Structural behaviour of geopolymer concrete reinforced with basalt FRP bars

Lead Research Organisation: University College London
Department Name: Civil Environmental and Geomatic Eng


Concrete is the most widely used construction material in the world. The production of ordinary Portland cement (OPC), a traditional binder material in concrete, accounts for around 8% of global CO2 emissions. The UK government has set a target to reduce CO2 emissions by at least 34% by 2020 and 80% by 2050. In addition, corrosion of reinforcing steel is one of major problems affecting the safety and durability of reinforced concrete (RC) structures. According to the Department for Transport, the annual cost of repairing RC structures damaged by corrosion is estimated to be £755 million in the UK. Thus, it is urgent to develop novel sustainable and durable RC systems for infrastructures. Geopolymer concrete made of a cement-free binder (termed 'geopolymer' and made from industrial wastes) as alternative to OPC offers 60-80% reductions in CO2 emissions and better performance and durability compared to OPC concrete. Due to its good resistance to corrosion and acids, cost effectiveness, high temperature resistance, etc., basalt fibre reinforced polymer (FRP) bar is rapidly emerging as a desirable substitute for steel rebar. These lead to the entirely novel idea of combing geopolymer concrete and basalt FRP bars in a composite system to improve the sustainability and durability of RC structures. This project aims to develop a comprehensive understanding of mechanical behaviour of this composite system using the combination of experimental and computational approaches, in order to expedite its use for structural applications, in particular for structures under extreme conditions, e.g. nuclear power plants and coastal structures. This will help significantly reduce CO2 emissions, repair and maintenance costs of RC structures.


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509577/1 01/10/2016 24/03/2022
1836739 Studentship EP/N509577/1 09/01/2017 06/07/2021 Gulia Trabacchin
Description FRP (Fibre Reinforced Polymers) bars have been recently adopted as internal reinforcement in concrete. Aramid (AFRP), carbon (CFRP) and glass (GFRP) FRP bars are the most common FRP reinforcement used in the construction industry. Basalt FRP (BFRP) bars recently emerged as a new type of composite thanks to the wide availability of basalt, a volcanic rock constituting the bottom of the oceans. The application of BFRP bars as internal reinforcement is still developing.
Geopolymer concrete (GPC), made of recycled industrial waste, has been used as a replacement for ordinary Portland cement concrete with promising results. The use of GPC allows the reduction of the CO2 emissions related to Portland clinker production, without compromising on the mechanical properties of the material.
My research aims to combine BFRP bars and GPC to obtain an innovative, sustainable and durable building system.
Due to their novelty, the interaction between the two, also called bond behaviour, is still uncertain and more research is necessary to understand the mechanisms underlying it. Thus, through the literature review, I identified the dominant parameters affecting the bond behaviour and I run preliminary experimental tests to investigate the interaction between BFRP bars and GPC under pull-out load. The experiments were carried out during a visiting period of four months at Wuhan University of Technology (China). The first results were promising and have been shared in the 1st International Conference in Innovation in Low-Carbon Cement & Concrete Technology in June 2019. Further experimental tests were planned to obtained more experimental data. However, the lab access has been limited due to Covid and the project has been adjusted accordingly. The bond behaviour between BFRP bars and GPC has been therefore investigated through analytical and numerical modelling to provide a clear understanding of the mechanisms underlying the bond.
Exploitation Route The aim of the research is to understand the bond between BFRP bars and GPC which is a fundamental aspect within the structural engineering properties. This work will encourage the use of these two materials. Eventually, they will be also included in the available design codes.
Sectors Construction,Environment,Transport

Description To undertake the experimental tests, a period of four months (April 2018 - July 2018) was spent at Wuhan University of Technology (WUT) in China. This was possible also thanks to a British Council - China Scholarship Council award that the author won in 2017. This visiting period allowed to continue the collaboration between UCL and WUT that was already in place and to create new relationships. The author was the first visiting student from UCL to visit WUT and in April 2019 a Chinese student from Wuhan will be visiting UCL for a period of one year.
First Year Of Impact 2017
Sector Education
Impact Types Cultural

Description Chadwick Scholarship
Amount £150,000 (GBP)
Organisation University College London 
Sector Academic/University
Country United Kingdom
Start 03/2022 
End 03/2026
Description Leaching behaviour of nickel and lead-zinc mining waste-based alkali-activated binders
Amount £24,000 (GBP)
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2020 
End 03/2022
Description Towards sustainable civil infrastructure and cities
Amount £10,000 (GBP)
Organisation University College London 
Sector Academic/University
Country United Kingdom
Start 12/2020 
End 11/2021
Description UK-China Joint Research and Innovation Partnership Fund
Amount £9,496 (GBP)
Funding ID 352639234 
Organisation British Council 
Sector Charity/Non Profit
Country United Kingdom
Start 04/2018 
End 07/2018
Description Pull-out tests a Wuhan University of Technology 
Organisation Wuhan University of Technology
Country China 
Sector Academic/University 
PI Contribution The author supervised MSc students during some experimental work for their final thesis.
Collaborator Contribution At that time, the universal testing machine necessary to carry out the pull-out tests on the samples was not available at UCL. Thus, WUT hosted the author and allowed to use their facilities to cast and test the samples and thus complete the experimental program.
Impact Not only the visiting period was useful to overcome technical limitations, but also to establish connections between the UK and China. The author had the chance to live in contact with the Chinese culture and build long-lasting academical and personal relationships.
Start Year 2017