Performance Evaluation of Sheep Wool Fibers and Recycled Aggregates in Mortar
Source abstract
Abstract
This paper examines the use of sheep wool and recycled aggregates (recycled concrete aggregate, reclaimed asphalt aggregate, recycled brick aggregate) in mortars. Nine cement mortars were prepared: a reference mortar with natural aggregate and no fibers, and eight mortars with 30% recycled aggregate, either fiber-free or micro-reinforced with 0.1% by mass of sheep wool fibers. The study investigates the effects of these components on the workability, mechanical properties, and microstructure of mortars. Micro-reinforcing mortars with sheep wool fibers or partially replacing natural aggregate with recycled aggregates reduces workability by up to 32%. Mortars with recycled concrete and recycled brick aggregates showed increased compressive and flexural strength compared to the reference mortar. The combined formulation (recycled brick with sheep wool micro-reinforcement) achieved the highest compressive strength, increasing by 24.3% while maintaining excellent flexural performance. Three-point bending tests with displacement control revealed improved post-crack behavior and greater ductility in fiber micro-reinforced specimens compared to those without fibers. The results support the use of sheep wool fibers in mortars, demonstrate the satisfactory performance of recycled aggregates, and indicate promising potential for formulations combining sheep wool fiber and recycled aggregate as sustainable and waste-reducing alternatives in mortars.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Innovative concrete reinforcement materials · Recycled Aggregate Concrete Performance · Natural Fiber Reinforced Composites
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Faculty of Civil Engineering, University of Rijeka, 51000 Rijeka, Croatia
Faculty of Civil Engineering, Architecture and Geodesy, University of Split, 21000 Split, Croatia
Department of Construction, University North, 42000 Varaždin, Croatia
References (63)
Show source-provided references
1. Junior, G.A.F., Leite, J.C.T., Mendez, G.d.P., Haddad, A.N., Silva, J.A.F., and da Costa, B.B.F. (2025). A Review of the Characteristics of Recycled Aggregates and the Mechanical Properties of Concrete Produced by Replacing Natural Coarse Aggregates with Recycled Ones—Fostering Resilient and Sustainable Infrastructures. Infrastructures, 10.10.3390/infrastructures10080213 ↗
2. Improved management of water resources in process industry by accounting for fluctuations of water content in feed streams and products10.1016/j.jwpe.2020.101870 ↗
3. Comparative mechanical performance evaluation of recycled brick aggregate concrete and natural aggregate concrete10.1016/j.jobe.2025.114702 ↗
4. Sand, gravel, and UN sustainable development goals: Confict, synergies, and pathways forward10.1016/j.oneear.2021.07.008 ↗
5. The role of powder content of the recycled aggregates of CDW in the behaviour of rendering mortars10.1016/j.conbuildmat.2019.03.058 ↗
6. Zhao, X. (2021). Stakeholder-associated factors influencing construction and demolition waste management: A systematic review. Buildings, 11.10.3390/buildings11040149 ↗
7. Development and performance evaluation of recycled brick waste-based geopolymer brick for improved physcio-mechanical, brick-bond and durability properties10.1016/j.jobe.2024.110701 ↗
8. Gherman, I.-E., Lakatos, E.-S., Clinci, S.D., Lungu, F., Constandoiu, V.V., Cioca, L.I., and Rada, E.C. (2023). Circularity Outlines in the Construction and Demolition Waste Management: A Literature Review. Recycling, 8.10.3390/recycling8050069 ↗
9. Spišáková, M., Mésároš, P., and Mandičák, T. (2021). Construction Waste Audit in the Framework of Sustainable Waste Management in Construction Projects—Case Study. Buildings, 11.10.3390/buildings11020061 ↗
10. Sustainable concrete with recycled brick and ceramic aggregates: A statistical validation and performance evaluation10.1016/j.nxmate.2025.101319 ↗
11. Mechanical and microstructural properties of glass powder-modified recycled brick-concrete aggregate concrete
12. Li, F., Jin, S., Cheng, P., Wang, Z., and Yang, Z. (2024). Study on Mechanical Properties and Carbon Emission Analysis of Polypropylene Fiber-Reinforced Brick Aggregate Concrete. Polymers, 16.10.3390/polym16243535 ↗
13. Mouna, Y., and Suryanto, B. (2025). Recycled Aggregate Concrete: Effect of Supplementary Cementitious Materials and Potential for Supporting Sustainable Construction. Materials, 18.10.3390/ma18225183 ↗
14. Teixeira, A.B., Sampaio, C.H., Moncunill, J.O., Lima, M.M.D., Herrera La Rosa, G.T., Veras, M.M., Ambrós, W.M., Cazacliu, B.G., and Solsona, A. (2025). Reuse of Coarse Aggregates Recovered from Demolished Concrete Through the Jigging Concentration Process in New Concrete Formulations. Materials, 18.10.3390/ma18184310 ↗
15. The fracture performance of modified recycled concrete: Influence of recycled aggregate and recycled powder10.1016/j.engfracmech.2025.111709 ↗
16. Effect of emulsifier on the interface structure and performance of reclaimed asphalt pavement aggregate cement concrete10.1016/j.conbuildmat.2024.139603 ↗
17. Performance of cement mortar mixes containing fine reclaimed asphalt pavement aggregates and zinc waste10.1680/jadcr.23.00046 ↗
18. Assessment of reclaimed asphalt pavement (RAP) as recycled aggregate for concrete10.1016/j.conbuildmat.2022.127745 ↗
19. Environmental performance and mechanical analysis of concrete containing recycled asphalt pavement (RAP) and waste precast concrete as aggregate10.1016/j.jhazmat.2013.11.040 ↗
20. Fresh, mechanical, and durability characteristics of self-consolidating concrete incorporating recycled asphalt pavements10.1061/(ASCE)MT.1943-5533.0000832 ↗
21. Use of animal fiber-reinforcement in construction materials: A review
22. Environment friendly, renewable and sustainable poly lactic acid (PLA) based natural fiber reinforced composites—A comprehensive review10.1016/j.jclepro.2021.127483 ↗
23. Fabrication and characterization of eco-friendly composite materials from natural animal fibers10.1016/j.heliyon.2021.e06954 ↗
24. A systematic review on sustainable green fibre reinforced composite and their analytical models10.1016/j.matpr.2021.03.739 ↗
25. Animal-based waste for building acoustic applications: A review10.1016/j.jobe.2023.108430 ↗
26. Eleutério, T., Trota, M.J., Meirelles, M.G., and Vasconcelos, H.C. (2025). A Review of Natural Fibers: Classification, Composition, Extraction, Treatments, and Applications. Fibers, 13.10.3390/fib13090119 ↗
27. A review of the recent developments in biocomposites based on natural fibres and their application perspectives10.1016/j.compositesa.2015.06.007 ↗
28. Mann, G.S., Azum, N., Khan, A., Rub, M.A., Hassan, M.I., Fatima, K., and Asiri, A.M. (2023). Green Composites Based on Animal Fiber and Their Applications for a Sustainable Future. Polymers, 15.10.3390/polym15030601 ↗
29. Midolo, G., Porto, S.M.C., Cascone, G., and Valenti, F. (2024). Sheep Wool Waste Availability for Potential Sustainable Re-Use and Valorization: A GIS-Based Model. Agriculture, 14.10.3390/agriculture14060872 ↗
30. Assessment of sheep wool waste as new resource for green building elements10.1016/j.buildenv.2022.109596 ↗
31. FAO (2025, December 01). Available online: https://www.fao.org/faostat/en/#data/QCL/visualize.
32. (2025, November 29). HRT Magazin. Available online: https://magazin.hrt.hr/price-iz-hrvatske/ovcja-vuna-postala-ekoloska-prijetnja-zbog-nedostatka-sustavnog-zbrinjavanja-11478185.
33. (2025, November 29). Regulation (EC) No 1069/2009 of the European Parliament and of the Council of 21 October 2009, Laying Down Health Rules as Regards Animal By-Products and Derived Products not Intended for Human Consumption and Repealing Regulation (EC) No 1774/2002 (Animal By-Products Regulation). Available online: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32009R1069.
34. (2025, November 29). Regulation (EU) No 142/2011 of 25 February 2011, Implementing Regulation (EC) No 1069/2009 of the European Parliament and of the Council Laying Down Health Rules as Regards Animal By-Products and Derived Products Not Intended for Human Consumption and Implementing Council Directive 97/78/EC as Regards Certain Samples and Items Exempt from Veterinary Checks at the Border Under that Directive (Text with EEA Relevance). Available online: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32011R0142.
35. Experimental investigation on using sheep wool as fiber reinforcement in concrete giving increment in overall strength10.1016/j.matpr.2020.11.938 ↗
36. Utilization of sheep wool as potential fibrous materials in the production of concrete composites10.1016/j.jobe.2020.101216 ↗
37. Enhanced acoustic properties of concrete composites comprising modified waste sheep wool fibers10.1016/j.jobe.2022.104815 ↗
38. Development and research of thermal-acoustical insulating materials based on natural fibres and polylactide binder10.4028/www.scientific.net/MSF.908.123 ↗
39. Acoustic Characterization of Natural Fibers for Sound Absorption Applications10.1016/j.buildenv.2015.05.029 ↗
40. Utilization of sheep wool as a building material10.1016/j.promfg.2019.02.208 ↗
41. Influence of Portland cement alkalinity on wool reinforced mortar10.1680/jcoma.20.00003 ↗
42. Fantilli, A.P., and Jóźwiak-Niedźwiedzka, D. (2019, January 26–28). The effect of hydraulic cements on the flexural behavior of wool reinforced mortars. Proceedings of the 3rd International Conference on Bio-Based Building Materials, Belfast, UK.
43. Natural and synthetic fiber reinforced recycled aggregate concrete subjected to standard fire temperature10.1016/j.heliyon.2024.e39676 ↗
44. Enhancement of recycled aggregate concrete properties through the incorporation of nanosilica and natural fibers10.1016/j.heliyon.2024.e39924 ↗
45. Experiments on concrete test beams with recycled aggregates and natural fibers10.1016/j.prostr.2024.09.394 ↗
46. Sheep’s wool insulation: A sustainable alternative use for a renewable resource?10.1016/j.resconrec.2014.01.004 ↗
47. Kozłowski, R. (2012). Chapter 8 Wool fibres. Handbook of Natural Fibres, Types, Properties and Factors Affecting Breeding and Cultivation, Woodhead Publishing.
48. Jóźwiak-Niedźwiedzka, D., and Fantilli, A.P. (2020). Wool-Reinforced Cement Based Composites. Materials, 13.10.3390/ma13163590 ↗
49. Toxicity characteristics of commercially manufactured insulation materials for building applications in Taiwan10.1016/j.conbuildmat.2006.05.051 ↗
50. (2011). Cement—Part 1: Composition, Specifications and Conformity Criteria for Common Cements (Standard No. EN 197-1:2011).
51. Nexe Group (2026, January 07). Grend CEM II/A-M(S-V) 42.5 N Technical Instructions. Available online: https://www.nexe.hr/en/products/cement/grand/.
52. (2018). Methods of Testing Cement—Part 6: Determination of Fineness (Standard No. EN 196-6:2018).
53. (2022). Tests for Mechanical and Physical Properties of Aggregates—Part 6: Determination of Particle Density and Water Absorption (Standard No. EN 1097-6: 2022).
54. (1997). Tests for Geometrical Properties of Aggregates—Part 1: Determination of Particle Size Distribution—Sieving Method (Standard No. EN 933-1:1997).
55. Influence of breeding conditions and sheep breeds on quantity and quality of wool in Croatia—Investigations of lstrian–Cres region
56. Investigation on Effects of Sheep Wool fiber on Properties of C-25 Concrete10.36348/sjce.2019.v03i06.001 ↗
57. Elmogahzy, Y.E. (2020). 8—Fibers. The Textile Institute Book Series, Engineering Textiles, Woodhead Publishing. [2nd ed.].10.1016/B978-0-08-102488-1.00008-3 ↗
58. (2003). Methods of Testing Cement—Part 1: Determination of Strength (Standard No. EN 196-1:2003).
59. (2004). Methods of Test for Mortar for Masonry—Part 3: Determination of Consistence of Fresh Mortar (by Flow Table) (Standard No. EN 1015-3:1999/A1:2004).
60. (2019). Methods of Test for Mortar for Masonry—Part 11: Determination of Flexural and Compressive Strength of Hardened Mortar (Standard No. EN 1015-11:2019).
61. Analysis of the physical and mechanical properties of mortar with the incorporation of natural wool fiber from Pantanal sheep10.54033/cadpedv22n5-175 ↗
62. Eco-Friendly Sustainable Concrete with Recycled Crushed Red Bricks: Evaluating Mechanical Performance and Durability
63. Influence of Different treatment and amount of Spanish broom and hemp fibres on the mechanical properties of reinforced cement mortars10.1016/j.conbuildmat.2020.121702 ↗