CFRP strengthening of ASR affected concrete piers of railway bridges

Alkali-Silica Reactions (ASR) occur in concrete due to chemical reactions between the alkali (sodium and potassium) hydroxides in the concrete pore solution. Under certain circumstances, these reactions cause internal expansion (commonly known as “concrete cancer”). The swelling within the concrete can potentially result in cracking of the concrete impairing its function and shortening its service life. This paper presents the outcomes of engineering inspections, material properties investigation and strengthening design of concrete piers and abutments of four railway bridges located on the Mildura Line in Victoria. The inspection findings are discussed in detail and engineering interpretation is presented including the potential remediation options for the observed defect including steel/concrete jacketing and CFRP wrapping. The cons and pros of these methods are discussed and CFRP wrap is selected as a suitable method. The assumptions for CFRP strengthening design and challenges during application of concrete epoxy injection and CFRP are highlighted.