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.

Cement compositions for use in subterranean wellbores that include a monophase amorphous hydraulic binder material (MAHBM). The MAHBM may include a plurality of particles having a silica core and an amorphous coating substantially surrounding the silica core. The coating may comprise a plurality of amorphous particles, such as α-dicalcium silicate hydrate nanoparticles or microparticles. The MAHBM may be used as a strength retrogression mitigating additive in a cement composition or used as a high temperature cement.

Provided herein are manufacturing processes that include (1) subjecting precursor-containing solids to dissolution under acoustic perturbation to yield an initial slurry including dissolved precursors; (2) subjecting the initial slurry to hydrothermal synthesis to yield a subsequent slurry including siliceous solids formed from the dissolved precursors; and (3) subjecting the subsequent slurry to cementation to yield a cemented siliceous solid. Also provided herein are cemented siliceous solids formed by the manufacturing processes.

Provided herein are manufacturing processes that include (1) subjecting precursor-containing solids to dissolution under acoustic perturbation to yield an initial slurry including dissolved precursors; (2) subjecting the initial slurry to hydrothermal synthesis to yield a subsequent slurry including siliceous solids formed from the dissolved precursors; and (3) subjecting the subsequent slurry to cementation to yield a cemented siliceous solid. Also provided herein are cemented siliceous solids formed by the manufacturing processes.

Synthetic pozzolans are produced using local materials to provide a cementitious material that is uniform in chemistry and properties independent of the location where the materials are obtained. Two methods of production are described. One is a high temperature process in which materials are processed in a semi-molten or molten state. The second process is a low temperature aqueous process.

The invention provides composite materials comprising novel bonding elements exhibiting unique microstructures and chemical compositions, and methods for their manufacture and uses, for example, in a variety of concrete components with or without aggregates in the infrastructure, construction, pavement and landscaping industries.

The invention provides composite materials comprising novel bonding elements exhibiting unique microstructures and chemical compositions, and methods for their manufacture and uses, for example, in a variety of concrete components with or without aggregates in the infrastructure, construction, pavement and landscaping industries.

A method of producing a carbonated composite material includes: providing a carbonatable cementitious material in particulate form; mixing the carbonatable cementitious material with water to produce a mix; forming a predetermined shape with the mix, wherein the predetermined shape has an initial pore structure containing an initial pore solution having a first pH; pre-conditioning the predetermined shape to remove a predetermined amount of the water from the predetermined shape to produce a pre-conditioned shape; carbonating the pre-conditioned shape in an environment comprising carbon dioxide to produce a modified pore structure containing a modified pore solution having and a second pH, wherein the difference between the first pH and the second pH is represented by a ΔpH, and the ΔpH is 1.0 or less.

A method of producing a carbonated composite material includes: providing a carbonatable cementitious material in particulate form; mixing the carbonatable cementitious material with water to produce a mix; forming a predetermined shape with the mix, wherein the predetermined shape has an initial pore structure containing an initial pore solution having a first pH; pre-conditioning the predetermined shape to remove a predetermined amount of the water from the predetermined shape to produce a pre-conditioned shape; carbonating the pre-conditioned shape in an environment comprising carbon dioxide to produce a modified pore structure containing a modified pore solution having and a second pH, wherein the difference between the first pH and the second pH is represented by a ΔpH, and the ΔpH is 1.0 or less.

The invention provides novel aerated composite materials made from a carbonatable calcium silicate composition, and formulations and methods of manufacture and use thereof, in particular, the use of novel additive mineral compositions in the form of magnesium, magnesium salts or magnesium oxides, to improve physical chemical properties of low density concrete materials. The low density, aerated material is comprised of calcium carbonate (CaCO.sub.3) and silica (SiO.sub.2), as cured products of carbonatable calcium silicate compositions.