Effect of environmental conditions on the properties of fresh and hardened concrete

The effect of varying environmental conditions, at the time of casting on the properties of fresh and hardened concrete was evaluated. The influence of air temperature, wind velocity, and relative humidity on plastic shrinkage, compressive strength, pulse velocity and pore structure of concrete was investigated. Results indicate that exposure conditions at the time of casting significantly affect plastic shrinkage of concrete. As expected elevated temperature affected porosity, compressive strength, and pulse velocity of concrete. Casting of concrete at elevated temperature decreased its compressive strength. Similarly, the pulse velocity of concrete cast at 45 degreesC was less than that of cast at 30 degreesC. The volume of total pores in the concrete specimens cast at 45 degreesC was more than that of cast at 30 degreesC. The lower pulse velocity and increased pore volume in the concrete cast at 45 degreesC than that cast at 30 degreesC may be attributed to the coarse pore structure formed in the former than the latter. Other weather parameters, such as relative humidity and wind velocity, also influence the properties of fresh and hardened concrete. (C) 2001 Elsevier Science Ltd. All rights reserved.