A type of composite material where the matrix material and additive are held together by covalently or non-covalently bound ligands is described. A particularly useful composite material covered by the present invention is a carbon nanotube-reinforced composite material where the matrix consists of a polymer, covalently attached to a linker, where said linker is non-covalently attached to the carbon nanotube.

Methods for the preparation of such composite materials are provided.

A method and sealant to seal microcracks as small as 30 μm by causing methyl methacrylate combined with one or more nanoparticles to flow into the microcrack to be sealed.

A method and sealant to seal microcracks as small as 30 μm by causing methyl methacrylate combined with one or more nanoparticles to flow into the microcrack to be sealed.

A low strength backfill material having a 28 days compressive strength less than approximately 2.0 MPa is provided. The backfill is suitable for use in areas with dense underground utilities due to its high excavatability and good thermal conductivity. The backfill includes a cementitious binder of approximately 1 weight percent to approximately 10 weight percent and fine aggregates in an amount of approximately 40 to approximately 75 weight percent. Filler is provided at 20 microns to approximately 100 microns for high flowability. A density-controlling agent of 0.0001-5 weight percent is used such that the density of a cured backfill material is approximately 1600 kg/m.sup.3 to 2000 kg/m.sup.3. Thermally conductive particles having a size range of approximately 0.01 microns to 500 microns in an amount of approximately 0.1 to 10 weight percent are evenly dispersed throughout the backfill.

A low strength backfill material having a 28 days compressive strength less than approximately 2.0 MPa is provided. The backfill is suitable for use in areas with dense underground utilities due to its high excavatability and good thermal conductivity. The backfill includes a cementitious binder of approximately 1 weight percent to approximately 10 weight percent and fine aggregates in an amount of approximately 40 to approximately 75 weight percent. Filler is provided at 20 microns to approximately 100 microns for high flowability. A density-controlling agent of 0.0001-5 weight percent is used such that the density of a cured backfill material is approximately 1600 kg/m.sup.3 to 2000 kg/m.sup.3. Thermally conductive particles having a size range of approximately 0.01 microns to 500 microns in an amount of approximately 0.1 to 10 weight percent are evenly dispersed throughout the backfill.

A sensor having one or more stopbands and method of using the same for detecting damage, cracking and debonding in a cement structure comprising a cementitious material and a plurality of periodic structures located in the cementitious material.

A sensor having one or more stopbands and method of using the same for detecting damage, cracking and debonding in a cement structure comprising a cementitious material and a plurality of periodic structures located in the cementitious material.

A type of composite material where the matrix material and additive are held together by covalently or non-covalently bound ligands is described. A particularly useful composite material covered by the present invention is a carbon nanotube-reinforced composite material where the matrix consists of a polymer, covalently attached to a linker, where said linker is non-covalently attached to the carbon nanotube. Methods for the preparation of such composite materials are provided.

A type of composite material where the matrix material and additive are held together by covalently or non-covalently bound ligands is described. A particularly useful composite material covered by the present invention is a carbon nanotube-reinforced composite material where the matrix consists of a polymer, covalently attached to a linker, where said linker is non-covalently attached to the carbon nanotube. Methods for the preparation of such composite materials are provided.

Fibers to be added to concrete to improve its properties are coated with an alkali-insoluble polymer, to provide adhesion of the fibers to the concrete. In a further improvement, nanoparticles are dispersed in an alkali-soluble polymer coating, and this is used to coat the fibers. When the fibers are mixed into the concrete mix, the nanoparticles are dispersed throughout the concrete, avoiding problems from agglomeration of the nanoparticles if simply added to the concrete mix.