This paper describes the results of experimental study on workability, mechanical properties, carbonation of concrete substituting fly-ash for cement less than 45% in hot weather. We obtained the following results. 1. Using fly-ash in hot weather could be more workability of concrete and could be more increasing compressive strength of concrete than that of non fly-ash. 2. We presented the curing period and the time to remove forms of concrete with 35℃ and 20℃. 3. The carbonation was greater as the replacement ratio of fly-ash became higher, but the carbonation of hot weather concreating was less than that of general weather concreating.
