Experimental investigation of flexure resistance performance of bio-beams reinforced with discrete randomly distributed fiber and bamboo

Microbial induced calcite precipitation (MICP) can bond sand particles together to improve the mechanical properties of sandy soil. This environmental-friendly technique has potential applications on construction materials such as bio-bricks and bio-beams. This study is to investigate the flexure resistance performance of bio-beams by adding discrete randomly distributed fiber and bamboo materials with multiple immersing MICP treatment. Different fiber proportions (0.1%, 0.2%, 0.3% and 0.4% by weight of dry sand) were used. MICP treated bio-beams were also reinforced by five different arrangements of bamboo strips. Four-point bending tests were conducted to evaluate the flexure behavior of fiber reinforced and bamboo reinforced bio-beams. Results showed that adding fiber in the MICP treated bio-beams can increased the ductility. The optimum fiber content was around 0.3%. Addition of 0.3% fiber can significantly prevent the post peak flexure strength loss and improved the ductility of bio-beams which had 400 kPa residual strength at 15% failure strain. Bamboo reinforced bio-beam can improve the flexure strength from 890 kPa to 1750 kPa. Meanwhile, multiple immersing MICP treatment can significantly improve the flexure strength of bio-beams up to 3.0 MPa, but the ductility of fiber reinforced bio-beam reduced after multiple treatment.