Stress-strain relationship of biomass concrete with bamboo as coarse aggregates under uniaxial compression

Based on the existing situation that natural aggregates are over-exploited and man-made aggregates have become a growing trend, this paper uses economical and abundant agricultural by-product, moso bamboo, as coarse aggregates to partially replace natural coarse aggregate (NCA) for casting a novel bamboo aggregate concrete (BAC), to minimize the use of NCA and to explore feasible sustainable construction materials. Monotonic axial compression tests were conducted on BAC to investigate the effects of bamboo coarse aggregate (BCA) replacement rate (r=0%∼45%) and modification methods (unmodified and epoxy mortar-modified) on failure modes, key mechanical property indexes, and compressive stress-strain relationship. Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy were utilized to analyze the chemical composition and microstructure of BAC. Results showed that when r≥15%, the strength of epoxy mortar-modified BAC can meet the strength requirements of most non-special structural components in general construction while exhibiting good ductility, so it is recommended to use r≥15% epoxy mortar-modified BCA. Finally, the conversion equations between the main mechanical property indexes and the stress-strain constitutive equations of BAC were proposed. The proposal of BAC is in line with the industry demand of vigorously promoting green building and sustainable building materials, and the study of its compression properties lays a theoretical foundation for its future engineering applications and structural design.