Provided herein are compositions, methods, and systems comprising vaterite and magnesium oxide.

Provided herein are compositions, methods, and systems comprising vaterite and magnesium oxide.

A method for making a carbonated precast concrete product includes: obtaining a mixture including at least one binder material, an aggregate, and water; molding the mixture into a molded intermediate; demolding the molded intermediate to obtain a demolded intermediate, the demolded intermediate having a first water-to-binder ratio; conditioning the demolded intermediate to provide a conditioned article having a second water-to-binder ratio less than the first water-to-binder ratio of the demolded intermediate; moisturizing at least one surface of the conditioned article with an aqueous medium, thereby causing a weight gain of the conditioned article and providing a moisturized product, a first portion of the moisturized product having a third water-to-binder ratio greater than a fourth water-to-binder ratio of a remainder of the moisturized product; and curing the moisturized product with carbon dioxide to obtain the carbonated precast concrete product.

This disclosure is directed to an improved ballistic construct including ballistic concrete cured in a ballistic fiberglass mold, where the ballistic fiberglass mold remains part of the construct after curing. The fiberglass ballistic construct is stronger than concrete alone and does not significantly increase the weight of the construct. The improved construct is useful for firearms training and in the erecting of bulletproof structures which need ballistics protection.

This disclosure is directed to an improved ballistic construct including ballistic concrete cured in a ballistic fiberglass mold, where the ballistic fiberglass mold remains part of the construct after curing. The fiberglass ballistic construct is stronger than concrete alone and does not significantly increase the weight of the construct. The improved construct is useful for firearms training and in the erecting of bulletproof structures which need ballistics protection.

It is disclosed the use of amorphous silica reagent produced from serpentine as pozzolane additive material, and more particularly a concrete mixture, such as high performance and ultra-high performance concrete, comprising a hydraulic binder; sand; aggregates, chemical admixture, mineral admixture as silica fume and an amorphous silica reagent (AmSR), wherein the AmSR is admixed for example with General Use Portland Cement and provides synergistic effect when combined with silica fume.

A method for preparing a graphene-nanosheets based concrete additive is disclosed. The method comprises mixing Polycarboxylate ether A (PCE-A) to a retarder - based salt solution to obtain a retarder-based Polycarboxylate ether A solution. In the next step, a retarder based PCE solution is obtained by adding Polycarboxylate ether B to the retarder based Polycarboxylate ether A solution to which graphene nanosheets are added. Further, an air entrainment agent is added to graphene nanosheets based PCE solution and further mixed to obtain the graphene nanosheets based concrete additive.

A method for making a carbonated precast concrete product includes: obtaining a mixture including at least one binder material, an aggregate, and water; molding the mixture into a molded intermediate; demolding the molded intermediate to obtain a demolded intermediate, the demolded intermediate having a first water-to-binder ratio; conditioning the demolded intermediate to provide a conditioned article having a second water-to-binder ratio less than the first water-to-binder ratio of the demolded intermediate; moisturizing at least one surface of the conditioned article with an aqueous medium, thereby causing a weight gain of the conditioned article and providing a moisturized product, a first portion of the moisturized product having a third water-to-binder ratio greater than a fourth water-to-binder ratio of a remainder of the moisturized product; and curing the moisturized product with carbon dioxide to obtain the carbonated precast concrete product.

A coated fiber comprising a fiber comprising polyester, and a coating on the fiber, said coating comprising a cross-linked silicone prepared by cross-linking on the fiber one or more silicon-containing compounds selected from an organosilane and organosilicone resin, wherein at least one of said silicon-containing compounds has at least three cross-linking groups is provided, together with a method of preparing such a fiber, a concrete composition comprising such coated fibers, and a method of preparing such a concrete composition.

A coated fiber comprising a fiber comprising polyester, and a coating on the fiber, said coating comprising a cross-linked silicone prepared by cross-linking on the fiber one or more silicon-containing compounds selected from an organosilane and organosilicone resin, wherein at least one of said silicon-containing compounds has at least three cross-linking groups is provided, together with a method of preparing such a fiber, a concrete composition comprising such coated fibers, and a method of preparing such a concrete composition.