Spalling of concrete cover induced by reinforcement

• Published in: Engineering structures Vol. 237; p. 112188
• Main Authors: Moccia, Francesco, Fernández Ruiz, Miguel, Muttoni, Aurelio
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.06.2021; Elsevier BV
• Subjects: Bond; Casting position effect; Concrete; Concrete tensile strength; Corrosion; Cover spalling; Digital imaging; Group effect; Pressure; Pull-out tests; Radial pressure; Reinforced concrete; Size effect; Size effects; Spalling; Cover spalling; Corrosion; Concrete tensile strength; Size effect; Radial pressure; Pull-out tests; Bond; Casting position effect; Group effect
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2021.112188

•Analysis of spalling failures based on detailed measurements.•Experimental tests with hydraulic inflator devices and pull-out tests.•Evaluation of casting position, size effect and group effect.•Mechanical model assessing spalling strength against internal radial pressure.•Assessment of spalling strength of pull-out bars. This paper investigates the phenomenon of cover spalling in reinforced concrete induced by bond or by the action of an inner pressure. This research is based on an experimental programme comprising a series of bond tests and a series of tests with inner-pressure on cylindrical openings. The inner-pressure test series (aimed at representing the conditions occurring for instance due to corrosion of reinforcement) was performed with hydraulic inflator devices embedded within concrete openings near to the free concrete surface. By means of detailed surface measurements performed with Digital Image Correlation, the mechanisms triggering spalling failures and the associated resistance are discussed and analysed thoroughly. This series investigates in addition a number of phenomena relevant to spalling failures, such as the influence of the casting position, group and size effects. The observed response, analysed by means of a mechanical analogy, is later used to investigate a series of structural tests performed on pull-out specimens. This analysis highlights the analogies and differences between the two types of tests (subjected to an imposed pressure or to bond stresses). On that basis, a comprehensive approach for treatment of bond-related cases failing by cover spalling is proposed, showing consistent agreement to the experimental evidence.