Biography
Dr Janet Lees is a Professor of Civil Engineering at the University of Cambridge and a Fellow of the Institution of Civil Engineers. Before embarking on a career in research, she spent time in Industry working both for a Consultant and for a Contractor. She received her PhD in Structural Engineering from the University of Cambridge. She is the leader of the Concrete Infrastructure Research Group (CIRG) within the Civil Engineering Division. The main research interests of her group relate to the development of more sustainable reinforced concrete infrastructure. Ongoing project areas include the strength assessment of existing infrastructure, tailored reinforced concrete infrastructure and the use of high performance materials in construction.
She is a Fellow of St John's College and a Director of the University of Cambridge EPSRC Centre for Doctoral Training in Future Infrastructure and Built Environment.
Research
The overarching aim of the Concrete Infrastructure Research Group (CIRG) is to provide more sustainable infrastructure. This is achieved through an improved understanding of existing infrastructure assets, the use of new materials and the creation of innovative structural solutions. Our priority is to investigate novel ways to combine these systems for further advantage.
Current project areas include:
Tailored Reinforced Concrete Infrastructure - Concrete is the most widely used material in the world. Cement, the key constituent of concrete, is responsible for about 5% of global carbon emissions related to human activities. This makes the current use of concrete particularly hazardous for the environment. Hence, it is vital to develop technologies aimed at minimising the use of cement in concrete structures while preserving, or improving, their innate strength and durability properties. In this context, the concept of tailored reinforced infrastructure represents a promising approach to target specific structural performance while employing less cement.
Existing Reinforced Concrete Infrastructure - Assessing the true capacity of deteriorated existing concrete structures represents a great challenge for engineers, since many controlling parameters are unknown. Unlike new design, assessors have no control on the design philosophy. The overestimation of the structural capacity can potentially put public safety at risk. However, overly conservative approaches can lead to onerous maintenance measures, sometimes unnecessary. A better understanding of the behaviour of existing infrastructure helps to support decision-making about reinforced concrete structures in service.
Publications
Selected Journal Publications (since 2020)*
* a full list of Journal Publications can be found elsewhere
| Blackshaw, G.A., Forsdyke, J.C. & Lees, J.M. (2024) Effects of exposure sequence and GGBS cement replacement on performance of concrete subjected to carbonation and chloride ingress. Mater Struct 57, 178. https://doi.org/10.1617/s11527-024-02438-3 |
| White, C., Lees, J. M., & MacAskill, K. (2024). Bridging the information gap using targeted digital transformation: process mapping large-scale concrete activity. Building Research & Information, 1–20. https://doi.org/10.1080/09613218.2024.2380331 |
| White, C., Forsdyke, J., Harrison, M., Desnerck, P. & Lees, J.M. (2024) Digital threads for sustainable concrete: A prototype traceability system, Structural Concrete, https://doi.org/10.1002/suco.202400398 |
| Giménez Fernández, M. & Lees, J. M. (2024). Symmetric prism characterisation test to infer heat generation and heat conduction properties of concrete, Construction and Building Materials, v. 425, 135731, https://doi.org/10.1016/j.conbuildmat.2024.135731. |
| White, C., & Lees, J. M. (2023). Yield stress prediction from 3D reconstruction of fresh concrete slump. Cement and Concrete Research, 174, 107331. https://doi.org/10.1016/J.CEMCONRES.2023.107331 |
| Forsdyke, J, Zviazhynski, B, Lees, J, & Conduit, G (2023). Probabilistic selection and design of concrete using machine learning. Data-Centric Engineering, 4, E9. https://doi.org/10.1017/dce.2023.5 |
| Preinstorfer, P, Yanik, S, Kirnbauer, J, Lees, JM and Robisson, A (2023) Cracking behaviour of textile-reinforced concrete with varying concrete cover and textile surface finish, Composite Structures, https://doi.org/10.1016/j.compstruct.2023.116859 |
| Forsdyke, JC, Lees, JM. (2023) Model fitting to concrete carbonation data with non-zero initial carbonation depth. Mater Struct 56, 22. https://doi.org/10.1617/s11527-023-02104-0 |
| Maier, M, Kechavarzi, C, Xu, X and Lees, JM. (2023) Temperature and humidity stability of fibre optic sensor cables for high resolution measurements. Sensors 23, no. 3: 1296. https://doi.org/10.3390/s23031296 |
| Mak, MWT and Lees, JM. (2023) Carbon reduction and strength enhancement in functionally graded reinforced concrete beams. Engineering Structures, v. 277, https://doi.org/10.1016/j.engstruct.2022.115358 |
| Mak, MWT and Lees, JM. (2023) Arch action in reinforced concrete subjected to shear. Engineering Structures, v. 274, https://doi.org/10.1016/j.engstruct.2022.115096 |
| Scott, P, Toumpanaki, E and Lees, JM. (2022) Solution Uptake in Cylindrical Carbon-Fibre-Reinforced Polymer (CFRP) Tendons, Advances in Polymer Technology, v. 2022, Article ID 1981256, 16 pages, 2022. https://doi.org/10.1155/2022/1981256 |
| Mak, MWT and Lees, JM. (2022) Bond strength and confinement in reinforced concrete. Construction and Building Materials, 355. https://doi.org/10.1016/j.conbuildmat.2022.129012 |
| Maier, M and Lees JM. (2022) Interlayer fracture behaviour of functionally layered concrete, Engineering Fracture Mechanics, 271, 108672. https://doi.org/10.1016/j.engfracmech.2022.108672 |
| Preinstorfer P, Huber, T, Reichenbach, S, Lees JM and Kromoser, B. (2022) Parametric Design Studies of Mass-Related Global Warming Potential and Construction Costs of FRP-Reinforced Concrete Infrastructure, Polymers, 14 (12), 2383. https://doi.org/10.3390/polym14122383 |
| Augusthus-Nelson L, Lees JM and Weekes L. (2021) Size effects in unreinforced and lightly reinforced concrete beams failing in flexure, Engineering Fracture Mechanics. https://doi.org/10.1016/j.engfracmech.2021.107987 |
| Foster, RM and Morley, CT and Lees, JM. (2020) Shear Capacity of Reinforced Concrete T-Beams Retrofit with Externally Bonded CFRP Fabric: A New Perspective. Journal of Structural Engineering, 146. 04020253-04020253. ISSN 0733-9445 https://doi.org/10.1061/(ASCE)ST.1943-541X.0002826 |
| Toumpanaki E, Lees JM and Terrasi GP. (2020) Analytical predictive model for the long-term bond performance of CFRP tendons in concrete, Composite Structures, 250, 112614 https://doi.org/10.1016/j.compstruct.2020.112614 |
| Brault A, Lees JM. (2020) Wet casting of multiple mix horizontally layered concrete elements. Construction and Building Materials, 247, 118514.https://doi.org/10.1016/j.conbuildmat.2020.118514 |
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Torelli G, Giménez Fernández M, Lees JM. (2020) Functionally graded concrete: Design objectives, production techniques and analysis methods for layered and continuously graded elements. Construction and Building Materials, 242, 118040. https://doi.org/10.1016/j.conbuildmat.2020.118040 |
| Torelli G, Lees JM. (2020) Interface bond strength of lightweight low-cement functionally layered elements. Construction and Building Materials, 249, 118614. https://doi.org/10.1016/j.conbuildmat.2020.118614 |
Selected Conference Papers/Technical Publications (since 2020)*
*A full list of Conference/Technical Publications can be found elsewhere
| Cocking, S., Giménez Fernández, M., Tziavos, N. and Lees, J.M. (2023) Acoustic Emission Attenuation In Single-Mix And Functionally Layered Concrete Slabs, 11th International Conference on Fracture Mechanics of Concrete and Concrete Structures. https://doi.org/10.21012/FC11.092349 |
| Preinstorfer, P., Mak, M.W.T & Lees, JM. (2023) Tailored structures with textile-reinforced concrete. CICE 2023 11th International Conference on FRP Composites in Civil Engineering (CICE 2023), Rio de Janeiro, Brazil. https://doi.org/10.5281/zenodo.8109698 |
| Mak, M.W.T., Lees, J.M. (2023). Enhancing the Shear Performance of Reinforced Concrete Beams with Functional Grading. In: Ilki, A., Çavunt, D., Çavunt, Y.S. (eds) Building for the Future: Durable, Sustainable, Resilient. fib Symposium 2023. Lecture Notes in Civil Engineering, vol 349. Springer, https://doi.org/10.1007/978-3-031-32519-9_151 |
| Preinstorfer, P., Lees, J.M. (2023). Enhancing Bond Performance by Functional Grading of Concrete. In: Ilki, A., Çavunt, D., Çavunt, Y.S. (eds) Building for the Future: Durable, Sustainable, Resilient. fib Symposium 2023. Lecture Notes in Civil Engineering, vol 350. Springer https://doi.org/10.1007/978-3-031-32511-3_59 |
| Preinstorfer, P., & Lees, J. (2022) Modelling of the splitting failure mode in textile-reinforced concrete. Fibre Polymer Composites in Construction 2022. 7-8 Sept 2022, Bradford, UK https://doi.org/10.17863/CAM.88415 |
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Weerasinghe, H.C., Mak, M.W.T. and Lees, J.M. (2022) Shear Behaviour in Slender Reinforced Concrete Beams without Stirrups, fib International Congress 2022 Oslo: Concrete Innovation for sustainability, 12-16 June 2022, Oslo, Norway https://doi.org/10.17863/CAM.84897 |
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Forsdyke, J., & Lees, J. (2022) An analysis of the potential for improving cement efficiency through functionally graded concrete elements with durability-driven concrete specification. IABSE Symposium Prague 2022 Challenges for Existing and Oncoming Structures, 25-27 May 2022, Prague, Czech Republic https://doi.org/10.17863/CAM.84002 |
| Mak, M.W.T., & Lees, J. (2022) Shear design in concrete beams without transverse reinforcement - A comparative study. IABSE Symposium Prague 2022 – Challenges for Existing and Oncoming Structures, 25-27 May 2022, Prague, Czech Republic https://doi.org/10.17863/CAM.80900 |
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Mak, M.W.T., & Lees, J. (2021) Effectiveness of arch behaviour in reinforced concrete beams subjected to shear. Second fib Italy YMG Symposium on Concrete and Concrete Structures - Proceedings, 18-19 November 2021, Rome, Italy https://doi.org/10.17863/CAM.77462 |
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Forsdyke, J., & Lees, J. (2021) Carbonation depth measurement of concretes exposed to different curing and preconditioning conditions, using image-processing tools. Second fib Italy YMG Symposium on Concrete and Concrete Structures - Proceedings, 18-19 November 2021, Rome, Italy https://doi.org/10.17863/CAM.78987 |
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Forsdyke, J., & Lees, J. (2021)An analysis of existing models for carbonation coefficient applied to tests under natural conditions. fib Symposium 2021: Concrete Structures: New Trends for Eco-Efficiency and Performance, 14-16 June 2021, Lisbon, Portugal https://doi.org/10.17863/CAM.75504 |
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Weerasinghe, H.C. and Lees, J.M. (2021), The Effect of Shear Crack Geometry on Aggregate Interlock Action in Reinforced Concrete, fib Symposium 2021: Concrete Structures: New Trends for Eco-Efficiency and Performance, 14-16 June 2021, Lisbon, Portugal https://doi.org/10.17863/CAM.72281 |
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Mak, M.W.T. and Lees, J.M. (2020) Assessment of corrosion-induced bond deterioration in reinforced concrete: Towards a splitting crack-based approach. 2020 IABSE Congress – Resilient technologies for sustainable infrastructure. 3-5 February 2021, Christchurch, New Zealand |
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Mak, M.W.T. and Lees, J.M. (2020) Behaviour of reinforced concrete half-joint beams with improper anchorage. 2020 fib Symposium: Concrete Structures for Resilient Society. 22-24 November 2020, Shanghai, China |
| Mak, M.W.T., Sheasby, M.P. and Lees, J.M. (2020). Effects of anchorage deterioration on the shear behaviour of reinforced concrete half-joint beams, fib Symposium 2020 on Concrete Structures for Resilient Society. https://doi.org/10.17863/CAM.58832 |
| Torelli, G., & Lees, J. M. (2020). A Plasticity Theory Approach for the Stability Analysis of Vertical Layers of Concrete in the Fresh State. In V. Mechtcherine, K. Khayat, & E. Secrieru (Eds.), Rheology and Processing of Construction Materials. Rheocon2 & SCC9 (pp. 628–635). Dresden, Germany: Springer International Publishing. |
