Reinforced concrete structure

Nesvijski, E.G., Nogin, S.I. Acoustic Emission Technics for Nondestructive Evaluation of Stress of Concrete and Reinforced Concrete Structures and Materials. Third Conference on Nondestructive Evaluation of Civil Structures and Materials, Boulder, CO, 1996. Nesvijski, E. G. Failure Forecast and the Acoustic Emission Silence Effect in Concrete. ASNT s Spring Conference, Houston, TX, 1997. 

The ultrasonic tomograph A1230 was developed to visualize in case of one side access the internal reinforced concrete structure at the depth of 1 m. This device uses 36-elements matrix array. 

Steel constructions and pipelines must either be electrically connected to the reinforcement of reinforced concrete structures or electrically separated. If they are connected, a current density of about 5 mA m should be applied to the external reinforcement and calculated on the total area of the concrete surface. 

Very often steel sheet pilings exist in conjunction with steel-reinforced concrete structures in harbors or locks. If cathodic protection is not necessary for the reinforced concrete structure, there is no hindrance to the ingress of the protection current due to the connection with the steel surfaces to be protected. The concrete surface has to be partly considered at the design stage. An example is the base of the ferry harbor at Puttgarden, which consists of reinforced concrete and is electrically connected to the uncoated steel sheet piling. 

Harbor structures are very accessible and can be investigated without the effects of wave motion. Grounding of steel pilings presents no problems and the work can be carried out from the quay (see the left-hand side of Fig. 16-13). With steel-reinforced concrete structures, measurements have to be made from a boat if no reliable contact has been provided in their eonstruction (see the right-hand side of Fig. 16-13). 

Cathodic protection of reinforcing steel with impressed current is a relatively new protection method. It was used experimentally at the end of the 1950s [21,22] for renovating steel-reinforced concrete structures damaged by corrosion, but not pursued further because of a lack of suitable anode materials so that driving voltages of 15 to 200 V had to be applied. Also, from previous experience [23-26], loss of adhesion between the steel and concrete due to cathodic alkalinity [see Eqs. (2-17) and (2-19)] was feared, which discouraged further technical development. 

Application of Cathodic Protection to Reinforced Concrete Structures... 

The decision to cathodically protect reinforced concrete structures depends on technical and economic considerations. Cathodic protection is not an economic process for small area displacements of the concrete due to corrosion of the reinforcing steel arising from insufficient concrete covering. On the other hand, the... 

The cathodic protection of reinforcing steel and stray current protection measures assume an extended electrical continuity through the reinforcing steel. This is mostly the case with rod-reinforced concrete structures however it should be verified by resistance measurements of the reinforcing network. To accomplish this, measuring cables should be connected to the reinforcing steel after removal of the concrete at different points widely separated from each other. To avoid contact resistances, the steel must be completely cleaned of rust at the contact points. 

There are different concrete replacement systems available for renovating reinforced concrete structures. They range from sprayed concrete without polymer additions to systems containing conducting polymers (PCC-mortar). Since with the latter alkalinity is lower, more rapid carbonization occurs on weathering [59] and the increased electrical resistivity has to be taken into account, so that with cathodic protection only sprayed concrete should be used as a repair mortar. 

Cathodic protection can be used as a renovation measure for steel-reinforced concrete structures (see Chapter 19). Although material costs of from 100 DM m" (particularly with preparation, erection, and spray coating costs) up to 300 DM m are quite high, they do not compare with the costs of demolition or partial replacement. ... 

MKI The Mark I containment consists of two separate structures (volumes) connected by a series of l.irae pipes One volume, the dry well, houses the reactor vessel and primary system components. The other i oUmic is a torus, called the wetwell, containing a large amount of water used for pressure suppression and as, i heai sink. The Brunswick units use a reinforced concrete structure with a steel liner. All other M,uk 1 cnni.un ments are free-standing steel structures, The Mark I containments are inerted during plant oper.mon i. prevent hydrogen combustion. 

Reinforced concrete structures that are fully immersed or buried in a corrosive environment may generally be protected using conventional cathodic... 

Rindner et al, Preliminary Estimate of Concrete Thicknesses and Construction Costs of Laced Reinforced Concrete Structures , PATR 4441... 

The high resistance and mass provided by reinforced concrete structures makes it particularly suited for buildings located in close proximity to explosion sources. Concrete also provides effective resistance to fire and projectile penetration which are important considerations in many explosion accidents. 

Carbon fiber introduction into commercial markets happened in the mid-1960s and since then their application has increased substantially. Some of these applications include airplanes, spacecraft parts, compressed gas tanks, automotive parts, bridges, reinforced concrete, structural reinforcement, recreational sports equipment, and electrochemical systems [6,7]. 

Latex-modified mortars and concretes have become promising materials for preventing chloride-induced corrosion and for repairing damaged reinforced concrete structures. In Japan and the USA, latex-modified mortar is widely used as a construction material in bridge deck overlays and patching compounds, and for finishing and repairs [99]. Polymer-cement hydrate-... 

Manual of standard practice for detailing reinforced concrete structures... 

AIRFORMED CERASHELL is based on the concept of air-supported forming, used successfully for the past 25 years with steel reinforced concrete structures. An airform, or balloon, is designed to inflate to a specific size and shape. Polyurethane foam is sprayed onto the inside surface of the balloon, with concrete as the interior coating. Steel reinforcing bars are pinned to the foam, prior to spraying the con-... 

NACE International Technical Committee Report No. 24204, Use of Reference Electrodes for Atmospherically Exposed Reinforced Concrete Structures , NACE International, Houston, TX, USA, March 2000,11 pp. 

High Explosives Used to Demolish Constituents of Reinforced Concrete Structures",ibid, (1988)... 

There are several fuel storage pools at Sellafield. The pools are reinforced concrete structures built with an above ground philosophy. Some pool walls are painted and the area above and below the water surface are covered with stainless steel. Pools where casks are received and where fuel containers are opened are generally lined with stainless steel with systems in place to detect any poolwater leakage. 

The preliminary technical-and-economic assessment has been performed for the two variants of the near surface SNF storage facility configuration variant 1 - SNF is placed into canisters within a built-in reinforced concrete structure variant 2 - SNF is placed in metal concrete containers. The variants suggested are characterized by the following values ... 

Dede, M., et al. Preliminary Estimate of Concrete Thicknesses and Construction Costs of Laced Reinforced Concrete Structures, Technical Report No. 1, Picatlnny Arsenal, Dover, N.J., October 1972. (U)... 

Acrylic-modified cement coatings protect atmospherically exposed reinforced concrete structures from attack by chloride ions, oxygen and water. 

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