Study on the causes of cracks in a reinforced concrete highway bridge

Abstract

Cracking in reinforced concrete highway bridges (RCHB) poses a serious threat to both structural and traffic safety. Identifying the causes of cracks is an important basis for determining subsequent treatment plans. To ascertain the causes of cracks in a reinforced concrete highway bridge, firstly, an on-site survey was conducted, including drilling concrete core samples and deploying measuring points to monitor the bridge’s settlement and crack changes. Secondly, the strength and alkali-silica reaction (ASR) of the collected concrete samples were experimentally studied, and micro-morphology and composition analysis of the samples were carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Finally, based on the crack phenomena observed in the bridge’s main structure, the causes of the cracks were analyzed using experimental data and microstructure observations. Combining the results of on-site monitoring and indoor tests, it was concluded that uneven settlement and low concrete strength were the primary causes of bridge cracking, while the impact of ASR could be neglected.