Search Results for construction materials

This article discusses the methods of pulp production, pulp processing, pulp bleaching, and paper manufacturing. It describes various types of digesters, their construction materials, the corrosion problems encountered, and methods to protect these digesters from corrosion. The article examines the corrosion problems in high-yield mechanical pulping, sulfite process, neutral sulfite semichemical pulping, chemical recovery, tall oil plants, wastewater treatment, and recovery boilers. It explains the stages of chlorine-based and nonchlorine bleaching, process water reuse for elemental chlorine-free and nonchlorine bleaching stages, selection of material for bleaching equipment, developments in oxygen bleaching, and the use of highly corrosion-resistant materials for bleach plant equipment. The article reviews the materials used in the construction of paper machine components and specific corrosion problems that affect them. It discusses the composition and corrosive nature of white water. The article also addresses the corrosion and chemical recovery associated with kraft pulping liquors.

Portland cement concrete has low environmental impact, versatility, durability, and economy, which make it the most abundant construction material in the world. This article details the types and causes of concrete degradation. Concrete can be degraded by corrosion of reinforcing steel and other embedded metals, chlorides, carbonation, galvanic corrosion, chemical attack, alkali-aggregate reaction, abrasion, erosion, and cavitation as well as many other factors. The article addresses the durability of concrete by two approaches, namely, the prescriptive approach and the performance approach. In the former, designers specify materials, proportions, and construction methods based on fundamental principles and practices that exhibit satisfactory performance. In the latter, designers identify functional requirements such as strength, durability, and volume changes and rely on concrete producers and contractors to develop concrete mixtures to meet those requirements.

This article discusses the processing, properties, and applications of various grades of lead and lead-base alloys with the aid of several tables and illustrations. It lists the Unified Numbering System (UNS) designations for various pure lead grades and lead-base alloys grouped according to nominal chemical composition. The properties of lead that make it useful in a wide variety of applications are also discussed. The largest usage of lead is in the lead acid storage batteries (in the grid plates, posts, and connector straps). Other applications include ammunition; cable sheathing; cast products such as type metals, terneplates, and foils; and building construction materials. Lead is also used as an alloying element in steel and in copper alloys to improve machinability and other characteristics. In many applications, lead is combined with stronger materials to make structures that have the best qualities of both materials such as the plumbum series.

Inorganic chemical-setting ceramic linings are one of the most widely used construction materials in designing the protective linings for industrial installations. Monolithic linings can be applied by cast or gunite (shotcreting) methods over steel or concrete as well as brick and mortar masonry. This article provides a discussion on the function of monolithic linings, the advantages of these materials, the types of applications in which these materials can be successfully used, and the limitations of these linings. It describes the application procedures that should be followed to ensure proper installation of a dual-lining system. The industrial applications that illustrate the corrosion resistance and some uses of monolithic linings, as well as other applications in wastewater treatment systems and the chemical industry, are discussed.

This article describes the eight chemical cleaning methods, namely, circulation, fill and soak, cascade, foam, vapor-phase organic, steam-injected, on-line chemical, and mechanical cleaning. It presents information on deposit types, solvents used to remove them, and construction material incompatibilities in a table. The article summarizes the uses of chemical cleaning solutions, including hydrochloric acid, phosphoric acid, and sulfamic acid, as well as the additives used to neutralize their impact on corrosion. It discusses the chemical cleaning procedures, including selection of cleaning method and solvent, documentation of cleaning, and corrosion monitoring in chemical cleaning.

This article discusses the properties, primary and secondary production, product forms and applications of various grades of lead and lead-base alloys with the aid of several tables and illustrations. It lists the Unified Numbering System (UNS) designations for various pure lead grades and lead-base alloys grouped according to nominal chemical composition. The properties of lead that make it useful in a wide variety of applications are also discussed. The largest use of lead is in lead-acid storage batteries. Other applications include ammunition, cable sheathing, cast products such as type metals, terneplate, foils, and building construction materials. Lead is also used as an alloying element in steel and in copper alloys to improve machinability. The article concludes with information on the principles of lead corrosion, corrosion resistance of lead in water, atmospheres, underground ducts, soil and chemicals.

Rapid prototyping (RP) is a field in manufacturing involving techniques/devices that produce prototype parts directly from computer-aided design models in a fraction of time. This article discusses the principles of RP and three major commercial processes, based on their layer creation method. These include selective cure layered processes, extrusion/droplet deposition processes, and sheet form fabricators. The article provides information on the three classes of RP, namely, voxel sequential volume addition, periphery cutting, and area sequential volume addition. It presents equations that represent build times for each of the three classes.

Construction-scale additive manufacturing, also known as construction three-dimensional printing (C3DP), has received significant attention as a technology that could transform the construction industry by offering a highly automated construction process for various applications. This article presents an overview of the current developments in C3DP as well as future prospects and discusses the technical and regulatory barriers to its widespread adoption by the construction industry. It also presents a detailed discussion on construction-scale additive manufacturing technologies.

This is an introductory article to special welding and joining topics focusing on various unique aspects related to three major joining technologies, namely, welding, brazing, and soldering.

Corrosion problems and materials selection for emissions control equipment can be difficult because of varied corrosive compounds present and the severe environments encountered. This article discusses the selection of materials for construction of flue gas desulfurization systems. It addresses the problems associated with materials for incinerator off-gas treatment equipment. The off-gases can be classified according to their corrosiveness as: industrial chemical, hospital, municipal solid, and sewage sludge. The article provides information on the selection of materials for the three most common types of dust collection equipment used in bulk solids processing, namely, fabric filters, electrostatic precipitators, and wet scrubbers. It also discusses a wide variety of corrosion problems encountered in chemical and pharmaceutical industries.

Due to its layer-by-layer process, 3D printing enables the formation of complex geometries using multiple materials. Three-dimensional printing for bone tissue engineering is called bioprinting and refers to the use of material-transfer processes for patterning and assembling biologically relevant materials, molecules, cells, tissues, and biodegradable biomaterials with a prescribed organization to accomplish one or more biological functions. Currently, 3D bioprinting constructs can be classified into two categories: acellular and cellular. This article introduces and discusses these two approaches based on the suitable materials for these constructs and the fabrication processes used to manufacture them. The materials are grouped into polymers, metals, and hydrogels. The article also summarizes the commonly used 3D printing techniques for these materials, as well as cell types used for various applications. Lastly, current challenges in tissue engineering are discussed.

The use of 3D bioprinting techniques has contributed to the development of novel cellular patterns and constructs in vitro, ex vivo, and even in vivo. There are three main bioprinting techniques: inkjet printing, extrusion printing (also known as bioextrusion), laser-induced forward transfer (LIFT) printing, which is also known as modified LIFT printing, matrix-assisted pulsed-laser evaporation direct write, and laser-based printing (laser-assisted bioprinting, or biological laser printing). This article provides an overview of the LIFT process, including the LIFT process introduction, different implementations, jetting dynamics, printability phase diagrams, and printing process simulations. Additionally, materials involved during LIFT are introduced in terms of bioink materials and energy-absorbing layer materials. Also, the printing of single cells and 2D and 3D constructs is introduced, showcasing the current state of the art with the ultimate goal for tissue- and organ-printing applications.

This article presents information regarding the use of protective coatings in municipal potable water systems, including raw water collection and transmission, water treatment plants, and treated water distribution. It provides useful guidance for the selection and use of protective coatings in these municipal water systems. The most commonplace corrosion-damage mechanisms are highlighted. The article describes the most common materials of construction found in municipal water systems, namely, cast iron, ductile iron, carbon steel, precast concrete cylinder pipe and reinforced concrete pipe, prestressed concrete tanks, and stainless steel. It provides information on the most common generic coating systems used for new steel tanks and water storage tanks. It concludes with a discussion of quality watch-outs when selecting or using protective coatings in municipal water systems.

Polymeric floor coatings refer to flooring materials composed of multicomponent thermoset resins formulated with various fillers and pigments that are installed in situ, usually over concrete substrates. Polymeric flooring systems, specified for all industrial and commercial environments, use a variety of polymer chemistries and are constructed in a variety of methods and designs. This article provides a description of the service conditions for the polymeric flooring systems. It provides information on polymeric flooring systems, including thin-film coatings, self-leveling systems, membrane systems, broadcast systems, troweled systems, and terrazzo. The article also focuses on properties, applications, testing, and factors and requirements to be considered during the installation of polymeric floor coatings. It concludes with a discussion about coating failures, including bonding, cracking, chemical attack, and moisture that affect the polymeric floor coatings on concrete.

Supercritical water oxidation (SCWO) is an effective process for the destruction of military and industrial wastes including wastewater sludge. This article discusses the unique properties of supercritical water and lists the main technological advantages of SCWO. For many waste streams, corrosion continues to be one of the central challenges to the full development of the SCWO technology. The article presents a summary of selected materials exposed to various environments as well as the observed form of corrosion in a table. It also illustrates the necessity to adopt a synergistic approach incorporating feed chemistry control, reactor design modifications, and intelligent materials selection, for mitigating degradation of SCWO systems.

This article provides a basic overview of bridge corrosion, where it occurs on steel and concrete bridge structures, and how to prevent corrosion by using coatings. It describes types of bridge designs, with illustrations, and presents information on how corrosion occurs in different bridge zones and areas, with illustrations. The article concludes with a discussion on the common methods of coating systems applications on bridge structures and key elements in coating condition assessment.