Without natural lime stone

clay

shale and sandstone

with the mass fracrion of demolition concrete in raw meal up to 95%~99%

along with ordinary calcining process

the cement clinkers (hereinafter called recycled clinkers for short) were produced. Experiments and analysis were employed to compare these recycled clinkers with the cement clinker which was manufactured by natural lime stone and sandstone. It is shown that the two types of clinkers have completely the same positions of characteristic peaks of XRD; the clinker minerals of recycled clinkers are formed normally; the two clinkers have similar chemical composition

and the rate value design of recycled clinkers are more likely to higher calcium and lower silicon; the content of f-CaO of recycled clinkers meets the requirements of soundness; the 3d strength of cements produced by recycled clinkers reaches the requirements of 42.5 grade Portland cement

and the 28d strength reaches the requirements of 52.5 grade.