University to begin stress-tests on ‘green concrete’

Scientists at the University of Bradford are set to begin laboratory tests on what could be the building material of the future - a ‘green’ or eco-friendly form of concrete.

This week will see the delivery of materials that will be used to create a number of ‘green’ concrete slabs, which will then be left to set for 28 days, after which stress testing will begin.

The project is being run by Prof Ashraf Ashour, Professor of Structural Engineering in the Faculty of Engineering & Informatics. In November, he won a prestigious Newton Prize Fund award and was presented with his certificate by University Vice Chancellor Professor Shirley Congdon earlier this month.

He said: “I am delighted to receive this award. We are excited about the next stage of the project, which is to cast six concrete slabs and then wait for a period of 28 days for them to properly set before stress testing them.”

“This, along with computational modelling, will give us more data to evaluate. The first slabs will be poured before Christmas and tested in the University’s heavy structures lab new year.”

Prof Ashour said that despite his team’s optimism, it could be several years before the product goes into mass production.

“There is a period of testing which needs to take place and then even when that is complete, it will be a case of convicing people to accept it. We are talking here about something which will completely change the construction industry. It’s something many people have dreamed of but it’s never been a reality, until now.

“In the short term, it will mean we can put buildings up by simply bolting sections together and then, instead of demolishing them in the future, we can simply unbolt them and re-use the component parts."

“In the longer term, this is going to help cut CO2 production and other waste associated with the building trade.”

Professor Congdon said: “Winning the Newton Prize is a major achievement for both Ashraf and the University. His 'green concrete' project not only has the potential to change the entire construction industry but to create thousands of new jobs in the process. It's projects like these which stand at the very heart of what we do here at Bradford. The University motto is 'give invention light' and this project certainly lives up to that.”

The project involves creating ‘demountable’ interlocking blocks which are made of an eco-friendly version of concrete, in that existing building waste can be incorporated into it and bound using a geopolymer binder.

Prof Ashour said the technique would be quicker, cheaper and faster than traditional building techniques and would enable robust structures to be built. The process is being tested in the UK and Turkey and will see the creation of columns, beams and slabs.

The geopolymeric concrete has a compressive strength of 52 MPa (megapascals). It is also about 45 per cent cheaper to manufacture than traditional concrete and because it uses demolition waste, it effectively reduces CO2 emissions.

The project could have massive implications both in the UK and abroad. For example, Turkey plans to demolish a third of its building stock (some 6.4m buildings) by 2040 and currently has no viable means of dealing with the amount of construction and demolition waste (CDW)  this would create.

Prof Ashour said a detailed full-scale field demonstration was being planned to showcase the project’s global application and significance.

In the UK, in 2014, DEFRA reported 202.8m tons of waste, 59 per cent of which was CDW, which is costly to dispose of. In 2016, the total rose to 221m tonnes, 62 per cent being CDW.