A low-density, high-strength concrete composition that is lightweight and self-compacting or non-self-compacting, with a low weight-fraction of aggregate to total dry raw materials, and a highly-homogenous distribution of a non-absorptive and closed-cell lightweight aggregate such as glass microspheres or copolymer polymer beads or a combination thereof, and the steps of providing the composition or components. Lightweight concretes formed therefrom have low density, high strength-to-weight ratios, and high R-value. The concrete has strength similar to that ordinarily found in structural lightweight concrete but at a lower density, such as an oven-dried density as low as 40 lbs./cu.ft. Such strength-to-density ratios range approximately from above 30 cu.ft/sq.in. to above 110 cu.ft/sq.in., with a 28-day compressive strength ranging from about 3400 to 8000 psi.

A low-density, high-strength concrete composition that is lightweight and self-compacting or non-self-compacting, with a low weight-fraction of aggregate to total dry raw materials, and a highly-homogenous distribution of a non-absorptive and closed-cell lightweight aggregate such as glass microspheres or copolymer polymer beads or a combination thereof, and the steps of providing the composition or components. Lightweight concretes formed therefrom have low density, high strength-to-weight ratios, and high R-value. The concrete has strength similar to that ordinarily found in structural lightweight concrete but at a lower density, such as an oven-dried density as low as 40 lbs./cu.ft. Such strength-to-density ratios range approximately from above 30 cu.ft/sq.in. to above 110 cu.ft/sq.in., with a 28-day compressive strength ranging from about 3400 to 8000 psi.

A method of cementing may include: measuring a feeding rate of water and a feeding rate of cement blend into a cement blender; calculating a cement retarder feeding rate and/or an accelerator feeding rate using a thickening time model, wherein the thickening time model uses at least a thickening time requirement, the feeding rate of water, and the feeding rate of cement blend, to calculate the cement retarder feeding rate and/or the accelerator feeding rate; introducing a cement retarder at the cement retarder feeding rate and/or an accelerator at the accelerator feeding rate into the cement blender; mixing at least the water, cement blend, and at least one of the cement retarder and/or the accelerator in the cement blender to provide a cement slurry; and placing the cement slurry in a wellbore.

A method of cementing may include: measuring a feeding rate of water and a feeding rate of cement blend into a cement blender; calculating a cement retarder feeding rate and/or an accelerator feeding rate using a thickening time model, wherein the thickening time model uses at least a thickening time requirement, the feeding rate of water, and the feeding rate of cement blend, to calculate the cement retarder feeding rate and/or the accelerator feeding rate; introducing a cement retarder at the cement retarder feeding rate and/or an accelerator at the accelerator feeding rate into the cement blender; mixing at least the water, cement blend, and at least one of the cement retarder and/or the accelerator in the cement blender to provide a cement slurry; and placing the cement slurry in a wellbore.

A highly thixotropic 3D printing concrete and a manufacturing method therefor are provided. The weight percentage of each component calculated per cube of concrete is: 35-40% of cement, 0.1-0.4% of polycarboxylate superplasticizer, 0.1-0.4% of polypropylene fiber, 1.0-3.0% of special thixotropic agent for 3D printing concrete, and 12.5-14.5% of water, and the remainder is sand.

A highly thixotropic 3D printing concrete and a manufacturing method therefor are provided. The weight percentage of each component calculated per cube of concrete is: 35-40% of cement, 0.1-0.4% of polycarboxylate superplasticizer, 0.1-0.4% of polypropylene fiber, 1.0-3.0% of special thixotropic agent for 3D printing concrete, and 12.5-14.5% of water, and the remainder is sand.

A highly thixotropic 3D printing concrete and a manufacturing method therefor are provided. The weight percentage of each component calculated per cube of concrete is: 35-40% of cement, 0.1-0.4% of polycarboxylate superplasticizer, 0.1-0.4% of polypropylene fiber, 1.0-3.0% of special thixotropic agent for 3D printing concrete, and 12.5-14.5% of water, and the remainder is sand.

A hydraulic composition for the construction of pavements, and in particular for the repair of pavements, includes a hydraulic binder including a cement, 0.18% to 0.35% of a superplasticiser, where the percentage is expressed by dry weight compared to the cement, and where the superplasticiser includes a branched polymer including at least one pendant chain, with a terminal function of the phosphonate or phosphate type, and 0.25% to 2% of a setting accelerator, where the percentage is expressed by dry weight compared to the cement, where the setting accelerator includes a calcium salt, where the hydraulic composition has a Water/Cement ratio higher than 0.38 and strictly less than 0.45.

A hydraulic composition for the construction of pavements, and in particular for the repair of pavements, includes a hydraulic binder including a cement, 0.18% to 0.35% of a superplasticiser, where the percentage is expressed by dry weight compared to the cement, and where the superplasticiser includes a branched polymer including at least one pendant chain, with a terminal function of the phosphonate or phosphate type, and 0.25% to 2% of a setting accelerator, where the percentage is expressed by dry weight compared to the cement, where the setting accelerator includes a calcium salt, where the hydraulic composition has a Water/Cement ratio higher than 0.38 and strictly less than 0.45.

A hydraulic composition for the construction of pavements, and in particular for the repair of pavements, includes a hydraulic binder including a cement, 0.18% to 0.35% of a superplasticiser, where the percentage is expressed by dry weight compared to the cement, and where the superplasticiser includes a branched polymer including at least one pendant chain, with a terminal function of the phosphonate or phosphate type, and 0.25% to 2% of a setting accelerator, where the percentage is expressed by dry weight compared to the cement, where the setting accelerator includes a calcium salt, where the hydraulic composition has a Water/Cement ratio higher than 0.38 and strictly less than 0.45.