Matrix tailoring of Engineered Cementitious Composites (ECC) with non-oil-coated, low tensile strength PVA fiber

Engineered Cementitious Composites (ECC) with ductile strain-hardening behavior has been recognized as a high performance and durable alternative to conventional concrete material. However, relative high initial material cost, mainly associated with high cost of PVA fibers commonly used in ECC mixtures, has limited broader field application of ECC in the construction, especially in Chinese market. In this study, new ECC mixture designs have been developed incorporating a type of lower-cost PVA fibers. Unlike the PVA fibers normally used, this low-cost PVA fiber has no surface oil coating and exhibit lower tensile strength, which are undesirable in basis of micromechanics underlying ECC design. High fly ash content, viscosity modifying admixture (VMA), fly ash cenosphere (FAC), and crumb rubber were incorporated into the mixture design to tailor the ECC matrix so as to compensate the micromechanical change associated with using the low-cost PVA fibers and to further enhance the performance of the resultant ECC mixture. It is found that the newly designed ECC mixtures with low-cost PVA fibers can achieve similar tensile strain capacity (up to 5.2%) with lower compressive and tensile strength when compared with previous ECC mixtures in literatures. The successful development of ECC with low-cost PVA fiber is expected to greatly promote the field application of ECC in China and give the references for the professionals to develop ECC with the local PVA fibers.