Sustainability in concrete construction can be increased by replacing cement with supplementary cementing materials like slag and fly ash.China are building new coal fired energy works and has the opportunity to increase their use of fly ash. Larger amount of fly ash can be used if loss in early strength is counteracted by finer grinding or special grinding (i.e. EMC) or accelerators. Cement with interground fly ash can even allow the use ofalkali reactive aggregate and further save environment. Water reducing agents can be used to make concrete with less overall binder and same strength and workability. Making more concrete with less cement content means less CO2 emission to the atmosphere and less use of limited natural resources, and thereby more sustainableconstruction.