Rate of Spread HRA and PCC

Low Rate of Spread

High Rate of Spread



Low Texture Depth



High Texture Depth

Above are two different different types of rate of spread of pre-coated chippings achieved and the resulting variation in Macro texture depth.The texture depth achieved from different rates of spread can be afected by several elements of the laying process.Temperature of the HRA,if too hot PCC can disapear into the mat resulting in low texture depth,too cold and the PCC will not be sufficiently embedded into the mat which may result in chip loss.Depth of material may also affect the rate of spread,too thin PCC will not be sufficiently embedded which may result in chip loss,to thick and PCC will disapear into HRA resulting in Low texture depth.The Roller drivers should also be aware of the diference in temperatures and the difference in thicknesses as they will have to either stay back or get on the mat quicker.