{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T22:02:46Z","timestamp":1771020166519,"version":"3.50.1"},"reference-count":28,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2020,4,14]],"date-time":"2020-04-14T00:00:00Z","timestamp":1586822400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Applied Sciences"],"abstract":"<jats:p>This work analyzes the technical and economic viability of using coarse recycled aggregates from crushed concrete in shotcrete, as a primary lining support in tunnels. Four incorporation ratios of coarse natural aggregate (CNA) with coarse recycled concrete aggregates from concrete (CRCA) were studied: 0%, 20%, 50% and 100%. The mechanical properties of the dry-mix shotcrete were obtained in an independent experimental campaign. Initially, the technical viability of CRCA shotcrete was validated for deep rock tunnels, based on the convergence-confinement method. Two cases were studied to determine the equivalent thickness for each combination of replacement ratio using CRCA shotcrete: (i) similar stiffness and (ii) similar yield stress. Subsequently, an economic assessment was performed. The stiffness criterion increased the thickness below 10% in both the 20% and 50% replacement ratios, which shows their technical viability with very marginal cost increase (&lt;5%). On the other hand, the maximum pressure criteria required higher increments, close to 30% in the 50% replacement ratio. A full replacement was proven to be impracticable in both analyses.<\/jats:p>","DOI":"10.3390\/app10082697","type":"journal-article","created":{"date-parts":[[2020,4,15]],"date-time":"2020-04-15T04:01:46Z","timestamp":1586923306000},"page":"2697","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Economic and Technical Viability of Using Shotcrete with Coarse Recycled Concrete Aggregates in Deep Tunnels"],"prefix":"10.3390","volume":"10","author":[{"given":"Gon\u00e7alo","family":"Duarte","sequence":"first","affiliation":[{"name":"Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1649-004 Lisbon, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7794-5075","authenticated-orcid":false,"given":"Rui","family":"Carrilho Gomes","sequence":"additional","affiliation":[{"name":"Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1649-004 Lisbon, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6766-2736","authenticated-orcid":false,"given":"Jorge","family":"de Brito","sequence":"additional","affiliation":[{"name":"Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1649-004 Lisbon, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0393-4039","authenticated-orcid":false,"given":"Miguel","family":"Bravo","sequence":"additional","affiliation":[{"name":"CERIS, Set\u00fabal\u2019s Polytechnic Institute, 2910-761 Set\u00fabal, Portugal"}]},{"given":"Jos\u00e9","family":"Nobre","sequence":"additional","affiliation":[{"name":"Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1649-004 Lisbon, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,14]]},"reference":[{"key":"ref_1","unstructured":"European Commission (2019, October 10). 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