摘   要：利用特种硅酸盐水泥FACC制备了免压蒸PHC管桩混凝土，研究了水泥掺量、水灰比、砂率、静停时间、升温速率、恒温时间、温度等因素对PHC管桩混凝土蒸养强度的影响，并采用XRD和SEM等表征方法对水化产物进行了矿物成分和形貌分析。结果表明，免压蒸PHC管桩最佳混凝土配合比为FACC 480 kg/m³、水灰比0.26～0.28、砂率32%～37%、养护制度为20 ℃静停2 h、升温速率0.3 ℃/min、恒温温度90 ℃、恒温时间4~6 h，开盖自然冷却脱模。在此基础上制备的免压蒸PHC管桩混凝土能减少延迟钙矾石的形成，强度达到C80以上，满足PHC管桩的使用要求。

Abstract： The non-autoclaved PHC pile concrete with special portland cement FACC is prepared. The parameters affecting the compressive strength of PHC pile concrete, such as cement content, W/C, sand ratio, rest period, heating rate, constant temperature and time etc. are investigated. Moreover, the type of hydration products is investigated by using SEM and XRD. The results show that the compressive strength of PHC pile concrete whose mix proportion is FACC 480 kg/m³， W/C ratio 0.26～0.28, sand ratio 32%～37% can meet the requirements in some areas. Furthermore, the experiment shows the best steam-cured system is 20 ℃ rest period lasting 2 h, heating rate at 0.3 ℃/min,  constant temperature at 90 ℃, constant temperature time lasting 4~6 h, nature cooling. The excellent mix ratio and steam-cured system can avoid the risk of expansion damage from delayed ettringite formation.