Abstract: Pseudoelastic elements are shaped in order to form springs which exhibit relatively constant force levels over a major fraction of maximum deflection capacity during loading and also during unloading. The shape of sail pseudoelastic elements is chosen to concentrate at least one of flexural and torsional deformations within limited regions. The element may be braced outside said regions in order to further concentrate deformations within said regions. Loading of said pseudoelastic springs thus produces strains within said regions which are largely corresponding to the upper pseudoelastic stress plateau where strain variations cause relatively small changes in stress. Unloading of said pseudoelastic springs also produces strains within said regions which are largely corresponding to the lower stress plateau of the pseudoelastic stress-strain curve where stress is subject to relatively small changes with strain variations.

Abstract: Concrete materials are impregnated with liquids which harden within concrete pores and microcracks, and develop a sharp contrast with the body of concrete in microscopic images. The impregnation process involves vacuum application to remove air from concrete pores and microcracks, followed by the introduction of liquids under pressure. The sharp contrast between the impregnated (and hardened) liquid and the body of concrete facilitates distinction of pores and microcracks in microscopic images for the purpose of automated image analysis.

Abstract: Concrete materials are impregnated with liquids which harden within concrete pores and microcracks, and develop a sharp contrast with the body of concrete in microscopic images. The impregnation process involves vacuum application to remove air from concrete pores and microcracks, followed by the introduction of liquids under pressure. The sharp contrast between the impregnated (and hardened) liquid and the body of concrete facilitates distinction of pores and microcracks in microscopic images for the purpose of automated image analysis.

Abstract: A thermoplastic polymer of relatively low melt temperature is blended with at least one of thermosets, elastomers, and thermoplastics of relatively high melt temperature in order to produce a polymer blend which absorbs relatively high quantities of latent heat without melting or major loss of physical and mechanical characteristics as temperature is raised above the melting temperature of the low-melt-temperature thermoplastic. The polymer blend can be modified by the addition of at least one of fillers, fibers, fire retardants, compatibilisers, colorants, and processing aids. The polymer blend may be used in applications where advantage can be taken of the absorption of excess heat by a component which remains solid and retains major fractions of its physical and mechanical characteristics while absorbing relatively high quantities of latent heat.

Abstract: Shape-memory fibers are incorporated into a metal matrix material with a level of fiber-to-matrix bonding so that upon localized failure of matrix under load, the strains in fibers debond them from the matrix to the extent that fibers do not all rupture at the location of matrix failure. The pull-out process of fibers ruptured away from the matrix failure location provides the composite material with substantially increased ductility and energy absorption capacity after localized failure of the matrix. Pre-tensioning of shape-memory fibers impose sustained stresses on matrix which enhance the strength and energy absorption capacity of the composite material. The shape-memory fibers may be incorporated into a metal matrix at their end so that fibers pull out from the matrix under load and provide an energy-absorbing assembly.

Abstract: Pulp fibers derived from wood or non-wood plants or recycled paper products, which are 0.1-30 mm long and about 0.001-0.1 mm in equivalent diameter, are individualized by mechanical action, blended with at least one of the dry ingredients of the cement-based material and then mixed with the remaining ingredients of conventional cement-based mixtures using conventional mixing equipment for effectively improving fresh and hardened properties of cement-based materials. Dispersion is achieved by individualizing the plant pulp fibers by mechanical action, and further by blending the individualized fibers with at least one of the dry ingredients of the mix and then with the remaining ingredients of the cement-based material, with fibers added at relatively low dosages of about 0.3-30 kg per cubic meter. The affinity of plant pulp fibers for water facilitates their dispersion in conventional cement-based mixtures.

Abstract: A CO.sub.2 pre-curing period is used prior to accelerated (steam or high-pressure steam) curing of cement and concrete products in order to: (1) prepare the products to withstand the high temperature and vapor pressure in the accelerated curing environment without microcracking and damage; and (2) incorporate the advantages of carbonation reactions in terms of dimensional stability, chemical stability, increased strength and hardness, and improved abrasion resistance into cement and concrete products without substantially modifying the conventional procedures of accelerated curing. Depending on the moisture content of the product, the invention may accomplish CO.sub.2 pre-curing by first drying the product (e.g. at slightly elevated temperature) and then expose it to a carbon dioxide-rich environment. Vigorous reactions of cement paste in the presence of carbon dioxide provide the products with enhanced strength, integrity and chemical and dimensional stability in a relatively short time period.

Abstract: Pulp fibers derived from wood or non-wood plants or recycled paper products are individualized and dispersed in water, and mixed into cement-based mixtures using conventional mixing procedures at relatively low dosages of about 0.3-30 kg of fiber per cubic meter of concrete. Once individualized, the affinity of plant pulp fibers for water facilitates their dispersion in normal cement-based mixtures. Fresh cement-based materials incorporating the dispersed individualized plant pulp fibers provide desirable workability, resistance to segregation and bleeding, pumpability, finishability, and reduced rebound when pneumatically applied. Hardened cement-based materials incorporating the dispersed individualized plant pulp fibers provide improvements in crack resistance, toughness, impact resistance, fatigue life, abrasion resistance, and other mechanical, physical and durability characteristics.

Abstract: A method and an apparatus is provided for accelerated processing of cement-bonded particleboard or fiberboard under pressure through the injection of a diluted carbon dioxide gas. The method and apparatus yield controlled, thorough and efficient acceleration of the curing process, reduce the cost and raw material consumption in the process, broaden the raw materials basis for the production of cement-bonded particleboard and fiberboard, and yield end products with improved mechanical, physical and durability characteristics. Streamlined processing plants with improved productivity and efficiency can be based around this invention for the production of cement-bonded particleboards and fiberboards with improved performance characteristics.

Abstract: Pulp fibers derived from wood or non-wood plants or recycled paper products, which are about 0.1-30 mm long and about 0.001-0.1 mm in diameter with length-to-diameter ratio of about 30-3000, are dispersed in conventional concrete mixtures using conventional mixing equipment for effectively improving fresh and hardened concrete properties at relatively low cost. Dispersion is achieved by individualizing the plant pulp fibers so that they are not fully bonded to each other, and dispersing the individual fibers in concrete at relatively low dosages of about 0.3-30 kg per cubic meter. Once individualized, the affinity of plant pulp fibers for water facilitates their dispersion in conventional concrete mixtures. Fresh concrete mixtures incorporating the dispersed individualized plant pulp fibers possess desirable workability, resistance to segregation and bleeding, pumpability, finishability, and reduced rebound when pneumatically applied.

Abstract: A non-shrink grout including Portland cement, sand and an additive which is a polymer incorporating at least one of a calcium compound and aluminum metal so as to be reactive with the cement. The grout when fresh expands during curing by gas formation and by hydration and expands when hardened. The grout is useful in construction.

Abstract: An expansive Portland cement incorporating an expansive additive which is a polymer incorporating a calcium compound reactive with the cement is described. The shrinkage compensating concrete produced is much less likely to crack and is used in slabs and other structural systems where cracking of the concrete is a problem.

Abstract: A hardened cementitious composite produced using conventional mixing techniques, including a microsilica-cement mixture and randomly distributed discontinuous polyamide fibers is described. Other mix ingredients used in forming the composite are superplasticizer, water and possibly aggregates and fly ash substituting for part of the Portland cement. The microsilica particles are essential in dispersing the fibers during the regular mixing, and in enhancing the fiber-cement interfacial bond. Microsilica also reduces the alkalinity of the matrix and helps in increasing the durability of polyamide fibers in the alkaline environment of cement. With their close spacing and superior bond to the matrix of the composite, the polyamide fibers are highly effective in increasing the ultimate tensile and flexural strength and in improving the ductility and toughness of the material.