Automated Whole Life Road Repair and Thin Surfacing

点击翻译按钮获取中文摘要

This project aims to research, produce and demonstrate novel pre-heating equipment for producing 'no-failure' pothole repairs. We adopt renewable power for this, displacing current use of hazardous and polluting LPG.Whilst alternative cold repair materials have been investigated, hot placed asphalt remains the preferred option for road wearing course. However, current equipment and methods used in repairing eg potholes are inherently unreliable, frequently characterized by early failure. There is a similar need to ensure long life and cost savings with thin asphalt overlays that promise to drastically reduce the CO2e footprint of road pavement upkeep.Eight years of investigation by the project team, including accelerated life testing of pothole repairs, proves that current equipment and methods are unreliable because they do not operate according to the fundamental principles of thermal energy transfer in material systems. Without this, it is not possible to predictably fuse newly applied asphalt to existing concrete or asphalt base and thus deliver repair life comparable to the residual life of the surrounding road. For predictable fusion, temperatures in the host-fill boundary region must exceed the so-called cessation temperature of asphalt (85 deg C) during the compaction process following pothole filling. Current uncalculated pre-heating using LPG flame heating may provide insufficient temperatures or risk damaging the bitumen binder.Using our in-house developed numerical models, founded on heat transfer science, we have discovered that commonly occurring combinations of climatic conditions, internal heat dissipation and imperfect heat transfer across the host-fill boundary can result in temperatures substantially lower (eg 50 deg C) than cessation temperature in the boundary region even when asphalt is introduced at high temperature (eg 160 deg C). Our in-house developed, unique, 3D printed, multi-thermocouple sensor, which simultaneous measures temperatures above and below this boundary has enabled us to prove this.