description
- According to the Global Footprint Network, we need the resources of 1.6 planet Earths to support the current lifestyle. Generations to come will suffer; therefore, the UN's Sustainable Development Goals provides a chance to promote a sustainable growth for all. This project is in line with the 17 goals to transform our world (i.e. goal 11 - Sustainable cities and communities). If agricultural waste can be 'upcycled' via a cutting edge, state of the art manufacturing process, they can be re-introduced on a large scale as modern and worthy of ample adoption for their qualities of performance and sustainability by the construction industry. Straw biomass use with an industrially feasible approach for manufacturing of construction products is an important element of the transition to low-carbon economy. This project aims to introduce a greatly improved, lightweight variant of compressed straw board (CSB) for the construction industry, strong enough to accommodate structural loads both in tension and under compression. It will exploit a novel concept of industrially efficient and highly selective removal of defects in straw feedstock, using scalable methods and tools. The optimising of the straw feedstock, i.e. removing its defects and improving its surface, will substantially enhance the performance of CSBs by 50%. This project is focussed on use of wheat straw (Triticum aestivum). However, the protocol should be applicable to other species in the family Poaceae, such as other cereal straw and, in particular, Norfolk reed (Phragmites australis). The residue left after separation of the grain from the stem of wheat straw is 16-20 million tonnes annually. Not all of this can be sent to livestock farms. Up to 10 million tonnes of wheat straw every year is either ploughed back into the land or put to very low-grade use. Our research can bring an end to the waste of this potentially valuable resource. The motivation for this research is derived from our developed and demonstrated pilot results, where an environmentally friendly pre-treatment was employed, which led to an improved interface between resins and the micro porous surface of straw. The results showed that chemical functionalities of various surface profiles (i.e. when cut longitudinally in half, inner and outer) altered the bonding performance, i.e. extractive, waxes, and silica concentrated on the outer surface, inhibited the bonding quality which translates into an inefficient stress transfer under load. The pre-treatment however, could significantly: (i) modify the surface of straw with the partial removal of extractives, waxes, and silica which made it more compatible with water based resins, (ii) cause the microcellular structure of straw to expand and hence induce the mechanical entanglement on a micro level upon resin solidification. Therefore, these pilot results have given us the motivation to upscale the pre-treatment.