With hourly wages continuing to mount higher and higher, new means of conserving labor and time are being sought continually. Labor-saving techniques have been adapted to paving, too, in an effort to keep pace with the tremendous increase in population and automobiles and at the same time control spiraling costs. To achieve this speed it was urgently necessary to devise some substitute for formed joints that would give equal or better results without necessitating large work crews. The best answer so far devised is the sawed joint which provides a weakened plane as a means of controlling the location of contraction cracks. It also creates a recess for the application of sealing material to prevent water and foreign materials from invading the joint and subgrade. It follows that joints must be sawed during the first several hours after pouring before tensile stresses build up to a point sufficient to cause cracking. On the other hand, premature sawing causes excessive spalling, water erosion, and blade wear on diamond blades. No time schedule can be set up for sawing since weather conditions vary too much. The proper time has varied from as few as 4 to as many as 12 hours after pouring. The best way to determine the proper time for sawing seems to be to make a short cut. It is the proper time for sawing if a slight raveling is apparent at the cut. If the concrete is damaged, sawing must be postponed. Essentially, the depth of joints needed for crack control is the same whether they are sawed or formed. There is, however, one factor that makes a big difference. The cost of formed joints is not much affected by their depth. Sawed joint costs, on the other hand, are greatly influenced by the depth of the cut. A 2 inch cut costs more than twice as much as a 1 inch cut. The minimum depth for sawed joints is 1 inch. Climate and aggregate size seem to be factors in determining the cut depth, but a 1 and one-half inch cut has been found successful in all states. Some designers use the rule of thumb that the depth of cut in both longitudinal and transverse joints should be one-sixth of the pavement thickness, or as deep as the diameter of the maximum size aggregate used.