° C., allowing it to dissolve with stirring as it cools to room temperature and refrigerating it overnight at 4° C. to form the aqueous solution, and, water in the amount of from 5.0 to 13 wt. %, based on the total weight of the granular wet cement composition; wherein the granular wet cement composition has a water saturation level of less than 58%, as defined by the percentage of voids filled with wet cement, which is cement plus water, as expressed by the following equation:
Water saturation=(V.sub.w+V.sub.c)/V.sub.V, wherein V.sub.w is the volume of water in the wet cement composition, V.sub.c is the volume of cement V.sub.c=m.sub.c/ρc, where m.sub.c is the mass of cement in the wet cement composition and ρc is the material density of the cement, and V.sub.V is the total void volume in the total mixture determined by measuring the particle density of each material other than cement and water, ρ.sub.i, measuring the total mass of each material other than cement and water, m.sub.i, measuring the total volume of all materials other than cement and water, V, by pouring them into a container and mixing well, and then calculating void volume V.sub.v=V−Σ(m.sub.i/ρ.sub.i); further wherein the granular wet cement composition has a slump as determined in accordance with ASTM C143 (2010) using a stainless steel cone height 80 mm, top diameter 40 mm, bottom diameter 90 mm, and a steel rod stirrer 9.5 mm diameter, 266.7 mm length by mixing the dry mix compositions in a plastic bag, adding the powder to the indicated amount of water in a Hobart mixing bowl, mixing twice on speed 1 for 15 s and stopping after mixing each time to scrape the sides of the bowl, slaking the mixture for 10 minutes and pouring the mixture in three equal layers into the stainless-steel cone which has been dampened with water via 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 sides of the cone and working to a vertical position to finish in the center, finishing the surface of the wet cement composition flush with the top of the cone, pulling the cone up and off of the wet cement composition and recording the slump within 30 seconds by measuring the total height of the cone and reporting the difference in the measured height and 80 mm, of 6 mm or less; and, still further wherein, all wt. % s in the dry mix composition add to 100%.

2. The granular wet cement composition as claimed in claim 1, wherein the composition comprises water in the amount of from greater than 5.0 to 10.5 wt. %, based on the total weight of the granular wet cement composition.

3. The granular wet cement composition as claimed in claim 1, wherein the cellulose ether or mix of two or more cellulose ethers has an aqueous solution viscosity at 1 wt. % cellulose ether solids, at 20° C., and a 514 s.sup.−1 shear rate, as determined using a strain-controlled rotational rheometer equipped with a Peltier temperature controller, TRIOS™ data acquisition software (TA Instruments) and DIN sample fixtures comprising concentric cylinders, employing a strain rate sweep from 0.03 to 300/s at ten points/decade, and as expressed as the average of two trials for each cellulose ether, ranging from 80 to 500 mPa.Math.s, the aqueous solution made by drying the cellulose ether powder overnight in a 70° C. vacuum oven, dispersing it into hot water at 70° C., allowing it to dissolve with stirring as it cools to room temperature and refrigerating it overnight (4° C.) to form the aqueous solution.

4. The granular wet cement composition as claimed in claim 1, wherein the coarse aggregate in the graded aggregate comprises a mixture of a first coarse aggregate having a sieve particle size of from 300 to 2000 microns and a second coarse aggregate having a sieve particle size of from 2000 microns to 18 mm, and, further wherein, the ratio of the sieve particle size of the second coarse aggregate to the sieve particle size of the first coarse aggregate ranges from 15:1 to 1.5:1.

5. The granular wet cement composition as claimed in claim 1, further comprising one or more superplasticizers chosen from a polycarboxylate ether, naphthalene sulfonate containing, lignosulfonate containing superplasticizers, or mixtures thereof.

6. The granular wet cement compositions as claimed in claim 1 that has a slump as determined in accordance with ASTM C143 (2010), using a stainless steel cone of height 80 mm, top diameter 40 mm, bottom diameter 90 mm, and a steel rod stirrer of 9.5 mm diameter, 266.7 mm length, of 4.5 mm or less.

7. The granular wet cement composition as claimed in claim 1 having a lubricity of from 22° to 36.8° or less, determined as the angle of the slope of a yield curve taken as the level of normal stress at which the compositions yield in shear testing plotted versus the normal stress at which the compositions are tested, wherein the normal stress is varied from 25% to 80% of the pre-shear normal stress in accordance with ASTM D6773-16 (2016), using 50,000 Pa as the pre-shear normal stress and then reducing normal stress and measuring over a normal stress range of from 12,500 Pa to at least 40,000 Pa with a point spacing of 5 points per decade of % of pre-shear normal stress.

8. The granular wet cement composition as claimed in claim 7 having a lubricity of 36.0° or less.

9. The granular wet cement composition as claimed in claim 1, wherein at least one of the one or more cellulose ethers has a side chain chosen from hydroxyethyl, hydroxypropyl, methyl, and combinations thereof.

10. The granular wet cement composition as claimed in claim 9, wherein at least one of the one or more cellulose ethers is a hydroxyethyl methyl cellulose ether having a hydroxyethyl content (MS) ranging from 0 and 0.4, and a methoxyl content (DS) of from 1.2 to 1.8 or is a hydroxyethyl cellulose having a hydroxyethyl content (MS) of from 1.4 to 2.4.

11. A method comprising: forming the granular wet cement composition as claimed in claim 1 by mixing water, hydraulic cement and graded aggregate to form a wet cement composition, adding thereto the cellulose ether composition and any superplasticizer(s) as a dry powder thereto and mixing in a pump or a pug mill mixer, applying the granular wet cement composition to a substrate without a mold or a form, and then paving or rolling the wet cement compositions to form a concrete or cement layer.

Description

EXAMPLES

[0083] The following examples illustrate the present invention. Unless otherwise indicated, all parts and percentages are by weight and all temperatures are in ° C. and all preparations and test procedures are carried out at ambient conditions of room temperature (23° C.) and pressure (1 atm). In the examples and Tables 1, 2, and 3 that follow, the following abbreviations were used: CE: cellulose ether; MPEG: Methoxypoly(ethylene glycol); MAA: Methacrylic acid; AA: Acrylic acid; MMA: Methyl methacrylate; PEO: Poly(ethylene oxide).

[0084] The following materials were used in the Examples that follow (All components were used as received): [0085] Silica sand: Sieve particle size of 300 micron (Fairmount Minerals 730, Fairmount Minerals LLC, Oklahoma City, OK); [0086] Crushed limestone: CaCO.sub.3, Sieve particle size 44 microns (MICRO-WHITE™ 100, Nagase Specialty Materials NA LLC, Itasca, IL); [0087] Manufactured sand: 6 mm sieve particle size; [0088] Portland cement: Type 1 Portland cement); [0089] water (deionized); [0090] Cellulose ether 1: Hydroxyethyl methylcellulose (HEMC), WALOCEL™ MW 15000 PFV cellulose ether, The Dow Chemical Co., Midland, MI (Dow), MS=0.17, DS=1.40); [0091] Cellulose ether 2: HEMC (WALOCEL™ M-20678 cellulose ether, Dow, MS=0.32, DS=1.73); [0092] Cellulose ether 3: Hydroxyethyl cellulose, CELLOSIZE™ QP 15000H cellulose ether, Dow, MS=2.0, DS=0; [0093] Cellulose ether 4: HEMC, WALOCEL™ MT 30000 cellulose ether, Dow, MS=0.40, DS=1.85); [0094] Cellulose ether 5: Hydroxypropyl Methyl Cellulose, METHOCEL™ 240S cellulose ether, DuPont, Wilmington, DE, MS=0.15, DS=1.81; [0095] Cellulose ether 6: HEMC, WALOCEL™ MT 10000 cellulose ether, Dow, MS=0.40, DS=1.85; [0096] Cellulose Ether 7: HEMC WALOCEL™ MKW 15000 cellulose ether, MS=0.22, DS=1.64; [0097] Cellulose Ether 8: HEMC WALOCEL™ MKX 15000 cellulose ether MS=0.258, DS=1.60; [0098] Viscosity modifier A: Diutan Gum natural high-molecular-weight gum produced by aerobic fermentation; KELCOCRETE™ DG-F gum, Cp Kelco Co., Atlanta, GA; [0099] Viscosity modifier B: aqueous solution of vinyl alcohol/vinyl acetate copolymer V-MAR™ F100 polymer, WR Grace GCP Applied Technologies, Chicago, IL (Grace); [0100] Viscosity modifier C: Blend of sodium gluconate water reducer and polyacrylic acid carboxylate viscosity modifier, V-MAR™ VSC500, Grace [0101] Superplasticizer 1: Polyaromatic (quinoline) sulfonate water reducer VISCTROL™, Euclid Chemical Co, Easton, PA (Euclid); [0102] Superplasticizer 2: MELFLUX™ 2651 F polycarboxylate ether, BASF, Ludwigshafen, DE; [0103] Superplasticizer 3: Sodium or calcium lignosulfonate water reducer, Eucon LR, Euclid; [0104] Superplasticizer 4: Aqueous poly(AA/MPEG) comb polymer esterification product of 200 g of 2000 MW MPEG (MPEG 2000) and 44.2 g of an aqueous poly(acrylic acid) containing sodium hypophosphite at 50 wt. % solids with a pH=3 and a viscosity of 500 mPa.Math.s as measured by Brookfield Viscometer using #2 spindle at 30 rpm, 25° C.; [0105] Superplasticizer 5: Sodium or calcium naphthalene sulfonate water reducer (TAMOL™ SN, Dow). [0106] PEO: CarboWax™ Polyethylene Glycol 400 (380-420 g/mol), Dow.

TABLE-US-00001 TABLE A Viscosities of 1 wt. % Aqueous Cellulose Ethers or Viscosity Modifiers at 20° C. Cellulose ether or η(514 s.sup.−1), Comparative mPa .Math. s 1 137 2 302 3 132 4 194 5 190 6 129 7 143 8 139 Viscosity modifier A* 74 Viscosity modifier B* 1.1 Viscosity modifier C* 1.3 Water* 1.0 *—Denotes Comparative Example.

[0107] To measure the viscosity in Table A, above, the cellulose ether powders were dried overnight in a 70° C. vacuum oven prior to use. Otherwise, all viscosity modifiers were used as received at a 1 wt. % solids content in deionized water. Cellulose ether solutions were prepared for testing at 1 wt. % solids by drying the powder, dispersing the powder into hot water at 70° C., followed by allowing to dissolve with stirring while cooling to room temperature and refrigerating overnight (4° C.). Viscosity was measured using a strain-controlled rotational rheometer (ARES-G2™, TA Instruments, New Castle, DE), equipped with a Peltier temperature controller, TRIOS™ data acquisition software (TA Instruments) and DIN sample fixtures comprising concentric cylinders except in the case of Viscosity modifiers B and C, where the DIN sample fixtures were replaced with double-wall concentric cylinder sample fixtures. Two trials were run for each sample, with the average of the two reported.

[0108] The following formulation method was used in the examples that follow:

[0109] Dry Mix and Wet cement Preparation: The indicated sand, limestone, cement, cellulosic ether, and superplasticizer in all of Tables 1A, 1B, 1C, 1D, 1E and 1F were dry mixed in a plastic bag for two minutes, and then added to the water in a mixing bowl (Hobart N50 Mixer, Hobart Corp., Troy, OH). Each formulation was mixed at a low rotation rate (136 RPM) for 15 seconds, while mixing bowl sides were scraped off and returned to the bowl bottom. The formulations were mixed at the same rotation rate again. In all tests, the wet cement compositions were tested within 10 min. after preparation. All compositions totaled 800 g powder solids, where 800 g is 100% of the total parts of dry powder. Water wt. % is based on the total formulation (granular wet cement) weight, which includes powder solids and water.

TABLE-US-00002 TABLE 1A Comparative Formulation 1 Without Cellulose Ether and Superplasticizer Material Wt. % Portland 15.0 Silica sand 65.0 Crushed limestone 20.0 Total Parts of Dry Powder 100.0 Water to powder ratio 0.135:1 Water fraction of total sample 11.89%

TABLE-US-00003 TABLE 1B Formulation 2 With Cellulose Ether at 54% Water Saturation Material Wt. % Portland Cement 15.0 Silica sand 65.0 Crushed limestone 20.0 Cellulose ether (See Tables 2, 3, 4 and 5) variable Total Parts of Dry Powder 100.0 Water to powder ratio 0.135:1 Water fraction of total sample 11.89%

TABLE-US-00004 TABLE 1C Comparative Formulation 3 With Cellulose Ether and 56% Water Saturation Material Wt. % Portland Cement 15.0 Silica sand 65.0 Crushed limestone 20.0 Cellulose ether (See Tables 2, 3, 4 and 5) variable Total Parts of Dry Powder 100.0 Water to powder ratio 0.142:1 Water fraction of total sample 12.4%

TABLE-US-00005 TABLE 1D Formulation 4 With 0.1 to 0.25% Cellulose ether and 56% Water Saturation Material Wt % Portland Cement 15.0 Silica sand 64.75 Crushed limestone 100 20.0 Cellulose ether (See Tables 2, 3, 4 and 5) variable Total Parts of Dry Powder 100.0 Water to powder ratio 0.142:1 Water fraction of total sample 12.4%

TABLE-US-00006 TABLE 1E Comparative Formulation 5 With 0.15% Cellulose Ether And 56% Water Saturation Material Wt % Portland Cement 15.0 Silica sand 64.85 Crushed limestone 20.0 Cellulose ether (See Tables 2, 3, 4 and 5) 0.150 Superplasticizer 0 Total Parts of Dry Powder 100.0 Water to powder ratio 0.142:1 Water fraction of total sample 12.4%

TABLE-US-00007 TABLE 1F.sup.1 Formulation 6 With Superplasticizer and Cellulose Ether or Viscosity Modifier Material Wt % Portland Cement 15.0 Silica sand 64.775 Crushed limestone 20.0 Cellulose ether (See Tables 2, 3, 4 and 5) 0.150 Superplasticizer 0.075 Total Parts of Dry Powder 100.000 Water to powder ratio 0.142:1 Water fraction of total sample 12.4% .sup.1In Table 1F, inventive compositions comprise cellulose ether and comparatives do not.

TABLE-US-00008 TABLE 1G Formulation 7 With 0.15% Cellulose Ether On Formulation Solids Material Wt % Portland Cement 15.0 Silica sand 64.85 Crushed limestone 20.0 Cellulose ether 1 0.15 Total Parts of Dry Powder 100.000 Water to powder ratio 0.142:1 Water fraction of total sample 12.4%

TABLE-US-00009 TABLE 1H Formulation 8 With Superplasticizer and 0.15% Cellulose Ether On Formulation Solids Material Wt % Portland Cement 15.0 Silica sand 64.775 Crushed limestone 20.0 Cellulose ether 1 0.15 Superplasticizer 2 0.075 Total Parts of Dry Powder 100.000 Water to powder ratio 0.142:1 Water fraction of total sample 12.4%

[0110] Test Methods: The following test methods were used in the examples that follow:

[0111] Water Saturation: Defined as the percent void volume that is filled with a cement paste. A cement paste includes both the cement and water volume fractions but excludes graded aggregate. Water Saturation is given by the equation

Water Saturation=(V.sub.w+V.sub.c)/V.sub.v,

wherein V.sub.w is the volume of water in the wet cement composition, V.sub.c is the volume of cement V.sub.c=m.sub.c/ρ.sub.c, where m.sub.c is the mass of cement in the wet cement composition and pc is the material density of the cement, and V.sub.v is the total void volume in the total mixture determined by measuring the particle density of each material other than cement and water, ρ.sub.i. The mass of each material, m.sub.i, other than cement and water was measured. The density of each material other than cement and water, ρ.sub.i, was determined by pouring each material into a graduated container to measure its volume. The volume of water, V.sub.w, was measured by pouring it into a graduated container. The mass of water, mw, was recorded. Likewise, the density and mass of the cement ρ.sub.i, and m.sub.i, was measured. From this, “void volume” V.sub.v=V−Σ(m.sub.i/ρ.sub.i) was calculated. The void volume also is referred to as voidage or inter-particle porosity ϵ=[V−Σ(m.sub.i/ρ.sub.i)]/V and is the converse of the “packing fraction”, which is given by 1−ϵ. To measure Water Saturation, the volume V.sub.w of the indicated amount of water the volume of dry cement, V.sub.c, as well as the mass and density of the cement were measured. Cement volume was recorded as V.sub.c=m.sub.c/ρ.sub.c, where m.sub.c is the mass of cement in the sample and ρ.sub.c is the material density of the cement. Water saturation=(V.sub.w+V.sub.c)/V.sub.v. To measure Water Saturation in a wet cement composition, a dry mixture of sand and aggregates, not including cement and water, was prepared and the dry volume, V of the given mixture was measured by pouring each into a graduated container. Then, the indicated wet cement composition was formed and the void volume determined.

[0112] Ring Shear Testing: Shear testing was performed in accordance with ASTM D6773-16 (Standard Test Method for Bulk Solids Using Schulze Ring Shear Tester, 2016). An automated shear ring tester, controlled by the software RSTCONTROL 95 for MS Windows (Dietmar Schulze, Wolfenbuttel, DE), was used to measure parameters with 50,000 Pa as the given pre-shear stress. The indicated wet cement composition samples were loaded into an annular test cell after being slaked for 10 minutes. Each sample weight was recorded. The test cell was then placed into the ring shear tester and the ring shear testing program was initiated. Three parameters were measured to quantify properties of the wet cement compositions: Unconfined yield strength, cohesion, and internal friction angle. Un-confined yield strength or Yield Strength quantifies the strength of a bulk solid under a level of compaction or consolidation in unconfined state (no confining side walls) and was determined as the stress level (normal) that caused the wet cement composition in an unconfined (unsupported) state to yield in response to shear. Internal friction angle (Lubricity), or the ability of particles in the composition to move against one another under shear, was determined as the slope of a yield curve measured by shear testing. Internal friction equals the resistance of the particles to moving against each other under compaction and shear and is the ratio of the maximum internal shear force that resists the movement of the particles to the normal force between the particles. Lubricity was determined as the slope of a yield curve measured by the ring shear tester, wherein the curve plots the maximum internal shear at which the particles resist movement versus normal stress at which the composition is exposed to normal compaction. Lower internal friction means higher lubricity. Cohesion determines the strength of the wet cement compositions when external forces are not applied and quantifies the attractive forces between particles.

[0113] Wet Cement Composition Extrusion: A strain-controlled capillary rheometer was set up to characterize extrusion performance at end-use conditions. The rheometer comprised a vertically-mounted testing frame (INSTRON model 5985 Instron, Norwood, MA) equipped with BLUEHILL3 data acquisition software (INSTRON), a 250-kN load cell mounted below the crosshead, a clevis pin (rated at 100 kN) connecting the load cell to a cylindrical metal piston (44.45 mm diameter), a stationary metal cylindrical barrel (200-mm length, 44.45 mm diameter) anchored to the lower test-frame table is designed to guide the downward motion of the piston (44.45 mm diameter), a conical transition from the barrel to the lower attached metal capillary (12.7 mm diameter, 50.8 mm length). The setup was placed in a constant temperature/humidity room (23° C. (73° F.), 50% humidity). The metal cylindrical barrel was hand filled with 300 grams of the indicated freshly-prepared wet cement compositions, and the compositions were pushed downward by the piston from the barrel into the capillary, and ultimately exited the capillary as a paste extrudate. A slow piston velocity (20 mm/min) was applied until a force F of 0.2 kN was achieved, and then the velocity was elevated to 500 mm/minute for the rest of the extrusion. The load-cell force F was measured as a function of piston displacement D. The piston displacement sometimes stopped before maximum displacement (160 mm) when the load cell approached its upper force limit (90 kN). Steady-state flow was identified when the extrusion force F measured by the load cell became insensitive to piston displacement D. The average force at a displacement of 100 mm (F at D=100 mm) was recorded as steady-state force F.sub.SS. Extrusions at 500 mm/min were completed in 9 to 20 seconds. The extrusion stress or σ was reported as the force F divided by the capillary cross-sectional area A, and was calculated, as follows: σ (MPa)=(F[N]/{π.Math.(D.sub.die[m]/2).sup.2}).Math.(10.sup.−6 MPa/Pa), with D.sub.die[m]=0.50 inch/39.3700787 inch/M=0.0127 M. The extrusion shear strain rate dγ/dt at the capillary wall (dγ/dt)=32Q/[π.Math.(D.sub.die).sup.3=514/s is based on the paste volume rate Q of flow (Q=v.sub.piston.Math.π.Math.(D.sub.die[m]/2).sup.2), the capillary diameter D.sub.die[m], and the piston velocity (v.sub.piston). The shear viscosity η (Pa.Math.s) at the capillary wall is defined as the ratio of the extrusion stress σ and the shear strain rate dγ/dt (514 s.sup.−1) at the capillary wall.

[0114] Rheology of Wet Cement Composition: Rheological data was measured at 20.0° C. with a stress-controlled rotational rheometer (AR-G2, TA Instruments, New Castle, DE) equipped with a Peltier temperature controller and using RHEOLOGY ADVANTAGE™ data acquisition software (TA Instruments, v5.5.24). Materials were sheared via rotation of a four-vaned stainless-steel rotor within a stainless-steel cup having an inside radius of 15.00 mm. The vane had an outside radius of 14.00 mm. The cup was filled to 42.00 mm immersed height. Approximate sample volume was 28.72 mL. Expressions used to translate transducer data into rheology were associated with DIN concentric-cylinder fixtures, so the rheology data were labelled as apparent rheology. Wet cement compositions were studied immediately after their preparation in a Hobart mixer. First, the recovery of the composition from flow in the Hobart mixer was monitored for 15 minutes with a time-resolved small-amplitude oscillatory shear flow (angular oscillation frequency of 1 rad/s, stress amplitude in the linear viscoelastic regime). The yield stress (σγ) of the recovered unconfined paste was determined with a stress amplitude sweep (1 to 5000 Pa, 25 points/decade). The yield stress was identified as the stress amplitude associated with the inflection point of the dependence of the magnitude of the complex shear modulus magnitude |G*| on the stress amplitude σ.sub.0. The inflection point was determined quantitatively with a nonlinear fit of data on semi-log axes with a sigmoidal function. Three replicate studies were performed using a fresh wet cement composition aliqout for each replicate and the results were averaged.

[0115] Slump of wet cement composition: Slump was determined by mixing dry ingredients in a plastic bag, adding the powder to the indicated amount of water in a Hobart mixing bowl, mixing twice on speed 1 for 15 s and stopping after mixing each time to scrape the sides of the bowl, slaking the mixture for 10 minutes and pouring the mixture in three equal layers into a stainless steel cone (height 80 mm, top diameter 40 mm and bottom diameter 90 mm) which has been dampened with water via a spray bottle and placed on a non-absorbent surface, filling each layer and mixing with a steel rod in a circular motion, positioning the rod parallel to the sides of the cone and working to a vertical position to finish in the center, finishing the surface of the wet cement composition flush with the top of the cone, pulling the cone up and off of the wet cement composition and recording the slump by measuring the total height of the cone and reporting the difference in the measured height and the initial 80 mm height.

TABLE-US-00010 TABLE 2 Cellulose Ether Ring Shear Testing of Wet Cement Compositions at 54% Water Saturation Ex- CE Vis- Yield Lub- am- Formu- Cellulose Level cosity Strength ricity ple lation Ether (CE) (wt. %) (Pa*s).sup.1 (kPa) (°) 1-1*  1* None 0 0.001 34 39 1-2   2  1 0.1 0.3 46 36.8 1-3   2  1 0.2 4 55 36.4 1-4   2  7 0.2 4 57 36.6 1-5   2  8 0.2 4 49 36.0 1-6   2  (50/50 0.2 4 46 36.9 blend of 4 and 6) 1-7   2  1 0.3 21 56 32.4 1-8   2  1 0.35 40 53 31.8 1-9   2  2 0.05 0.11 46 39 1-10  2  2 0.1 1.44 55 36.6 1-11  2  2 0.2 22 57 33.4 1-12  2  5 0.1 0.8 54 36.7 1-13  2  5 0.2 8 58 34.1 1-14  2  5 0.3 30 54 30.4 1-15  2  3 0.2 8 45 36.6 1-16* 2* Viscosity modifier A 0.1 2 52 37.5 1-17* 2* Viscosity modifier A 0.175 10 52 37.5 1-18* 2* Viscosity modifier A 0.35 50 54 37.1 1-19* 2* Superplasticizer 1 0.2 41 37.2 1-20* 2* Superplasticizer 1 0.7 1 41 36.4 1-21* 2* Viscosity modifier B 0.075 36 37.6 1-22* 2* Viscosity modifier B 0.12 37 37.1 1-23* 2* Viscosity modifier B 0.25 34 37.1 1-24* 2* Viscosity modifier C 0.075 32 37 1-25* 2* Viscosity modifier C 0.15 27 37.4 1-26* 2* Viscosity modifier C 0.3 27 36.9 1-27* 2* PEO 0.5 32 37.4 1-28* 2* PEO 0.75 33 38 1-29* 2* PEO 1 32 38 *Denotes Comparative Example; .sup.1At 20.0° C. using a stress-controlled rotational rheometer (AR-G2, TA Instruments).

[0116] As shown in Table 2, above, only the inventive examples 1-2 through 1-15 exhibited acceptable yield strength of 45 kPa or more at an acceptably low angle of lubricity of less than 37 degrees. The inventive compositions thus are readily compacted without consolidating and provide sufficient yield strength to resist changing shape in the absence of compaction forces.

TABLE-US-00011 TABLE 3 Extrusion and Rheology Testing Data At 56% Water Saturation Ex- Ex- For- Cellulose Wt. Yield trusion am- mu- Ether % Stress Force, Extrudate ple lation (CE) CE σ.sub.Y (Pa) kN Appearance 2-1* 3* None 0 770 83.2 Wet, does not hold shape, force climbed to max and extrusion incomplete 2-2  4 1 0.1 1,097 55.6 Low dampness, holds shape, force held steady and climbed at end 2-3  4 1 0.15 1,590 33.2 No dampness, holds shape, force held steady 2-4  4 1 0.2 983 25.7 Low dampness, holds shape, force held steady 2-5  4 1 0.25 960 20.4 Low dampness, holds shape, force held steady *Denotes Comparative Example.

[0117] As shown in Table 3, above, the inventive wet cement compositions in Examples 2-2, 2-3, 2-4 and 2-5 with low viscosity cellulose ether all compacted without consolidation and were compacted to a point where force was no longer displaced.

TABLE-US-00012 TABLE 4 Extrusion and Oscillation Rheometry Testing Including Various Superplasticizers At 56% Water Saturation Cellulose Yield Yield Ether SP Strength Lubricity Stress Extrusion Force kN Example Formulation (wt. %) (wt. %) (kPa) (°) σ.sub.Y (Pa) and appearance 3-1   5 1 None 51 36.9 1,590 33.2; (0.15%) No dampness, holds shape, force held steady 3-2   6 1 (0.15%) 2 (0.015) 54 35.6 1,180 24.7; Low dampness, holds shape, force held steady 3-3   6 1 (0.15%) |2 51 29.5 850 13.6; (0.0375) Low dampness, holds shape, force held steady 3-4   6 1 (0.15%) 2 (0.075) 33 22.4 226 2.8; Medium dampness, trouble holding shape, force held steady 3-5   6 1 (0.15%) 4 (0.015) 56 36.4 — — 3-6   6 1 (0.15%) 4 56 35.6 — — (0.0375) 3-7   6 1 (0.15%) 4 (0.075) 57 32.5 — — 3-8*  6 Viscosity 4 (0.015) 51 37.4 — — modifier A (0.15%) 3-9*  6 Viscosity 4 49 37.4 — — modifier A (0.0375) (0.15%) 3-10* 6 Viscosity 4 (0.075) 50 37.4 — — modifier A (0.15%) *Denotes Comparative Example

[0118] As shown in Table 4, above, all inventive wet cement compositions 3-1 to 3-7 gave acceptable lubricity angles and yield strengths except for example 3-4, which had a 56 water saturation, a large amount of water, and had trouble compacting.

TABLE-US-00013 TABLE 5 Slump of Indicated Wet Cement Formulations Example Formulation Slump (mm) Saturation %  5-1* 3 (CE = 0 wt. %) 2.98 56 5-2 7 (CE 1 = 0.15 wt. %) 1.37 56 5-3 8 (CE 1 = 0.15 wt. % + 4.1 56 0.015 SP wt. %)  5-4* 1 0 54 5-5 2 (CE 1 = 0.15 wt. %) 0 54 5-6 8 (same as 5-3) 0 54 *—Denotes Comparative Example.

[0119] As shown in Table 5, above, the slump, which is directly correlated to the yield stress of the mixture, is a sensitive function of the water saturation. At 54% water saturation all of Examples 5-4, 5-5 and 5-6 have yield stress above the critical limit for self-consolidation. At 56% water saturation despite the low viscosity of cellulose ether 1, the inventive composition of Example 5-2 enables limited or controlled slump relative to compositions not containing the cellulose ether in Comparative Example 5-1. Meanwhile, a superplasticizer increases the slump within reasonable limits.