Basic Chemical Tests of Concrete during the Assessment of Structure Suitability—Discussion on Selected Industrial Structures

Abstract

Making a decision to perform an overhaul of a damaged reinforced concrete structure should be preceded by an analysis of the real durability of that structure after the repair in connection with the anticipated service life. One of the basic problems is the avoidance of further corrosion of concrete and steel after the repair, which depends on the degree of concrete contamination with harmful chemical factors. It is particularly important to determine the content of chloride and sulfate ions which cause corrosion. Concrete pH is equally significant because it conditions effective passivation of the reinforcement. The paper presents the basic issues related to the main chemical threats, including the main sources of their origin as well as their limit values. It emphasizes the importance of conducting the chemical tests of concrete, which should be treated as one of the methods of determining structure suitability for an overhaul, especially in the context of subsequent durability. This seems obvious to an experienced specialist, but in practice, such studies are often ignored. Those considerations are backed up with selected examples of reinforced concrete industrial structures exposed to aggressive chemicals during their operation. The text shows the correlation between their technical condition and chemical test results as well as the influence of those results on making decisions concerning effective overhauls.

Diagnostics of Concrete and Steel in Elements of an Historic Reinforced Concrete Structure

“…Electrochemical tests are particularly valuable because of the possibility of conducting them in the field with simultaneous assessment of the interaction of the current steel and concrete properties in real operating conditions. They make it possible to determine areas exposed to corrosion on the surface of elements as well as the degree of reinforcement corrosion advancement and to forecast its progression over time [ 10 , 11 , 16 ]. These tests are performed using specialised devices that allow the measurement of appropriate electrical quantities, the values of which indicate the course of the corrosion process on the reinforcement [ 1 , 10 , 14 ].…”

“…However, not only should a well-prepared program of diagnostic tests account for an assessment of the existing condition, it should also provide a forecast for the durability of the structure in the future. This applies in particular to load-bearing structures operated in unfavourable environmental conditions, in which the design assumptions for ensuring adequate durability were incorrect [ 1 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. In the article [ 16 ], the authors pay special attention to the chemical tests of the material taken from the structure (usually small samples of the material obtained while performing semi-destructive tests), which allows assessment of the chemical condition of the elements in the context of protection against corrosion during its future operation.…”

“…This applies in particular to load-bearing structures operated in unfavourable environmental conditions, in which the design assumptions for ensuring adequate durability were incorrect [1,[7][8][9][10][11][12][13][14][15][16]. In the article [16], the authors pay special attention to the chemical tests of the material taken from the structure (usually small samples of the material obtained while performing semi-destructive tests), which allows assessment of the chemical condition of the elements in the context of protection against corrosion during its future operation. The authors believe that the decisive factor in the possibility of effective and durable repair of a corroded reinforced concrete structure is its chemical condition.…”

Energy simulation and heat absorption of 3R cement in multivariable resource optimization to reduce temperature calefaction

“…44 The appearance of color displayed in the internal surface of the concrete was compared with the rainbow test indicator to confirm the appropriate value pH of the concrete and to indicate the level of carbonation in it. 45 Figure 11 shows the experimental result of the carbonation depth of conventional and 3RC samples after phenolphthalein indicator spread. The results indicate that the pH value of concrete is >9.5, which appears in both samples it achieved the average range of pH observation in concrete.…”

Diagnostics of the RC Roofing Structure of the 100-Year-Old Municipal Theatre Facility

“…Non-destructive testing of concrete elements has been popularised in [ 26 , 27 , 28 ]. Due to the exposure of the elements to aggressive industrial influences, chemical tests of the concrete also provide reliable results [ 29 ]. The extensive descriptions of experimental methods of detecting structural damage that use ultrasonic methods based on the nonlinear Lambda wave principle were presented in [ 30 ] and the methods based on colinear nonlinear mixed-frequency ultrasound can be found in [ 31 ].…”