Installation — business terrible - 1 part
September 8th, 2015
Naturally, installation of the hydromassage equipment it is necessary to entrust specialists, othe[...]
Current Research Topics
A substantial amount of research is being carried at the NSF Center for Science and Technology of Advanced Cement-Based Materials at Northwestern University [32]. A survey of the literature is kept by The American Ceramic Society [33, 34]. Four general critical areas, necessary to maintain technological leadership, have been identified by the US industry [35]: (1) design and structural systems, (2) constituent materials, (3) concrete production, delivery, and placement, and (4) repair and rehabilitation (Table 3). Topics of current scientific research include characterization of microstructural features (e. g., C-S-H gel, pore shape, heterogeneity), mechanical properties (model prediction, measurement, performance improvement), chemical behavior (e. g., in corrosive environments, hydration process, CaCO3 efflorescence), characteristics of concrete at elevated temperatures. Other specific areas include test methods to determine properties (i. e., fatigue, creep, and chemical properties) of FRP, which are reproducible and reliable. Repair of structures is a relevant area that has several worldwide organizations involved. In addition to the American Concrete Institute (ACI), groups providing information include the International Concrete Repair Institute, Concrete Repair Association (U. K.), Building Research Establishment (U. K.), American Concrete Pavement Association, American Association of State Highway Transportation Officials, The Concrete Society (U. K.), The Cathodic Protection Association (U. K.), and US Army Corps of Engineers.
Table 4 summarizes recent developments regarding cement and concrete materials. Improved materials and advanced sensors are needed for very demanding applications
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Table 3 Main research needs in the concrete industry [adapted from 35] Design and Structural Systems
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such as concrete in offshore oil platforms [36] and in the nuclear industry where concrete structures have performed well [37]. However, as these structures age, degradation due to environmental effects threaten their durability. Items of note are corrosion of steel reinforcement following carbonation of the concrete or ingress of chloride ions, excessive loss of posttensioning force, leaching of concrete, and leakage of posttensioning system corrosion inhibitor through cracks in the concrete.
Table 4 Recent US patents on cement-related materials development Assignee Number Short title
Cement structure containing a waterproofing layer Dusting-inhibited cement with improved strength Cement clinker and cement containing the same Polymers for high-flow and high-strength concrete Cement retarder and cement retardative sheet Additives for cement materials and cement materials Road repair material comprising cement and resin Synthetic polymer fibers into cement mixtures Cement dispersants
Cement retarder and cement retardative sheet
Fiber reinforcement of cement composites
Copolymers as cement additives
Compositions for controlling alkali-silica reaction
Hardener for waste-containing cement articles
Cement composition inhibit drying shrinkage
Accelerated curing of cement-based materials
Alkali-reactive aggregate and sulphate resistance
Early-strength-enhancing admixture for precast cement
Light-weight insulating concrete
Cement-based injection grout
Unitized cement admixture
(Phosphorous acid) Admixture for cement
(Waterless) Polymer concrete composition
High Tg polymer for portland cement mortar
Improved rheology of cement-products
Alkali-activated class C fly ash cement
Cement and products using such cement
Ultra high-strength hydraulic cement compositions