Internal curing by superabsorbent polymers in ultra-high performance concrete
Internal curing by superabsorbent polymers in ultra-high performance concrete
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DOI：
10.1016/j.cemconres.2015.05.005
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发表时间：
2015-10-01
影响因子：
11.4
通讯作者：
Lura, P.
中科院分区：
文献类型：
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作者：
Justs, J.;Wyrzykowski, M.;Lura, P.
为了限制可能导致超高性能混凝土（UHPC）早期开裂的自干燥和自收缩，可以采用通过高吸水性聚合物（SAP）进行内部固化。研究了水灰比低于 0.25 的水泥浆和 UHPC，无论是否含有 SAP。首先通过 SEM 图像分析测定硬化水泥浆体溶液聚合 SAP 的吸收能力。据观察，在水泥水化过程中，SAP 空腔部分被硅酸钙石填充。等温量热法表明，SAP 的水夹带延迟了主要水化峰值，而几天后，它以类似于增加水灰比的方式增加了水化程度。 SAP的内部固化可有效减少内部相对湿度的降低和自收缩。尽管机械性能会受到 SAP 添加的影响，但 28 天后可以达到近 150 MPa 的抗压强度。 (C) 2015 Elsevier Ltd. 保留所有权利。
To limit self-desiccation and autogenous shrinkage that may lead to early-age cracking of ultra-high performance concrete (UHPC), internal curing by means of superabsorbent polymers (SAP) may be employed. Cement pastes and UHPC with water-to-cement ratio below 0.25, with or without SAP, were studied. The absorption capacity of a solution-polymerized SAP was first determined on hardened cement pastes by SEM image analysis. It was observed that the SAP cavities become partially filled with portlandite during cement hydration. Isothermal calorimetry showed that water entrainment with SAP delays the main hydration peak, while after a couple of days it increases the degree of hydration in a manner similar to increasing the water-to-cement ratio. Internal curing by SAP is effective in reducing the internal relative humidity decrease and the autogenous shrinkage. Although the mechanical properties are affected by SAP addition, it is possible to reach compressive strengths of almost 150 MPa at 28 days. (C) 2015 Elsevier Ltd. All rights reserved.