Search Results for concrete

This article presents a brief description of the fundamental characteristics of concrete and its constituents for understanding concrete fracture surfaces. It discusses the following two types of fractures: fractures induced in the laboratory and existing (service) fractures. The article provides a discussion on how existing crack surfaces differ from induced fractures: color, hardness, luster, depth of carbonation, deposits on crack surfaces, and propagation around or through aggregates.

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 is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of sulfur concrete and asphalt and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the crystal morphology, noninterconnecting voids, and microvoids of these surfaces.

Rehabilitation is the process of repairing or modifying reinforced concrete structures to a desired useful condition. This article describes the operational steps for the structural assessment of reinforced concrete structures. It discusses the classification of composite materials reinforcing systems for strengthening reinforced concrete structures, such as shop-manufactured and field-manufactured structures. The article reviews the materials property requirements for designing reinforcing systems to strengthen the reinforced concrete structures. It discusses the fiber-reinforced polymer (FRP)-reinforced concrete behavior that depends on flexural, shear, or axial failures. Surface preparation procedures for rehabilitation techniques of reinforced concrete structures using bonded FRP materials are also discussed. The article provides information on the applications of rehabilitation of concrete structures. It explains data recording and acceptance criteria for rehabilitation of concrete structures with composite materials.