养护条件对含SAP高性能水泥基材料强度的影响

养护条件对含SAP高性能水泥基材料强度的影响

The low water-to-binder ratio of high-performance cementitious materials makes the hydration of cementitious materials very limited, and the change of external conditions will affect the water content and performance development in the system, which is more obvious in ultra-high-performance concrete. In this paper, natural curing, water curing, sealed curing and short-term water curing in the later stage were adopted to study the influence of curing methods on the strength of high-performance cementitious materials with a water-to-binder ratio of 0.18 - 0.24, and the influence of the particle size of SAP was further analyzed. The results showed that: SAP effectively eliminates the adverse effect of SAP pores on the strength of mortar with the same initial water-to-binder ratio, especially under natural curing; when encountering water in the later stage, the dehydrated SAP reabsorbs water, which can弥补 the defect of insufficient early water curing time and ensure a further increase in strength, and the larger the amount of SAP added, the more obvious the弥补 effect. Therefore, when the early water curing time of cementitious materials with a low water-to-binder ratio is short, short-term water curing in the later stage is very necessary, especially when SAP is added.

高性能水泥基材料的低水胶比使胶凝材料水化非常有限，而外界条件变化会影响体系中含水量及性能发展，这在超高性能混凝土更为明显。本文采用自然养护、水养、密封养护以及后期短暂水养护，研究了养护方式对水胶比为0.18~0.24的高性能水泥基材料强度的影响，并进一步分析SAP粒径的影响。结果发现： SAP有效消除SAP孔对相同初始水胶比砂浆强度的不利影响，尤其在自然养护下；后期遇水时失水SAP重新吸水，可以弥补早期水养时间不足的缺陷，保证强度进一步增加，且SAP掺量越大，弥补效果越明显。因此，低水胶比水泥基材料早期水养时间较短时，后期短暂的水养非常必要，尤其掺入SAP时。