{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T06:27:59Z","timestamp":1781591279411,"version":"3.54.5"},"reference-count":26,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2022,6,17]],"date-time":"2022-06-17T00:00:00Z","timestamp":1655424000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Regional Development Fund (ERDF)","award":["1.1.1.3\/18\/A\/001 (PVS 3912.6.2)"],"award-info":[{"award-number":["1.1.1.3\/18\/A\/001 (PVS 3912.6.2)"]}]},{"name":"Doctoral Grant program of Riga Technical University in Latvia","award":["1.1.1.3\/18\/A\/001 (PVS 3912.6.2)"],"award-info":[{"award-number":["1.1.1.3\/18\/A\/001 (PVS 3912.6.2)"]}]},{"name":"RTU Science Support Fund","award":["1.1.1.3\/18\/A\/001 (PVS 3912.6.2)"],"award-info":[{"award-number":["1.1.1.3\/18\/A\/001 (PVS 3912.6.2)"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Fiber Bragg grating (FBG) optical sensors are state-of-the-art technology that can be integrated into the road structure, providing real-time traffic-induced strain readings and ensuring the monitoring of the road\u2019s structural health. By implementing specific FBG sensors, it is possible to detect each vehicle\u2019s axle count and the induced strain changes in the road structure. In this study, FBG sensors are embedded at the top of the 240-mm-thick cement-treated reclaimed asphalt pavement mixture layer of the road (specifically, 25 mm deep within the road). Optical sensors\u2019 signal interrogation units are used to measure the strain and temperature and collect data of the road\u2019s passing vehicles, starting from passenger cars that have two axles and up to heavy trucks that have six axles. Passenger cars with 2 axles generate a typical (90% events) strain of 0.8\u20134.1 \u03bcm\/m, the 2-axle minibus 5.5\u20138.5 \u03bcm\/m, 2\u20133-axle trucks 11\u201326 \u03bcm\/m, but 4\u20136-axle trucks 14\u201336 \u03bcm\/m per each axle. A large number of influencing parameters determine the pavement design leading to the great uncertainty in the prediction of the strain at the boundary between the asphalt surface and cement-treated base layers. Real-time strain and temperature measurements help to understand the actual behavior of the pavement structure under an applied load, thus assisting in validating the proposed pavement design.<\/jats:p>","DOI":"10.3390\/s22124581","type":"journal-article","created":{"date-parts":[[2022,6,19]],"date-time":"2022-06-19T21:19:26Z","timestamp":1655673566000},"page":"4581","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":42,"title":["Road Pavement Structural Health Monitoring by Embedded Fiber-Bragg-Grating-Based Optical Sensors"],"prefix":"10.3390","volume":"22","author":[{"given":"Janis","family":"Braunfelds","sequence":"first","affiliation":[{"name":"Communication Technologies Research Center, Riga Technical University, LV-1048 Riga, Latvia"},{"name":"Institute of Telecommunications, Riga Technical University, LV-1048 Riga, Latvia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ugis","family":"Senkans","sequence":"additional","affiliation":[{"name":"Communication Technologies Research Center, Riga Technical University, LV-1048 Riga, Latvia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peteris","family":"Skels","sequence":"additional","affiliation":[{"name":"Department of Roads and Bridges, Riga Technical University, LV-1048 Riga, Latvia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rims","family":"Janeliukstis","sequence":"additional","affiliation":[{"name":"Institute of Materials and Structures, Riga Technical University, LV-1048 Riga, Latvia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8268-3674","authenticated-orcid":false,"given":"Jurgis","family":"Porins","sequence":"additional","affiliation":[{"name":"Institute of Telecommunications, Riga Technical University, LV-1048 Riga, Latvia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0571-6409","authenticated-orcid":false,"given":"Sandis","family":"Spolitis","sequence":"additional","affiliation":[{"name":"Communication Technologies Research Center, Riga Technical University, LV-1048 Riga, Latvia"},{"name":"Institute of Telecommunications, Riga Technical University, LV-1048 Riga, Latvia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5156-5162","authenticated-orcid":false,"given":"Vjaceslavs","family":"Bobrovs","sequence":"additional","affiliation":[{"name":"Institute of Telecommunications, Riga Technical University, LV-1048 Riga, Latvia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,17]]},"reference":[{"key":"ref_1","unstructured":"(2022, May 24). 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