Dynamic compressive properties of rubberized mortar reinforced with straw-fiber additive

Abstract

Numerous techniques have been suggested to repurpose and recycle rubber, aiming to mitigate its ecological impact. Among these approaches, incorporating rubber into construction materials stands out as a noteworthy strategy. However, this incorporation of rubber typically leads to a marginal reduction in the mechanical robustness of the mortar. To counterbalance this limitation, innovative substances have been advocated for integration. Notably, straw fiber, renowned for its exceptional fibrous attributes, emerges as a prime candidate. Thus, it is desirable to systematically evaluate its effects on both the mechanical and microstructural attributes and it is the objective of this study to investigate the dynamic compressive properties of straw-fiber reinforced rubberized mortar (SFRM). The investigative methodologies encompass scanning electron microscope (SEM) analysis, X-ray computed tomography (CT) scans, quasi-static and dynamic compression tests employing a split Hopkinson pressure bar. Complementary examinations involving sieving assessments and fractal computations were also conducted. The experimental findings unveil a uniform dispersion of rubber powder and straw fibers within the mortar matrix, although the bonding is relatively weak. The dynamic compressive strength of SFRM exhibits a linear correlation with escalating loading rates, whereas an augmentation in the straw fiber ratio correlates with a reduction in strength. However, the inclusion of fibers significantly improved the capacity for dynamic energy absorption. Furthermore, based on the sieving test and fractal calculation, it was found that the optimal crushing resistance of rubberized mortar is achieved at a fiber ratio of 1.5. This study underscores the augmented capability of SFRM to withstand high-loading-rate compressive forces, thereby fortifying structures against shock and blast loads.