The world gets a little greyer every year. According to a paper published in 2014 concrete—an aggregate material made by mixing cement, sand and gravel—is the second-most consumed substance in the ...

Jianzhuang Xiao is a professor of recycled concrete materials and structures at Tongji University, Shanghai, China, and a vice-president at Guangxi University, Nanning, China. Zongjin Li is a ...