Concrete can be one of the most durable building materials and structures made of concrete can have a long service life. Consumption is projected to reach approximately 40 billion tons in 2017. Despite this the testing of concrete at all stages of its life cycle is still in its early stages although testing for corrosion is well established. Further many of the tests today are time consuming, expensive, and provide results only after it has been poured and set. Embodiments of the invention provide concrete suppliers, construction companies, regulators, architects, and others with rapid testing and performance data regarding the cure, performance, corrosion of concrete at different points in its life cycle based upon a simple electrical tests that remove subjectivity, allow for rapid assessment, are integrable to the construction process, and provided full life cycle assessment. Wireless sensors can be embedded from initial loading through post-cure into service life.

Ground surface comprising a substrate (110) having a Young's modulus of between 100 and 1000 GPa, and in which the ground surface has, on a working surface (120), a Vickers hardness of between 1300 and 10 000 kgf/mm.sup.2, and/or a surface coating forming the working surface, in which the surface coating contains amorphous carbon and/or titanium nitride and/or chromium nitride and/or tungsten carbide.

Disclosed is a gas sensing material for methylbenzene detection. Specifically, the gas sensing material includes a nanocomposite of Cr.sub.2O.sub.3 and ZnCr.sub.2O.sub.4. The content of Cr in the nanocomposite is from 67.0 at. % to 90.0 at. %, based on the sum of the contents of Cr and Zn atoms. The gas sensing material is highly selective to methylbenzenes over other gases and is highly sensitive to methylbenzenes. Also disclosed are methods for preparing the gas sensing material. The methods facilitate control over the composition of the gas sensing material and enable rapid synthesis of the gas sensing material at low temperature. Also disclosed is a gas sensor including the gas sensing material.

Concrete can be one of the most durable building materials and structures made of concrete can have a long service life. Consumption is projected to reach approximately 40 billion tons in 2017. Despite this the testing of concrete at all stages of its life cycle is still in its early stages although testing for corrosion is well established. Further many of the tests today are time consuming, expensive, and provide results only after it has been poured and set. Embodiments of the invention provide concrete suppliers, construction companies, regulators, architects, and others with rapid testing and performance data regarding the cure, performance, corrosion of concrete at different points in its life cycle based upon a simple electrical tests that remove subjectivity, allow for rapid assessment, are integrable to the construction process, and provided full life cycle assessment. Wireless sensors can be embedded from initial loading through post-cure into service life.

Disclosed are a rock similar material satisfying a water-induced strength degradation characteristic and a preparation method and use thereof. The rock similar material satisfying the water-induced strength degradation characteristic includes an aggregate, a cementing material, and an additive, where the aggregate includes quartz sand, barite powder, and bentonite, and the cementing material includes cement and gypsum.

Compositions and methods for terminating water flow in a subterranean formation are described. The compositions include a calcium aluminate cement, a Portland cement, and a non-aqueous carrier fluid.

Fiber reinforced aerogel composites, including a transparent composite material that contains an aerogel and fibers embedded into the aerogel and/or bonded to one or more surfaces of the aerogel, and composites that contain an aerogel tile and an assemblage of fibers embedded into the aerogel tile or bonded to the aerogel tile that are useful as Cherenkov radiators for the detection and identification of subatomic particles. Also, methods of making and using the composites.

For measuring the stress history in a simple form, which is widely applicable to various types of structural materials which the elastic modulus is different from each other, a large number of calcite particles is embedded as a stress sensor in a cement-based composite material that can be elastically deformed after receiving an external.

A twin-crystal density of the calcite particles is measured after an external force is applied to the composite material, to convert the twin-crystal density to a strain by an approximate formula set in terms of a strain ε (%) generated in the composite material and a twin-crystal density Dtw (lines/mm) of the calcite particles, and further to convert this strain to a stress by the elastic modulus of the composite material, whereby to estimate the history of stress and strain. The approximate formula between strain and twin-crystal density is independent of the modulus of the composite material and is used in a common form.

Disclosed is a rock similar material satisfying a water-induced strength degradation characteristic and a preparation method and use thereof. The rock similar material satisfying the water-induced strength degradation characteristic includes an aggregate, a cementing material, and an additive, where the aggregate includes quartz sand, barite powder, and bentonite, and the cementing material includes cement and gypsum.

A simulated concrete mixture combines aggregate, sand, mortar clay, and additive. The mixture is hydrated with enough water or a hydrating solution to create a simulated concrete material having a desired slump. Useful aggregates include any type of aggregate used as a base for concretes, and useful additives include soaps, detergents, surfactants, and flocculants. The material can be refreshed with water or a refresher solution. The hydrating solution and refreshing solution are solution of water and additive. The simulated concrete material can be manipulated until its consistency becomes unworkable, after which it can be refreshed with water or refresher solution.