The present disclosure involves systems and methods for applying CO2 to concrete, which may be performed in-situ or through a separate, stand-alone process. According to another embodiment disclosed herein, a system and method for applying CO2 to one or more materials used in the production of concrete is also provided.

A combination of components for use in making asphalt concrete from a mixture of virgin aggregate material with recycled asphalt products and/or recycled asphalt shingles encompasses a direct dryer for heating virgin aggregate material; a pre-dryer for heating recycled asphalt product and/or recycled asphalt shingles, said pre-dryer using warm exhaust gas from said direct dryer to heat the recycled asphalt product and/or recycled asphalt shingles; and means for conveying warm exhaust gas from said direct dryer to said pre-dryer.

The invention provides methods and compositions for carbonation of cement mixes using pressurized carbon dioxide delivered to the mix.

A hot mix asphalt (HMA) or warm mix asphalt (WMA) plant features material transfer by shear action of segmented screws and directional flights standing on an inner drum. Indirect convective material heating is initiated by a heating source located inside of the inner drum. Material mixing, heating, melting, and uniform coating, all take place as a single simultaneous process. As the result of processing, regular HMA (or WMA) or up to 100% RAP (or ARS) recycled HMA (or WMA) can be produced. Many heat sources, such as a conventional oil burner and the surface combustion burner, may also be utilized in the plant. The plant may be combined with paving units for an integrated, mobile paving system.

The invention provides methods and compositions for increasing stiffness or rate of stiffening of concrete mixes by carbonation of the mix, preferably while viscosity remains at a level suitable for the intended use of the concrete mix.

The invention provides methods and compositions for increasing stiffness or rate of stiffening of concrete mixes by carbonation of the mix, preferably while viscosity remains at a level suitable for the intended use of the concrete mix.

An apparatus for cooling a concrete mixture, including a mobile base, and an arm support assembly. The arm support assembly is pivotally attached to the mobile base, and wherein the arm support assembly is configured to fold against the mobile base for transport. An arm assembly, wherein the arm assembly is configured to move along the arm support assembly, and wherein the arm assembly is configured to fold against the arm support assembly for transport. A lance assembly, wherein the lance assembly is configured to be inserted into a cement mixer, wherein the lance assembly is configured to fold against the arm assembly for transport. A method for cooling a concrete mixture, including positioning the lance and cement truck to enter the opening of a cement truck. Inserting the lance into the cement truck and introducing liquid nitrogen into the concrete mixer and thereby mixing with the cement mixture.

Compositions and methods are provided for a system in which liquid carbon dioxide, or a mixture of liquid and gaseous carbon dioxide, is converted to solid carbon dioxide by exiting an orifice at a sufficient pressure drop, e.g., for delivery of carbon dioxide to a concrete mixture in a mixer.

Compositions and methods are provided for a system in which liquid carbon dioxide, or a mixture of liquid and gaseous carbon dioxide, is converted to solid carbon dioxide by exiting an orifice at a sufficient pressure drop, e.g., for delivery of carbon dioxide to a concrete mixture in a mixer.

The invention provides compositions and methods directed to carbonation of a cement mix during mixing. The carbonation may be controlled by one or more feedback mechanisms to adjust carbon dioxide delivery based on one or more characteristics of the mix or other aspects of the mixing operation.