Treatments of plant biomass for cementitious building materials – A review

•Review uses of biomass-based cement and concrete composites.•Describe difficulties arising when using biomass in cement and concrete composites.•Describe solutions like coating, impregnation, chemical and physical treatments. The use of plant biomass for developing energy efficient and low cost construction materials is an emerging field in building construction and civil engineering. Although the biomass-based cement and concrete composites have several advantages, such as low densities, low amount of CO2 gas emission, good thermal and acoustic insulation, there are also disadvantages or open questions like the durability of biomass in alkaline cement matrix, the high absorption of water and the cement-biomass compatibility, all deteriorating concrete mechanical properties, which are already intrinsically low due to the low mechanical properties of biomass-based fillers. This review gives the necessary basis in plant structure and composition for understanding how and why many treatments tested on biomass for overcoming the above-mentioned difficulties are acting. This paper reviews research papers and patents on the treatments tested to improve the mechanical properties, durability and compatibility of biomass for its use as concrete fillers for building materials.