{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T13:11:36Z","timestamp":1788873096619,"version":"build-2803163510"},"reference-count":40,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T00:00:00Z","timestamp":1788825600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NIT Science and Technology Innovation Fun","award":["KCTD006"],"award-info":[{"award-number":["KCTD006"]}]},{"name":"Postgraduate Research & Practice Innovation Program of Jiangsu Province","award":["26CXJH5547"],"award-info":[{"award-number":["26CXJH5547"]}]},{"name":"The Youth science and technology talent lifting project program from Jiangsu Science and Technology Association","award":["TJ-2023\u2013024"],"award-info":[{"award-number":["TJ-2023\u2013024"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>This study investigates metakaolin-based geopolymer recycled mortar (GRM) in which recycled fine aggregate (RFA) was volumetrically replaced by pumice powder (PP) at 0% and 60\u2013100%. Ambient compressive and tensile bond strengths were measured, followed by exposure to 600\u2013800 \u00b0C for 1\u20133 h. The evaluation encompassed mass loss ratio, residual mechanical properties, temperature sensitivity, micro-phase evolution, and strength-normalized carbon intensity. Results demonstrated that PP replacement produced a non-monotonic response, governed by the trade-off between improved particle packing and the depletion of the rigid granular skeleton. Among the PP-containing mixtures, PP70 (70% replacement) showed a comparatively favorable mechanical response, with an ambient compressive strength of 31.7 MPa and a mean residual compressive strength of 18.8 MPa (59.3% of its initial value) after exposure to 800 \u00b0C for 3 h. Notably, tensile bond strength exhibited greater temperature sensitivity than compressive strength, with deterioration accelerating significantly above 700 \u00b0C. SEM and XRD analyses elucidated this macroscopic divergence via a two-stage damage mechanism: while dehydration and matrix contraction dominated at 600 \u00b0C, prolonged exposure at 800 \u00b0C induced structural rearrangement, with the dominant damage becoming increasingly concentrated at the RFA\u2013matrix interface. Although substituting RFA with processed PP inherently increased the absolute embodied carbon, PP70 exhibited the lowest strength-normalized carbon intensity among the modified mixtures after exposure to 800 \u00b0C for 3 h. These findings indicate that, among the investigated high-volume PP mixtures, PP70 provided a comparatively favorable compromise between thermal-mechanical performance and environmental cost.<\/jats:p>","DOI":"10.3390\/ma19183819","type":"journal-article","created":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T12:51:48Z","timestamp":1788871908000},"page":"3819","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["High-Temperature Performance of Metakaolin-Based Geopolymer Recycled Mortar with Pumice Powder"],"prefix":"10.3390","volume":"19","author":[{"given":"Xudong","family":"Zhu","sequence":"first","affiliation":[{"name":"School of Civil Engineering, Nantong Institute of Technology, Nantong 226002, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6492-952X","authenticated-orcid":false,"given":"Feifei","family":"Jiang","sequence":"additional","affiliation":[{"name":"School of Civil Engineering, Nantong Institute of Technology, Nantong 226002, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"given":"Changwei","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Urban Construction, Changzhou University, Changzhou 213164, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2763-2812","authenticated-orcid":false,"given":"Hui","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Urban Construction, Changzhou University, Changzhou 213164, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"given":"Pinghua","family":"Zhu","sequence":"additional","affiliation":[{"name":"School of Civil Engineering, Nantong Institute of Technology, Nantong 226002, China"},{"name":"School of Urban Construction, Changzhou University, Changzhou 213164, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Yang","family":"Li","sequence":"additional","affiliation":[{"name":"Jiangsu Xiechuang Traffic Construction Co., Ltd., Changzhou 213119, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]},{"given":"Tianyu","family":"Ma","sequence":"additional","affiliation":[{"name":"School of Urban Construction, Changzhou University, Changzhou 213164, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"conceptualization","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1080","DOI":"10.1016\/j.jclepro.2011.02.010","article-title":"Costs and Carbon Emissions for Geopolymer Pastes in Comparison to Ordinary Portland Cement","volume":"19","author":"McLellan","year":"2011","journal-title":"J. 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