Case study on the Knowledge Transfer Partnership (KTP) between Miles Macadam Ltd and Aston University, funded by Innovate UK.

About Miles Macadam

Miles Macadam manufactures and installs asphalt and cement based materials for road and industrial surfacing, a product known as ‘grouted macadam’. The company has been operating for over 50 years and is one of the UK’s market leaders, working for both the public and private sectors.

The challenge that the KTP was set up to address

The grouts that Miles Macadam use in their surfacing products contain fly ash, a waste product from coal-fired power stations, which now has to be imported. As a result, the quality of this fly ash is variable and the supply can be erratic. Miles Macadam would like to find a more sustainable alternatives to support the company’s environmental ambitions while providing similar or enhanced properties. Ideally this alternative material could also replace some of the cement in their products, to further reduce its carbon footprint. One of the other intriguing possibilities to lower the carbon footprint is the use of biochar, a carbon-rich material that is produced from processing organic matter such as wood or agricultural waste at very high temperatures.

In addition, using waste-processed materials would conserve virgin resources and will reduce the costs and dependence on imported materials.

Why a KTP was the ideal route

To identify the best type of biochar or other sustainable material requires skills in both chemical and civil engineering which Miles Macadam does not have in house. Aston University has the research expertise to characterise alternatives to fly ash and assess how they affect performance, both in the handling of the product and its final properties.

Lead academic on the KTP, Professor Mujib Rahman, is a Chartered Engineer with more than twenty years' experience in the field, five of which were spent in industry. He leads Aston University’s Department of Civil Engineering and has extensive research expertise in the fundamental characterisation of asphalt and concrete materials. Working with Professor Rahman will be Dr Moura Mehravar, also from Civil Engineering and Dr Jaiwei Wang, Head of the Department of Chemical Engineering and Applied Chemistry. Dr Mehravar’s research focuses on the application of bio-inspired materials in the construction industry, in particular on the application of biochar for ground improvement. Dr Wang brings his extensive expertise in biomass technology to the project as a member of Aston University’s Energy and Bioproducts Research Institute, a unique hub of bioenergy research and technology development.

What the research will involve

The detailed and complex research required to address the challenge involves analysis of different types of biochar (carbon content, graphene and chemical adsorbtion properties) and other materials that fit Miles Macadam’s environmental criteria, such as lignin (a plant-based polymer) and ladle slag (a by-product of steel making). Based on the chemical composition of the materials, the team will choose two or three to take forward for further investigation. They will carry out laboratory tests to see how well these materials mix into the asphalt and concrete grouts and how they affect their consistency, flow rate and curing process. The team will then test the hardened grouts for water absorbency and strength, including if the materials can withstand heavy weights. They will use Aston University’s specialist environmental testing facility to see how the materials respond to extended cycles of freezing and thawing, mimicking the weather conditions that they may be subject to when used. Once the best candidate materials have been identified, they will be tested in real world conditions at a Miles Macadam site to see how easy they are to work with. Finally, the team will carry out a life cycle analysis, to identify the material’s unit cost, longevity and overall environmental impact.

The potential benefits of the research

By finding alternative materials that can lower carbon, replace fly ash and reduce the amount of cement in their grouts, Miles Macadam hope to ensure a more secure supply and reduce their carbon emissions. Supplying products that support the ambitions of their clients to tackle climate change will give the company a competitive edge. Biochar particularly, is CO2 negative as over its lifetime it absorbs more CO2 than it emits and, with proper research, be used to ‘trap’ carbon within building and civil engineering projects. Miles Macadam’s long-term vision is to help develop a stronger UK market for this sustainable product.

For Aston University, the KTP will help the researchers develop a deeper understanding of how materials (such as biochar, lignin and ladle slag) behave in civil engineering applications, which could open up research into further applications for the materials.

What the partners say

Andrew Scorer, Co-Director, Miles Macadam Ltd:

“This is the first KTP we’ve been involved in and we’re very excited about it, as are many of our clients who are really keen for us to develop more sustainable products. Aston University clearly has the expertise we need to assess the different ingredients for our grouts and we’re looking forward to working with the team on it.”

Professor Mujib Rahman, Head of the Department of Civil Engineering, Aston University:

“This project brings together different expertise from across the University’s School of Engineering and Applied Sciences, to help Miles Macadam future proof their products and reduce their and their clients’ CO2 emissions. It’s going to be fascinating to look in depth at the properties of biochar and see not only how it can work for Miles Macadam’s particular needs but also how it might be used in many other situations as well. There is huge potential for this sustainable product.”

Dr Moura Mehravar, Lecturer in the Department of Civil Engineering, Aston University:

“Working on a KTP like this is very rewarding, as you’re able to see something tangible emerge from the research you carry out. I’m looking forward to helping Miles Macadam find alternative materials for their grouts and hopefully extend the knowledge we gain through the project to other construction materials.”