A cementitious composition including recycled superabsorbent polymer (RSAP) and a cementitious material. The RSAP has a purity level of at least 85 percent by weight of the RSAP. Also provided is a cementitious composition where the RSAP has substantially low levels of one or more residual drug entities. Also provided is a method for the construction of a self-sealing cement sheath, the method comprising: supplying a self-sealing slurry of a cementitious composition including cementitious material, an aqueous fluid, and RSAP into an underground geological formation, and allowing the self-sealing slurry of the cementitious composition to cure, thereby forming the self-sealing cement sheath. The RSAP is capable of swelling in the presence of fluid to seal any cracks formed in the self-sealing slurry during curing.

The present invention discloses a crack-resistant ultra-high performance concrete (UHPC) for underground engineering in water-rich strata, preparation method, and application thereof, belonging to the technical field of building materials. The concrete is prepared from the following raw materials in parts by weight: 550-650 parts of cement, 140-180 parts of fly ash, 120-150 parts of silica fume, 200-300 parts of calcined shield tunnel slag, 30-50 parts of micron-scale magnesium oxide, 30-50 parts of nano-scale magnesium oxide, 30-50 parts of rheology-modifying material, 800-1000 parts of lightweight aggregate, 4-8 parts of water reducer, and 50-200 parts of water. The rheology-modifying material has a fluidity ratio of 106%. The present invention incorporates calcined shield tunnel slag, micron/nano-scale magnesium oxide, and lightweight aggregate into the UHPC, which effectively suppresses shrinkage and reduces crack formation.

Cement compositions that can capture carbon dioxide and related methods are generally described. These cement compositions can supplement and/or be added to concrete-forming materials to form concrete that can sequester carbon dioxide directly within the concrete.

A method for producing an additive manufactured object, the method comprising layering a composition for additive manufacturing comprising a water-curable inorganic composition and a heat-sensitive gelling agent, and non-fluidizing the composition for additive manufacturing by heating at the time of layering and/or after layering, wherein the heat-sensitive gelling agent contains an aqueous medium, a polymer dispersed in the aqueous medium, and a nonionic surfactant having a cloud point of 30 C. or higher and an HLB value of 10 to 18, and the heat-sensitive gelling agent is a heat-sensitive gelling agent having a value of al/a0 of 15 or more when a penetration resistance value at 173 C. immediately after defoaming is defined as a0 and a penetration resistance value at 173 C. after microwave heating at 600 W for 30 seconds after defoaming is defined as a1.

Method for producing a supplementary cementitious material from concrete waste and similar materials, supplementary cementitious material obtainable by the method, use of the supplementary cementitious material for making hydraulic building materials and alkali activated binders, method for manufacturing alkali activated binders, composite binders and alkali activated binders comprising the supplementary cementitious material, and use of the composite binder for making hydraulic building materials.

Cement compositions comprising a modified styrenic block copolymers and methods for making/using the same are disclosed. The modified styrenic block copolymer has at least one monoalkenyl arene polymer block A, at least one conjugated diene polymer block B, and at least an epoxy functional group or derivative thereof. The modified styrenic block copolymer has a degree of epoxidation of up to 10-90%. The cement composition can be used in subterranean applications, as well as in building and construction materials. The modified styrenic block copolymers swell upon contact water or other aqueous fluids to seal cracks in the cement.

A mortar composition, in particular a leveling mortar composition, including: a) 10-50 wt. % of a hydraulic binder, b) 10-25 wt. % of lightweight aggregates, c) 30-50 wt. % of further aggregates which have a particle density that is higher than the particle density of the lightweight aggregates, d) 0.5-5 wt. % of a polymer.

The present invention relates to a geopolymer produced from a synthetic aluminosilicate. The synthetic aluminosilicate was produced by sol gel technology, heat treated and, later, activated using sodium silicate and sodium hydroxide in solution, having as a final product a synthetic geopolymer. The final product was submitted to CO.sub.2 adsorption analysis using thermogravimetry for adsorbed quantification. In addition to the pure geopolymer, it is also possible to produce the synthetic geopolymer with the addition of surfactant, or in the composite form with the addition of zeolite, or heat treated to form a zeolite or functionalized with amine, for example, to increase the adsorption capacity.

Additives for cementitious compositions are stabilized against particle agglomeration. The additive may be provided in an aqueous liquid admixture composition for cementitious compositions that includes the additive, a polymer thickener, and water, where the particles are stabilized against agglomeration and the admixture is stabilized against physical separation. The method for stabilizing the additive against particle agglomeration utilizes a pH sensitive thickener that may be activated through neutralization of acid groups on the polymer thickener. Methods of making cementitious compositions and hardened cementitious structures using the stabilized additive and admixture are also disclosed.

Composite cement compositions and slurries for treating a well following a water-based wellbore operation are provided and comprise cement comprising at least one of cement particles and cementitious material, water, and water swellable particulates that are embedded in the cement, derived from an elastomeric material, and present at a concentration of at least about 2% by weight of the cement but no more than about 30% by weight of the cement. Methods for treating a well drilled with a water-based drilling mud are provided and comprise pumping the composite cement compositions and slurries into the well and treating the well by allowing the composite cement compositions and slurries to set or cure after being pumped into the well.