No abstract

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.

No abstract

Crumb rubber concrete (CRC) is a concrete that contains rubber crumbs. This article presents a study of three experiments on long aged CRC specimens that were cored from a decade old CRC bridge deck in Tianjin, China. The three experimental tests conducted were: (1) the flexural stress–strain test on semi-circular disk specimens; (2) the accelerated steel-rebar corrosion test and (3) the carbonation test. In addition, the in situ carbonation test was also carried out on the CRC bridge deck. The flexural stress–strain test results showed that the CRC semi-circular disk specimens exhibited a ductile pattern and high-energy absorbing capacity with its flexural tensile strength being at 5 MPa and the flexural modulus of 10 GPa. The steel corrosion rust rate via the calculation of steel mass loss before and after the test in the accelerated steel-rebar corrosion test remained extremely low. The carbonation test results showed that in comparison with the prediction of two popular carbonation models, the carbonation in the CRC bridge deck took place at a much slower rate during the last 13 years. All of the results obtained in this study are reported for the first-time and indicate that these CRC cored specimens exhibit good mechanical properties and excellent durability characteristics after a decade in service, which may provide the technical knowledge for the possible future application of CRC in concrete constructions.

No abstract