Research on preparation and engineering application of UHPC for precast structure joints
In order to prepare UHPC for splicing of prefabricated structures,the effects of specific surface area of slag powder,aggregate mortar ratio and machine-made sand replacement rate on workability and mechanical properties of UHPC were investigated.The results show that the larger the specific surface area of slag powder,the higher the viscosity of UHPC slurry,but on the other hand,the faster the hydration reaction degree,the faster the strength development.The 3d compressive strength of UHPC prepared by slag powder with a specific surface area of 800 m2/kg is 96 MPa,and the 28 d compressive strength is 143 MPa.With the increase of aggregate mortar ratio,the workability and mechanical properties decreased.After mechanical sand replacement,there are more interfa-cial transition zones in the slurry structure,the strength decreases further,and the strain softening occurs in the uniaxial tensile curve.The elongation of UHPC prepared by 0.9 aggregate mortar ratio and 50％sand replacement rate is 720 mm,28 d compressive strength is 128 MPa,ultimate tensile strength is 9.3 MPa,ultimate tensile strain is 0.21％,and uniaxial tensile strain shows strain hardening.Its comprehensive performance is more excellent,and it is suitable for the wet joint strengthening project of prefabricated box girder.
万方数据
维普
