The following are some suggestions that will help to obtain better test results: one, mold and maintaining specimens in an area that is isolated form construction traffic and is not subject to vibration. Often specimens are left in a construction office or tool shed for better protection from the weather, but they might be worse off due to the unstable condition of their platform during the very critical setting period. Two, temperature and humidity are extremely important during the first 24 hours. Temperature can be controlled in the summer by storing under wet burlap or damp sand. If wet burlap is used it should be covered with polyethylene at night to retain moisture. During cold weather specimens should be stored in an insulated box and provided with a heater (such as an electric light bulb) if left outside. Specimens placed in heated areas should be covered with polyethylene or other non-absorbent cover to prevent drying out. Air temperature must be maintained between 60 to 80 degrees F. and moisture must be prevented. Three, specimens should be stripped form their molds he morning after casting and transferred to a moist environment that complies with the standard curing method prescribed by ASTM C 31. If specimens are desired for field curing they should be in addition to those required for concrete acceptance. Specimens for standard curing should never be left on the job after the first day. Four, if it is necessary to transport specimens they should be cushioned to prevent possible fracture and covered to prevent further loss of moisture. Single use molds offer good protection during transfer to the lab and should be left in place until the specimens reach the point of final curing. Where the transportation of specimens is a frequent occurrence, a sturdily built box for such purpose is a good investment. Five, cylinders in cardboard molds should never be immersed in water of placed in very wet sand or sawdust for curing at any time. Expansion of molds due to absorption can cause significant reduction in strengths.