An improved process for the preparation of aggregates for use with mixtures of various carbonatable substances, in particular mixtures comprising pulverised fuel ash and/or steel slag. The mixtures also comprise a carbonatable binder. The process comprises the steps of a. blending a combination of two carbonatable wastes, b. mixing the blended carbonatable waste with a carbonatable binder, c. mixing the blended carbonatable waste and binder with water, and d. carbonating the damp blended carbonatable waste in the presence of carbon dioxide.

An improved process for the preparation of aggregates for use with mixtures of various carbonatable substances, in particular mixtures comprising pulverised fuel ash and/or steel slag. The mixtures also comprise a carbonatable binder. The process comprises the steps of a. blending a combination of two carbonatable wastes, b. mixing the blended carbonatable waste with a carbonatable binder, c. mixing the blended carbonatable waste and binder with water, and d. carbonating the damp blended carbonatable waste in the presence of carbon dioxide.

A mortar composition, which includes (i) a treated palm oil fuel ash, wherein the treated palm oil fuel ash is the only binder present, (ii) a fine aggregate, (iii) an alkali activator containing an aqueous solution of sodium hydroxide and sodium silicate, and (iv) aluminum hydroxide as a strength enhancer. A cured mortar made from the mortar composition is also disclosed with advantageous compressive strength properties.

Concrete compositions containing cement, a fine aggregate such as sand, a coarse aggregate such as crushed limestone, an industrial waste material such as electric arc furnace dust, cement kiln dust, oil ash, or limestone powder. High performance concretes made therefrom and methods of producing such concretes are also specified. The addition of industrial waste materials and nano silica provides enhanced mechanical strength (e.g. compressive strength, flexural strength) and improved durability (e.g. resistance to penetration of chloride ions) to the high performance concretes.

Concrete compositions containing cement, a fine aggregate such as sand, a coarse aggregate such as crushed limestone, an industrial waste material such as electric arc furnace dust, cement kiln dust, oil ash, or limestone powder. High performance concretes made therefrom and methods of producing such concretes are also specified. The addition of industrial waste materials and nano silica provides enhanced mechanical strength (e.g. compressive strength, flexural strength) and improved durability (e.g. resistance to penetration of chloride ions) to the high performance concretes.

A controlled low strength material has constituents that include a cement, an aggregate, a heavy oil fly ash, and a water. The controlled low strength material has a compressive strength in a range of 300 kPa to 2.1 MPa. In certain embodiments, the heavy oil fly ash can be part of a heavy oil fly ash slurry.

A controlled low strength material has constituents that include a cement, an aggregate, a heavy oil fly ash, and a water. The controlled low strength material has a compressive strength in a range of 300 kPa to 2.1 MPa. In certain embodiments, the heavy oil fly ash can be part of a heavy oil fly ash slurry.

Oil ash comprising carbon in an amount in the range of 60% to 89% is an effective set retarder in a cement composition. The oil ash prolonged the initial and final setting time of cement paste and retained the slump flow in concrete for a longer time than concrete without the retarder. Also, the addition of oil ash to cement marginally improved the compressive strength of concrete. The advantage of oil ash is that it can be used as a solid retarder of cement hydration to substitute for the conventional commercial retarding admixtures with a limited shelf-life.

Oil ash comprising carbon in an amount in the range of 60% to 89% is an effective set retarder in a cement composition. The oil ash prolonged the initial and final setting time of cement paste and retained the slump flow in concrete for a longer time than concrete without the retarder. Also, the addition of oil ash to cement marginally improved the compressive strength of concrete. The advantage of oil ash is that it can be used as a solid retarder of cement hydration to substitute for the conventional commercial retarding admixtures with a limited shelf-life.

Concrete compositions containing cement, a fine aggregate such as sand, a coarse aggregate such as crushed limestone, an industrial waste material such as electric arc furnace dust, cement kiln dust, oil ash, or limestone powder. High performance concretes made therefrom and methods of producing such concretes are also specified. The addition of industrial waste materials and nano silica provides enhanced mechanical strength (e.g. compressive strength, flexural strength) and improved durability (e.g. resistance to penetration of chloride ions) to the high performance concretes.