Development of a new hempcrete 'wall' formulation with advanced hygrothermal properties

仅建筑物就占人类温室气体排放量的40%左右。新的生物复合材料有可能大大减少与建筑物建造有关的隐含能源，因为在其使用寿命期间，它们通过光合作用吸收大气中的二氧化碳，并且通常可以回收或堆肥，减少拆除后的废物影响。大麻-石灰混凝土，一般称为“Hempcrete”，是一种特别有前途的生物复合材料，其可以具有许多独特的优点，包括：优异的热和储热性能;高声学性能;可达到建筑规范标准;优异的气密性水平;低热桥接;高水分缓冲;良好的耐火性;抗害虫;高耐久性;高碳封存;简化和减少木结构建筑中涉及的层数和工序。然而，大麻混凝土的性质和性能在很大程度上取决于成分量的规格和粘合剂的类型。拟议研究的总体目标是开发一种新的大麻混凝土“墙”配方，这种配方将具有优异的湿热性能，特别适合在第一民族和偏远的北方社区应用。为实现这一目标将采取的具体步骤包括：（a）表征大麻草和粘合剂的物理和热性能;（B）开发大麻预处理工艺;（c）考虑到可用性、价格和隐含能量，确定粘合剂的最佳选择;（d）确定开发混合物中大麻草、粘合剂和水的确切数量;及（e）研究已发展的大麻混凝土混合物的物理、热力及机械特性。建议的研究项目可带来多项潜在的社会、经济及效益，其中最重要的包括：（1）通过减少与建筑材料生产相关的能源消耗和碳排放，为实现《巴黎协定》做出贡献;（2）开发可负担得起的当地材料，提供良好的室内空气质量，从而对人们的健康产生积极影响;（3）促进建筑领域和材料生产的可持续发展。

Buildings alone are responsible for around 40% of all human greenhouse emissions. New bio-composite materials offer the potential to significantly reduce the embodied energy related to the construction of buildings as during their lifetime they absorb atmospheric carbon dioxide through photosynthesis and can often be recycled or composted reducing their waste impact after demolition. Hemp-lime concrete, generically called "Hempcrete", is a particularly promising bio-composite material which can have many distinct advantages including: excellent thermal and heat storage properties; high acoustic performance; achievable building code standard; excellent level of airtightness; low thermal bridging; high moisture buffering; good fire resistance; pest resistant; high durability; high carbon sequestration; simplification and reduction in the number of layers and processes involved in timber-frame construction. However, hempcrete properties and performance greatly depend on specification of the ingredient amounts and the type of binder. The overall goal of the proposed research is to develop a new hempcrete "wall" formulation that will have excellent hygrothermal properties, and which is particularly suitable for applications in First Nations and remote Northern communities. The specific steps that will be undertaken to achieve this goal include: (a) characterize physical and thermal properties of hemp hurd and binders; (b) develop hemp pretreatment process; (c) identify the best option for the binder considering availability, price and embodied energy, (d) determine exact quantities of hemp hurd, binder and water within develop mixes; and (e) characterize physical, thermal and mechanical properties of developed hempcrete mixes.The potential social, economic and benefits of the proposed research project are numerous and the most important include: (1) contribute to achieving the Paris Agreement by reducing energy consumption and carbon emissions related to the production of building materials; (2) develop affordable, local material that provides excellent indoor air quality and thus has a positive effect on peoples' health; and (3) promote sustainable development in construction field and material production.