Evaporation of Water from Concrete Surfaces

Surface drying of freshly placed concrete is influenced by the evaporative conditions of the job-site microclimate. The influence of the combined effects of air and concrete temperature, relative humidity, and wind speed are often estimated by use of the equations graphically represented by the evaporation rate nomograph published in multiple ACI documents and elsewhere. This paper further explores the background of the nomograph, from its origins over 200 years ago to its current form, which is based on evaporation rates observed at Lake Hefner in Oklahoma in 1950 to 1951. By understanding the background and the fundamental relationships expressed in the nomograph, one comes to understand its intent, capability, limitations, and instructions for proper use. [PUBLICATION ABSTRACT]