Mechano-Chemical Activation of Incinerator Bottom Ash for Use as a Cement Substitute

About the Project

Incineration of municipal solid waste (MSW) generates approximately 3 million tonnes of incinerator bottom ash (IBA) each year in the UK. Around 80 wt.% of the residue is IBA, with coarse fractions (> 4 mm) reused in road and concrete applications, while finer fractions (< 4 mm) are largely landfilled due to contamination and low pozzolanic reactivity. Reactive aluminium in IBA can cause hydrogen release and expansion in concrete, so pre-treatment is essential to ensure stability and performance.

Accelerated mineral carbonation, particularly wet carbonation, provides a promising solution for both CO₂ sequestration and IBA valorisation. Through reactions between CO₂ and alkaline components (Ca, Mg), stable carbonates form on particle surfaces, enhancing cement hydration and early-age strength while consuming reactive Al.

This PhD project aims to develop a novel mechano-chemical activation process for fine IBA that simultaneously enhances reactivity, stabilises the material, and sequesters CO₂, enabling its reuse as a supplementary cementitious material. The objectives are to: (1) use eco-friendly alkaline wastewater for activation and carbonation; (2) improve reactivity and dimensional stability; (3) optimise process parameters for maximum CO₂ uptake and minimal metal leaching; (4) produce cementitious binders with up to 20% treated IBA; and (5) explore reuse of carbonated wastewater for closed-loop processing.

The process combines wet grinding, alkaline activation, and CO₂ carbonation in a single step, with operating conditions optimised for particle fineness, complete Al removal, and high carbonation efficiency. The performance of carbonated IBA in concrete will be evaluated through physical, chemical, and mechanical tests, including leaching safety assessments.

Expected outcomes include an integrated, low-impact treatment method that transforms fine IBA into safe, reactive cement substitutes while reducing CO₂ emissions, waste landfilling, and wastewater generation, thereby contributing to circular, sustainable concrete production.

Interested candidates must have a good understanding of alternative cement binder systems, concrete sample preparation and testing, and analyses involving reaction mechanisms, mechanical performance and microstructural development.

The successful candidate will join the Manchester CREATES (Concrete Materials, Resource Efficiency and Advanced TEchnology for Sustainability) team. For more details on research team activities, please visit www.manchestercreates.com

Eligibility

Applicants should have, or expect to achieve, at least a 2.1 honours degree or a master’s (or international equivalent) in a relevant science or engineering related discipline.

Funding

This 3.5-year PhD is for self-funded students. Exceptional candidates will be considered for Faculty funding (this will include an annual tax-free stipend of £20,780 and tuition fees will be paid. We expect the stipend to increase each year).

At The University of Manchester, we offer a range of scholarships, studentships and awards at university, faculty and department level, to support both UK and overseas postgraduate researchers.

The start date is October 2026.

We recommend that you apply early as the advert will be removed once the position has been filled.

Before you apply

We strongly recommend that you contact the supervisor(s) for this project before you apply. Please include details of your current level of study, academic background and any relevant experience and include a paragraph about your motivation to study this PhD project.

How to apply

Apply online through our website: https://uom.link/pgr-apply-2425

When applying, you’ll need to specify the full name of this project, the name of your supervisor, if you already having funding or if you wish to be considered for available funding through the university, details of your previous study, and names and contact details of two referees.

Your application will not be processed without all of the required documents submitted at the time of application, and we cannot accept responsibility for late or missed deadlines. Incomplete applications will not be considered.

After you have applied you will be asked to upload the following supporting documents:

• Final Transcript and certificates of all awarded university level qualifications
• Interim Transcript of any university level qualifications in progress
• CV
• Supporting statement: A one or two page statement outlining your motivation to pursue postgraduate research and why you want to undertake postgraduate research at Manchester, any relevant research or work experience, the key findings of your previous research experience, and techniques and skills you’ve developed. (This is mandatory for all applicants and the application will be put on hold without it).
• Contact details for two referees (please make sure that the contact email you provide is an official university/work email address as we may need to verify the reference)
• English Language certificate (if applicable)

If you have any questions about making an application, please contact our admissions team by emailing FSE.doctoralacademy.admissions@manchester.ac.uk.