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Nano-engineered ultra-high performance concrete for controlled autogenous shrinkage using nanocellulose
Cement and Concrete Research ( IF 11.4 ) Pub Date : 2020-11-01 , DOI: 10.1016/j.cemconres.2020.106217 Ousmane A. Hisseine , Nancy A. Soliman , Balázs Tolnai , Arezki Tagnit-Hamou
Cement and Concrete Research ( IF 11.4 ) Pub Date : 2020-11-01 , DOI: 10.1016/j.cemconres.2020.106217 Ousmane A. Hisseine , Nancy A. Soliman , Balázs Tolnai , Arezki Tagnit-Hamou
Abstract For its superior mechanical strength and durability aspects, ultra–high performance concrete (UHPC) offers an advanced construction solution for resilient concrete infrastructures. Nonetheless, one major handicap of UHPC is autogenous shrinkage, particularly for insitu casting. This study proposes nanoengineering using nanoscale cellulose filaments as a novel approach for controlling autogenous shrinkage of UHPC. A typical UHPC mix was redesigned by incorporating cellulose filaments at 0–0.30% by mass of cement while varying silica fume content from 25 to 15%. Results indicate that cellulose filaments can significantly mitigate autogenous shrinkage by a twofold mechanism. The first is an internal curing effect leading to characteristic volumetric expansions at very-early-ages, thereby significantly attenuating autogenous shrinkage. Thus, reduction in autogenous shrinkage of 45–75%, 22–53%, and 20–40% were achieved at 24 hours, 7 days, and 14 days, respectively. The second mechanism pertains to a nanoreinforcing effect leading to matrix bridging, thereby improving volumetric stability. On the other hand, while adjusting silica fume content from 25 to 15% does not affect early-age autogenous shrinkage (~0–4% reduction at 1 day), this measure can allow reducing 7-days autogenous shrinkage by up to 28%. However, given the remarkable role of silica fume in the mechanical performance of UHPC, mixtures with 15% silica fume recorded 21–25% drop in flexural capacity. Interestingly, nanoengineering UHPC with cellulose filaments enabled obtaining UHPCs with 25% silica fume exhibiting as low autogenous shrinkage as UHPCs with 15% silica fume while maintaining the enhanced flexural strength offered at 25% silica fume content.
中文翻译:
使用纳米纤维素控制自收缩的纳米工程超高性能混凝土
摘要 由于其卓越的机械强度和耐久性,超高性能混凝土 (UHPC) 为弹性混凝土基础设施提供了先进的施工解决方案。尽管如此,UHPC 的一个主要障碍是自收缩,特别是对于原位铸造。这项研究提出了使用纳米级纤维素长丝的纳米工程作为控制 UHPC 自收缩的新方法。典型的 UHPC 混合物经过重新设计,纤维素长丝占水泥质量的 0-0.30%,同时硅粉含量从 25% 到 15% 不等。结果表明,纤维素长丝可以通过双重机制显着减轻自收缩。第一个是内部固化效应,导致早期特征体积膨胀,从而显着减弱自收缩。因此,在 24 小时、7 天和 14 天时,自体收缩率分别降低了 45-75%、22-53% 和 20-40%。第二种机制与导致基质桥接的纳米增强效应有关,从而提高体积稳定性。另一方面,虽然将硅粉含量从 25% 调整到 15% 不会影响早期自收缩(1 天减少约 0-4%),但该措施可以将 7 天自收缩减少多达 28% . 然而,考虑到硅粉在 UHPC 机械性能中的显着作用,含有 15% 硅粉的混合物的弯曲能力下降了 21-25%。有趣的是,
更新日期:2020-11-01
中文翻译:
使用纳米纤维素控制自收缩的纳米工程超高性能混凝土
摘要 由于其卓越的机械强度和耐久性,超高性能混凝土 (UHPC) 为弹性混凝土基础设施提供了先进的施工解决方案。尽管如此,UHPC 的一个主要障碍是自收缩,特别是对于原位铸造。这项研究提出了使用纳米级纤维素长丝的纳米工程作为控制 UHPC 自收缩的新方法。典型的 UHPC 混合物经过重新设计,纤维素长丝占水泥质量的 0-0.30%,同时硅粉含量从 25% 到 15% 不等。结果表明,纤维素长丝可以通过双重机制显着减轻自收缩。第一个是内部固化效应,导致早期特征体积膨胀,从而显着减弱自收缩。因此,在 24 小时、7 天和 14 天时,自体收缩率分别降低了 45-75%、22-53% 和 20-40%。第二种机制与导致基质桥接的纳米增强效应有关,从而提高体积稳定性。另一方面,虽然将硅粉含量从 25% 调整到 15% 不会影响早期自收缩(1 天减少约 0-4%),但该措施可以将 7 天自收缩减少多达 28% . 然而,考虑到硅粉在 UHPC 机械性能中的显着作用,含有 15% 硅粉的混合物的弯曲能力下降了 21-25%。有趣的是,