Material and durability study of a 10-year-old crumb rubber concrete bridge deck in Tianjin, China

In early August 2006, a crumb rubber concrete (CRC) bridge deck was constructed in a suburb of Tianjin, China. Although small, measuring 24 × 8 × 0·12 m, it was the first instance of the application of a CRC bridge deck reported in public literature. More than 10 years have passed since, and the last inspection of the deck carried out in June 2017 showed that few cracks have developed in the deck surface. Visual inspection of the bottom of the bridge deck showed no sign of stains owing to water leakage. At the same time, six samples were cored from the deck and were evaluated for split strength, density and rubber content. Four cored samples were further scanned by computerised image software to reveal the distribution of rubber crumbs. In March 2019, water permeability and carbonation tests were carried out on the deck as well as on a nearby plain concrete bridge deck. This study reports on these findings and discusses issues such as flexural strength and rubber floating, and provides recommendations for rubber content in crack-controlling CRC mix design. This study concludes that the Tianjin CRC bridge deck is in good condition, that the material properties show little deterioration and that its durability has been sustained.