Mastic asphalt is a type of asphalt which differs from dense graded asphalt (asphalt concrete) in that it has a higher asphalt/bitumen (binder) content, usually around 7–10% of the whole aggregate mix, as opposed to rolled asphalt concrete, which has only around 5% added asphalt/bitumen. This thermoplastic substance is widely used in the building industry for waterproofing flat roofs and tanking underground. Mastic asphalt is heated to a temperature of 210 °C (410 °F) and is spread in layers to form an impervious barrier about 20 millimeters (0.79 inches) thick. COUNT 5
QSN1 How much additional binder does rolled asphalt concrete have? ANS1 5% QSN2 How is asphalt used in the construction industry? ANS2 waterproofing QSN3 What is the percentage of binder in mastic asphalt? ANS3 7–10% QSN4 Prior to spreading, how hot is mastic asphalt heated? ANS4 210 °C QSN5 What is the usual thickness of the mastic spread on roofs? ANS5 20 millimeters