Carbonatable calcium silicate-based cements and concretes having mineral additives, and methods thereof
The invention provides novel methods and novel additive compositions and use thereof in a wide range of concrete production for improving properties of concrete materials, such as durability and aestheticity. The methods and compositions of the invention may be applied in a variety of cement and concrete components in the infrastructure, construction, pavement and landscaping industries.
1. A method for forming a concrete product, comprising:
forming a liquid admixture comprising one or more minerals and at least one organic polymer;
prior to curing cement to form a concrete product, adding to the concrete mixture an admixture comprising one or more minerals; and
curing the cement to form a concrete product,
wherein the cement is a carbonatable calcium silicate-based cement, and the one or more minerals are selected from the group consisting of magnesium, magnesium oxide, magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium acetate, ground dolomite, ground limestone, suspension of magnesium hydroxide, and combinations thereof.
2. The method of claim 1 , wherein the one or more minerals account for about 0.02% to about 20% of the carbonatable calcium silicate-based cement.
3. The method of claim 1 , further comprising adjusting the pH of the concrete mixture prior to curing the cement to form a concrete product.
4. The method of claim 1 , wherein the carbonatable calcium silicate-based cement comprises calcium silicate, wherein the calcium silicate comprises one or more of CS (wollastonite or pseudowollastonite), C3 S2 (rankinite), or C2S (belite, larnite, bredigite) discrete calcium silicate phases.
5. The method of claim 4 , wherein the calcium silicate further comprises an amorphous calcium silicate phase at about 10% or more by mass of the total phases.
6. The method of claim 1 , wherein the carbonatable calcium silicate-based cement comprises one or more of CS (wollastonite or pseudowollastonite), C3S2 (rankinite), or C2S (belite, larnite, bredigite) discrete calcium silicate phases, wherein the calcium silicate further comprises an amorphous calcium silicate phase at about 10% or more by mass of the total phases.
7. The method of claim 1 , wherein the one or more minerals are selected from the group consisting of submicron magnesium oxide powder, magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium acetate, and combinations thereof.
8. The method of claim 6 , wherein the carbonatable calcium silicate-based cement comprises one or more melilite type phases having the general formula (Ca,Na,K) 2 [(Mg, Fe 2+ ,Fe 3+ ,Al,Si) 3 O 7 ] or ferrite type phases having the general formula Ca 2 (Al,Fe 3+ ) 2 O 5 .
9. The method of claim 8 , wherein the carbonatable calcium silicate-based cement comprises elemental Ca and elemental Si are present in the composition at a molar ratio from about 0.5 to about 1.5.
10. The method of claim 9 , wherein the carbonatable calcium silicate-based cement comprises metal oxides of Al, Fe and Mg are present in the composition at about 30% or less by mass.