Development of plant-concrete composites containing pretreated corn stalk bio-aggregates and different type of binders

Traditional binders (ordinary Portland cement; OPC and lime) due to their high alkaline nature show poor bio-compatibility and degradation of hydration products when mixed with the lignocellulosic materials. As a result, produced plant-concrete composites (PCC) exhibit inferior mechanical and durability properties. In this regard, this paper adopts the approach of pretreatment of corn stalk particles (alkalization and hydrophobic pretreatment) and use of alternative binders (geopolymer; GP and magnesium phosphate cements; MPC) to address these performance related issues. Results showed significant improvement in microstructure of PCCs and interface bonding between the binders and corn stalk aggregates due to hydrophobic pretreatment. Among the PCCs containing different type of binders, MPC based PCCs exhibited superior performance in term of strength, and hygroscopic properties as compared to OPC and GP based PCCs. Reduction in porosity and drying shrinkage was also prominent for the PCC prepared with GP and MPC binders and hydrophobic pretreated corn stalk aggregates. However, thermal conductivity of PCCs was increased for PCCs containing pretreated corn stalk aggregates.