Muzenski Scott, Flores-Vivian Ismael, Farahi Behrouz, Sobolev Konstantin
Department of Civil and Environmental Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León, San Nicolás de los Garza C.P. 66450, Mexico.
Nanomaterials (Basel). 2020 Nov 19;10(11):2291. doi: 10.3390/nano10112291.
Ultrahigh performance concrete (UHPC), which is characterized by dense microstructure and strain hardening behavior, provides exceptional durability and a new level of structural response to modern structures. However, the design of the UHPC matrix often requires the use of high quantities of supplementary cementitious materials, such as silica fume, which can significantly increase the cost and elevate the production expenses associated with silica fume handling. This paper demonstrates that a fiber-reinforced composite with properties similar to conventional UHPC can be realized with very low quantities of silica fume, such as 1% by mass of cementitious materials. The proposed UHPC is based on reference Type I cement or Type V Portland cement with very low CA (<1%) that also complies with Class H oil well cement specification, silica fume, small quantities of AlO nanofibers, and high-density polyethylene or polyvinyl alcohol macro fibers. Previous research has demonstrated that nanofibers act as a seeding agent to promote the formation of compact and nanoreinforced calcium silicate hydrate (C-S-H) clusters within the interparticle and nanofiber spaces, providing a nanoreinforcing effect. This approach produces a denser and stronger matrix. This research expands upon this principle by adding synthetic fibers to ultrahigh strength cement-based composites to form a material with properties approaching that of UHPC. It is indicated that the developed material provides improved strain hardening and compressive strength at the level of 160 MPa.
超高性能混凝土（UHPC）具有致密的微观结构和应变硬化行为，为现代结构提供了卓越的耐久性和新的结构响应水平。然而，UHPC基体的设计通常需要使用大量的辅助胶凝材料，如硅灰，这会显著增加成本并提高与硅灰处理相关的生产费用。本文表明，使用非常少量的硅灰（如占胶凝材料质量的1%）就能实现一种性能与传统UHPC相似的纤维增强复合材料。所提出的UHPC基于I型基准水泥或CA含量极低（<1%）且符合H级油井水泥规范的V型波特兰水泥、硅灰、少量AlO纳米纤维以及高密度聚乙烯或聚乙烯醇宏观纤维。先前的研究表明，纳米纤维作为晶种促进在颗粒间和纳米纤维空间内形成致密且纳米增强的硅酸钙水合物（C-S-H）簇，提供纳米增强效果。这种方法产生更致密、更强的基体。本研究通过向超高强度水泥基复合材料中添加合成纤维来扩展这一原理，以形成一种性能接近UHPC的材料。结果表明，所开发的材料在160 MPa的水平上提供了改进的应变硬化和抗压强度。
