Cement is the ‘glue’ in concrete, the foundation upon which our modern civilisation is built. However, this comes with a huge environmental cost - cement production generates 8% of global CO2 emissions, and half of all materials extracted from Earth are used in concrete.
Luckily, recently developed low-carbon alkali-activated cements that we are investigating exhibit enhanced properties (e.g. strength and durability) and reduce CO2 emissions by >80%, compared to traditional Portland cement (PC), and are made almost entirely from industrial wastes.
These cements require superplasticising copolymer dispersants to improve workability and flow characteristics, particularly for ultra-high performance concrete. However, dispersant behaviour differs significantly in each case due to extensive differences between aqueous and solid state chemistry in these cements, compared to PC. New alkali-resistant high-performance dispersants are urgently required for these next-generation low-carbon cements to make them practical for use in large-scale construction applications.
In this PhD project we will examine the interactions between organic superplasticisers and inorganic cement particles in these next-generation low-carbon alkali-activated cements, and then use this knowledge to design novel superplasticisers with enhanced performance. We will adopt a new in situ characterisation approach (including surface-specific techniques and both spectroscopic and microstructural characterisation) to investigate the mechanisms and kinetics of organic-inorganic interactions, and their effects on cement performance.
This study will link raw materials characteristics (particle size/distribution, morphology, surface area/chemistry, superplasticiser structure, molecular weight) with processes controlling dispersion and fluidisation, reaction, and physical property development.
Specifically, it will examine how interactions between organic superplasticisers and inorganic cement particles affect:
(i) dispersion and fluidisation;
(ii) reaction and setting;
(iii) physical property development.
Data from these low-carbon alkali-activated cements will be benchmarked against data from PC-based cements.
We will discover the fundamental processes controlling dispersion, fluidisation and reaction of these next-generation low-carbon alkali-activated cements, and use this knowledge to design, synthesise and test novel superplasticisers with enhanced performance. This will drive implementation and a circular economy, help decarbonise cement production, and help give humanity the best possible chance of mitigating climate change.
Based in the Department of Chemical and Biological Engineering, and the Department of Chemistry, the successful candidate will be will be joining a team of multidisciplinary researchers of the Energy Institute at The University of Sheffield to develop research and innovation for decarbonisation. Energy Institute at The University of Sheffield, UK is where the brightest minds come together to build a sustainable, secured and greener world. It is the largest Energy Institute in Europe which provides a platform for breakthrough research and innovation collaboration and partnership across industry sectors and government policies, addressing global energy resources and climate change challenges. Its transformational research and innovation bring the biggest social, environmental and economic impact for people and planet.
The successful candidate will join the research groups of both Dr Walkley (PI) and Professor Armes (Co-I), and will benefit from being a member of a friendly and collegial group with world-leading expertise and facilities. The complementary research expertise of the supervisory team will benefit the student by providing a broad perspective of the research topic.
The Sustainable Materials at Sheffield group (in the Department of Chemical and Biological Engineering) and the Armes group (in the Department of Chemistry) are world-leading research teams, located in highly-rated and very successful departments, building from over 100 years of history in cements research at Sheffield. We investigate interesting and important cements and related materials, and copolymer dispersants, for applications in infrastructure and nuclear sectors, publish our work in the leading journals and conferences in the field, and take great pride in the fact that alumni have gone on to the highest levels of success in both academia and industry.
Both the Department of Chemical and Biological Engineering and the Department of Chemistry rank among the top in the UK, and have among the highest levels of research income.
Start Date of Studentship: 26th Sept 2022
Please see this link for information on how to apply: https://www.sheffield.ac.uk/cbe/postgraduate/phd/how-apply. Please include the name of your proposed supervisor and the title of the PhD project within your application.
This interdisciplinary project spans chemical engineering, materials engineering, and organic and inorganic chemistry. It is ideally suited to a mature, highly numerate graduate with good communication skills, a passion for scientific and engineering research, and enthusiasm to tackle globally relevant and uniquely challenging chemical engineering and chemistry problems.
Applicants should have a first or upper second class UK honours degree or equivalent in a related discipline (Chemical/Materials/Environmental/Civil Engineering, Materials/Inorganic/Organic Chemistry or Mineralogy/Geochemistry). A strong undergraduate background in organic/inorganic chemistry and chemical/materials engineering, with an interest in driving sustainability is desired. If English is not your first language then you must have an International English Language Testing System (IELTS) average of 6.5 or above with at least 6.0 in each component, or equivalent. Please see this link for further information: https://www.sheffield.ac.uk/postgraduate/phd/apply/english-language.
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