ABSTRACT
ABSTRACT: In recent years, thermal crack at early age of concrete has been one of the restricted factors affecting the durability of concrete structure and becomes a hidden peril of the structures. Considering the characteristics of Sutong Bridge, such as high main tower, large mass of concrete, high strength grade of concrete, thermal crack at early stage of concrete was studied applying temperature-stress testing machine. When designing mix proportion of concrete, some methods were used, such as mixing a certain amount of fly ash, reducing dosage of cementitious materials, decreasing sand-aggregation ratio and mixing polypropylene fiber in the root of main tower. Early-age curing of concrete was also strengthened. The results indicated that good performance of C50 high performance concrete was got, including the workability, mechanical properties, the anti-cracking and volume stability. And there was no early age thermal crack in the project.
