{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T05:19:20Z","timestamp":1788153560822,"version":"build-2803163510"},"reference-count":46,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T00:00:00Z","timestamp":1787875200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Research Center of Hubei Small Town Development, Hubei Engineering University","award":["2025K020"],"award-info":[{"award-number":["2025K020"]}]},{"award":["2025K020"],"award-info":[{"award-number":["2025K020"]}],"id":[{"id":"https:\/\/ror.org\/05amnwk22","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Long-distance Navigation Engineering Project of Jiangxi Association for Science and Technology","award":["2025-87"],"award-info":[{"award-number":["2025-87"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Lithium slag-based geopolymer (LSG) provides a promising route for the high-value utilization of lithium slag; however, its pronounced shrinkage deformation continues to restrict engineering applications. To clarify the multi-scale mechanism by which fibers regulate LSG shrinkage, this study investigated the effects of single and hybrid additions of carbon nanotubes (CNTs) and hooked-end steel fibers (HSFs). The 90 d drying shrinkage test quantified shrinkage-reduction efficiency for mono- and hybrid-fiber systems. MIP was used for porosity and pore size distribution analysis; SEM examined fiber dispersion, interfacial bonding, and CNT-HSF synergy. At 90 d, 0.15% CNTs and 1.5% HSFs reduced shrinkage by 5.7% and 26.8%, respectively, whereas the C0.15-H1.5 hybrid mixture achieved a maximum reduction of 31.33% relative to the control. HSF addition increased porosity from 15.5% to 23.1% and the average pore diameter from 23.36 to 50.82 nm. Macroscopic shrinkage was reduced because interfacial friction and hooked-end anchorage provided mechanical restraint. In addition, based on fiber pull-out behavior and a simplified interfacial bond-slip model, the effective confinement radius at the fiber\u2013matrix interface was analyzed, and the concept of fiber-confined zones was proposed. Results show that CNTs refine pore structure and bridge microcracks, whereas HSFs provide mechanical restraint through interfacial friction and anchorage. The hybrid CNT-HSF system achieved a maximum drying shrinkage reduction of 31.33%, higher than the corresponding theoretical additive value. The spatial overlap of fiber-confined zones is identified as the key mechanism for forming a weakly rigid framework that suppresses macroscopic shrinkage.<\/jats:p>","DOI":"10.3390\/ma19173656","type":"journal-article","created":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T04:24:03Z","timestamp":1788150243000},"page":"3656","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effects and Mechanisms of Hooked-End Steel Fibers and Carbon Nanotubes on the Shrinkage of Lithium Slag-Based Geopolymers: Role of Fiber-Confined Zones"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7959-6027","authenticated-orcid":false,"given":"Cai","family":"Wu","sequence":"first","affiliation":[{"name":"School of Civil Engineering, Hubei Engineering University, Xiaogan 432000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"given":"Zhuo","family":"Luo","sequence":"additional","affiliation":[{"name":"School of Civil Engineering, Hubei Engineering University, Xiaogan 432000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]},{"given":"Xueping","family":"Zhou","sequence":"additional","affiliation":[{"name":"School of Civil Engineering and Surveying & Mapping Engineering (Nanchang), Jiangxi University of Science and Technology, Ganzhou 341000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0615-580X","authenticated-orcid":false,"given":"Daopei","family":"Zhu","sequence":"additional","affiliation":[{"name":"School of Civil Engineering and Surveying & Mapping Engineering (Nanchang), Jiangxi University of Science and Technology, Ganzhou 341000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,28]]},"reference":[{"key":"ref_1","first-page":"52","article-title":"Critical issues in the supply chain of lithium for electric vehicle batteries","volume":"24","author":"Egbue","year":"2012","journal-title":"EMJ-Eng. 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