Alumina-modified colloidal silica nanoparticles mitigate Alkali Silica Reaction (ASR) in cementitious compositions. Additives containing the nanoparticles are used in methods of reducing ASR in concrete and to form cementitious compositions. Cementitious products, such as concrete, made by these methods are described herein.

Trona-accelerated composition for backfilling trenches are described. The compositions consist of aggregate (e.g., sand), Portland cement, Trona, water and sometimes air. The compositions may have a compressive strength of between 10 psi and 100 psi after 4 hours, a compressive strength of between 75 psi and 500 psi after 28 days, and a penetration resistance of between 4.5 tsf and 200 tsf after 4 hours. Also disclosed are methods of filling a trench with fast-setting flowable fill.

Alkali activated concrete compositions containing natural pozzolan, ground granulated blast furnace slag, alkali activators such as an alkali hydroxide and an alkali silicate, and optionally fine and coarse aggregates. Alkali activated concretes made therefrom and methods of making such concretes are also specified. The inclusion of ground granulated blast furnace slag provides significantly superior mechanical strength (e.g. compressive strength) to the alkali activated concretes within 12-24 hours of curing at 30-60 C.

A railway tie being constructed of an engineered cementitious composite (ECC) material having: (1) a minimum of 2% tensile ductility of ECC, (2) complete absence of alkali-silica reaction (ASR), (3) high fatigue resistance of ECC at least five times that of normal concrete, (4) self-healing ability of ECC requiring only water and air, and (5) customization of ECC for lower stiffness in the tie (60% that of normal concrete) and higher abrasion resistance in the seat (three times that of normal concrete).

A cladding system for use on the external surface of a building structure that includes a continuous rail system to attach a cladding panel that interlocks with itself. The rail system includes a tongue and groove system to attach the cladding system to the building thereby avoiding the need to use discrete anchors. The cladding panel is formed of a high strength concrete matrix and, optionally, a plurality of twisted steel micro reinforcements (TSMR) dispersed therein.

Alkali activated concrete compositions containing natural pozzolan, ground granulated blast furnace slag, alkali activators such as an alkali hydroxide and an alkali silicate, and optionally fine and coarse aggregates. Alkali activated concretes made therefrom and methods of making such concretes are also specified. The inclusion of ground granulated blast furnace slag provides significantly superior mechanical strength (e.g. compressive strength) to the alkali activated concretes within 12-24 hours of curing at 30-60 C.

Cementitious mixtures, compositions for use in cementitious mixtures, and methods of producing cementitious mixtures wherein the compositions are suitable for modifying or improving certain properties of the cementitious mixtures. The compositions include a superabsorbent polymer (SAP) hydrogel having a macromolecular network structure, and at least one pozzolanic material that is chemically incorporated into the macromolecular network structure of the SAP hydrogel.

Cement slurries, cured cements, and methods of making cured cement and methods of using cement slurries are provided. The cement slurries have, among other attributes, improved elasticity and self-healing properties and may be used, for instance, in the oil and gas drilling industry. The cement slurry comprises water, a cement precursor material, and a block copolymer composition. The block copolymer composition has at least one copolymer backbone, with each copolymer backbone comprising at least two hard segments. Furthermore, a soft segment is disposed between the at least two hard segments. The copolymer backbone has at least one anhydride group grafted onto the soft segment, and the anhydride group is crosslinked by an aminosilane crosslinker.

A macro-cement and associated methods useful for preparing pastes, mortars, concretes and other cement-based materials having high workability, high density, and high strength are disclosed. A method of producing a macro-cement includes cement, supplemental cementitious materials (SCM's), including siliceous submicron-sized particles and nano-sized particles, and polymers in the form of liquid or dry chemical admixtures for concrete. The cement mixture may be used for making ultra-high performance concrete (UHPC).

A macro-cement and associated methods useful for preparing pastes, mortars, concretes and other cement-based materials having high workability, high density, and high strength are disclosed. A method of producing a macro-cement includes cement, supplemental cementitious materials (SCM's), including siliceous submicron-sized particles and nano-sized particles, and polymers in the form of liquid or dry chemical admixtures for concrete. The cement mixture may be used for making ultra-high performance concrete (UHPC).