饱和面干处理方式对再生细骨料UHPC自收缩性能的影响

饱和面干再生细骨料具有内养护效应，可以提高超高性能混凝土（UHPC）的抗裂性能。采用预湿饱和面干和外加水饱和面干处理再生细骨料（RFA），将再生细骨料替代50%河砂，制备UHPC。研究不同处理方式获得的饱和面干再生细骨料对UHPC抗压强度、内部相对湿度及自收缩的影响，并利用MIP进行机理解释。研究结果表明，总水胶比为0.24时，与采用预湿饱和面干RFA的UHPC相比，采用外加水饱和面干RFA的UHPC，其大于50nm孔体积增多，抗压强度降低；内部相对湿度减少，自收缩增大；但其28d的抗压强度只降低了3.2%，且7d的自收缩只提高10.5%。考虑到施工的方便性，仍建议在UHPC中采用外加水饱和面干RFA。研究成果为再生细骨料UHPC的应用提供依据。

Effect of different saturated surface dry methods on the autogenous shrinkage of UHPC with recycled fine aggregate

Saturated surface dry recycled fine aggregate has internal curing effect, which can be used to improve the cracking resistance of ultra-high performance concrete (UHPC). Different saturated surface dry methods, namely pre-wetting saturated surface dry and saturated surface dry by adding extra water, were used, and ultra-high performance concrete (UHPC) was prepared by replacing 50% river sand with recycled fine aggregate (RFA) under. The effect of saturated surface dry recycled fine aggregate obtained by different methods on the compressive strength, internal relative humidity and autogenous shrinkage of UHPC was studied, and the mechanism was explained by MIP test. The results show that when the total water-binder ratio is 0.24, compared to UHPC with pre-wetting saturated surface dry RFA, the large than 50 nm pore volume of UHPC with RFA under saturated surface dry by adding extra water becomes larger, and its compressive strength decreases; its internal relative humidity decreases and its autogenous shrinkage increases; however, its compressive strength of UHPC at age of 28d is only reduced by 3.2%, and its autogenous shrinkage at age of 7d is only increased by 10.5%. Considering the convenience of construction, it is still recommended to use the RFA under saturated surface dry by adding extra water in UHPC. The research results provide a basis for the application of recycled fine aggregate UHPC.