Construction and Building Materials 346 (2022) 128355 0950-0618/© 2022 Elsevier Ltd. All rights reserved. Bending behavior of engineered cementitious composites (ECC) with different recycled and virgin polymer fbers H.Z. Ehrenbring a , F. Pacheco a , R. Christ b , B.F. Tutikian a, * a Universidade do Vale do Rio dos Sinos (UNISINOS), S˜ ao Leopoldo, BR 93022-290, Brazil b Department of Civil and Environmental. Universidad de la Costa, CUC, Calle 58 # 55e66, Barranquilla, Atlantico, Colombia A R T I C L E INFO Keywords: Engineered Cementitious Composites Polyvinyl alcohol fbers Polypropylene fbers Recycled polyester fbers Tensile behavior ABSTRACT This study evaluated Engineered Cementitious Composites (ECC) with polyvinyl alcohol (PVA), polypropylene (PP) or recycled polyester (POL) fbers inserted in a matrix with elevated silica fume content. Several PP (2.2–2.6%) and POL (2.3–2.7%) contents were tested and compared to a compound containing 2.0% PVA. Flexural bending strength tests, the bending rupture modulus, number and width of cracks and deformation were measured at 5 different curing ages (7, 14, 28, 56 e 84 days). The test results also showed that in the fresh state, ECCPVA2.0 presented the best result with an average spread of 255 mm, followed by ECCPP2.4 and ECCPOL2.3. All Γ values obtained confrmed that all composites attained plastic consistency. In the hardened state, com- posites with POL fbers had tensile strength performance similar to PVA fbers with regards to deformation, defection, rupture modulus, average crack width and number of cracks. In addition, ECCPOL2.7 demonstrated mechanical properties superior to ECCPVA2.0. So, the use of 2.7% POL content resulted in strengths higher than the reference PVA compound and demonstrated the potential of POL fbers in ECC development at ages over 28 days. The use of recycled POL fbers, at a content of 2.7%, resulted in an increase in the ductility of the com- posite, reaching the values of ECC-PVA at 28 and 84 days. On the other hand, PP composites did not present the expected behavior of an ECC. More specifcally, the matrix had high tensile strength, modulus of elasticity and tenacity, which limited crack formation and overloaded the reinforcement fbers. Thus, PP fbers were deemed incompatible for ECCs with rich matrices. 1. Introduction Worldwide demand for habitation and infrastructure increases exponentially every year [62]. Consequently, materials are evolving to achieve increased durability and sustainability of construction projects [3,40]. Most durability studies of reinforced concrete structures focused on compression strength and permeability [16,4–6]. However, these two properties did not necessarily ensure durability since they were usually evaluated under laboratory conditions in uncracked samples and did not directly correlate to the service life of a structure [40]. Cracking is a possible common occurrence which creates preferential pathways to the ingress of aggressive agents even in a low permeability material [7,8]. So, the durability of a reinforced concrete structure is related to the material resilience [22,40]. The resilience of a structure built from cementitious composites could be understood as its ability to control the formation of cracks [20,65]. Ranade et al. [52], Turk and Nehdi [9] and Zhang, et al. [66] noted that ductile materials provided increased resilience in concrete structures, for example, as the ECC. The desired ductile cementitious composite would allow the formation of multiple microcracks in the section from increased tension and have high specifc deformation (ε) and defection (δ), as observed in the behavior of the ECC. The ECC was developed with 2% PVA fbers and 5% deformation [41]. Micromechanics are used to explain the behavior of ECCs [28,63,1]. The ductile response of these cementitious composites are a result of the fbers in the matrix with diameters below 50 μm, interface interactions in the 10 μm scale and formation of cracks of about 100 μm [40,44]. Once the matrix cracks, dispersed fbers prevent uncontrolled growth of the opening and increase the energy required to further propagate the microcracks [59]. The stresses are redistribution in the matrix leads and formation of new openings and the start of a new cracking cycle. The more cracking cycles that occur, the higher the * Corresponding author. E-mail addresses: hzamis@unisinos.br (H.Z. Ehrenbring), fernandapache@unisinos.br (F. Pacheco), rchirst@unisinos.br (R. Christ), bftutikian@unisinos.br (B.F. Tutikian). Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat https://doi.org/10.1016/j.conbuildmat.2022.128355 Received 2 March 2022; Received in revised form 8 May 2022; Accepted 2 July 2022