Graphene enhanced concrete sleeper for lower embodied carbon

在英国，老化的基础设施和人口增长正在增加对混凝土的需求，尤其是在铁路部门;其中需要20，000英里的新轨道。水泥（混凝土的粘合剂）的生产释放出作为CaCO 3煅烧的直接副产品的CO2。这些直接排放加上间接过程排放（交通、过程能源等），占全球排放量的8%-10%。混凝土行业已经为脱碳做出了巨大努力;但是，在此情况下，第二，为了实现英国的气候目标，迫切需要一个更雄心勃勃的脱碳阶段。该项目愿景通过开发新的用于承重轨枕应用的石墨烯增强混凝土（GEC）材料。我们的石墨烯计量方法可使机械强度提高50%。此外，减少混凝土体积、减少水泥含量和减少所需钢筋数量（得益于上级机械性能）的组合将使总碳足迹减少高达50%。关键目标：1.审查我们目前具有高石墨烯负载的外加剂配方，以确保与网络铁路标准规定的轨枕混凝土配合比设计的兼容性。2.确定混凝土轨枕中的最佳外加剂剂量（混凝土中石墨烯含量保持<0.1wt%）。在第二阶段的轨枕试验中证明科学性，以证明轨枕应用的好处。虽然其他GEC正在开发中，但大多数新兴技术不适合结构应用。那些旨在针对结构应用的GEC产品正在努力克服将石墨烯纳米片（GNP）分散在水泥中的挑战。现有的方法导致多余的空气进入混凝土的微观结构，严重限制了结构性能。我们已经克服了分散的挑战，实现了比最先进的石墨烯负载高5倍的石墨烯负载，具有均匀的分散性，并且没有过量的空气夹带。英国铁路网络的基础设施管理公司Network-Rail不包括在赠款财团中，但将成为早期技术采用者，为市场提供明确的路线。此外，我们是即将出台的新轨枕标准的指导小组成员，该标准将被重新编写，以鼓励在轨枕中使用低碳产品。

In the UK, ageing infrastructure and population growth are increasing demand for concrete, not least in the rail sector; where 20,000 miles of new track are needed.The production of cement (concrete's binding agent) releases CO2 as a direct by-product of CaCO3 calcination. These direct emissions, in combination with indirect process-emissions (transport, process energy etc), represent a staggering 8-10% of global emissions.The concrete sector has undertaken substantial efforts towards decarbonisation already; however, a second-phase of more ambitious decarbonisation is urgently needed in order to meet UK climate targets.This project vision directly addresses this urgent decarbonisation need through the development of novel graphene-enhanced concrete (GEC) materials for load-bearing sleeper applications. Our method of graphene dosing delivers a 50% improvement in mechanical strength. In addition, a combination of reduced concrete volume, reduced cement content and reduction in amount of steel reinforcement needed (thanks to the superior mechanical performance) will reduce total carbon-footprint by up to 50%.Key Objectives:1. To review our current admixture formulations with high graphene loading for compatibility with sleeper concrete mix designs, prescribed to Network Rail standards.2. To define optimum admixture dosing into concrete sleepers (with graphene content of concrete remaining <0.1wt%).3. Prove the science in sleeper trials at Phase 2 stage to demonstrate the benefits for sleeper applications.Whilst other GECs are in development, most emerging technologies are not suitable for structural applications. Those GEC products that aim to target structural applications are struggling to overcome the challenge of dispersing graphene nano-platelets (GNPs) within cement. Existing approaches result in the incorporation of excess air into concrete's microstructure, severely limiting structural performance. We have overcome the dispersion challenge, enabling 5x greater graphene-loading than the state-of-the-art, with uniform dispersion, and no excess air entrainment.Network-Rail, infrastructure manager of the UK rail-network, are not included in the grant consortium, but will be early technology adopters, providing a clear route to market. In addition, we are on the steering group for the development of the forthcoming new sleeper standard, which will be re-written to encourage low embodied carbon products to be used in sleepers.