Small and medium span bridges occupy a large proportion in highway construction, while the superstructure of small and medium span bridges has various forms. In order to provide practical and effective carbon reduction guidance to reduce carbon emissions for highway bridge construction, carbon emissions of three types of superstructure, precast small box girder, cast-in-situ box girder and steel-concrete composite beam, which are widely used in medium and small span bridges, are studied respectively. Firstly, carbon emission calculation boundary of the bridge construction period is defined. The construction period is divided into building material production stage, material transportation stage and mechanical construction stage. Carbon emission models of the above three types of superstructure during construction period are established respectively. Carbon emission of the bridge is analyzed quantitatively. Then, the carbon emissions during the operation, maintenance and demolition phases are further analyzed. The results of comparison show that, the material production stage is the most carbon emission link. Precast small box girder is the superstructure form with the lowest carbon emission during bridge construction. However, if considering the carbon emission during operation, maintenance and demolition, the superstructure form with the lowest carbon emission is steel-concrete composite girder. The study will provide references for the future development of green low carbon design, construction and operation and maintenance of highway bridges.

CICTP