Cementitious compositions for decreasing the rate of water vapor emissions from concrete and methods for preparing and using the same

Abstract

Cementitious compositions and processes for preparing and using the cementitious compositions are provided. The cementitious compositions are characterized by the property of a reduced or an attenuated water vapor emission of a hardened concrete formed therefrom.

1 . A cementitious composition for attenuating a water vapor emission from a concrete comprising:
 a hydraulic cement;   a superplasticizer; and   a finely divided material having a particle size of less than about 75 microns.   
     
     
         2 . The cementitious composition according to  claim 1 , wherein the finely divided material is a cement replacement. 
     
     
         3 . The cementitious composition according to  claim 2 , wherein the finely divided material comprises limestone fines. 
     
     
         4 . The cementitious composition according to  claim 2 , wherein the finely divided material is selected from the group consisting of a pozzolan, a ground granulated blast furnace slag, and any combination thereof. 
     
     
         5 . The cementitious composition according to  claim 4 , wherein the pozzolan comprises a fly ash. 
     
     
         6 . The cementitious composition according to  claim 4 , wherein the pozzolan comprises a highly reactive pozzolan. 
     
     
         7 . The cementitious composition according to  claim 1 , wherein the superplasticizer is a polycarboxylate superplasticizer. 
     
     
         8 . The cementitious composition according to  claim 1 , further comprising an aggregate. 
     
     
         9 . The cementitious composition according to  claim 8 , wherein:
 the hydraulic cement having a concentration in a range from about 25% to about 70% by weight based on the total weight of the cementitious composition;   the finely divided material having a concentration in a range from about 3% to about 80% by weight based on the total weight of the cementitious composition; and   the superplasticizer having a concentration in a range from about 4 to about 16 ounces per 100 pounds of the cementitious composition.   
     
     
         10 . The cementitious composition according to  claim 8 , wherein the aggregate comprises a fine aggregate and a coarse aggregate. 
     
     
         11 . The cementitious composition according to  claim 10 , wherein a ratio by weight of the fine aggregate to the total aggregate is from about 0.25 to about 1.00. 
     
     
         12 . A cementitious mix comprising the cementitious composition of  claim 1  and an amount of water sufficient to provide a water to cementitious ratio of from about 0.2 to about 0.4. 
     
     
         13 . A cementitious mix comprising:
 a hydraulic cement having a concentration from about 10% to about 30% by weight based on a total weight of cementitious compounds;   an aggregate having a concentration from about 45% to about 65% by weight based on the total weight of cementitious compounds;   a densifying calcium silicate precursor having a concentration from about 2.5% to about 25% by weight based on the total weight of cementitious compounds;   an amount of water sufficient to provide a water to cementitious ratio of from about 0.2 to about 0.4; and   a polycarboxylate superplasticizer having a concentration from about 4 ounces to about 16 ounces per 100 pounds of cementitious compounds, wherein the cementitious mix is used to prepare a concrete having an attenuated water vapor emission.   
     
     
         14 . A method of preparing a cementitious composition comprising the steps of:
 mixing a hydraulic cement with a finely divided material having a particle size of less than about 75 microns; and   adding a superplasticizer,   
       wherein the cementitious composition is used to prepare a concrete having an attenuated water vapor emission. 
     
     
         15 . The method according to  claim 14 , wherein the finely divided material comprises a cement replacement, the cement replacement selected from the group consisting of a pozzolan, a ground granulated blast furnace slag, and any combination thereof. 
     
     
         16 . The method according to  claim 15 , wherein a ratio by weight of the cement replacement to the total weight of the cementitious composition is in a range from about 0.03 to about 0.8. 
     
     
         17 . The method according to  claim 14 , wherein the finely divided material comprises a cement replacement, the cement replacement comprises a calcium carbonate containing material having a concentration of from about 0.13% to about 7% by weight based on the total weight of the cementitious composition. 
     
     
         18 . The method according to  claim 14 , additionally comprising the step of incorporating an aggregate in the cementitious composition. 
     
     
         19 . A method of preparing a concrete structure using a cementitious composition comprising the steps of:
 providing the cementitious composition comprising a hydraulic cement, a finely divided material having a particle size of less than about 75 microns, and a superplasticizer;   blending an amount of water into the cementitious composition to prepare a cementitious mix;   using the cementitious mix to preform the concrete structure; and   curing the preformed cementitious mix to a hardened concrete,   
       wherein the hardened concrete has an attenuated water vapor emission. 
     
     
         20 . The method according to  claim 19 , additionally comprising the step of applying a regimen for facilitating a more rapid curing of the cementitious mix to the hardened concrete. 
     
     
         21 . The method according to  claim 19 , wherein the amount of water is minimized to an amount that is sufficient to hydrolyze the cementitious composition and allow the prepared cementitious mix to achieve a desired level of plasticity 
     
     
         22 . The method according to  claim 19 , the amount of water, a concentration of the superplasticizer, and a ratio by weight of the finely divided material to the cement are proportioned to achieve a desired level of plasticity while achieving a desired property of a hardened concrete. 
     
     
         23 . The method according to  claim 22 , the desired property is selected from the group consisting of minimizing an amount of time needed to achieve a water vapor emission of the hardened concrete, minimizing an amount of time needed to achieve an internal relative humidity of the hardened concrete, a reduced shrinkage of the hardened concrete, a maximum heat of hydration, and any combination thereof.