Multiple cover blocks cement spacer: Fly ash,construction waste,sand,crushed stone, cinder,clay.cement,can be used as raw materials of making concrete spacer block. Producing baking-free bricks is a ideal way of eliminating the environmental pollution,saving the land resources, comprehensive utilizing the industrial residue and building up family fortunes Cement spacer specification: 1.High compressive strength 2.No deformation with temperature fluctuations 3.Excellent physical and chemical resistance 4.Low permeability 5.Excellent bond with concrete 6. No hairline cracks between the spacer and concrete