About
Yuvaraj Dhandapani is currently working as a Research Fellow (in Durability of Cement and Concrete Materials) at the University of Leeds, UK. Prior to joining U. Leeds, He completed his PhD dissertation from the Building Technology and Construction Management (BTCM) division at Indian Institute of Technology Madras, India.
His research interests include cement chemistry & concrete microstructure, durability of concrete structures, low carbon construction materials and transport properties.
What drives me to work on concrete science?
Evolving concrete science to develop binding materials for sustainable future
Modern city space is often called a concrete jungle. Cement and concrete are some of the most significant developments in the last two centuries which has led to massive scaling up of infrastructure development across the world. Consumption of concrete stands at over several billion tons. It is essential to engineer concrete for different purposes to ensure the durability and longevity of constructed facilities. Despite being the building blocks of infrastructure and building systems, concrete is also considered as a material which consumes an extensive amount of natural resource (See the article, Concrete: the most destructive material on Earth). Resources consumption occurs at multiple levels in concrete systems which include the use of naturally occurring limestone for the production of binding materials (i.e, cement), quarrying mountains to produce aggregate, extraction of sand from the river bed and finally, the use of freshwater to produce concrete. Most importantly, conventional binding materials is one of the significant contributors to global CO2 emission. It is of utmost importance to development binding materials to replace and substitute the emission-intensive portland cement is one of the major sources of CO2 emission. Developing alternatives for cementitious materials from widely available resource and integrating waste materials into the materials flow cycle in cementitious materials is of utmost importance for a sustainable future
Durability of concrete structures – An alarming problem
One of the major ways to improve the sustainable use of cement and concrete is by improving the efficiency of construction materials so that they remain durable in an aggressive environment. The concrete structure is often the built-in aggressive environment and often subjected to deterioration due to several factors. ‘Restore and improve urban infrastructure’ is identified as one of the Grand Challenges for Engineering in the 21st century to improve life on the planet. Interaction of the chlorides and atmospheric CO2 is one of the primary durability concerns for a concrete structure. This is a more alarming concern for the new generation of construction materials which are more prone to carbonation in comparison to conventional ones. Several new formulations of construction materials are being developed where conventional wisdom and standards developed based on portland cement would no longer suffice. One of my major research centres on applying some cutting-edge characterisation techniques to address the problem at a more fundamental level to evolve a better scientific understanding of the structure-property relationship in complex binding materials which would improve the adoption of the new-gen materials in concrete construction.
Calcined clay-limestone cement for sustainable future
My PhD dissertation was a part of the Limestone Calcined Clay Cement (LC3) project funded by SDC. LC3-project is a collaborative research program between EPFL (Switzerland), UCLV (Cuba) and TARA, IIT Delhi and IIT Madras (India). The project focuses on developing low carbon and resource-efficient cement. My PhD focused on assessing the durability performance of limestone calcined clay cement, as a part of the Low Carbon Cement Project at IIT Madras.
Know more about LC3 in the below link
(Extract from the IIT Madras Press statement, dated 20 March 2020, on my PhD research)
Chennai, March 20 (IANS) Indian Institute of Technology Madras (IIT-M) on Friday said its new study shows that concrete made from clay fly ash, and limestone hold promise as replacements for cement.
The IIT-M researchers have provided clarity on the link between microstructural development and durability performance of concrete through their investigation on concrete with ternary blended cements, which will help the construction industry to produce more eco-friendly concrete than available now.
Concrete is the most widely used construction material in the world - seven cubic kilometres of concrete are manufactured each year, which works to one cubic metre of concrete for every human on earth.
Conventional concrete is made of cement, fine aggregate particles such as sand and coarse aggregate particles from rock, mixed with water; this mixture hardens with time because of the reaction of cement with water, the Institute said.
Modern concrete, however, includes chemical and mineral additives that impart unique properties. It is common today to find the cement to be a mixture of two or three different ingredients.
The current research, funded by Swiss Agency for Development and Cooperation, deals with the exploration of properties of a three-component cement.
"Worldwide, there are research efforts in developing alternative concrete additives and energy efficient binders that can produce a more sustainable form of concrete. The UN Environment Programme (UNEP) has stressed on the need for cement substitution to decarbonise cement industry," said Professor Manu Santhanam, Department of Civil Engineering, IIT Madras.
According to the researchers, the study unravels the complex nature of interactions of this three-component system involving ordinary cement, limestone powder and calcined clay, called LC3, which leads to the production of highly durable concrete in aggressive environments such as sea water.
The research team studied the role of physical structure alterations on three binder types - plain Portland cement, fly ash-based binder and calcined clay-limestone binder (LC3).
The researchers adopted a fundamental approach based on cement chemistry and identified the chemical composition of the blended cement system as a critical factor in the development of nanoscale pore structure, which is the key to concrete durability.
The evolution of pore structure decides the permeability of concrete to water and aggressive chemicals - the finer the pore structure, the lesser the permeability.
Ternary blended systems such as LC3 impart a finer pore structure to concrete at early ages, which is not possible with plain cement or even fly ash blended cement.
Further, the unique reaction chemistry of the three components in LC3 results in a complex arrangement of cement reaction products, which make the concrete microstructure denser and helps to attain strength and durability at an early age.
"While several composite cementitious materials are being explored, clear understanding of the microstructure-dependant factors that lead to these superior performance characteristics in concrete is not yet available," Santhanam added.
The governing factors controlling durability performance must be analysed in order to understand how the various components contribute to the performance of the concrete, according to the Institute.
"Our primary focus was always to understand the behaviour at the scale of cement reaction and further integrate this information with concrete performance, which is a challenging task," said study co-author Yuvaraj Dhandapani, PhD Student.
"Since we have clarified and fine-tuned performance at the microscale, all type of concretes made with LC3 could attain superior performance to ingress of water or chlorides along with excellent early strength development," Dhandapani added.
"To facilitate practical adoption, we have also confirmed these characteristics on a range of different concrete types used in the construction activities," he added.