Strain Hardening Behaviour and Multiple Cracking Characteristics of Natural Fiber Based Engineered Cementitious Composite Specimens Under Tension Loads
摘要
Engineered cementitious composites (ECC) belong to the class of high-performance concrete possessing a large tensile strain capacity of up to 6%. In this study, an attempt is made to produce a novel strain hardening ECC with different types of plant based natural fibers such as flax, hemp, kenaf, and pineapple. Standard coupon specimens of size 330 mm × 60 mm × 13 mm complying with the ASTM E8-13a standards were fabricated and tested under direct tension loads. A minimum of three coupons were tested for each sample to understand the overall behavior of ECC with different fiber combinations. Test results revealed that the use of natural fibers produced excellent strain levels up to 3.0%. In specific, the use of flax and kenaf fibers showed a large tensile strain level of more than 5% without comprising the ultimate tensile stress of 12.0 N/mm2 and 8.9 N/mm2 respectively. Moreover, the microstructural examination of tested specimens revealed a strong interfacial bond between the natural fibers and ECC matrix leading to better stress redistribution and crack bridging mechanism like that of conventional artificial fiber-based ECC.