Joint sawing is a method of providing crack control in concrete paving that is efficient and consistent with high speed paving procedures. The method contributes to improved pavement smoothness and durability. Sawing can be coordinated with paving operations on any type of project- airports, county roads, residential streets, or pavements built at the rate of a mile a day. The time when concrete joints are sawed is crucial. The best assurance that sawing is done at the proper time is the employment of an experienced saw operator. There are no hard and fast rules for timing joint sawing. A good operator relies upon his experience to determine when the concrete is ready to be cut. The type of blade is also important in timing joint sawing. Diamond tipped blades last longer when concrete strength is high. When diamond-tipped blades are to be used, sawing is delayed as long as possible- preferably until just before the occurrence of random cracking. Transverse pavement joints perform best when joints are sawed consecutively. This permits all joints to begin opening at about the same time and makes joint movements more uniform, improving sealant performance. On high-production projects it may be necessary on hot days to saw relief joints at intervals of about 60 feet to prevent early random cracking. The intermediate joints are sawed later. However, this in only an emergency procedure to reduce uncontrolled cracking and it has the disadvantage of causing larger movements at the relief joints and subsequent difficulties in maintaining adequate seals at these locations. When this system is used for floors the intervening joints should be sawed at an age of no more than 3 days.