{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T07:02:31Z","timestamp":1784530951819,"version":"3.55.0"},"reference-count":36,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2026,7,19]],"date-time":"2026-07-19T00:00:00Z","timestamp":1784419200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Qinghai Provincial Central Government Guides Local Science and Technology Development Fund Project","award":["2026-SF-Z48"],"award-info":[{"award-number":["2026-SF-Z48"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>To enhance the crack resistance and toughness of cement mortar, steel fibers (SF), carbon fibers (CF), and their hybrid combinations were incorporated at various volume fractions. Cubic specimens with single or double prefabricated holes were tested using compressive and splitting tensile tests combined with digital image correlation technology (DIC). to evaluate mechanical properties, crack propagation, and failure patterns. Results indicate that steel fibers primarily suppressed macrocracks via bridging and improved strength, while carbon fibers inhibited microcrack initiation and promoted uniform strain distribution. Hybrid fibers achieved combined reinforcement, with the S2C02 mixture exhibiting the best overall performance: compressive strength increased by 39.7\u201355.1%, tensile strength by 70.45\u201375.9%, and the toughness and tensile\/compressive ratio were enhanced. DIC analysis showed reduced strain concentration, more uniform strain fields, delayed crack propagation, and a transition from brittle to quasi-ductile failure. These findings demonstrate an optimal hybrid fiber dosage and reveal the combined mechanism of steel\u2013carbon fibers in defect-containing cement mortar, providing guidance for material design and performance optimization.<\/jats:p>","DOI":"10.3390\/ma19143101","type":"journal-article","created":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T06:09:09Z","timestamp":1784527749000},"page":"3101","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Mechanical Properties and Crack Propagation Behavior of Defective Cement Mortar Reinforced with Hybrid Steel\u2013Carbon Fibers"],"prefix":"10.3390","volume":"19","author":[{"given":"Gaozhen","family":"Hu","sequence":"first","affiliation":[{"name":"School of Civil and Transportation Engineering, Qinghai Minzu University, Xining 810007, China"},{"name":"Qinghai Provincial Key Laboratory of Tibet Plateau Highway Construction Maintenance Technology, Xining 810003, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liang","family":"Li","sequence":"additional","affiliation":[{"name":"Qinghai Provincial Key Laboratory of Tibet Plateau Highway Construction Maintenance Technology, Xining 810003, China"},{"name":"Qinghai Lake Tourism Development Group Co, Ltd., Xining 810003, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anhua","family":"Xu","sequence":"additional","affiliation":[{"name":"School of Civil and Transportation Engineering, Qinghai Minzu University, Xining 810007, China"},{"name":"Qinghai Provincial Key Laboratory of Tibet Plateau Highway Construction Maintenance Technology, Xining 810003, China"},{"name":"School of Water Conservancy and Civil Engineering, Qinghai Vocational and Technical University, Xining 810016, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuanji","family":"Li","sequence":"additional","affiliation":[{"name":"Qinghai Provincial Key Laboratory of Tibet Plateau Highway Construction Maintenance Technology, Xining 810003, China"},{"name":"School of Water Conservancy and Civil Engineering, Qinghai Vocational and Technical University, Xining 810016, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chenchen","family":"Zhang","sequence":"additional","affiliation":[{"name":"Qinghai Provincial Key Laboratory of Tibet Plateau Highway Construction Maintenance Technology, Xining 810003, China"},{"name":"School of Water Conservancy and Civil Engineering, Qinghai Vocational and Technical University, Xining 810016, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shiren","family":"La","sequence":"additional","affiliation":[{"name":"School of Civil and Transportation Engineering, Qinghai Minzu University, Xining 810007, China"},{"name":"Qinghai Provincial Key Laboratory of Tibet Plateau Highway Construction Maintenance Technology, Xining 810003, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"20220329","DOI":"10.1515\/rams-2022-0329","article-title":"Research progress on properties of cement-based composites incorporating graphene oxide","volume":"62","author":"Zhang","year":"2023","journal-title":"Rev. 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