Olive oil production in the Mediterranean region generates large quantities of agro-industrial byproducts, posing environmental challenges. This study investigates the use of olive kernel shells (OKS) as a partial replacement for coarse aggregates in the production of self-compacting concrete (SCC) to enhance sustainability and reduce waste. OKS were oven-dried, conditioned to the laboratory air-dry state, and incorporated at 5–25% replacement levels by aggregate volume. The fresh and hardened properties of SCC were evaluated following EFNARC and ASTM standards. Results show that slump flow decreased from 700 mm (control) to 550 mm (25% OKS) due to higher water absorption of OKS, while fresh density declined from 2548 kg/m³ to 2015 kg/m³, confirming the lightweight nature of the mixes. Segregation resistance improved with higher OKS content, dropping from 22% to 12%. In hardened concrete, dry density reduced from 2429 kg/m³ to 1949 kg/m³, and ultrasonic pulse velocity (UPV) decreased from 4.8 km/s to 3.2 km/s. The compressive strength at 28 days decreased from 55 MPa (control) to 28 MPa (25% OKS), while the 5% OKS mixture retained the highest mechanical performance among the tested replacement levels, achieving 50 MPa compressive and 4.8 MPa flexural strength, suitable for lightweight structural applications. These findings demonstrate that incorporating up to 5% OKS as a coarse aggregate replacement can produce eco-efficient, lightweight SCC with acceptable mechanical performance.

Aggregate Replacement, Agricultural Waste, Development, Eco-Friendly Self-Compacting Concrete, Fresh Properties, Mechanical Characteristics

[1] M. Nasir, A.A. Bahraq, M. Ibrahim, M. Zubair, M.A. Aziz, K.S. Alotaibi, R.A. Alajmah, Techno-ecological Optimization of Silico-Manganese Fume and Blast Furnace Slag Blended Cement Mortar Using Response Surface Methodology. International Journal of Concrete Structures and Materials, 19(1), 2025: 119. https://doi.org/10.1186/s40069-025-00847-4
[2] H.M. Hamada, F. Abed, K. Tracy, B.A. Tayeh, Utilizing Raw Desert Sand as a Sustainable Fine Aggregate: Impact on Concrete Performance and Environmental Benefits. International Journal of Concrete Structures and Materials, 19(1), 2025: 110. https://doi.org/10.1186/s40069-025-00853-6
[3] I. Netinger Grubeša, D. Šamec, S. Juradin, M. Hadzima-Nyarko, Utilizing Agro-Waste as Aggregate in Cement Composites: A Comprehensive Review of Properties, Global Trends, and Applications. Materials, 18(10), 2025: 2195. https://doi.org/10.3390/ma18102195
[4] A. Arvizu-Montes, M.J. Martinez-Echevarria, Vegetable Fibers in Cement Composites: A Bibliometric Analysis, Current Status, and Future Outlooks. Materials, 18(2), 2025: 333.
https://doi.org/10.3390/ma18020333
[5] N. Ahmad Zamri, S. Ismail, A. Husin, Assessment of permeability and dry shrinkage in oil palm shell concrete enhanced by surface treatment with styrene acrylic emulsion. Materiales de Construcción, 75(357), 2025: e365. https://doi.org/10.3989/mc.2025.383724
[6] Z. Jin, S. Mao, Y. Zheng, K. Liang, Pre-treated corn straw fiber for fiber-reinforced concrete preparation with high resistance to chloride ions corrosion. Case Studies in Construction Materials, 19, 2023: e02368. https://doi.org/10.1016/j.cscm.2023.e02368
[7] T.R. Caixeta Silva, L.A. Silva de Aquino, L.C. Mesquita, M.G. Marques, A.R.G. de Azevedo, M.T. Marvila, Innovative Cementitious Composites Produced with Corn Straw Fiber: Effect of the Alkaline Treatments. Applied Sciences, 14(23), 2024: 11117. https://doi.org/10.3390/app142311117
[8] Z. Wu, X. Wang, Z. Chen, Experimental study on preparation and performance of the Corn Straw Fiber (CSF) reinforced EPS concrete. Journal of Building Engineering, 89, 2024: 109378.
https://doi.org/10.1016/j.jobe.2024.109378
[9] S. Subhani, S.M. Subhani, A. Bahurudeen, Utilization of sugarcane bagasse ash in binary, ternary, and quaternary blended cement concrete – A waste to wealth approach. Materials Today Sustainability, 28, 2024: 100954. https://doi.org/10.1016/j.mtsust.2024.100954
[10] M.F. Ullah, H. Tang, A. Ullah, Z. Toth, M. Ahmad, A. Alzlfawi, Mechanical and environmental performance of sugarcane bagasse ash from Khyber Pakhtunkhwa in sustainable concrete. Scientific Reports, 15, 2025: 24571. https://doi.org/10.1038/s41598-025-10383-6
[11] U. Amjad, M. Sarir, D. Khan, I. Ul Haq, M.W.A. Khawaja, K. Mahmood, Effect of Sugar Cane Bagasse Ash Incorporated as Viscosity Modifying Agent on Fresh, Microstructure and Mechanical Properties of Self-Compacting Concrete. International Journal of Concrete Structures and Materials, 19(1), 2025: 2. https://doi.org/10.1186/s40069-024-00718-4
[12] R. Yang, Z. Guan, L. Zhang, Y. Shu, Mechanical properties and microstructure of pre-treated luffa fiber reinforced cement mortar. PLOS ONE, 20(2), 2025: e0314213.
https://doi.org/10.1371/journal.pone.0314213
[13] J. Radić, A. Ereš, A. Hlebec, I.N. Grubeša, M. Hadzima-Nyarko, Mechanical Performance of Mortars with Biomass Ash. Advanced Engineering Letters, 5(2), 2026: 88-100.
https://doi.org/10.46793/adeletters.2026.5.2.3
[14] M.A. Tijani, W.O. Ajagbe, O.A. Agbede, Recycling sorghum husk and palm kernel shell wastes for pervious concrete production. Journal of Cleaner Production, 380, 2022: 134976.
https://doi.org/10.1016/j.jclepro.2022.134976
[15] D. El Khoueiry, C. Maalouf, T. Moussa, A. Piot, C. Bliard, E. Wurtz, State of the art on miscanthus properties and its use in the building sector. Journal of Building Physics, 50(1), 2026: 3–44.
https://doi.org/10.1177/17442591251389443
[16] A.M. Ajayi, A.I. Coker, O.T. Oyebanjo, I.M. Adebanjo, O.G. Ademowo, Ananas comosus (L) Merrill (pineapple) fruit peel extract demonstrates antimalarial, anti-nociceptive and anti-inflammatory activities in experimental models. Journal of Ethnopharmacology, 282, 2022: 114576.
https://doi.org/10.1016/j.jep.2021.114576
[17] W. Chawalitsakunchai, P. Dittanet, S. Loykulnant, P. Sae-oui, S. Tanpichai, A. Seubsai, P. Prapainainar, Properties of natural rubber reinforced with nano cellulose from pineapple leaf agricultural waste. Materials Today Communications, 28, 2021: 102594.
https://doi.org/10.1016/j.mtcomm.2021.102594
[18] A.R.G. de Azevedo, M. Amin, M. Hadzima-Nyarko, I.S. Agwa, A.M. Zeyad, B.A. Tayeh, A. Adesina, Possibilities for the application of agro-industrial wastes in cementitious materials: A brief review of the Brazilian perspective. Cleaner Materials, 3, 2022: 100040. https://doi.org/10.1016/j.clema.2021.100040
[19] G. Silva, S. Kim, R. Aguilar, J. Nakamatsu, Natural fibers as reinforcement additives for geopolymers–A review of potential eco-friendly applications to the construction industry. Sustainable Materials and Technologies, 23, 2020: e00132. https://doi.org/10.1016/j.susmat.2019.e00132
[20] H. Bui, N. Sebaibi, M. Boutouil, D. Levacher, Determination and review of physical and mechanical properties of raw and treated coconut fibers for their recycling in construction materials. Fibers, 8(6), 2020: 37. https://doi.org/10.3390/fib8060037
[21] R. de Araujo Alves Lima, D. Kawasaki Cavalcanti, J. de Souza e Silva Neto, H. Meneses da Costa, M.D. Banea, Effect of surface treatments on interfacial properties of natural intralaminar hybrid composites. Polymer Composites, 41(1), 2020: 314-325. https://doi.org/10.1002/pc.25371
[22] O.A. Ogunyewo, P. Upadhyay, G.H. Rajacharya, O.E. Okereke, L. Faas, L.D. Gómez, S.S. Yazdani, Accessory enzymes of hypercellulolytic Penicillium funiculosum facilitate complete saccharification of sugarcane bagasse. Biotechnology for Biofuels, 14(1), 2021: 171. https://doi.org/10.1186/s13068-021-02020-x
[23] J.R. Nahuat-Sansores, K.d.C. García-Uitz, J.C. Cruz-Argüello, C.A. Ramírez-Pinto, R.E. Vega-Azamar, D.L. Trejo-Arroyo, Y. Vidal Valdez, Valorization of Sugarcane Bagasse Ash (SCBA) in Cementitious Composites: Hydration Behavior, Nanomodification and Sustainability Performance. Recycling, 11(3), 2026: 54. https://doi.org/10.3390/recycling11030054
[24] D.-H. Le, Y.-N. Sheen, Assessment of properties of mortars modified with sugarcane bagasse ash processed by heating at different temperatures as cement replacement. European Journal of Environmental and Civil Engineering, 27(1), 2022: 393-415.
https://doi.org/10.1080/19648189.2022.2047794
[25] K. Gunasekaran, G. Pennarasi, V. Deeptha Thattai, T.N. Brinda, Study on coconut shell concrete hollow blocks and the shrinkage, durability and bond properties of mixes used. European Journal of Environmental and Civil Engineering, 25(1), 2018: 73-89.
https://doi.org/10.1080/19648189.2018.1516165
[26] M. Kuruc, Z. Štefunková, Properties of Olive Stones with a View to Their Use as Lightweight Aggregate in Construction Mortars. Slovak Journal of Civil Engineering, 32(1), 2024: 52-57. https://doi.org/10.2478/sjce-2024-0007
[27] N.M.S. Hasan, M.H.R. Sobuz, N.M.N. Shaurdho, M.A. Basit, S.C. Paul, M.M. Meraz, M.J. Miah, Investigation of lightweight and green concrete characteristics using coconut shell aggregate as a replacement for conventional aggregates. International Journal of Civil Engineering, 22(1), 2024: 37-53. https://doi.org/10.1007/s40999-023-00881-x
[28] A. Tavana Amlashi, E. Mohammadi Golafshani, S.A. Ebrahimi, A. Behnood, Estimation of the compressive strength of green concretes containing rice husk ash: a comparison of different machine learning approaches. European Journal of Environmental and Civil Engineering, 27(2), 2022: 961-983. https://doi.org/10.1080/19648189.2022.2068657
[29] J. Hadipramana, A.A.A. Samad, A.Z. Ahmad Mujahid, N. Mohamad, F.V. Riza, Contribution of RHA granules as filler to improve the impact resistance of foamed concrete. Key Engineering Materials, 594, 2014: 93-97. https://doi.org/10.4028/www.scientific.net/KEM.594-595.93
[30] Standard specification for Portland cement (ASTM C150/C150M-23). ASTM International, West Conshohocken, PA, 2023.
[31] Standard specification for concrete aggregates (ASTM C33/C33M-23). ASTM International, West Conshohocken, PA, 2023.
[32] Standard test method for relative density (specific gravity) and absorption of coarse aggregate (ASTM C127-24). ASTM International, West Conshohocken, PA, 2024.
[33] Testing hardened concrete—Part 5: Flexural strength of test specimens (BS EN 12390-5:2019). British Standards Institution (BSI), London, UK, 2019.
[34] Specification and guidelines for self-compacting concrete. EFNARC, 2002.
[35] Standard test method for density, absorption, and voids in hardened concrete (ASTM C642-23). ASTM International, West Conshohocken, PA, 2023.
[36] Standard test method for pulse velocity through concrete (ASTM C597-09). ASTM International, West Conshohocken, PA, 2009.
[37] Testing hardened concrete – Part 3: Compressive strength of test specimens (BS EN 12390-3:2019). British Standards Institution (BSI), London, UK, 2019.
[38] S.O. Odeyemi, R. Abdulwahab, M.A. Adisa, M.A. Olawale, U.N. Wilson, A.-B. Odunayo Shittu, A.T. Abdulhameed, Sustainable self-compacting concrete with agro-waste and recycled aggregates. Discover Concrete and Cement, 2, 2026: 9. https://doi.org/10.1007/s44416-026-00049-5
[39] M. Li, H. Yi, Y. Su, Study on reducing water absorption of recycled aggregates (RAs) by microbial mineralization. Materials, 17(7), 2024: 1612. https://doi.org/10.3390/ma17071612
[40] S.U. Azunna, Compressive strength of concrete with palm kernel shell as a partial replacement for coarse aggregate. SN Applied Sciences 1, 2019: 342. https://doi.org/10.1007/s42452-019-0334-6
[41] IS 13311: Method of non-destructive testing of concrete – Part 1: Ultrasonic pulse velocity. Bureau of Indian Standards (BIS), New Delhi, 1992.
[42] F. Abutaha, H.A. Razak, J. Kanadasan, Effect of palm oil clinker (POC) aggregates on fresh and hardened properties of concrete. Construction and Building Materials, 112, 2016: 416-423.
https://doi.org/10.1016/j.conbuildmat.2016.02.172
[43] S.A. Memon, U. Javed, R.A. Khushnood, Eco-friendly utilization of corncob ash as partial replacement of sand in concrete. Construction and Building Materials, 195, 2019: 165-177.
https://doi.org/10.1016/j.conbuildmat.2018.11.063
[44] K. Chahour, D. Aboutaleb, B. Safi, T. Mazari, M. Zeghad, Granulated foam glass based on mineral wastes used for building materials. Building Acoustics, 24(4), 2017: 281-294.
https://doi.org/10.1177/1351010X17739434
[45] M. Belmokaddem, A. Mahi, Y. Senhadji, B.Y. Pekmezci, Mechanical and physical properties and morphology of concrete containing plastic waste as aggregate. Construction and Building Materials, 257, 2020: 119559. https://doi.org/10.1016/j.conbuildmat.2020.119559
[46] S.C. Devi, R.A. Khan, Compressive strength and durability behavior of graphene oxide reinforced concrete composites containing recycled concrete aggregate. Journal of Building Engineering, 32, 2020: 101800. https://doi.org/10.1016/j.jobe.2020.101800
[47] M. Abu Bakr, M. Farhan, S. Khursheed, N. Haq, S.M.M. Hasnain, Sustainable Self-Compacting Recycled Aggregate Concrete Incorporating Industrial Byproducts and Agricultural Waste: Rheological, Strength, and Durability Properties. ACS Omega, 10(25), 2025: 26382–26391.
https://doi.org/10.1021/acsomega.4c10374
[48] S. Yang, L. Wang, Effect of Internal Curing on Characteristics of Self-Compacting Concrete by Using Fine and Coarse Lightweight Aggregates. Journal of Materials in Civil Engineering, 29(10), 2017: 04017186. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002044
[49] F. Wu, C. Liu, W. Sun, Y. Ma, L. Zhang, Effect of peach shell as lightweight aggregate on mechanics and creep properties of concrete. European Journal of Environmental and Civil Engineering, 24(14), 2019: 2534-2552. https://doi.org/10.1080/19648189.2018.1515667
[50] E.A. Olanipekun, K.O. Olusola, O. Ata, A comparative study of concrete properties using coconut shell and palm kernel shell as coarse aggregates. Building and Environment, 41(3), 2006: 297-301. https://doi.org/10.1016/j.buildenv.2005.01.029
[51] F.K. Alqahtani, I. Zafar, Characterization of processed lightweight aggregate and its effect on physical properties of concrete. Construction and Building Materials, 230, 2020: 116992.
https://doi.org/10.1016/j.conbuildmat.2019.116992
[52] N. Sathiparan, H.T.S.M. De Zoysa, The effects of using agricultural waste as partial substitute for sand in cement blocks. Journal of Building Engineering, 19, 2018: 216-227.
https://doi.org/10.1016/j.jobe.2018.04.023
[53] F. Barreca, C.R. Fichera, Use of olive stone as an additive in cement lime mortar to improve thermal insulation. Energy and Buildings, 62, 2013: 507-513. https://doi.org/10.1016/j.enbuild.2013.03.040