State of the art of the recycling of construction & demolition waste

News - 11 July 2017

The international HISER conference took place at TU Delft from 21 - 23 June 2017. The gathering brought researchers together with experts from the business community to share ideas, showcases and knowledge in the field of recycling and management of construction and demolition waste. 

Currently 461 million tons per year of (ever more) complex construction and demolition waste (C&DW) are generated in the European Union. The average recycling rate is around 46%. There is therefore still a significant loss of potentially valuable minerals, metals and organic materials all over Europe. Several initiatives are ongoing around the world to develop methodologies and technologies to turn these waste streams into resources for the benefit of the economy and the environment.

The conference intended to provide researchers and industry experts with the opportunity to exchange their ideas and showcases in advanced/innovative technologies and methodologies to process and valorise C&DW in the context of the circular economy.

Among them, the EU funded HISER project ( which aims to develop and demonstrate novel, cost-effective technological and non-technological holistic solutions for a higher recovery of raw materials from ever more complex C&DW, by considering circular economy approaches throughout the building value chain (from end-of-life buildings to new buildings).

There were a number of surprises at the conference that attracted 125 attendees: 

Francois de Larrard is the research director of the world’s largest cement company, LafargeHolcim. He revealed that LafargeHolcim has built a number of infrastructural works out of recycled concrete and that, occasioned by the positive experiences, the company has decided to implement the large-scale launch of recycled concrete on the market. The company has an English language publication to explain all the relevant issues concerning recycled concrete to engineers. 

Prof. Jian-Zhuang Xiao of Tongji University reported that his institution has had high-rise buildings built using recycled concrete in an earthquake-prone region of in China. This was decided upon because of recycled concrete’s favourable mechanical properties when it comes to quakes. Prof. Xiao and TU Delft’s Resources & Recycling group both expressed the desire to use the conference to arrive at a cooperation to provide access to China’s enormous construction and demolition waste flows for the production of recycled concrete

Part of the conference involved a visit to the industrial site in Hoorn where TU Delft in collaboration with Strukton/GBN and Mebin/Heidelberg has developed concrete recycling technology with funding from the European Commission (projects C2CA, HISER, VEEP).

This new technology consists of four innovative technologies aimed at solving problems that affected older forms of recycled concrete. Prior variants were, for instance, mechanically weaker because the surface of the recycled aggregate was not treated optimally and too much fine particulate matter ended up in the mortar. Recycled aggregate was not checked online for contaminants and the cement was not reclaimed as a binder. These four innovations therefore create improved acceptance of recycled concrete by the market and enable considerable cuts in CO2 emission

All pictures are available on this website.

This event was organised by Francesco di Maio, assistant professor at TU Delft, in collaboration with the H2020 project BAMB - Building as Material Banks

On this picture: organiser Francesco Di Maio (left) and Prof.dr. Jian-Zhuang Xiao of Tongji University (middle at the industrial site in Hoorn).