可泵送免压蒸C80PHC混凝土制备、养护与性能研究

Preparation,Curing and Performance Study on Pumping Non-autoclaved C80 PHC Concrete

以超细粉煤灰为免压蒸混凝土掺合料,研究其掺量对混凝土流动性能、力学性能的影响。结果表明,超细粉煤灰掺量低于16%时,混凝土坍落度、脱模强度与其掺量正相关;掺量大于16%时,对其流动性、脱模强度影响不大,甚至降低;掺入超细粉煤灰,混凝土拉压比提高,脆性降低。所研制的C80PHC混凝土坍落度达150mm,经蒸汽养护(匀速升温2h、恒温5h、降温1h,恒温温度85℃)后脱模强度达到79.4MPa,28d抗压强度达到87.4MPa。

Ultra-fine fly ash was utilized as the admixture of concrete by non-autoclaved curing. The fluidity and mechanical properties of concrete were investigated with different dosages of ultra-fine fly ash. The results show that the slump and demoulding strength of concrete are in a positive correlation with the dosage of ultra-fine fly ash lower than16%. The slump and demoulding strength rarely increase or even decrease a little when the dosage exceeding 16%. The tensile/compressive strength ratio increases with fly ash due to a reduction in brittleness. The demoulding strength and 28 d strength of C80 PHC concrete with a slump of 150 mm reach to 79.4MPa and 87.4MPa respectively after a steaming curing（uniform raising temperature for 2h, constant temperature of 85℃ for 5h, lowering temperature for 1h）.