不同类型PCE对UHPC性能影响研究

STUDY ON THE EFFECT OF DIFFERENT PCE TYPES ON THE PERFORMANCE OF STEAM FREE UHPC

为保证超高性能混凝土(UHPC)良好的早期强度,通常需要蒸养措施,然而蒸养成本较高,为提升免蒸养UHPC性能,通过制备聚羧酸减水剂(PCE)、早强型PCE和硅酸钙晶核PCE(CSH-PCE),研究对免蒸养UHPC拌和物和易性和UHPC力学性能的影响。结果表明掺入3种不同类型的PCE对UHPC坍落度的影响差异性并不明显,但掺入早强型PCE和CSH-PCE后会造成免蒸养UHPC坍落度1h经时损失明显下降,初凝时间缩短,早期力学性能明显提升,同时掺入早强型PCE造成了UHPC的28d抗压、抗折和劈裂抗拉强度的下降。文中研究为UHPC中不同类型PCE的开发和使用提供技术参考。

Steam curing measures are usually required to ensure the good early strength of UHPC,but the cost of steam curing is high.To improve the performance of non-steam cured UHPC,the effects of three kinds of PCE on the workability and mechanical properties of UHPC mixture without steam curing are studied by preparing standard PCE,hardening accelerating type PCE,and CSH-PCE.The results show that the influence of different types of PCE on the slump of UHPC is not obvious,whereas hardening accelerating type PCE and CSH-PCE cause the slump loss of UHPC in 1h to decrease significantly,the initial setting time to shorten,and the early mechanical properties to im⁃prove significantly.The incorporation of early-strength PCE results in the decrease of 28d compressive strength,flex⁃ural strength,and splitting tensile strength of UHPC.This paper provides a technical reference for the use of differ⁃ent types of PCE in UHPC.