Investigating thermal cracking in mass concrete of a bridge abutment: field measurements and numerical modelling

Concrete is the most extensively used construction material in the world due to its widespread availability and ease of placement. However, the hydration process after concrete placement generates a significant amount of heat. For beams, columns, and slabs that have a large surface area-to-volume ratio, this heat dissipates easily through the surface. However, for dams, raft foundations, and bridge abutments, heat dissipation is slow due to the small surface area-to-volume ratio. Such units are identified as ‘Mass concrete’ and require special consideration for managing this heat generation and thermal behaviour to avoid thermal cracking. This article presents a case study where cracking was observed during the construction of a highway bridge abutment in Oman. The study discusses forensic measurements and uses numerical modelling to investigate and identify the cause of cracking. The numerical model used showed good agreement with the field measurements and revealed that the cracking occurred due to a thermal shock caused by the early exposure of the mass concrete surface to low ambient temperature. The study also proposes measures to control and minimise thermal cracking in arid regions like Oman.