Carbonation curing method to produce wet-cast slag-based concrete products

A method of producing a wet-cast slag-based concrete product comprising steps of:

• 1) providing a slag-based binder, an aggregate and water;
• 2) mixing the slag based binder, the aggregate and the water to produce a workable non-zero-slump concrete composition comprising a first water to slag-based binder ratio by weight of greater than 0.2;
• 3) a) casting and/or placing the non-zero-slump concrete by transferring and/or consolidating the non-zero-slump concrete composition into an air-tight mould wherein said air-tight mould is comprising at least one gas pipe and/or at least one gas lance;
• or
• b) casting and/or placing the non-zero-slump concrete by transferring and/or consolidating the non-zero-slump concrete composition into an air-tight mould and further comprising a step of inserting the at least one gas pipe and/or the at least one gas lance into the non-zero-slump concrete composition;
• or
• c) casting and/or placing the non-zero-slump concrete by transferring and/or consolidating the non-zero-slump concrete composition into an air-tight mould, the mould comprising a mould wall and a plurality of inlets in the mould wall, wherein the plurality of inlets are optionally closed to retain the non-zero-slump concrete;
• or
• d) casting and/or placing the non-zero-slump concrete by transferring and/or consolidating the non-zero-slump concrete composition into a mould, the mould comprising a mould wall defining an open top surface and a plurality of inlets in the mould wall, wherein the plurality of inlets are optionally closed to retain the workable non-zero-slump concrete;
• 4) pre-conditioning the non-zero-slump concrete composition within the mould with at least one of i) air flow and/or pressurized air from the at least one gas lance, if one of options 3a) or 3b) is selected, ii) heaters and iii) heating element wires embedded in the non-zero-slump concrete, to produce a pre-conditioned slag-based intermediate comprising a second water to slag-based binder ratio by weight that is less than the first water to slag-based binder ratio by weight;
• 5) sealing the air-tight mould when the casting corresponds to casting step 3a), 3b) or 3c);
• 6) after steps 2) to 5), curing the pre-conditioned slag-based intermediate with a gas containing carbon dioxide;
• from the at least one gas pipe and/or the at least one gas lance when the casting and/or placing the non-zero-slump concrete by transferring and/or consolidating the non-zero-slump concrete composition corresponds to step 3a) or 3b);
• or
• via the plurality of inlets in the mould wall when the casting and/or placing the non-zero-slump concrete by transferring and/or consolidating the non-zero-slump concrete composition corresponds to step 3c);
• or
• in a chamber/enclosed space/vessel/room via the plurality of inlets in the mould wall and the open top surface when the casting and/or placing the non-zero-slump concrete by transferring and/or consolidating the non-zero-slump concrete composition corresponds to step 3d),
• to produce a moulded wet-cast slag-based concrete product, and
• 7) after the curing of the pre-conditioned slag-based intermediate, demoulding the moulded wet-cast slag-based concrete product to provide the wet-cast slag-based concrete product.