Dry mixes and cements containing cellulose ethers as lubricative additives for roller compacted concrete applications and methods of using them

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−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·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=(Vw+Vc)/VV,
• wherein Vw is the volume of water in the wet cement composition, Vc is the volume of cement Vc=mc/ρc, where mc is the mass of cement in the wet cement composition and ρc is the material density of the cement, and VV is the total void volume in the total mixture determined by measuring the particle density of each material other than cement and water, ρi, measuring the total mass of each material other than cement and water, mi, 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 Vv=V−Σ(mi/ρi);
• 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%.