Study of Concrete under Combined Action of Aggressive Environment and Long-Term Loading

Abstract

A significant part of reinforced concrete structures is subjected to intensive environmental impact during operation. This can cause local destruction and failure of buildings if obligatory measures are not taken to protect them from corrosion. This is especially true for industrial buildings, where the environment could be contaminated with aggressive products or waste. An important issue is the development of methods for calculating the load-bearing capacity and serviceability of reinforced concrete structures with corrosion damage. The main reason for this is the necessity to determine the durability and reliability of buildings and structures and the estimation of their safe operation time. As corrosion damages of concrete are a critical issue, more detailed experimental studies are needed. This paper presents experimental studies of concrete prisms under the simultaneous action of an aggressive environment and a constant level of compressive force. In total, 32 prisms under different loading conditions and in different aggressive medium were tested. Samples were divided in series, for which different load levels were chosen (0.25fck, 0.35fck, 0.45fck). Additionally, control samples in the air and immersed in water were tested. During the experiment, different parameters were monitored and recorded: decrease of cross-sectional size, the temperature and environmental humidity. Results of the study showed that destruction occurred due to the presence of corrosion damages of concrete and a reduction of the cross-sectional area. The stresses in the concrete at the destruction stage were less than the value of the prism strength by 10–12%. It was established that along the contour of the section, there is a partially degraded layer of concrete of 1.5–3.7 mm thickness, with corrosion microcracks and corrosion products. Additionally, experimental and theoretical diagrams of concrete with corrosion damages were obtained and compared. The ultimate deformations of concrete with corrosion damage, which correspond to the prismatic strength of concrete, in comparison with undamaged concrete were lower by 11–18%. Therefore, the concrete strength is decreased during exploitation under loading in an aggressive environment, which needs to be taken into account during calculations.

Calculation Model for Estimation of Residual Bearing Capacity of Damaged Reinforced Concrete Slender Columns

“…A significant part of reinforced concrete structures during operation is exposure to intense environmental influences [17]. This can cause the local destruction and failure of buildings if mandatory measures are not taken to protect them from corrosion [18].…”

Measurement of corrosion rates on reinforcement using the field test

“…There are many factors and/or actions that could decrease the reliability of structures and bridges such, as the movement of a foundation, structural overloading, accidental damage, corrosion, excessive deflections and so on [1,2]. Each type of building or civil engineering works, could be subjected to some of these factors, including climatic conditions.…”

Exploitation of reinforced concrete constructions on a ground base with force and environmental influences

“…In conditions of long-term exploitation of reinforced concrete constructions, it is necessary to assess their stress-strain state as a result of corrosion damage, determine reliability, durability and residual service life, taking into account the reduction in the cross-sectional area of concrete and reinforcement [5][6][7][8][9][10].…”