Experimental study and application of manufactured sand self-compacting concrete in concrete-filled-steel-tube arch bridge: A case study

Utilizing manufactured sand (MS) with high content of stone dust, mix proportion tests were carried to investigate the influence factors of preparing self-compacting concrete (SCC) with good performance. Results showed that, with the stone dust content no more than 9% and the addition of expansion agent not exceed 10%, the prepared MS-SCC has no slump loss within 4 h for the fresh status and have compressive strength over 55 MPa for the harden status. To further verify the workability of the prepared MS-SCC for the “filling down and pumping up” concrete pouring method, field full-scale filling simulation test was carried out. Results showed that the prepared MS-SCC performed well in construction workability, which could pass through the headed studs and internal stiffening plates in the semi-open tube segment smoothly. All the above results have been successfully applied on both the Zongxi River Bridge and the Xianghuoyan Bridge, which are two similar concrete-filled-steel-tube (CFST)arch bridge located adjacent in mountainous areas with poor engineering conditions. Therefore, although the research results of this paper have certain particularity, they are still valuable to form application guidelines of MS-SCC with high stone dust content in the mountainous areas of southwest China.